diff options
Diffstat (limited to 'drivers/s390/cio/css.c')
| -rw-r--r-- | drivers/s390/cio/css.c | 575 |
1 files changed, 575 insertions, 0 deletions
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c new file mode 100644 index 0000000..87bd70e --- /dev/null +++ b/drivers/s390/cio/css.c @@ -0,0 +1,575 @@ +/* + * drivers/s390/cio/css.c + * driver for channel subsystem + * $Revision: 1.85 $ + * + * Copyright (C) 2002 IBM Deutschland Entwicklung GmbH, + * IBM Corporation + * Author(s): Arnd Bergmann (arndb@de.ibm.com) + * Cornelia Huck (cohuck@de.ibm.com) + */ +#include <linux/module.h> +#include <linux/init.h> +#include <linux/device.h> +#include <linux/slab.h> +#include <linux/errno.h> +#include <linux/list.h> + +#include "css.h" +#include "cio.h" +#include "cio_debug.h" +#include "ioasm.h" +#include "chsc.h" + +unsigned int highest_subchannel; +int need_rescan = 0; +int css_init_done = 0; + +struct pgid global_pgid; +int css_characteristics_avail = 0; + +struct device css_bus_device = { + .bus_id = "css0", +}; + +static struct subchannel * +css_alloc_subchannel(int irq) +{ + struct subchannel *sch; + int ret; + + sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA); + if (sch == NULL) + return ERR_PTR(-ENOMEM); + ret = cio_validate_subchannel (sch, irq); + if (ret < 0) { + kfree(sch); + return ERR_PTR(ret); + } + if (irq > highest_subchannel) + highest_subchannel = irq; + + if (sch->st != SUBCHANNEL_TYPE_IO) { + /* For now we ignore all non-io subchannels. */ + kfree(sch); + return ERR_PTR(-EINVAL); + } + + /* + * Set intparm to subchannel address. + * This is fine even on 64bit since the subchannel is always located + * under 2G. + */ + sch->schib.pmcw.intparm = (__u32)(unsigned long)sch; + ret = cio_modify(sch); + if (ret) { + kfree(sch); + return ERR_PTR(ret); + } + return sch; +} + +static void +css_free_subchannel(struct subchannel *sch) +{ + if (sch) { + /* Reset intparm to zeroes. */ + sch->schib.pmcw.intparm = 0; + cio_modify(sch); + kfree(sch); + } + +} + +static void +css_subchannel_release(struct device *dev) +{ + struct subchannel *sch; + + sch = to_subchannel(dev); + if (!cio_is_console(sch->irq)) + kfree(sch); +} + +extern int css_get_ssd_info(struct subchannel *sch); + +static int +css_register_subchannel(struct subchannel *sch) +{ + int ret; + + /* Initialize the subchannel structure */ + sch->dev.parent = &css_bus_device; + sch->dev.bus = &css_bus_type; + sch->dev.release = &css_subchannel_release; + + /* make it known to the system */ + ret = device_register(&sch->dev); + if (ret) + printk (KERN_WARNING "%s: could not register %s\n", + __func__, sch->dev.bus_id); + else + css_get_ssd_info(sch); + return ret; +} + +int +css_probe_device(int irq) +{ + int ret; + struct subchannel *sch; + + sch = css_alloc_subchannel(irq); + if (IS_ERR(sch)) + return PTR_ERR(sch); + ret = css_register_subchannel(sch); + if (ret) + css_free_subchannel(sch); + return ret; +} + +struct subchannel * +get_subchannel_by_schid(int irq) +{ + struct subchannel *sch; + struct list_head *entry; + struct device *dev; + + if (!get_bus(&css_bus_type)) + return NULL; + down_read(&css_bus_type.subsys.rwsem); + sch = NULL; + list_for_each(entry, &css_bus_type.devices.list) { + dev = get_device(container_of(entry, + struct device, bus_list)); + if (!dev) + continue; + sch = to_subchannel(dev); + if (sch->irq == irq) + break; + put_device(dev); + sch = NULL; + } + up_read(&css_bus_type.subsys.rwsem); + put_bus(&css_bus_type); + + return sch; +} + +static inline int +css_get_subchannel_status(struct subchannel *sch, int schid) +{ + struct schib schib; + int cc; + + cc = stsch(schid, &schib); + if (cc) + return CIO_GONE; + if (!schib.pmcw.dnv) + return CIO_GONE; + if (sch && sch->schib.pmcw.dnv && + (schib.pmcw.dev != sch->schib.pmcw.dev)) + return CIO_REVALIDATE; + if (sch && !sch->lpm) + return CIO_NO_PATH; + return CIO_OPER; +} + +static int +css_evaluate_subchannel(int irq, int slow) +{ + int event, ret, disc; + struct subchannel *sch; + unsigned long flags; + + sch = get_subchannel_by_schid(irq); + disc = sch ? device_is_disconnected(sch) : 0; + if (disc && slow) { + if (sch) + put_device(&sch->dev); + return 0; /* Already processed. */ + } + /* + * We've got a machine check, so running I/O won't get an interrupt. + * Kill any pending timers. + */ + if (sch) + device_kill_pending_timer(sch); + if (!disc && !slow) { + if (sch) + put_device(&sch->dev); + return -EAGAIN; /* Will be done on the slow path. */ + } + event = css_get_subchannel_status(sch, irq); + CIO_MSG_EVENT(4, "Evaluating schid %04x, event %d, %s, %s path.\n", + irq, event, sch?(disc?"disconnected":"normal"):"unknown", + slow?"slow":"fast"); + switch (event) { + case CIO_NO_PATH: + case CIO_GONE: + if (!sch) { + /* Never used this subchannel. Ignore. */ + ret = 0; + break; + } + if (disc && (event == CIO_NO_PATH)) { + /* + * Uargh, hack again. Because we don't get a machine + * check on configure on, our path bookkeeping can + * be out of date here (it's fine while we only do + * logical varying or get chsc machine checks). We + * need to force reprobing or we might miss devices + * coming operational again. It won't do harm in real + * no path situations. + */ + spin_lock_irqsave(&sch->lock, flags); + device_trigger_reprobe(sch); + spin_unlock_irqrestore(&sch->lock, flags); + ret = 0; + break; + } + if (sch->driver && sch->driver->notify && + sch->driver->notify(&sch->dev, event)) { + cio_disable_subchannel(sch); + device_set_disconnected(sch); + ret = 0; + break; + } + /* + * Unregister subchannel. + * The device will be killed automatically. + */ + cio_disable_subchannel(sch); + device_unregister(&sch->dev); + /* Reset intparm to zeroes. */ + sch->schib.pmcw.intparm = 0; + cio_modify(sch); + put_device(&sch->dev); + ret = 0; + break; + case CIO_REVALIDATE: + /* + * Revalidation machine check. Sick. + * We don't notify the driver since we have to throw the device + * away in any case. + */ + if (!disc) { + device_unregister(&sch->dev); + /* Reset intparm to zeroes. */ + sch->schib.pmcw.intparm = 0; + cio_modify(sch); + put_device(&sch->dev); + ret = css_probe_device(irq); + } else { + /* + * We can't immediately deregister the disconnected + * device since it might block. + */ + spin_lock_irqsave(&sch->lock, flags); + device_trigger_reprobe(sch); + spin_unlock_irqrestore(&sch->lock, flags); + ret = 0; + } + break; + case CIO_OPER: + if (disc) { + spin_lock_irqsave(&sch->lock, flags); + /* Get device operational again. */ + device_trigger_reprobe(sch); + spin_unlock_irqrestore(&sch->lock, flags); + } + ret = sch ? 0 : css_probe_device(irq); + break; + default: + BUG(); + ret = 0; + } + return ret; +} + +static void +css_rescan_devices(void) +{ + int irq, ret; + + for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) { + ret = css_evaluate_subchannel(irq, 1); + /* No more memory. It doesn't make sense to continue. No + * panic because this can happen in midflight and just + * because we can't use a new device is no reason to crash + * the system. */ + if (ret == -ENOMEM) + break; + /* -ENXIO indicates that there are no more subchannels. */ + if (ret == -ENXIO) + break; + } +} + +struct slow_subchannel { + struct list_head slow_list; + unsigned long schid; +}; + +static LIST_HEAD(slow_subchannels_head); +static DEFINE_SPINLOCK(slow_subchannel_lock); + +static void +css_trigger_slow_path(void) +{ + CIO_TRACE_EVENT(4, "slowpath"); + + if (need_rescan) { + need_rescan = 0; + css_rescan_devices(); + return; + } + + spin_lock_irq(&slow_subchannel_lock); + while (!list_empty(&slow_subchannels_head)) { + struct slow_subchannel *slow_sch = + list_entry(slow_subchannels_head.next, + struct slow_subchannel, slow_list); + + list_del_init(slow_subchannels_head.next); + spin_unlock_irq(&slow_subchannel_lock); + css_evaluate_subchannel(slow_sch->schid, 1); + spin_lock_irq(&slow_subchannel_lock); + kfree(slow_sch); + } + spin_unlock_irq(&slow_subchannel_lock); +} + +typedef void (*workfunc)(void *); +DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL); +struct workqueue_struct *slow_path_wq; + +/* + * Rescan for new devices. FIXME: This is slow. + * This function is called when we have lost CRWs due to overflows and we have + * to do subchannel housekeeping. + */ +void +css_reiterate_subchannels(void) +{ + css_clear_subchannel_slow_list(); + need_rescan = 1; +} + +/* + * Called from the machine check handler for subchannel report words. + */ +int +css_process_crw(int irq) +{ + int ret; + + CIO_CRW_EVENT(2, "source is subchannel %04X\n", irq); + + if (need_rescan) + /* We need to iterate all subchannels anyway. */ + return -EAGAIN; + /* + * Since we are always presented with IPI in the CRW, we have to + * use stsch() to find out if the subchannel in question has come + * or gone. + */ + ret = css_evaluate_subchannel(irq, 0); + if (ret == -EAGAIN) { + if (css_enqueue_subchannel_slow(irq)) { + css_clear_subchannel_slow_list(); + need_rescan = 1; + } + } + return ret; +} + +static void __init +css_generate_pgid(void) +{ + /* Let's build our path group ID here. */ + if (css_characteristics_avail && css_general_characteristics.mcss) + global_pgid.cpu_addr = 0x8000; + else { +#ifdef CONFIG_SMP + global_pgid.cpu_addr = hard_smp_processor_id(); +#else + global_pgid.cpu_addr = 0; +#endif + } + global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident; + global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine; + global_pgid.tod_high = (__u32) (get_clock() >> 32); +} + +/* + * Now that the driver core is running, we can setup our channel subsystem. + * The struct subchannel's are created during probing (except for the + * static console subchannel). + */ +static int __init +init_channel_subsystem (void) +{ + int ret, irq; + + if (chsc_determine_css_characteristics() == 0) + css_characteristics_avail = 1; + + css_generate_pgid(); + + if ((ret = bus_register(&css_bus_type))) + goto out; + if ((ret = device_register (&css_bus_device))) + goto out_bus; + + css_init_done = 1; + + ctl_set_bit(6, 28); + + for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) { + struct subchannel *sch; + + if (cio_is_console(irq)) + sch = cio_get_console_subchannel(); + else { + sch = css_alloc_subchannel(irq); + if (IS_ERR(sch)) + ret = PTR_ERR(sch); + else + ret = 0; + if (ret == -ENOMEM) + panic("Out of memory in " + "init_channel_subsystem\n"); + /* -ENXIO: no more subchannels. */ + if (ret == -ENXIO) + break; + if (ret) + continue; + } + /* + * We register ALL valid subchannels in ioinfo, even those + * that have been present before init_channel_subsystem. + * These subchannels can't have been registered yet (kmalloc + * not working) so we do it now. This is true e.g. for the + * console subchannel. + */ + css_register_subchannel(sch); + } + return 0; + +out_bus: + bus_unregister(&css_bus_type); +out: + return ret; +} + +/* + * find a driver for a subchannel. They identify by the subchannel + * type with the exception that the console subchannel driver has its own + * subchannel type although the device is an i/o subchannel + */ +static int +css_bus_match (struct device *dev, struct device_driver *drv) +{ + struct subchannel *sch = container_of (dev, struct subchannel, dev); + struct css_driver *driver = container_of (drv, struct css_driver, drv); + + if (sch->st == driver->subchannel_type) + return 1; + + return 0; +} + +struct bus_type css_bus_type = { + .name = "css", + .match = &css_bus_match, +}; + +subsys_initcall(init_channel_subsystem); + +/* + * Register root devices for some drivers. The release function must not be + * in the device drivers, so we do it here. + */ +static void +s390_root_dev_release(struct device *dev) +{ + kfree(dev); +} + +struct device * +s390_root_dev_register(const char *name) +{ + struct device *dev; + int ret; + + if (!strlen(name)) + return ERR_PTR(-EINVAL); + dev = kmalloc(sizeof(struct device), GFP_KERNEL); + if (!dev) + return ERR_PTR(-ENOMEM); + memset(dev, 0, sizeof(struct device)); + strncpy(dev->bus_id, name, min(strlen(name), (size_t)BUS_ID_SIZE)); + dev->release = s390_root_dev_release; + ret = device_register(dev); + if (ret) { + kfree(dev); + return ERR_PTR(ret); + } + return dev; +} + +void +s390_root_dev_unregister(struct device *dev) +{ + if (dev) + device_unregister(dev); +} + +int +css_enqueue_subchannel_slow(unsigned long schid) +{ + struct slow_subchannel *new_slow_sch; + unsigned long flags; + + new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC); + if (!new_slow_sch) + return -ENOMEM; + memset(new_slow_sch, 0, sizeof(struct slow_subchannel)); + new_slow_sch->schid = schid; + spin_lock_irqsave(&slow_subchannel_lock, flags); + list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head); + spin_unlock_irqrestore(&slow_subchannel_lock, flags); + return 0; +} + +void +css_clear_subchannel_slow_list(void) +{ + unsigned long flags; + + spin_lock_irqsave(&slow_subchannel_lock, flags); + while (!list_empty(&slow_subchannels_head)) { + struct slow_subchannel *slow_sch = + list_entry(slow_subchannels_head.next, + struct slow_subchannel, slow_list); + + list_del_init(slow_subchannels_head.next); + kfree(slow_sch); + } + spin_unlock_irqrestore(&slow_subchannel_lock, flags); +} + + + +int +css_slow_subchannels_exist(void) +{ + return (!list_empty(&slow_subchannels_head)); +} + +MODULE_LICENSE("GPL"); +EXPORT_SYMBOL(css_bus_type); +EXPORT_SYMBOL(s390_root_dev_register); +EXPORT_SYMBOL(s390_root_dev_unregister); +EXPORT_SYMBOL_GPL(css_characteristics_avail); |
