diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-rpmsg | 75 | ||||
| -rw-r--r-- | Documentation/rpmsg.txt | 293 | ||||
| -rw-r--r-- | drivers/Kconfig | 2 | ||||
| -rw-r--r-- | drivers/Makefile | 1 | ||||
| -rw-r--r-- | drivers/rpmsg/Kconfig | 5 | ||||
| -rw-r--r-- | drivers/rpmsg/Makefile | 1 | ||||
| -rw-r--r-- | drivers/rpmsg/virtio_rpmsg_bus.c | 1026 | ||||
| -rw-r--r-- | include/linux/mod_devicetable.h | 9 | ||||
| -rw-r--r-- | include/linux/rpmsg.h | 326 | ||||
| -rw-r--r-- | include/linux/virtio_ids.h | 1 |
10 files changed, 1739 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-rpmsg b/Documentation/ABI/testing/sysfs-bus-rpmsg new file mode 100644 index 0000000..189e419 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-rpmsg @@ -0,0 +1,75 @@ +What: /sys/bus/rpmsg/devices/.../name +Date: June 2011 +KernelVersion: 3.3 +Contact: Ohad Ben-Cohen <ohad@wizery.com> +Description: + Every rpmsg device is a communication channel with a remote + processor. Channels are identified with a (textual) name, + which is maximum 32 bytes long (defined as RPMSG_NAME_SIZE in + rpmsg.h). + + This sysfs entry contains the name of this channel. + +What: /sys/bus/rpmsg/devices/.../src +Date: June 2011 +KernelVersion: 3.3 +Contact: Ohad Ben-Cohen <ohad@wizery.com> +Description: + Every rpmsg device is a communication channel with a remote + processor. Channels have a local ("source") rpmsg address, + and remote ("destination") rpmsg address. When an entity + starts listening on one end of a channel, it assigns it with + a unique rpmsg address (a 32 bits integer). This way when + inbound messages arrive to this address, the rpmsg core + dispatches them to the listening entity (a kernel driver). + + This sysfs entry contains the src (local) rpmsg address + of this channel. If it contains 0xffffffff, then an address + wasn't assigned (can happen if no driver exists for this + channel). + +What: /sys/bus/rpmsg/devices/.../dst +Date: June 2011 +KernelVersion: 3.3 +Contact: Ohad Ben-Cohen <ohad@wizery.com> +Description: + Every rpmsg device is a communication channel with a remote + processor. Channels have a local ("source") rpmsg address, + and remote ("destination") rpmsg address. When an entity + starts listening on one end of a channel, it assigns it with + a unique rpmsg address (a 32 bits integer). This way when + inbound messages arrive to this address, the rpmsg core + dispatches them to the listening entity. + + This sysfs entry contains the dst (remote) rpmsg address + of this channel. If it contains 0xffffffff, then an address + wasn't assigned (can happen if the kernel driver that + is attached to this channel is exposing a service to the + remote processor. This make it a local rpmsg server, + and it is listening for inbound messages that may be sent + from any remote rpmsg client; it is not bound to a single + remote entity). + +What: /sys/bus/rpmsg/devices/.../announce +Date: June 2011 +KernelVersion: 3.3 +Contact: Ohad Ben-Cohen <ohad@wizery.com> +Description: + Every rpmsg device is a communication channel with a remote + processor. Channels are identified by a textual name (see + /sys/bus/rpmsg/devices/.../name above) and have a local + ("source") rpmsg address, and remote ("destination") rpmsg + address. + + A channel is first created when an entity, whether local + or remote, starts listening on it for messages (and is thus + called an rpmsg server). + + When that happens, a "name service" announcement is sent + to the other processor, in order to let it know about the + creation of the channel (this way remote clients know they + can start sending messages). + + This sysfs entry tells us whether the channel is a local + server channel that is announced (values are either + true or false). diff --git a/Documentation/rpmsg.txt b/Documentation/rpmsg.txt new file mode 100644 index 0000000..409d9f9 --- /dev/null +++ b/Documentation/rpmsg.txt @@ -0,0 +1,293 @@ +Remote Processor Messaging (rpmsg) Framework + +Note: this document describes the rpmsg bus and how to write rpmsg drivers. +To learn how to add rpmsg support for new platforms, check out remoteproc.txt +(also a resident of Documentation/). + +1. Introduction + +Modern SoCs typically employ heterogeneous remote processor devices in +asymmetric multiprocessing (AMP) configurations, which may be running +different instances of operating system, whether it's Linux or any other +flavor of real-time OS. + +OMAP4, for example, has dual Cortex-A9, dual Cortex-M3 and a C64x+ DSP. +Typically, the dual cortex-A9 is running Linux in a SMP configuration, +and each of the other three cores (two M3 cores and a DSP) is running +its own instance of RTOS in an AMP configuration. + +Typically AMP remote processors employ dedicated DSP codecs and multimedia +hardware accelerators, and therefore are often used to offload CPU-intensive +multimedia tasks from the main application processor. + +These remote processors could also be used to control latency-sensitive +sensors, drive random hardware blocks, or just perform background tasks +while the main CPU is idling. + +Users of those remote processors can either be userland apps (e.g. multimedia +frameworks talking with remote OMX components) or kernel drivers (controlling +hardware accessible only by the remote processor, reserving kernel-controlled +resources on behalf of the remote processor, etc..). + +Rpmsg is a virtio-based messaging bus that allows kernel drivers to communicate +with remote processors available on the system. In turn, drivers could then +expose appropriate user space interfaces, if needed. + +When writing a driver that exposes rpmsg communication to userland, please +keep in mind that remote processors might have direct access to the +system's physical memory and other sensitive hardware resources (e.g. on +OMAP4, remote cores and hardware accelerators may have direct access to the +physical memory, gpio banks, dma controllers, i2c bus, gptimers, mailbox +devices, hwspinlocks, etc..). Moreover, those remote processors might be +running RTOS where every task can access the entire memory/devices exposed +to the processor. To minimize the risks of rogue (or buggy) userland code +exploiting remote bugs, and by that taking over the system, it is often +desired to limit userland to specific rpmsg channels (see definition below) +it can send messages on, and if possible, minimize how much control +it has over the content of the messages. + +Every rpmsg device is a communication channel with a remote processor (thus +rpmsg devices are called channels). Channels are identified by a textual name +and have a local ("source") rpmsg address, and remote ("destination") rpmsg +address. + +When a driver starts listening on a channel, its rx callback is bound with +a unique rpmsg local address (a 32-bit integer). This way when inbound messages +arrive, the rpmsg core dispatches them to the appropriate driver according +to their destination address (this is done by invoking the driver's rx handler +with the payload of the inbound message). + + +2. User API + + int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len); + - sends a message across to the remote processor on a given channel. + The caller should specify the channel, the data it wants to send, + and its length (in bytes). The message will be sent on the specified + channel, i.e. its source and destination address fields will be + set to the channel's src and dst addresses. + + In case there are no TX buffers available, the function will block until + one becomes available (i.e. until the remote processor consumes + a tx buffer and puts it back on virtio's used descriptor ring), + or a timeout of 15 seconds elapses. When the latter happens, + -ERESTARTSYS is returned. + The function can only be called from a process context (for now). + Returns 0 on success and an appropriate error value on failure. + + int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst); + - sends a message across to the remote processor on a given channel, + to a destination address provided by the caller. + The caller should specify the channel, the data it wants to send, + its length (in bytes), and an explicit destination address. + The message will then be sent to the remote processor to which the + channel belongs, using the channel's src address, and the user-provided + dst address (thus the channel's dst address will be ignored). + + In case there are no TX buffers available, the function will block until + one becomes available (i.e. until the remote processor consumes + a tx buffer and puts it back on virtio's used descriptor ring), + or a timeout of 15 seconds elapses. When the latter happens, + -ERESTARTSYS is returned. + The function can only be called from a process context (for now). + Returns 0 on success and an appropriate error value on failure. + + int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst, + void *data, int len); + - sends a message across to the remote processor, using the src and dst + addresses provided by the user. + The caller should specify the channel, the data it wants to send, + its length (in bytes), and explicit source and destination addresses. + The message will then be sent to the remote processor to which the + channel belongs, but the channel's src and dst addresses will be + ignored (and the user-provided addresses will be used instead). + + In case there are no TX buffers available, the function will block until + one becomes available (i.e. until the remote processor consumes + a tx buffer and puts it back on virtio's used descriptor ring), + or a timeout of 15 seconds elapses. When the latter happens, + -ERESTARTSYS is returned. + The function can only be called from a process context (for now). + Returns 0 on success and an appropriate error value on failure. + + int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len); + - sends a message across to the remote processor on a given channel. + The caller should specify the channel, the data it wants to send, + and its length (in bytes). The message will be sent on the specified + channel, i.e. its source and destination address fields will be + set to the channel's src and dst addresses. + + In case there are no TX buffers available, the function will immediately + return -ENOMEM without waiting until one becomes available. + The function can only be called from a process context (for now). + Returns 0 on success and an appropriate error value on failure. + + int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst) + - sends a message across to the remote processor on a given channel, + to a destination address provided by the user. + The user should specify the channel, the data it wants to send, + its length (in bytes), and an explicit destination address. + The message will then be sent to the remote processor to which the + channel belongs, using the channel's src address, and the user-provided + dst address (thus the channel's dst address will be ignored). + + In case there are no TX buffers available, the function will immediately + return -ENOMEM without waiting until one becomes available. + The function can only be called from a process context (for now). + Returns 0 on success and an appropriate error value on failure. + + int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst, + void *data, int len); + - sends a message across to the remote processor, using source and + destination addresses provided by the user. + The user should specify the channel, the data it wants to send, + its length (in bytes), and explicit source and destination addresses. + The message will then be sent to the remote processor to which the + channel belongs, but the channel's src and dst addresses will be + ignored (and the user-provided addresses will be used instead). + + In case there are no TX buffers available, the function will immediately + return -ENOMEM without waiting until one becomes available. + The function can only be called from a process context (for now). + Returns 0 on success and an appropriate error value on failure. + + struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *rpdev, + void (*cb)(struct rpmsg_channel *, void *, int, void *, u32), + void *priv, u32 addr); + - every rpmsg address in the system is bound to an rx callback (so when + inbound messages arrive, they are dispatched by the rpmsg bus using the + appropriate callback handler) by means of an rpmsg_endpoint struct. + + This function allows drivers to create such an endpoint, and by that, + bind a callback, and possibly some private data too, to an rpmsg address + (either one that is known in advance, or one that will be dynamically + assigned for them). + + Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint + is already created for them when they are probed by the rpmsg bus + (using the rx callback they provide when they registered to the rpmsg bus). + + So things should just work for simple drivers: they already have an + endpoint, their rx callback is bound to their rpmsg address, and when + relevant inbound messages arrive (i.e. messages which their dst address + equals to the src address of their rpmsg channel), the driver's handler + is invoked to process it. + + That said, more complicated drivers might do need to allocate + additional rpmsg addresses, and bind them to different rx callbacks. + To accomplish that, those drivers need to call this function. + Drivers should provide their channel (so the new endpoint would bind + to the same remote processor their channel belongs to), an rx callback + function, an optional private data (which is provided back when the + rx callback is invoked), and an address they want to bind with the + callback. If addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will + dynamically assign them an available rpmsg address (drivers should have + a very good reason why not to always use RPMSG_ADDR_ANY here). + + Returns a pointer to the endpoint on success, or NULL on error. + + void rpmsg_destroy_ept(struct rpmsg_endpoint *ept); + - destroys an existing rpmsg endpoint. user should provide a pointer + to an rpmsg endpoint that was previously created with rpmsg_create_ept(). + + int register_rpmsg_driver(struct rpmsg_driver *rpdrv); + - registers an rpmsg driver with the rpmsg bus. user should provide + a pointer to an rpmsg_driver struct, which contains the driver's + ->probe() and ->remove() functions, an rx callback, and an id_table + specifying the names of the channels this driver is interested to + be probed with. + + void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv); + - unregisters an rpmsg driver from the rpmsg bus. user should provide + a pointer to a previously-registered rpmsg_driver struct. + Returns 0 on success, and an appropriate error value on failure. + + +3. Typical usage + +The following is a simple rpmsg driver, that sends an "hello!" message +on probe(), and whenever it receives an incoming message, it dumps its +content to the console. + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/rpmsg.h> + +static void rpmsg_sample_cb(struct rpmsg_channel *rpdev, void *data, int len, + void *priv, u32 src) +{ + print_hex_dump(KERN_INFO, "incoming message:", DUMP_PREFIX_NONE, + 16, 1, data, len, true); +} + +static int rpmsg_sample_probe(struct rpmsg_channel *rpdev) +{ + int err; + + dev_info(&rpdev->dev, "chnl: 0x%x -> 0x%x\n", rpdev->src, rpdev->dst); + + /* send a message on our channel */ + err = rpmsg_send(rpdev, "hello!", 6); + if (err) { + pr_err("rpmsg_send failed: %d\n", err); + return err; + } + + return 0; +} + +static void __devexit rpmsg_sample_remove(struct rpmsg_channel *rpdev) +{ + dev_info(&rpdev->dev, "rpmsg sample client driver is removed\n"); +} + +static struct rpmsg_device_id rpmsg_driver_sample_id_table[] = { + { .name = "rpmsg-client-sample" }, + { }, +}; +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_sample_id_table); + +static struct rpmsg_driver rpmsg_sample_client = { + .drv.name = KBUILD_MODNAME, + .drv.owner = THIS_MODULE, + .id_table = rpmsg_driver_sample_id_table, + .probe = rpmsg_sample_probe, + .callback = rpmsg_sample_cb, + .remove = __devexit_p(rpmsg_sample_remove), +}; + +static int __init init(void) +{ + return register_rpmsg_driver(&rpmsg_sample_client); +} +module_init(init); + +static void __exit fini(void) +{ + unregister_rpmsg_driver(&rpmsg_sample_client); +} +module_exit(fini); + +Note: a similar sample which can be built and loaded can be found +in samples/rpmsg/. + +4. Allocations of rpmsg channels: + +At this point we only support dynamic allocations of rpmsg channels. + +This is possible only with remote processors that have the VIRTIO_RPMSG_F_NS +virtio device feature set. This feature bit means that the remote +processor supports dynamic name service announcement messages. + +When this feature is enabled, creation of rpmsg devices (i.e. channels) +is completely dynamic: the remote processor announces the existence of a +remote rpmsg service by sending a name service message (which contains +the name and rpmsg addr of the remote service, see struct rpmsg_ns_msg). + +This message is then handled by the rpmsg bus, which in turn dynamically +creates and registers an rpmsg channel (which represents the remote service). +If/when a relevant rpmsg driver is registered, it will be immediately probed +by the bus, and can then start sending messages to the remote service. + +The plan is also to add static creation of rpmsg channels via the virtio +config space, but it's not implemented yet. diff --git a/drivers/Kconfig b/drivers/Kconfig index 27b34bf..516faf6 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -134,6 +134,8 @@ source "drivers/iommu/Kconfig" source "drivers/remoteproc/Kconfig" +source "drivers/rpmsg/Kconfig" + source "drivers/virt/Kconfig" source "drivers/devfreq/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index f1019b7..3fdc177 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -127,6 +127,7 @@ obj-$(CONFIG_HWSPINLOCK) += hwspinlock/ obj-$(CONFIG_NFC) += nfc/ obj-$(CONFIG_IOMMU_SUPPORT) += iommu/ obj-$(CONFIG_REMOTEPROC) += remoteproc/ +obj-$(CONFIG_RPMSG) += rpmsg/ # Virtualization drivers obj-$(CONFIG_VIRT_DRIVERS) += virt/ diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig new file mode 100644 index 0000000..811fede --- /dev/null +++ b/drivers/rpmsg/Kconfig @@ -0,0 +1,5 @@ +# RPMSG always gets selected by whoever wants it +config RPMSG + tristate + select VIRTIO + select VIRTIO_RING diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile new file mode 100644 index 0000000..7617fcb --- /dev/null +++ b/drivers/rpmsg/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_RPMSG) += virtio_rpmsg_bus.o diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c new file mode 100644 index 0000000..257683e --- /dev/null +++ b/drivers/rpmsg/virtio_rpmsg_bus.c @@ -0,0 +1,1026 @@ +/* + * Virtio-based remote processor messaging bus + * + * Copyright (C) 2011 Texas Instruments, Inc. + * Copyright (C) 2011 Google, Inc. + * + * Ohad Ben-Cohen <ohad@wizery.com> + * Brian Swetland <swetland@google.com> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#define pr_fmt(fmt) "%s: " fmt, __func__ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/virtio.h> +#include <linux/virtio_ids.h> +#include <linux/virtio_config.h> +#include <linux/scatterlist.h> +#include <linux/dma-mapping.h> +#include <linux/slab.h> +#include <linux/idr.h> +#include <linux/jiffies.h> +#include <linux/sched.h> +#include <linux/wait.h> +#include <linux/rpmsg.h> +#include <linux/mutex.h> + +/** + * struct virtproc_info - virtual remote processor state + * @vdev: the virtio device + * @rvq: rx virtqueue + * @svq: tx virtqueue + * @rbufs: kernel address of rx buffers + * @sbufs: kernel address of tx buffers + * @last_sbuf: index of last tx buffer used + * @bufs_dma: dma base addr of the buffers + * @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders. + * sending a message might require waking up a dozing remote + * processor, which involves sleeping, hence the mutex. + * @endpoints: idr of local endpoints, allows fast retrieval + * @endpoints_lock: lock of the endpoints set + * @sendq: wait queue of sending contexts waiting for a tx buffers + * @sleepers: number of senders that are waiting for a tx buffer + * @ns_ept: the bus's name service endpoint + * + * This structure stores the rpmsg state of a given virtio remote processor + * device (there might be several virtio proc devices for each physical + * remote processor). + */ +struct virtproc_info { + struct virtio_device *vdev; + struct virtqueue *rvq, *svq; + void *rbufs, *sbufs; + int last_sbuf; + dma_addr_t bufs_dma; + struct mutex tx_lock; + struct idr endpoints; + struct mutex endpoints_lock; + wait_queue_head_t sendq; + atomic_t sleepers; + struct rpmsg_endpoint *ns_ept; +}; + +/** + * struct rpmsg_channel_info - internal channel info representation + * @name: name of service + * @src: local address + * @dst: destination address + */ +struct rpmsg_channel_info { + char name[RPMSG_NAME_SIZE]; + u32 src; + u32 dst; +}; + +#define to_rpmsg_channel(d) container_of(d, struct rpmsg_channel, dev) +#define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv) + +/* + * We're allocating 512 buffers of 512 bytes for communications, and then + * using the first 256 buffers for RX, and the last 256 buffers for TX. + * + * Each buffer will have 16 bytes for the msg header and 496 bytes for + * the payload. + * + * This will require a total space of 256KB for the buffers. + * + * We might also want to add support for user-provided buffers in time. + * This will allow bigger buffer size flexibility, and can also be used + * to achieve zero-copy messaging. + * + * Note that these numbers are purely a decision of this driver - we + * can change this without changing anything in the firmware of the remote + * processor. + */ +#define RPMSG_NUM_BUFS (512) +#define RPMSG_BUF_SIZE (512) +#define RPMSG_TOTAL_BUF_SPACE (RPMSG_NUM_BUFS * RPMSG_BUF_SIZE) + +/* + * Local addresses are dynamically allocated on-demand. + * We do not dynamically assign addresses from the low 1024 range, + * in order to reserve that address range for predefined services. + */ +#define RPMSG_RESERVED_ADDRESSES (1024) + +/* Address 53 is reserved for advertising remote services */ +#define RPMSG_NS_ADDR (53) + +/* sysfs show configuration fields */ +#define rpmsg_show_attr(field, path, format_string) \ +static ssize_t \ +field##_show(struct device *dev, \ + struct device_attribute *attr, char *buf) \ +{ \ + struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); \ + \ + return sprintf(buf, format_string, rpdev->path); \ +} + +/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */ +rpmsg_show_attr(name, id.name, "%s\n"); +rpmsg_show_attr(src, src, "0x%x\n"); +rpmsg_show_attr(dst, dst, "0x%x\n"); +rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n"); + +/* + * Unique (and free running) index for rpmsg devices. + * + * Yeah, we're not recycling those numbers (yet?). will be easy + * to change if/when we want to. + */ +static unsigned int rpmsg_dev_index; + +static ssize_t modalias_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); + + return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name); +} + +static struct device_attribute rpmsg_dev_attrs[] = { + __ATTR_RO(name), + __ATTR_RO(modalias), + __ATTR_RO(dst), + __ATTR_RO(src), + __ATTR_RO(announce), + __ATTR_NULL +}; + +/* rpmsg devices and drivers are matched using the service name */ +static inline int rpmsg_id_match(const struct rpmsg_channel *rpdev, + const struct rpmsg_device_id *id) +{ + return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0; +} + +/* match rpmsg channel and rpmsg driver */ +static int rpmsg_dev_match(struct device *dev, struct device_driver *drv) +{ + struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); + struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv); + const struct rpmsg_device_id *ids = rpdrv->id_table; + unsigned int i; + + for (i = 0; ids[i].name[0]; i++) + if (rpmsg_id_match(rpdev, &ids[i])) + return 1; + + return 0; +} + +static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env) +{ + struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); + + return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT, + rpdev->id.name); +} + +/* for more info, see below documentation of rpmsg_create_ept() */ +static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp, + struct rpmsg_channel *rpdev, rpmsg_rx_cb_t cb, + void *priv, u32 addr) +{ + int err, tmpaddr, request; + struct rpmsg_endpoint *ept; + struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev; + + if (!idr_pre_get(&vrp->endpoints, GFP_KERNEL)) + return NULL; + + ept = kzalloc(sizeof(*ept), GFP_KERNEL); + if (!ept) { + dev_err(dev, "failed to kzalloc a new ept\n"); + return NULL; + } + + ept->rpdev = rpdev; + ept->cb = cb; + ept->priv = priv; + + /* do we need to allocate a local address ? */ + request = addr == RPMSG_ADDR_ANY ? RPMSG_RESERVED_ADDRESSES : addr; + + mutex_lock(&vrp->endpoints_lock); + + /* bind the endpoint to an rpmsg address (and allocate one if needed) */ + err = idr_get_new_above(&vrp->endpoints, ept, request, &tmpaddr); + if (err) { + dev_err(dev, "idr_get_new_above failed: %d\n", err); + goto free_ept; + } + + /* make sure the user's address request is fulfilled, if relevant */ + if (addr != RPMSG_ADDR_ANY && tmpaddr != addr) { + dev_err(dev, "address 0x%x already in use\n", addr); + goto rem_idr; + } + + ept->addr = tmpaddr; + + mutex_unlock(&vrp->endpoints_lock); + + return ept; + +rem_idr: + idr_remove(&vrp->endpoints, request); +free_ept: + mutex_unlock(&vrp->endpoints_lock); + kfree(ept); + return NULL; +} + +/** + * rpmsg_create_ept() - create a new rpmsg_endpoint + * @rpdev: rpmsg channel device + * @cb: rx callback handler + * @priv: private data for the driver's use + * @addr: local rpmsg address to bind with @cb + * + * Every rpmsg address in the system is bound to an rx callback (so when + * inbound messages arrive, they are dispatched by the rpmsg bus using the + * appropriate callback handler) by means of an rpmsg_endpoint struct. + * + * This function allows drivers to create such an endpoint, and by that, + * bind a callback, and possibly some private data too, to an rpmsg address + * (either one that is known in advance, or one that will be dynamically + * assigned for them). + * + * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint + * is already created for them when they are probed by the rpmsg bus + * (using the rx callback provided when they registered to the rpmsg bus). + * + * So things should just work for simple drivers: they already have an + * endpoint, their rx callback is bound to their rpmsg address, and when + * relevant inbound messages arrive (i.e. messages which their dst address + * equals to the src address of their rpmsg channel), the driver's handler + * is invoked to process it. + * + * That said, more complicated drivers might do need to allocate + * additional rpmsg addresses, and bind them to different rx callbacks. + * To accomplish that, those drivers need to call this function. + * + * Drivers should provide their @rpdev channel (so the new endpoint would belong + * to the same remote processor their channel belongs to), an rx callback + * function, an optional private data (which is provided back when the + * rx callback is invoked), and an address they want to bind with the + * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will + * dynamically assign them an available rpmsg address (drivers should have + * a very good reason why not to always use RPMSG_ADDR_ANY here). + * + * Returns a pointer to the endpoint on success, or NULL on error. + */ +struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *rpdev, + rpmsg_rx_cb_t cb, void *priv, u32 addr) +{ + return __rpmsg_create_ept(rpdev->vrp, rpdev, cb, priv, addr); +} +EXPORT_SYMBOL(rpmsg_create_ept); + +/** + * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint + * @ept: endpoing to destroy + * + * Should be used by drivers to destroy an rpmsg endpoint previously + * created with rpmsg_create_ept(). + */ +void rpmsg_destroy_ept(struct rpmsg_endpoint *ept) +{ + struct virtproc_info *vrp = ept->rpdev->vrp; + + mutex_lock(&vrp->endpoints_lock); + idr_remove(&vrp->endpoints, ept->addr); + mutex_unlock(&vrp->endpoints_lock); + + kfree(ept); +} +EXPORT_SYMBOL(rpmsg_destroy_ept); + +/* + * when an rpmsg driver is probed with a channel, we seamlessly create + * it an endpoint, binding its rx callback to a unique local rpmsg + * address. + * + * if we need to, we also announce about this channel to the remote + * processor (needed in case the driver is exposing an rpmsg service). + */ +static int rpmsg_dev_probe(struct device *dev) +{ + struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); + struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver); + struct virtproc_info *vrp = rpdev->vrp; + struct rpmsg_endpoint *ept; + int err; + + ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, rpdev->src); + if (!ept) { + dev_err(dev, "failed to create endpoint\n"); + err = -ENOMEM; + goto out; + } + + rpdev->ept = ept; + rpdev->src = ept->addr; + + err = rpdrv->probe(rpdev); + if (err) { + dev_err(dev, "%s: failed: %d\n", __func__, err); + rpmsg_destroy_ept(ept); + goto out; + } + + /* need to tell remote processor's name service about this channel ? */ + if (rpdev->announce && + virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) { + struct rpmsg_ns_msg nsm; + + strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE); + nsm.addr = rpdev->src; + nsm.flags = RPMSG_NS_CREATE; + + err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR); + if (err) + dev_err(dev, "failed to announce service %d\n", err); + } + +out: + return err; +} + +static int rpmsg_dev_remove(struct device *dev) +{ + struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); + struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver); + struct virtproc_info *vrp = rpdev->vrp; + int err = 0; + + /* tell remote processor's name service we're removing this channel */ + if (rpdev->announce && + virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) { + struct rpmsg_ns_msg nsm; + + strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE); + nsm.addr = rpdev->src; + nsm.flags = RPMSG_NS_DESTROY; + + err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR); + if (err) + dev_err(dev, "failed to announce service %d\n", err); + } + + rpdrv->remove(rpdev); + + rpmsg_destroy_ept(rpdev->ept); + + return err; +} + +static struct bus_type rpmsg_bus = { + .name = "rpmsg", + .match = rpmsg_dev_match, + .dev_attrs = rpmsg_dev_attrs, + .uevent = rpmsg_uevent, + .probe = rpmsg_dev_probe, + .remove = rpmsg_dev_remove, +}; + +/** + * register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus + * @rpdrv: pointer to a struct rpmsg_driver + * + * Returns 0 on success, and an appropriate error value on failure. + */ +int register_rpmsg_driver(struct rpmsg_driver *rpdrv) +{ + rpdrv->drv.bus = &rpmsg_bus; + return driver_register(&rpdrv->drv); +} +EXPORT_SYMBOL(register_rpmsg_driver); + +/** + * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus + * @rpdrv: pointer to a struct rpmsg_driver + * + * Returns 0 on success, and an appropriate error value on failure. + */ +void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv) +{ + driver_unregister(&rpdrv->drv); +} +EXPORT_SYMBOL(unregister_rpmsg_driver); + +static void rpmsg_release_device(struct device *dev) +{ + struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); + + kfree(rpdev); +} + +/* + * match an rpmsg channel with a channel info struct. + * this is used to make sure we're not creating rpmsg devices for channels + * that already exist. + */ +static int rpmsg_channel_match(struct device *dev, void *data) +{ + struct rpmsg_channel_info *chinfo = data; + struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); + + if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src) + return 0; + + if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst) + return 0; + + if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE)) + return 0; + + /* found a match ! */ + return 1; +} + +/* + * create an rpmsg channel using its name and address info. + * this function will be used to create both static and dynamic + * channels. + */ +static struct rpmsg_channel *rpmsg_create_channel(struct virtproc_info *vrp, + struct rpmsg_channel_info *chinfo) +{ + struct rpmsg_channel *rpdev; + struct device *tmp, *dev = &vrp->vdev->dev; + int ret; + + /* make sure a similar channel doesn't already exist */ + tmp = device_find_child(dev, chinfo, rpmsg_channel_match); + if (tmp) { + /* decrement the matched device's refcount back */ + put_device(tmp); + dev_err(dev, "channel %s:%x:%x already exist\n", + chinfo->name, chinfo->src, chinfo->dst); + return NULL; + } + + rpdev = kzalloc(sizeof(struct rpmsg_channel), GFP_KERNEL); + if (!rpdev) { + pr_err("kzalloc failed\n"); + return NULL; + } + + rpdev->vrp = vrp; + rpdev->src = chinfo->src; + rpdev->dst = chinfo->dst; + + /* + * rpmsg server channels has predefined local address (for now), + * and their existence needs to be announced remotely + */ + rpdev->announce = rpdev->src != RPMSG_ADDR_ANY ? true : false; + + strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE); + + /* very simple device indexing plumbing which is enough for now */ + dev_set_name(&rpdev->dev, "rpmsg%d", rpmsg_dev_index++); + + rpdev->dev.parent = &vrp->vdev->dev; + rpdev->dev.bus = &rpmsg_bus; + rpdev->dev.release = rpmsg_release_device; + + ret = device_register(&rpdev->dev); + if (ret) { + dev_err(dev, "device_register failed: %d\n", ret); + put_device(&rpdev->dev); + return NULL; + } + + return rpdev; +} + +/* + * find an existing channel using its name + address properties, + * and destroy it + */ +static int rpmsg_destroy_channel(struct virtproc_info *vrp, + struct rpmsg_channel_info *chinfo) +{ + struct virtio_device *vdev = vrp->vdev; + struct device *dev; + + dev = device_find_child(&vdev->dev, chinfo, rpmsg_channel_match); + if (!dev) + return -EINVAL; + + device_unregister(dev); + + put_device(dev); + + return 0; +} + +/* super simple buffer "allocator" that is just enough for now */ +static void *get_a_tx_buf(struct virtproc_info *vrp) +{ + unsigned int len; + void *ret; + + /* support multiple concurrent senders */ + mutex_lock(&vrp->tx_lock); + + /* + * either pick the next unused tx buffer + * (half of our buffers are used for sending messages) + */ + if (vrp->last_sbuf < RPMSG_NUM_BUFS / 2) + ret = vrp->sbufs + RPMSG_BUF_SIZE * vrp->last_sbuf++; + /* or recycle a used one */ + else + ret = virtqueue_get_buf(vrp->svq, &len); + + mutex_unlock(&vrp->tx_lock); + + return ret; +} + +/** + * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed + * @vrp: virtual remote processor state + * + * This function is called before a sender is blocked, waiting for + * a tx buffer to become available. + * + * If we already have blocking senders, this function merely increases + * the "sleepers" reference count, and exits. + * + * Otherwise, if this is the first sender to block, we also enable + * virtio's tx callbacks, so we'd be immediately notified when a tx + * buffer is consumed (we rely on virtio's tx callback in order + * to wake up sleeping senders as soon as a tx buffer is used by the + * remote processor). + */ +static void rpmsg_upref_sleepers(struct virtproc_info *vrp) +{ + /* support multiple concurrent senders */ + mutex_lock(&vrp->tx_lock); + + /* are we the first sleeping context waiting for tx buffers ? */ + if (atomic_inc_return(&vrp->sleepers) == 1) + /* enable "tx-complete" interrupts before dozing off */ + virtqueue_enable_cb(vrp->svq); + + mutex_unlock(&vrp->tx_lock); +} + +/** + * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed + * @vrp: virtual remote processor state + * + * This function is called after a sender, that waited for a tx buffer + * to become available, is unblocked. + * + * If we still have blocking senders, this function merely decreases + * the "sleepers" reference count, and exits. + * + * Otherwise, if there are no more blocking senders, we also disable + * virtio's tx callbacks, to avoid the overhead incurred with handling + * those (now redundant) interrupts. + */ +static void rpmsg_downref_sleepers(struct virtproc_info *vrp) +{ + /* support multiple concurrent senders */ + mutex_lock(&vrp->tx_lock); + + /* are we the last sleeping context waiting for tx buffers ? */ + if (atomic_dec_and_test(&vrp->sleepers)) + /* disable "tx-complete" interrupts */ + virtqueue_disable_cb(vrp->svq); + + mutex_unlock(&vrp->tx_lock); +} + +/** + * rpmsg_send_offchannel_raw() - send a message across to the remote processor + * @rpdev: the rpmsg channel + * @src: source address + * @dst: destination address + * @data: payload of message + * @len: length of payload + * @wait: indicates whether caller should block in case no TX buffers available + * + * This function is the base implementation for all of the rpmsg sending API. + * + * It will send @data of length @len to @dst, and say it's from @src. The + * message will be sent to the remote processor which the @rpdev channel + * belongs to. + * + * The message is sent using one of the TX buffers that are available for + * communication with this remote processor. + * + * If @wait is true, the caller will be blocked until either a TX buffer is + * available, or 15 seconds elapses (we don't want callers to + * sleep indefinitely due to misbehaving remote processors), and in that + * case -ERESTARTSYS is returned. The number '15' itself was picked + * arbitrarily; there's little point in asking drivers to provide a timeout + * value themselves. + * + * Otherwise, if @wait is false, and there are no TX buffers available, + * the function will immediately fail, and -ENOMEM will be returned. + * + * Normally drivers shouldn't use this function directly; instead, drivers + * should use the appropriate rpmsg_{try}send{to, _offchannel} API + * (see include/linux/rpmsg.h). + * + * Returns 0 on success and an appropriate error value on failure. + */ +int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst, + void *data, int len, bool wait) +{ + struct virtproc_info *vrp = rpdev->vrp; + struct device *dev = &rpdev->dev; + struct scatterlist sg; + struct rpmsg_hdr *msg; + int err; + + /* bcasting isn't allowed */ + if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) { + dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst); + return -EINVAL; + } + + /* + * We currently use fixed-sized buffers, and therefore the payload + * length is limited. + * + * One of the possible improvements here is either to support + * user-provided buffers (and then we can also support zero-copy + * messaging), or to improve the buffer allocator, to support + * variable-length buffer sizes. + */ + if (len > RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) { + dev_err(dev, "message is too big (%d)\n", len); + return -EMSGSIZE; + } + + /* grab a buffer */ + msg = get_a_tx_buf(vrp); + if (!msg && !wait) + return -ENOMEM; + + /* no free buffer ? wait for one (but bail after 15 seconds) */ + while (!msg) { + /* enable "tx-complete" interrupts, if not already enabled */ + rpmsg_upref_sleepers(vrp); + + /* + * sleep until a free buffer is available or 15 secs elapse. + * the timeout period is not configurable because there's + * little point in asking drivers to specify that. + * if later this happens to be required, it'd be easy to add. + */ + err = wait_event_interruptible_timeout(vrp->sendq, + (msg = get_a_tx_buf(vrp)), + msecs_to_jiffies(15000)); + + /* disable "tx-complete" interrupts if we're the last sleeper */ + rpmsg_downref_sleepers(vrp); + + /* timeout ? */ + if (!err) { + dev_err(dev, "timeout waiting for a tx buffer\n"); + return -ERESTARTSYS; + } + } + + msg->len = len; + msg->flags = 0; + msg->src = src; + msg->dst = dst; + msg->reserved = 0; + memcpy(msg->data, data, len); + + dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n", + msg->src, msg->dst, msg->len, + msg->flags, msg->reserved); + print_hex_dump(KERN_DEBUG, "rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1, + msg, sizeof(*msg) + msg->len, true); + + sg_init_one(&sg, msg, sizeof(*msg) + len); + + mutex_lock(&vrp->tx_lock); + + /* add message to the remote processor's virtqueue */ + err = virtqueue_add_buf_gfp(vrp->svq, &sg, 1, 0, msg, GFP_KERNEL); + if (err < 0) { + /* + * need to reclaim the buffer here, otherwise it's lost + * (memory won't leak, but rpmsg won't use it again for TX). + * this will wait for a buffer management overhaul. + */ + dev_err(dev, "virtqueue_add_buf_gfp failed: %d\n", err); + goto out; + } + + /* tell the remote processor it has a pending message to read */ + virtqueue_kick(vrp->svq); + + err = 0; +out: + mutex_unlock(&vrp->tx_lock); + return err; +} +EXPORT_SYMBOL(rpmsg_send_offchannel_raw); + +/* called when an rx buffer is used, and it's time to digest a message */ +static void rpmsg_recv_done(struct virtqueue *rvq) +{ + struct rpmsg_hdr *msg; + unsigned int len; + struct rpmsg_endpoint *ept; + struct scatterlist sg; + struct virtproc_info *vrp = rvq->vdev->priv; + struct device *dev = &rvq->vdev->dev; + int err; + + msg = virtqueue_get_buf(rvq, &len); + if (!msg) { + dev_err(dev, "uhm, incoming signal, but no used buffer ?\n"); + return; + } + + dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n", + msg->src, msg->dst, msg->len, + msg->flags, msg->reserved); + print_hex_dump(KERN_DEBUG, "rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1, + msg, sizeof(*msg) + msg->len, true); + + /* use the dst addr to fetch the callback of the appropriate user */ + mutex_lock(&vrp->endpoints_lock); + ept = idr_find(&vrp->endpoints, msg->dst); + mutex_unlock(&vrp->endpoints_lock); + + if (ept && ept->cb) + ept->cb(ept->rpdev, msg->data, msg->len, ept->priv, msg->src); + else + dev_warn(dev, "msg received with no recepient\n"); + + sg_init_one(&sg, msg, sizeof(*msg) + len); + + /* add the buffer back to the remote processor's virtqueue */ + err = virtqueue_add_buf_gfp(vrp->rvq, &sg, 0, 1, msg, GFP_KERNEL); + if (err < 0) { + dev_err(dev, "failed to add a virtqueue buffer: %d\n", err); + return; + } + + /* tell the remote processor we added another available rx buffer */ + virtqueue_kick(vrp->rvq); +} + +/* + * This is invoked whenever the remote processor completed processing + * a TX msg we just sent it, and the buffer is put back to the used ring. + * + * Normally, though, we suppress this "tx complete" interrupt in order to + * avoid the incurred overhead. + */ +static void rpmsg_xmit_done(struct virtqueue *svq) +{ + struct virtproc_info *vrp = svq->vdev->priv; + + dev_dbg(&svq->vdev->dev, "%s\n", __func__); + + /* wake up potential senders that are waiting for a tx buffer */ + wake_up_interruptible(&vrp->sendq); +} + +/* invoked when a name service announcement arrives */ +static void rpmsg_ns_cb(struct rpmsg_channel *rpdev, void *data, int len, + void *priv, u32 src) +{ + struct rpmsg_ns_msg *msg = data; + struct rpmsg_channel *newch; + struct rpmsg_channel_info chinfo; + struct virtproc_info *vrp = priv; + struct device *dev = &vrp->vdev->dev; + int ret; + + print_hex_dump(KERN_DEBUG, "NS announcement: ", + DUMP_PREFIX_NONE, 16, 1, + data, len, true); + + if (len != sizeof(*msg)) { + dev_err(dev, "malformed ns msg (%d)\n", len); + return; + } + + /* + * the name service ept does _not_ belong to a real rpmsg channel, + * and is handled by the rpmsg bus itself. + * for sanity reasons, make sure a valid rpdev has _not_ sneaked + * in somehow. + */ + if (rpdev) { + dev_err(dev, "anomaly: ns ept has an rpdev handle\n"); + return; + } + + /* don't trust the remote processor for null terminating the name */ + msg->name[RPMSG_NAME_SIZE - 1] = '\0'; + + dev_info(dev, "%sing channel %s addr 0x%x\n", + msg->flags & RPMSG_NS_DESTROY ? "destroy" : "creat", + msg->name, msg->addr); + + strncpy(chinfo.name, msg->name, sizeof(chinfo.name)); + chinfo.src = RPMSG_ADDR_ANY; + chinfo.dst = msg->addr; + + if (msg->flags & RPMSG_NS_DESTROY) { + ret = rpmsg_destroy_channel(vrp, &chinfo); + if (ret) + dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret); + } else { + newch = rpmsg_create_channel(vrp, &chinfo); + if (!newch) + dev_err(dev, "rpmsg_create_channel failed\n"); + } +} + +static int rpmsg_probe(struct virtio_device *vdev) +{ + vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done }; + const char *names[] = { "input", "output" }; + struct virtqueue *vqs[2]; + struct virtproc_info *vrp; + void *bufs_va; + int err = 0, i; + + vrp = kzalloc(sizeof(*vrp), GFP_KERNEL); + if (!vrp) + return -ENOMEM; + + vrp->vdev = vdev; + + idr_init(&vrp->endpoints); + mutex_init(&vrp->endpoints_lock); + mutex_init(&vrp->tx_lock); + init_waitqueue_head(&vrp->sendq); + + /* We expect two virtqueues, rx and tx (and in this order) */ + err = vdev->config->find_vqs(vdev, 2, vqs, vq_cbs, names); + if (err) + goto free_vrp; + + vrp->rvq = vqs[0]; + vrp->svq = vqs[1]; + + /* allocate coherent memory for the buffers */ + bufs_va = dma_alloc_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE, + &vrp->bufs_dma, GFP_KERNEL); + if (!bufs_va) + goto vqs_del; + + dev_dbg(&vdev->dev, "buffers: va %p, dma 0x%x\n", bufs_va, + vrp->bufs_dma); + + /* half of the buffers is dedicated for RX */ + vrp->rbufs = bufs_va; + + /* and half is dedicated for TX */ + vrp->sbufs = bufs_va + RPMSG_TOTAL_BUF_SPACE / 2; + + /* set up the receive buffers */ + for (i = 0; i < RPMSG_NUM_BUFS / 2; i++) { + struct scatterlist sg; + void *cpu_addr = vrp->rbufs + i * RPMSG_BUF_SIZE; + + sg_init_one(&sg, cpu_addr, RPMSG_BUF_SIZE); + + err = virtqueue_add_buf_gfp(vrp->rvq, &sg, 0, 1, cpu_addr, + GFP_KERNEL); + WARN_ON(err < 0); /* sanity check; this can't really happen */ + } + + /* suppress "tx-complete" interrupts */ + virtqueue_disable_cb(vrp->svq); + + vdev->priv = vrp; + + /* if supported by the remote processor, enable the name service */ + if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) { + /* a dedicated endpoint handles the name service msgs */ + vrp->ns_ept = __rpmsg_create_ept(vrp, NULL, rpmsg_ns_cb, + vrp, RPMSG_NS_ADDR); + if (!vrp->ns_ept) { + dev_err(&vdev->dev, "failed to create the ns ept\n"); + err = -ENOMEM; + goto free_coherent; + } + } + + /* tell the remote processor it can start sending messages */ + virtqueue_kick(vrp->rvq); + + dev_info(&vdev->dev, "rpmsg host is online\n"); + + return 0; + +free_coherent: + dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE, bufs_va, + vrp->bufs_dma); +vqs_del: + vdev->config->del_vqs(vrp->vdev); +free_vrp: + kfree(vrp); + return err; +} + +static int rpmsg_remove_device(struct device *dev, void *data) +{ + device_unregister(dev); + + return 0; +} + +static void __devexit rpmsg_remove(struct virtio_device *vdev) +{ + struct virtproc_info *vrp = vdev->priv; + int ret; + + vdev->config->reset(vdev); + + ret = device_for_each_child(&vdev->dev, NULL, rpmsg_remove_device); + if (ret) + dev_warn(&vdev->dev, "can't remove rpmsg device: %d\n", ret); + + idr_remove_all(&vrp->endpoints); + idr_destroy(&vrp->endpoints); + + vdev->config->del_vqs(vrp->vdev); + + dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE, + vrp->rbufs, vrp->bufs_dma); + + kfree(vrp); +} + +static struct virtio_device_id id_table[] = { + { VIRTIO_ID_RPMSG, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; + +static unsigned int features[] = { + VIRTIO_RPMSG_F_NS, +}; + +static struct virtio_driver virtio_ipc_driver = { + .feature_table = features, + .feature_table_size = ARRAY_SIZE(features), + .driver.name = KBUILD_MODNAME, + .driver.owner = THIS_MODULE, + .id_table = id_table, + .probe = rpmsg_probe, + .remove = __devexit_p(rpmsg_remove), +}; + +static int __init rpmsg_init(void) +{ + int ret; + + ret = bus_register(&rpmsg_bus); + if (ret) { + pr_err("failed to register rpmsg bus: %d\n", ret); + return ret; + } + + ret = register_virtio_driver(&virtio_ipc_driver); + if (ret) { + pr_err("failed to register virtio driver: %d\n", ret); + bus_unregister(&rpmsg_bus); + } + + return ret; +} +module_init(rpmsg_init); + +static void __exit rpmsg_fini(void) +{ + unregister_virtio_driver(&virtio_ipc_driver); + bus_unregister(&rpmsg_bus); +} +module_exit(rpmsg_fini); + +MODULE_DEVICE_TABLE(virtio, id_table); +MODULE_DESCRIPTION("Virtio-based remote processor messaging bus"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h index b29e7f6..92aef8a 100644 --- a/include/linux/mod_devicetable.h +++ b/include/linux/mod_devicetable.h @@ -414,6 +414,15 @@ struct hv_vmbus_device_id { __attribute__((aligned(sizeof(kernel_ulong_t)))); }; +/* rpmsg */ + +#define RPMSG_NAME_SIZE 32 +#define RPMSG_DEVICE_MODALIAS_FMT "rpmsg:%s" + +struct rpmsg_device_id { + char name[RPMSG_NAME_SIZE]; +}; + /* i2c */ #define I2C_NAME_SIZE 20 diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h new file mode 100644 index 0000000..a8e50e4 --- /dev/null +++ b/include/linux/rpmsg.h @@ -0,0 +1,326 @@ +/* + * Remote processor messaging + * + * Copyright (C) 2011 Texas Instruments, Inc. + * Copyright (C) 2011 Google, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name Texas Instruments nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef _LINUX_RPMSG_H +#define _LINUX_RPMSG_H + +#include <linux/types.h> +#include <linux/device.h> +#include <linux/mod_devicetable.h> + +/* The feature bitmap for virtio rpmsg */ +#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */ + +/** + * struct rpmsg_hdr - common header for all rpmsg messages + * @src: source address + * @dst: destination address + * @reserved: reserved for future use + * @len: length of payload (in bytes) + * @flags: message flags + * @data: @len bytes of message payload data + * + * Every message sent(/received) on the rpmsg bus begins with this header. + */ +struct rpmsg_hdr { + u32 src; + u32 dst; + u32 reserved; + u16 len; + u16 flags; + u8 data[0]; +} __packed; + +/** + * struct rpmsg_ns_msg - dynamic name service announcement message + * @name: name of remote service that is published + * @addr: address of remote service that is published + * @flags: indicates whether service is created or destroyed + * + * This message is sent across to publish a new service, or announce + * about its removal. When we receive these messages, an appropriate + * rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe() + * or ->remove() handler of the appropriate rpmsg driver will be invoked + * (if/as-soon-as one is registered). + */ +struct rpmsg_ns_msg { + char name[RPMSG_NAME_SIZE]; + u32 addr; + u32 flags; +} __packed; + +/** + * enum rpmsg_ns_flags - dynamic name service announcement flags + * + * @RPMSG_NS_CREATE: a new remote service was just created + * @RPMSG_NS_DESTROY: a known remote service was just destroyed + */ +enum rpmsg_ns_flags { + RPMSG_NS_CREATE = 0, + RPMSG_NS_DESTROY = 1, +}; + +#define RPMSG_ADDR_ANY 0xFFFFFFFF + +struct virtproc_info; + +/** + * rpmsg_channel - devices that belong to the rpmsg bus are called channels + * @vrp: the remote processor this channel belongs to + * @dev: the device struct + * @id: device id (used to match between rpmsg drivers and devices) + * @src: local address + * @dst: destination address + * @ept: the rpmsg endpoint of this channel + * @announce: if set, rpmsg will announce the creation/removal of this channel + */ +struct rpmsg_channel { + struct virtproc_info *vrp; + struct device dev; + struct rpmsg_device_id id; + u32 src; + u32 dst; + struct rpmsg_endpoint *ept; + bool announce; +}; + +typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32); + +/** + * struct rpmsg_endpoint - binds a local rpmsg address to its user + * @rpdev: rpmsg channel device + * @cb: rx callback handler + * @addr: local rpmsg address + * @priv: private data for the driver's use + * + * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as + * it binds an rpmsg address with an rx callback handler. + * + * Simple rpmsg drivers shouldn't use this struct directly, because + * things just work: every rpmsg driver provides an rx callback upon + * registering to the bus, and that callback is then bound to its rpmsg + * address when the driver is probed. When relevant inbound messages arrive + * (i.e. messages which their dst address equals to the src address of + * the rpmsg channel), the driver's handler is invoked to process it. + * + * More complicated drivers though, that do need to allocate additional rpmsg + * addresses, and bind them to different rx callbacks, must explicitly + * create additional endpoints by themselves (see rpmsg_create_ept()). + */ +struct rpmsg_endpoint { + struct rpmsg_channel *rpdev; + rpmsg_rx_cb_t cb; + u32 addr; + void *priv; +}; + +/** + * struct rpmsg_driver - rpmsg driver struct + * @drv: underlying device driver + * @id_table: rpmsg ids serviced by this driver + * @probe: invoked when a matching rpmsg channel (i.e. device) is found + * @remove: invoked when the rpmsg channel is removed + * @callback: invoked when an inbound message is received on the channel + */ +struct rpmsg_driver { + struct device_driver drv; + const struct rpmsg_device_id *id_table; + int (*probe)(struct rpmsg_channel *dev); + void (*remove)(struct rpmsg_channel *dev); + void (*callback)(struct rpmsg_channel *, void *, int, void *, u32); +}; + +int register_rpmsg_device(struct rpmsg_channel *dev); +void unregister_rpmsg_device(struct rpmsg_channel *dev); +int register_rpmsg_driver(struct rpmsg_driver *drv); +void unregister_rpmsg_driver(struct rpmsg_driver *drv); +void rpmsg_destroy_ept(struct rpmsg_endpoint *); +struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *, + rpmsg_rx_cb_t cb, void *priv, u32 addr); +int +rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool); + +/** + * rpmsg_send() - send a message across to the remote processor + * @rpdev: the rpmsg channel + * @data: payload of message + * @len: length of payload + * + * This function sends @data of length @len on the @rpdev channel. + * The message will be sent to the remote processor which the @rpdev + * channel belongs to, using @rpdev's source and destination addresses. + * In case there are no TX buffers available, the function will block until + * one becomes available, or a timeout of 15 seconds elapses. When the latter + * happens, -ERESTARTSYS is returned. + * + * Can only be called from process context (for now). + * + * Returns 0 on success and an appropriate error value on failure. + */ +static inline int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len) +{ + u32 src = rpdev->src, dst = rpdev->dst; + + return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true); +} + +/** + * rpmsg_sendto() - send a message across to the remote processor, specify dst + * @rpdev: the rpmsg channel + * @data: payload of message + * @len: length of payload + * @dst: destination address + * + * This function sends @data of length @len to the remote @dst address. + * The message will be sent to the remote processor which the @rpdev + * channel belongs to, using @rpdev's source address. + * In case there are no TX buffers available, the function will block until + * one becomes available, or a timeout of 15 seconds elapses. When the latter + * happens, -ERESTARTSYS is returned. + * + * Can only be called from process context (for now). + * + * Returns 0 on success and an appropriate error value on failure. + */ +static inline +int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst) +{ + u32 src = rpdev->src; + + return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true); +} + +/** + * rpmsg_send_offchannel() - send a message using explicit src/dst addresses + * @rpdev: the rpmsg channel + * @src: source address + * @dst: destination address + * @data: payload of message + * @len: length of payload + * + * This function sends @data of length @len to the remote @dst address, + * and uses @src as the source address. + * The message will be sent to the remote processor which the @rpdev + * channel belongs to. + * In case there are no TX buffers available, the function will block until + * one becomes available, or a timeout of 15 seconds elapses. When the latter + * happens, -ERESTARTSYS is returned. + * + * Can only be called from process context (for now). + * + * Returns 0 on success and an appropriate error value on failure. + */ +static inline +int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst, + void *data, int len) +{ + return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true); +} + +/** + * rpmsg_send() - send a message across to the remote processor + * @rpdev: the rpmsg channel + * @data: payload of message + * @len: length of payload + * + * This function sends @data of length @len on the @rpdev channel. + * The message will be sent to the remote processor which the @rpdev + * channel belongs to, using @rpdev's source and destination addresses. + * In case there are no TX buffers available, the function will immediately + * return -ENOMEM without waiting until one becomes available. + * + * Can only be called from process context (for now). + * + * Returns 0 on success and an appropriate error value on failure. + */ +static inline +int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len) +{ + u32 src = rpdev->src, dst = rpdev->dst; + + return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false); +} + +/** + * rpmsg_sendto() - send a message across to the remote processor, specify dst + * @rpdev: the rpmsg channel + * @data: payload of message + * @len: length of payload + * @dst: destination address + * + * This function sends @data of length @len to the remote @dst address. + * The message will be sent to the remote processor which the @rpdev + * channel belongs to, using @rpdev's source address. + * In case there are no TX buffers available, the function will immediately + * return -ENOMEM without waiting until one becomes available. + * + * Can only be called from process context (for now). + * + * Returns 0 on success and an appropriate error value on failure. + */ +static inline +int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst) +{ + u32 src = rpdev->src; + + return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false); +} + +/** + * rpmsg_send_offchannel() - send a message using explicit src/dst addresses + * @rpdev: the rpmsg channel + * @src: source address + * @dst: destination address + * @data: payload of message + * @len: length of payload + * + * This function sends @data of length @len to the remote @dst address, + * and uses @src as the source address. + * The message will be sent to the remote processor which the @rpdev + * channel belongs to. + * In case there are no TX buffers available, the function will immediately + * return -ENOMEM without waiting until one becomes available. + * + * Can only be called from process context (for now). + * + * Returns 0 on success and an appropriate error value on failure. + */ +static inline +int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst, + void *data, int len) +{ + return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false); +} + +#endif /* _LINUX_RPMSG_H */ diff --git a/include/linux/virtio_ids.h b/include/linux/virtio_ids.h index 85bb0bb..b37c521 100644 --- a/include/linux/virtio_ids.h +++ b/include/linux/virtio_ids.h @@ -34,6 +34,7 @@ #define VIRTIO_ID_CONSOLE 3 /* virtio console */ #define VIRTIO_ID_RNG 4 /* virtio ring */ #define VIRTIO_ID_BALLOON 5 /* virtio balloon */ +#define VIRTIO_ID_RPMSG 7 /* virtio remote processor messaging */ #define VIRTIO_ID_9P 9 /* 9p virtio console */ #endif /* _LINUX_VIRTIO_IDS_H */ |
