diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devices.txt | 5 | ||||
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 9 | ||||
| -rw-r--r-- | Documentation/memory-barriers.txt | 4 | ||||
| -rw-r--r-- | Documentation/networking/operstates.txt | 161 | ||||
| -rw-r--r-- | Documentation/scsi/ChangeLog.megaraid | 25 | ||||
| -rw-r--r-- | Documentation/spi/pxa2xx | 234 | ||||
| -rw-r--r-- | Documentation/spi/spi-summary | 34 | ||||
| -rw-r--r-- | Documentation/watchdog/watchdog-api.txt | 3 |
8 files changed, 467 insertions, 8 deletions
diff --git a/Documentation/devices.txt b/Documentation/devices.txt index 3c406ac..b369a8c 100644 --- a/Documentation/devices.txt +++ b/Documentation/devices.txt @@ -1721,11 +1721,6 @@ Your cooperation is appreciated. These devices support the same API as the generic SCSI devices. - 97 block Packet writing for CD/DVD devices - 0 = /dev/pktcdvd0 First packet-writing module - 1 = /dev/pktcdvd1 Second packet-writing module - ... - 98 char Control and Measurement Device (comedi) 0 = /dev/comedi0 First comedi device 1 = /dev/comedi1 Second comedi device diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 421bcff..43ab119 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -57,6 +57,15 @@ Who: Jody McIntyre <scjody@steamballoon.com> --------------------------- +What: sbp2: module parameter "force_inquiry_hack" +When: July 2006 +Why: Superceded by parameter "workarounds". Both parameters are meant to be + used ad-hoc and for single devices only, i.e. not in modprobe.conf, + therefore the impact of this feature replacement should be low. +Who: Stefan Richter <stefanr@s5r6.in-berlin.de> + +--------------------------- + What: Video4Linux API 1 ioctls and video_decoder.h from Video devices. When: July 2006 Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6 diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index 92f0056..c61d8b8 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -1031,7 +1031,7 @@ conflict on any particular lock. LOCKS VS MEMORY ACCESSES ------------------------ -Consider the following: the system has a pair of spinlocks (N) and (Q), and +Consider the following: the system has a pair of spinlocks (M) and (Q), and three CPUs; then should the following sequence of events occur: CPU 1 CPU 2 @@ -1678,7 +1678,7 @@ CPU's caches by some other cache event: smp_wmb(); <A:modify v=2> <C:busy> <C:queue v=2> - p = &b; q = p; + p = &v; q = p; <D:request p> <B:modify p=&v> <D:commit p=&v> <D:read p> diff --git a/Documentation/networking/operstates.txt b/Documentation/networking/operstates.txt new file mode 100644 index 0000000..4a21d9b --- /dev/null +++ b/Documentation/networking/operstates.txt @@ -0,0 +1,161 @@ + +1. Introduction + +Linux distinguishes between administrative and operational state of an +interface. Admininstrative state is the result of "ip link set dev +<dev> up or down" and reflects whether the administrator wants to use +the device for traffic. + +However, an interface is not usable just because the admin enabled it +- ethernet requires to be plugged into the switch and, depending on +a site's networking policy and configuration, an 802.1X authentication +to be performed before user data can be transferred. Operational state +shows the ability of an interface to transmit this user data. + +Thanks to 802.1X, userspace must be granted the possibility to +influence operational state. To accommodate this, operational state is +split into two parts: Two flags that can be set by the driver only, and +a RFC2863 compatible state that is derived from these flags, a policy, +and changeable from userspace under certain rules. + + +2. Querying from userspace + +Both admin and operational state can be queried via the netlink +operation RTM_GETLINK. It is also possible to subscribe to RTMGRP_LINK +to be notified of updates. This is important for setting from userspace. + +These values contain interface state: + +ifinfomsg::if_flags & IFF_UP: + Interface is admin up +ifinfomsg::if_flags & IFF_RUNNING: + Interface is in RFC2863 operational state UP or UNKNOWN. This is for + backward compatibility, routing daemons, dhcp clients can use this + flag to determine whether they should use the interface. +ifinfomsg::if_flags & IFF_LOWER_UP: + Driver has signaled netif_carrier_on() +ifinfomsg::if_flags & IFF_DORMANT: + Driver has signaled netif_dormant_on() + +These interface flags can also be queried without netlink using the +SIOCGIFFLAGS ioctl. + +TLV IFLA_OPERSTATE + +contains RFC2863 state of the interface in numeric representation: + +IF_OPER_UNKNOWN (0): + Interface is in unknown state, neither driver nor userspace has set + operational state. Interface must be considered for user data as + setting operational state has not been implemented in every driver. +IF_OPER_NOTPRESENT (1): + Unused in current kernel (notpresent interfaces normally disappear), + just a numerical placeholder. +IF_OPER_DOWN (2): + Interface is unable to transfer data on L1, f.e. ethernet is not + plugged or interface is ADMIN down. +IF_OPER_LOWERLAYERDOWN (3): + Interfaces stacked on an interface that is IF_OPER_DOWN show this + state (f.e. VLAN). +IF_OPER_TESTING (4): + Unused in current kernel. +IF_OPER_DORMANT (5): + Interface is L1 up, but waiting for an external event, f.e. for a + protocol to establish. (802.1X) +IF_OPER_UP (6): + Interface is operational up and can be used. + +This TLV can also be queried via sysfs. + +TLV IFLA_LINKMODE + +contains link policy. This is needed for userspace interaction +described below. + +This TLV can also be queried via sysfs. + + +3. Kernel driver API + +Kernel drivers have access to two flags that map to IFF_LOWER_UP and +IFF_DORMANT. These flags can be set from everywhere, even from +interrupts. It is guaranteed that only the driver has write access, +however, if different layers of the driver manipulate the same flag, +the driver has to provide the synchronisation needed. + +__LINK_STATE_NOCARRIER, maps to !IFF_LOWER_UP: + +The driver uses netif_carrier_on() to clear and netif_carrier_off() to +set this flag. On netif_carrier_off(), the scheduler stops sending +packets. The name 'carrier' and the inversion are historical, think of +it as lower layer. + +netif_carrier_ok() can be used to query that bit. + +__LINK_STATE_DORMANT, maps to IFF_DORMANT: + +Set by the driver to express that the device cannot yet be used +because some driver controlled protocol establishment has to +complete. Corresponding functions are netif_dormant_on() to set the +flag, netif_dormant_off() to clear it and netif_dormant() to query. + +On device allocation, networking core sets the flags equivalent to +netif_carrier_ok() and !netif_dormant(). + + +Whenever the driver CHANGES one of these flags, a workqueue event is +scheduled to translate the flag combination to IFLA_OPERSTATE as +follows: + +!netif_carrier_ok(): + IF_OPER_LOWERLAYERDOWN if the interface is stacked, IF_OPER_DOWN + otherwise. Kernel can recognise stacked interfaces because their + ifindex != iflink. + +netif_carrier_ok() && netif_dormant(): + IF_OPER_DORMANT + +netif_carrier_ok() && !netif_dormant(): + IF_OPER_UP if userspace interaction is disabled. Otherwise + IF_OPER_DORMANT with the possibility for userspace to initiate the + IF_OPER_UP transition afterwards. + + +4. Setting from userspace + +Applications have to use the netlink interface to influence the +RFC2863 operational state of an interface. Setting IFLA_LINKMODE to 1 +via RTM_SETLINK instructs the kernel that an interface should go to +IF_OPER_DORMANT instead of IF_OPER_UP when the combination +netif_carrier_ok() && !netif_dormant() is set by the +driver. Afterwards, the userspace application can set IFLA_OPERSTATE +to IF_OPER_DORMANT or IF_OPER_UP as long as the driver does not set +netif_carrier_off() or netif_dormant_on(). Changes made by userspace +are multicasted on the netlink group RTMGRP_LINK. + +So basically a 802.1X supplicant interacts with the kernel like this: + +-subscribe to RTMGRP_LINK +-set IFLA_LINKMODE to 1 via RTM_SETLINK +-query RTM_GETLINK once to get initial state +-if initial flags are not (IFF_LOWER_UP && !IFF_DORMANT), wait until + netlink multicast signals this state +-do 802.1X, eventually abort if flags go down again +-send RTM_SETLINK to set operstate to IF_OPER_UP if authentication + succeeds, IF_OPER_DORMANT otherwise +-see how operstate and IFF_RUNNING is echoed via netlink multicast +-set interface back to IF_OPER_DORMANT if 802.1X reauthentication + fails +-restart if kernel changes IFF_LOWER_UP or IFF_DORMANT flag + +if supplicant goes down, bring back IFLA_LINKMODE to 0 and +IFLA_OPERSTATE to a sane value. + +A routing daemon or dhcp client just needs to care for IFF_RUNNING or +waiting for operstate to go IF_OPER_UP/IF_OPER_UNKNOWN before +considering the interface / querying a DHCP address. + + +For technical questions and/or comments please e-mail to Stefan Rompf +(stefan at loplof.de). diff --git a/Documentation/scsi/ChangeLog.megaraid b/Documentation/scsi/ChangeLog.megaraid index 09f6300..c173806 100644 --- a/Documentation/scsi/ChangeLog.megaraid +++ b/Documentation/scsi/ChangeLog.megaraid @@ -1,3 +1,28 @@ +Release Date : Mon Apr 11 12:27:22 EST 2006 - Seokmann Ju <sju@lsil.com> +Current Version : 2.20.4.8 (scsi module), 2.20.2.6 (cmm module) +Older Version : 2.20.4.7 (scsi module), 2.20.2.6 (cmm module) + +1. Fixed a bug in megaraid_reset_handler(). + Customer reported "Unable to handle kernel NULL pointer dereference + at virtual address 00000000" when system goes to reset condition + for some reason. It happened randomly. + Root Cause: in the megaraid_reset_handler(), there is possibility not + returning pending packets in the pend_list if there are multiple + pending packets. + Fix: Made the change in the driver so that it will return all packets + in the pend_list. + +2. Added change request. + As found in the following URL, rmb() only didn't help the + problem. I had to increase the loop counter to 0xFFFFFF. (6 F's) + http://marc.theaimsgroup.com/?l=linux-scsi&m=110971060502497&w=2 + + I attached a patch for your reference, too. + Could you check and get this fix in your driver? + + Best Regards, + Jun'ichi Nomura + Release Date : Fri Nov 11 12:27:22 EST 2005 - Seokmann Ju <sju@lsil.com> Current Version : 2.20.4.7 (scsi module), 2.20.2.6 (cmm module) Older Version : 2.20.4.6 (scsi module), 2.20.2.6 (cmm module) diff --git a/Documentation/spi/pxa2xx b/Documentation/spi/pxa2xx new file mode 100644 index 0000000..9c45f3d --- /dev/null +++ b/Documentation/spi/pxa2xx @@ -0,0 +1,234 @@ +PXA2xx SPI on SSP driver HOWTO +=================================================== +This a mini howto on the pxa2xx_spi driver. The driver turns a PXA2xx +synchronous serial port into a SPI master controller +(see Documentation/spi/spi_summary). The driver has the following features + +- Support for any PXA2xx SSP +- SSP PIO and SSP DMA data transfers. +- External and Internal (SSPFRM) chip selects. +- Per slave device (chip) configuration. +- Full suspend, freeze, resume support. + +The driver is built around a "spi_message" fifo serviced by workqueue and a +tasklet. The workqueue, "pump_messages", drives message fifo and the tasklet +(pump_transfer) is responsible for queuing SPI transactions and setting up and +launching the dma/interrupt driven transfers. + +Declaring PXA2xx Master Controllers +----------------------------------- +Typically a SPI master is defined in the arch/.../mach-*/board-*.c as a +"platform device". The master configuration is passed to the driver via a table +found in include/asm-arm/arch-pxa/pxa2xx_spi.h: + +struct pxa2xx_spi_master { + enum pxa_ssp_type ssp_type; + u32 clock_enable; + u16 num_chipselect; + u8 enable_dma; +}; + +The "pxa2xx_spi_master.ssp_type" field must have a value between 1 and 3 and +informs the driver which features a particular SSP supports. + +The "pxa2xx_spi_master.clock_enable" field is used to enable/disable the +corresponding SSP peripheral block in the "Clock Enable Register (CKEN"). See +the "PXA2xx Developer Manual" section "Clocks and Power Management". + +The "pxa2xx_spi_master.num_chipselect" field is used to determine the number of +slave device (chips) attached to this SPI master. + +The "pxa2xx_spi_master.enable_dma" field informs the driver that SSP DMA should +be used. This caused the driver to acquire two DMA channels: rx_channel and +tx_channel. The rx_channel has a higher DMA service priority the tx_channel. +See the "PXA2xx Developer Manual" section "DMA Controller". + +NSSP MASTER SAMPLE +------------------ +Below is a sample configuration using the PXA255 NSSP. + +static struct resource pxa_spi_nssp_resources[] = { + [0] = { + .start = __PREG(SSCR0_P(2)), /* Start address of NSSP */ + .end = __PREG(SSCR0_P(2)) + 0x2c, /* Range of registers */ + .flags = IORESOURCE_MEM, + }, + [1] = { + .start = IRQ_NSSP, /* NSSP IRQ */ + .end = IRQ_NSSP, + .flags = IORESOURCE_IRQ, + }, +}; + +static struct pxa2xx_spi_master pxa_nssp_master_info = { + .ssp_type = PXA25x_NSSP, /* Type of SSP */ + .clock_enable = CKEN9_NSSP, /* NSSP Peripheral clock */ + .num_chipselect = 1, /* Matches the number of chips attached to NSSP */ + .enable_dma = 1, /* Enables NSSP DMA */ +}; + +static struct platform_device pxa_spi_nssp = { + .name = "pxa2xx-spi", /* MUST BE THIS VALUE, so device match driver */ + .id = 2, /* Bus number, MUST MATCH SSP number 1..n */ + .resource = pxa_spi_nssp_resources, + .num_resources = ARRAY_SIZE(pxa_spi_nssp_resources), + .dev = { + .platform_data = &pxa_nssp_master_info, /* Passed to driver */ + }, +}; + +static struct platform_device *devices[] __initdata = { + &pxa_spi_nssp, +}; + +static void __init board_init(void) +{ + (void)platform_add_device(devices, ARRAY_SIZE(devices)); +} + +Declaring Slave Devices +----------------------- +Typically each SPI slave (chip) is defined in the arch/.../mach-*/board-*.c +using the "spi_board_info" structure found in "linux/spi/spi.h". See +"Documentation/spi/spi_summary" for additional information. + +Each slave device attached to the PXA must provide slave specific configuration +information via the structure "pxa2xx_spi_chip" found in +"include/asm-arm/arch-pxa/pxa2xx_spi.h". The pxa2xx_spi master controller driver +will uses the configuration whenever the driver communicates with the slave +device. + +struct pxa2xx_spi_chip { + u8 tx_threshold; + u8 rx_threshold; + u8 dma_burst_size; + u32 timeout_microsecs; + u8 enable_loopback; + void (*cs_control)(u32 command); +}; + +The "pxa2xx_spi_chip.tx_threshold" and "pxa2xx_spi_chip.rx_threshold" fields are +used to configure the SSP hardware fifo. These fields are critical to the +performance of pxa2xx_spi driver and misconfiguration will result in rx +fifo overruns (especially in PIO mode transfers). Good default values are + + .tx_threshold = 12, + .rx_threshold = 4, + +The "pxa2xx_spi_chip.dma_burst_size" field is used to configure PXA2xx DMA +engine and is related the "spi_device.bits_per_word" field. Read and understand +the PXA2xx "Developer Manual" sections on the DMA controller and SSP Controllers +to determine the correct value. An SSP configured for byte-wide transfers would +use a value of 8. + +The "pxa2xx_spi_chip.timeout_microsecs" fields is used to efficiently handle +trailing bytes in the SSP receiver fifo. The correct value for this field is +dependent on the SPI bus speed ("spi_board_info.max_speed_hz") and the specific +slave device. Please note the the PXA2xx SSP 1 does not support trailing byte +timeouts and must busy-wait any trailing bytes. + +The "pxa2xx_spi_chip.enable_loopback" field is used to place the SSP porting +into internal loopback mode. In this mode the SSP controller internally +connects the SSPTX pin the the SSPRX pin. This is useful for initial setup +testing. + +The "pxa2xx_spi_chip.cs_control" field is used to point to a board specific +function for asserting/deasserting a slave device chip select. If the field is +NULL, the pxa2xx_spi master controller driver assumes that the SSP port is +configured to use SSPFRM instead. + +NSSP SALVE SAMPLE +----------------- +The pxa2xx_spi_chip structure is passed to the pxa2xx_spi driver in the +"spi_board_info.controller_data" field. Below is a sample configuration using +the PXA255 NSSP. + +/* Chip Select control for the CS8415A SPI slave device */ +static void cs8415a_cs_control(u32 command) +{ + if (command & PXA2XX_CS_ASSERT) + GPCR(2) = GPIO_bit(2); + else + GPSR(2) = GPIO_bit(2); +} + +/* Chip Select control for the CS8405A SPI slave device */ +static void cs8405a_cs_control(u32 command) +{ + if (command & PXA2XX_CS_ASSERT) + GPCR(3) = GPIO_bit(3); + else + GPSR(3) = GPIO_bit(3); +} + +static struct pxa2xx_spi_chip cs8415a_chip_info = { + .tx_threshold = 12, /* SSP hardward FIFO threshold */ + .rx_threshold = 4, /* SSP hardward FIFO threshold */ + .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */ + .timeout_microsecs = 64, /* Wait at least 64usec to handle trailing */ + .cs_control = cs8415a_cs_control, /* Use external chip select */ +}; + +static struct pxa2xx_spi_chip cs8405a_chip_info = { + .tx_threshold = 12, /* SSP hardward FIFO threshold */ + .rx_threshold = 4, /* SSP hardward FIFO threshold */ + .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */ + .timeout_microsecs = 64, /* Wait at least 64usec to handle trailing */ + .cs_control = cs8405a_cs_control, /* Use external chip select */ +}; + +static struct spi_board_info streetracer_spi_board_info[] __initdata = { + { + .modalias = "cs8415a", /* Name of spi_driver for this device */ + .max_speed_hz = 3686400, /* Run SSP as fast a possbile */ + .bus_num = 2, /* Framework bus number */ + .chip_select = 0, /* Framework chip select */ + .platform_data = NULL; /* No spi_driver specific config */ + .controller_data = &cs8415a_chip_info, /* Master chip config */ + .irq = STREETRACER_APCI_IRQ, /* Slave device interrupt */ + }, + { + .modalias = "cs8405a", /* Name of spi_driver for this device */ + .max_speed_hz = 3686400, /* Run SSP as fast a possbile */ + .bus_num = 2, /* Framework bus number */ + .chip_select = 1, /* Framework chip select */ + .controller_data = &cs8405a_chip_info, /* Master chip config */ + .irq = STREETRACER_APCI_IRQ, /* Slave device interrupt */ + }, +}; + +static void __init streetracer_init(void) +{ + spi_register_board_info(streetracer_spi_board_info, + ARRAY_SIZE(streetracer_spi_board_info)); +} + + +DMA and PIO I/O Support +----------------------- +The pxa2xx_spi driver support both DMA and interrupt driven PIO message +transfers. The driver defaults to PIO mode and DMA transfers must enabled by +setting the "enable_dma" flag in the "pxa2xx_spi_master" structure and and +ensuring that the "pxa2xx_spi_chip.dma_burst_size" field is non-zero. The DMA +mode support both coherent and stream based DMA mappings. + +The following logic is used to determine the type of I/O to be used on +a per "spi_transfer" basis: + +if !enable_dma or dma_burst_size == 0 then + always use PIO transfers + +if spi_message.is_dma_mapped and rx_dma_buf != 0 and tx_dma_buf != 0 then + use coherent DMA mode + +if rx_buf and tx_buf are aligned on 8 byte boundary then + use streaming DMA mode + +otherwise + use PIO transfer + +THANKS TO +--------- + +David Brownell and others for mentoring the development of this driver. + diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary index a5ffba3..068732d3 100644 --- a/Documentation/spi/spi-summary +++ b/Documentation/spi/spi-summary @@ -414,7 +414,33 @@ to get the driver-private data allocated for that device. The driver will initialize the fields of that spi_master, including the bus number (maybe the same as the platform device ID) and three methods used to interact with the SPI core and SPI protocol drivers. It will -also initialize its own internal state. +also initialize its own internal state. (See below about bus numbering +and those methods.) + +After you initialize the spi_master, then use spi_register_master() to +publish it to the rest of the system. At that time, device nodes for +the controller and any predeclared spi devices will be made available, +and the driver model core will take care of binding them to drivers. + +If you need to remove your SPI controller driver, spi_unregister_master() +will reverse the effect of spi_register_master(). + + +BUS NUMBERING + +Bus numbering is important, since that's how Linux identifies a given +SPI bus (shared SCK, MOSI, MISO). Valid bus numbers start at zero. On +SOC systems, the bus numbers should match the numbers defined by the chip +manufacturer. For example, hardware controller SPI2 would be bus number 2, +and spi_board_info for devices connected to it would use that number. + +If you don't have such hardware-assigned bus number, and for some reason +you can't just assign them, then provide a negative bus number. That will +then be replaced by a dynamically assigned number. You'd then need to treat +this as a non-static configuration (see above). + + +SPI MASTER METHODS master->setup(struct spi_device *spi) This sets up the device clock rate, SPI mode, and word sizes. @@ -431,6 +457,9 @@ also initialize its own internal state. state it dynamically associates with that device. If you do that, be sure to provide the cleanup() method to free that state. + +SPI MESSAGE QUEUE + The bulk of the driver will be managing the I/O queue fed by transfer(). That queue could be purely conceptual. For example, a driver used only @@ -440,6 +469,9 @@ But the queue will probably be very real, using message->queue, PIO, often DMA (especially if the root filesystem is in SPI flash), and execution contexts like IRQ handlers, tasklets, or workqueues (such as keventd). Your driver can be as fancy, or as simple, as you need. +Such a transfer() method would normally just add the message to a +queue, and then start some asynchronous transfer engine (unless it's +already running). THANKS TO diff --git a/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt index c5beb54..21ed511 100644 --- a/Documentation/watchdog/watchdog-api.txt +++ b/Documentation/watchdog/watchdog-api.txt @@ -36,6 +36,9 @@ timeout or margin. The simplest way to ping the watchdog is to write some data to the device. So a very simple watchdog daemon would look like this: +#include <stdlib.h> +#include <fcntl.h> + int main(int argc, const char *argv[]) { int fd=open("/dev/watchdog",O_WRONLY); if (fd==-1) { |
