diff options
Diffstat (limited to 'drivers/ide/ide-io.c')
| -rw-r--r-- | drivers/ide/ide-io.c | 904 |
1 files changed, 904 insertions, 0 deletions
diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c new file mode 100644 index 000000000..4867b67b6 --- /dev/null +++ b/drivers/ide/ide-io.c @@ -0,0 +1,904 @@ +/* + * IDE I/O functions + * + * Basic PIO and command management functionality. + * + * This code was split off from ide.c. See ide.c for history and original + * copyrights. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * 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. + * + * For the avoidance of doubt the "preferred form" of this code is one which + * is in an open non patent encumbered format. Where cryptographic key signing + * forms part of the process of creating an executable the information + * including keys needed to generate an equivalently functional executable + * are deemed to be part of the source code. + */ + + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/string.h> +#include <linux/kernel.h> +#include <linux/timer.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/genhd.h> +#include <linux/blkpg.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/pci.h> +#include <linux/delay.h> +#include <linux/ide.h> +#include <linux/completion.h> +#include <linux/reboot.h> +#include <linux/cdrom.h> +#include <linux/seq_file.h> +#include <linux/device.h> +#include <linux/kmod.h> +#include <linux/scatterlist.h> +#include <linux/bitops.h> + +#include <asm/byteorder.h> +#include <asm/irq.h> +#include <linux/uaccess.h> +#include <asm/io.h> + +int ide_end_rq(ide_drive_t *drive, struct request *rq, blk_status_t error, + unsigned int nr_bytes) +{ + /* + * decide whether to reenable DMA -- 3 is a random magic for now, + * if we DMA timeout more than 3 times, just stay in PIO + */ + if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) && + drive->retry_pio <= 3) { + drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY; + ide_dma_on(drive); + } + + if (!blk_update_request(rq, error, nr_bytes)) { + if (rq == drive->sense_rq) { + drive->sense_rq = NULL; + drive->sense_rq_active = false; + } + + __blk_mq_end_request(rq, error); + return 0; + } + + return 1; +} +EXPORT_SYMBOL_GPL(ide_end_rq); + +void ide_complete_cmd(ide_drive_t *drive, struct ide_cmd *cmd, u8 stat, u8 err) +{ + const struct ide_tp_ops *tp_ops = drive->hwif->tp_ops; + struct ide_taskfile *tf = &cmd->tf; + struct request *rq = cmd->rq; + u8 tf_cmd = tf->command; + + tf->error = err; + tf->status = stat; + + if (cmd->ftf_flags & IDE_FTFLAG_IN_DATA) { + u8 data[2]; + + tp_ops->input_data(drive, cmd, data, 2); + + cmd->tf.data = data[0]; + cmd->hob.data = data[1]; + } + + ide_tf_readback(drive, cmd); + + if ((cmd->tf_flags & IDE_TFLAG_CUSTOM_HANDLER) && + tf_cmd == ATA_CMD_IDLEIMMEDIATE) { + if (tf->lbal != 0xc4) { + printk(KERN_ERR "%s: head unload failed!\n", + drive->name); + ide_tf_dump(drive->name, cmd); + } else + drive->dev_flags |= IDE_DFLAG_PARKED; + } + + if (rq && ata_taskfile_request(rq)) { + struct ide_cmd *orig_cmd = ide_req(rq)->special; + + if (cmd->tf_flags & IDE_TFLAG_DYN) + kfree(orig_cmd); + else if (cmd != orig_cmd) + memcpy(orig_cmd, cmd, sizeof(*cmd)); + } +} + +int ide_complete_rq(ide_drive_t *drive, blk_status_t error, unsigned int nr_bytes) +{ + ide_hwif_t *hwif = drive->hwif; + struct request *rq = hwif->rq; + int rc; + + /* + * if failfast is set on a request, override number of sectors + * and complete the whole request right now + */ + if (blk_noretry_request(rq) && error) + nr_bytes = blk_rq_sectors(rq) << 9; + + rc = ide_end_rq(drive, rq, error, nr_bytes); + if (rc == 0) + hwif->rq = NULL; + + return rc; +} +EXPORT_SYMBOL(ide_complete_rq); + +void ide_kill_rq(ide_drive_t *drive, struct request *rq) +{ + u8 drv_req = ata_misc_request(rq) && rq->rq_disk; + u8 media = drive->media; + + drive->failed_pc = NULL; + + if ((media == ide_floppy || media == ide_tape) && drv_req) { + scsi_req(rq)->result = 0; + } else { + if (media == ide_tape) + scsi_req(rq)->result = IDE_DRV_ERROR_GENERAL; + else if (blk_rq_is_passthrough(rq) && scsi_req(rq)->result == 0) + scsi_req(rq)->result = -EIO; + } + + ide_complete_rq(drive, BLK_STS_IOERR, blk_rq_bytes(rq)); +} + +static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf) +{ + tf->nsect = drive->sect; + tf->lbal = drive->sect; + tf->lbam = drive->cyl; + tf->lbah = drive->cyl >> 8; + tf->device = (drive->head - 1) | drive->select; + tf->command = ATA_CMD_INIT_DEV_PARAMS; +} + +static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf) +{ + tf->nsect = drive->sect; + tf->command = ATA_CMD_RESTORE; +} + +static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf) +{ + tf->nsect = drive->mult_req; + tf->command = ATA_CMD_SET_MULTI; +} + +/** + * do_special - issue some special commands + * @drive: drive the command is for + * + * do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS, + * ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive. + */ + +static ide_startstop_t do_special(ide_drive_t *drive) +{ + struct ide_cmd cmd; + +#ifdef DEBUG + printk(KERN_DEBUG "%s: %s: 0x%02x\n", drive->name, __func__, + drive->special_flags); +#endif + if (drive->media != ide_disk) { + drive->special_flags = 0; + drive->mult_req = 0; + return ide_stopped; + } + + memset(&cmd, 0, sizeof(cmd)); + cmd.protocol = ATA_PROT_NODATA; + + if (drive->special_flags & IDE_SFLAG_SET_GEOMETRY) { + drive->special_flags &= ~IDE_SFLAG_SET_GEOMETRY; + ide_tf_set_specify_cmd(drive, &cmd.tf); + } else if (drive->special_flags & IDE_SFLAG_RECALIBRATE) { + drive->special_flags &= ~IDE_SFLAG_RECALIBRATE; + ide_tf_set_restore_cmd(drive, &cmd.tf); + } else if (drive->special_flags & IDE_SFLAG_SET_MULTMODE) { + drive->special_flags &= ~IDE_SFLAG_SET_MULTMODE; + ide_tf_set_setmult_cmd(drive, &cmd.tf); + } else + BUG(); + + cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE; + cmd.valid.in.tf = IDE_VALID_IN_TF | IDE_VALID_DEVICE; + cmd.tf_flags = IDE_TFLAG_CUSTOM_HANDLER; + + do_rw_taskfile(drive, &cmd); + + return ide_started; +} + +void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd) +{ + ide_hwif_t *hwif = drive->hwif; + struct scatterlist *sg = hwif->sg_table, *last_sg = NULL; + struct request *rq = cmd->rq; + + cmd->sg_nents = __blk_rq_map_sg(drive->queue, rq, sg, &last_sg); + if (blk_rq_bytes(rq) && (blk_rq_bytes(rq) & rq->q->dma_pad_mask)) + last_sg->length += + (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; +} +EXPORT_SYMBOL_GPL(ide_map_sg); + +void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes) +{ + cmd->nbytes = cmd->nleft = nr_bytes; + cmd->cursg_ofs = 0; + cmd->cursg = NULL; +} +EXPORT_SYMBOL_GPL(ide_init_sg_cmd); + +/** + * execute_drive_command - issue special drive command + * @drive: the drive to issue the command on + * @rq: the request structure holding the command + * + * execute_drive_cmd() issues a special drive command, usually + * initiated by ioctl() from the external hdparm program. The + * command can be a drive command, drive task or taskfile + * operation. Weirdly you can call it with NULL to wait for + * all commands to finish. Don't do this as that is due to change + */ + +static ide_startstop_t execute_drive_cmd (ide_drive_t *drive, + struct request *rq) +{ + struct ide_cmd *cmd = ide_req(rq)->special; + + if (cmd) { + if (cmd->protocol == ATA_PROT_PIO) { + ide_init_sg_cmd(cmd, blk_rq_sectors(rq) << 9); + ide_map_sg(drive, cmd); + } + + return do_rw_taskfile(drive, cmd); + } + + /* + * NULL is actually a valid way of waiting for + * all current requests to be flushed from the queue. + */ +#ifdef DEBUG + printk("%s: DRIVE_CMD (null)\n", drive->name); +#endif + scsi_req(rq)->result = 0; + ide_complete_rq(drive, BLK_STS_OK, blk_rq_bytes(rq)); + + return ide_stopped; +} + +static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq) +{ + u8 cmd = scsi_req(rq)->cmd[0]; + + switch (cmd) { + case REQ_PARK_HEADS: + case REQ_UNPARK_HEADS: + return ide_do_park_unpark(drive, rq); + case REQ_DEVSET_EXEC: + return ide_do_devset(drive, rq); + case REQ_DRIVE_RESET: + return ide_do_reset(drive); + default: + BUG(); + } +} + +/** + * start_request - start of I/O and command issuing for IDE + * + * start_request() initiates handling of a new I/O request. It + * accepts commands and I/O (read/write) requests. + * + * FIXME: this function needs a rename + */ + +static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq) +{ + ide_startstop_t startstop; + +#ifdef DEBUG + printk("%s: start_request: current=0x%08lx\n", + drive->hwif->name, (unsigned long) rq); +#endif + + /* bail early if we've exceeded max_failures */ + if (drive->max_failures && (drive->failures > drive->max_failures)) { + rq->rq_flags |= RQF_FAILED; + goto kill_rq; + } + + if (drive->prep_rq && !drive->prep_rq(drive, rq)) + return ide_stopped; + + if (ata_pm_request(rq)) + ide_check_pm_state(drive, rq); + + drive->hwif->tp_ops->dev_select(drive); + if (ide_wait_stat(&startstop, drive, drive->ready_stat, + ATA_BUSY | ATA_DRQ, WAIT_READY)) { + printk(KERN_ERR "%s: drive not ready for command\n", drive->name); + return startstop; + } + + if (drive->special_flags == 0) { + struct ide_driver *drv; + + /* + * We reset the drive so we need to issue a SETFEATURES. + * Do it _after_ do_special() restored device parameters. + */ + if (drive->current_speed == 0xff) + ide_config_drive_speed(drive, drive->desired_speed); + + if (ata_taskfile_request(rq)) + return execute_drive_cmd(drive, rq); + else if (ata_pm_request(rq)) { + struct ide_pm_state *pm = ide_req(rq)->special; +#ifdef DEBUG_PM + printk("%s: start_power_step(step: %d)\n", + drive->name, pm->pm_step); +#endif + startstop = ide_start_power_step(drive, rq); + if (startstop == ide_stopped && + pm->pm_step == IDE_PM_COMPLETED) + ide_complete_pm_rq(drive, rq); + return startstop; + } else if (!rq->rq_disk && ata_misc_request(rq)) + /* + * TODO: Once all ULDs have been modified to + * check for specific op codes rather than + * blindly accepting any special request, the + * check for ->rq_disk above may be replaced + * by a more suitable mechanism or even + * dropped entirely. + */ + return ide_special_rq(drive, rq); + + drv = *(struct ide_driver **)rq->rq_disk->private_data; + + return drv->do_request(drive, rq, blk_rq_pos(rq)); + } + return do_special(drive); +kill_rq: + ide_kill_rq(drive, rq); + return ide_stopped; +} + +/** + * ide_stall_queue - pause an IDE device + * @drive: drive to stall + * @timeout: time to stall for (jiffies) + * + * ide_stall_queue() can be used by a drive to give excess bandwidth back + * to the port by sleeping for timeout jiffies. + */ + +void ide_stall_queue (ide_drive_t *drive, unsigned long timeout) +{ + if (timeout > WAIT_WORSTCASE) + timeout = WAIT_WORSTCASE; + drive->sleep = timeout + jiffies; + drive->dev_flags |= IDE_DFLAG_SLEEPING; +} +EXPORT_SYMBOL(ide_stall_queue); + +static inline int ide_lock_port(ide_hwif_t *hwif) +{ + if (hwif->busy) + return 1; + + hwif->busy = 1; + + return 0; +} + +static inline void ide_unlock_port(ide_hwif_t *hwif) +{ + hwif->busy = 0; +} + +static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif) +{ + int rc = 0; + + if (host->host_flags & IDE_HFLAG_SERIALIZE) { + rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy); + if (rc == 0) { + if (host->get_lock) + host->get_lock(ide_intr, hwif); + } + } + return rc; +} + +static inline void ide_unlock_host(struct ide_host *host) +{ + if (host->host_flags & IDE_HFLAG_SERIALIZE) { + if (host->release_lock) + host->release_lock(); + clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy); + } +} + +void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq) +{ + struct request_queue *q = drive->queue; + + /* Use 3ms as that was the old plug delay */ + if (rq) { + blk_mq_requeue_request(rq, false); + blk_mq_delay_kick_requeue_list(q, 3); + } else + blk_mq_delay_run_hw_queue(q->queue_hw_ctx[0], 3); +} + +blk_status_t ide_issue_rq(ide_drive_t *drive, struct request *rq, + bool local_requeue) +{ + ide_hwif_t *hwif = drive->hwif; + struct ide_host *host = hwif->host; + ide_startstop_t startstop; + + if (!blk_rq_is_passthrough(rq) && !(rq->rq_flags & RQF_DONTPREP)) { + rq->rq_flags |= RQF_DONTPREP; + ide_req(rq)->special = NULL; + } + + /* HLD do_request() callback might sleep, make sure it's okay */ + might_sleep(); + + if (ide_lock_host(host, hwif)) + return BLK_STS_DEV_RESOURCE; + + spin_lock_irq(&hwif->lock); + + if (!ide_lock_port(hwif)) { + ide_hwif_t *prev_port; + + WARN_ON_ONCE(hwif->rq); +repeat: + prev_port = hwif->host->cur_port; + if (drive->dev_flags & IDE_DFLAG_SLEEPING && + time_after(drive->sleep, jiffies)) { + ide_unlock_port(hwif); + goto plug_device; + } + + if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) && + hwif != prev_port) { + ide_drive_t *cur_dev = + prev_port ? prev_port->cur_dev : NULL; + + /* + * set nIEN for previous port, drives in the + * quirk list may not like intr setups/cleanups + */ + if (cur_dev && + (cur_dev->dev_flags & IDE_DFLAG_NIEN_QUIRK) == 0) + prev_port->tp_ops->write_devctl(prev_port, + ATA_NIEN | + ATA_DEVCTL_OBS); + + hwif->host->cur_port = hwif; + } + hwif->cur_dev = drive; + drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED); + + /* + * Sanity: don't accept a request that isn't a PM request + * if we are currently power managed. This is very important as + * blk_stop_queue() doesn't prevent the blk_fetch_request() + * above to return us whatever is in the queue. Since we call + * ide_do_request() ourselves, we end up taking requests while + * the queue is blocked... + */ + if ((drive->dev_flags & IDE_DFLAG_BLOCKED) && + ata_pm_request(rq) == 0 && + (rq->rq_flags & RQF_PM) == 0) { + /* there should be no pending command at this point */ + ide_unlock_port(hwif); + goto plug_device; + } + + scsi_req(rq)->resid_len = blk_rq_bytes(rq); + hwif->rq = rq; + + spin_unlock_irq(&hwif->lock); + startstop = start_request(drive, rq); + spin_lock_irq(&hwif->lock); + + if (startstop == ide_stopped) { + rq = hwif->rq; + hwif->rq = NULL; + if (rq) + goto repeat; + ide_unlock_port(hwif); + goto out; + } + } else { +plug_device: + if (local_requeue) + list_add(&rq->queuelist, &drive->rq_list); + spin_unlock_irq(&hwif->lock); + ide_unlock_host(host); + if (!local_requeue) + ide_requeue_and_plug(drive, rq); + return BLK_STS_OK; + } + +out: + spin_unlock_irq(&hwif->lock); + if (rq == NULL) + ide_unlock_host(host); + return BLK_STS_OK; +} + +/* + * Issue a new request to a device. + */ +blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + ide_drive_t *drive = hctx->queue->queuedata; + ide_hwif_t *hwif = drive->hwif; + + spin_lock_irq(&hwif->lock); + if (drive->sense_rq_active) { + spin_unlock_irq(&hwif->lock); + return BLK_STS_DEV_RESOURCE; + } + spin_unlock_irq(&hwif->lock); + + blk_mq_start_request(bd->rq); + return ide_issue_rq(drive, bd->rq, false); +} + +static int drive_is_ready(ide_drive_t *drive) +{ + ide_hwif_t *hwif = drive->hwif; + u8 stat = 0; + + if (drive->waiting_for_dma) + return hwif->dma_ops->dma_test_irq(drive); + + if (hwif->io_ports.ctl_addr && + (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0) + stat = hwif->tp_ops->read_altstatus(hwif); + else + /* Note: this may clear a pending IRQ!! */ + stat = hwif->tp_ops->read_status(hwif); + + if (stat & ATA_BUSY) + /* drive busy: definitely not interrupting */ + return 0; + + /* drive ready: *might* be interrupting */ + return 1; +} + +/** + * ide_timer_expiry - handle lack of an IDE interrupt + * @data: timer callback magic (hwif) + * + * An IDE command has timed out before the expected drive return + * occurred. At this point we attempt to clean up the current + * mess. If the current handler includes an expiry handler then + * we invoke the expiry handler, and providing it is happy the + * work is done. If that fails we apply generic recovery rules + * invoking the handler and checking the drive DMA status. We + * have an excessively incestuous relationship with the DMA + * logic that wants cleaning up. + */ + +void ide_timer_expiry (struct timer_list *t) +{ + ide_hwif_t *hwif = from_timer(hwif, t, timer); + ide_drive_t *drive; + ide_handler_t *handler; + unsigned long flags; + int wait = -1; + int plug_device = 0; + struct request *rq_in_flight; + + spin_lock_irqsave(&hwif->lock, flags); + + handler = hwif->handler; + + if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) { + /* + * Either a marginal timeout occurred + * (got the interrupt just as timer expired), + * or we were "sleeping" to give other devices a chance. + * Either way, we don't really want to complain about anything. + */ + } else { + ide_expiry_t *expiry = hwif->expiry; + ide_startstop_t startstop = ide_stopped; + + drive = hwif->cur_dev; + + if (expiry) { + wait = expiry(drive); + if (wait > 0) { /* continue */ + /* reset timer */ + hwif->timer.expires = jiffies + wait; + hwif->req_gen_timer = hwif->req_gen; + add_timer(&hwif->timer); + spin_unlock_irqrestore(&hwif->lock, flags); + return; + } + } + hwif->handler = NULL; + hwif->expiry = NULL; + /* + * We need to simulate a real interrupt when invoking + * the handler() function, which means we need to + * globally mask the specific IRQ: + */ + spin_unlock(&hwif->lock); + /* disable_irq_nosync ?? */ + disable_irq(hwif->irq); + + if (hwif->polling) { + startstop = handler(drive); + } else if (drive_is_ready(drive)) { + if (drive->waiting_for_dma) + hwif->dma_ops->dma_lost_irq(drive); + if (hwif->port_ops && hwif->port_ops->clear_irq) + hwif->port_ops->clear_irq(drive); + + printk(KERN_WARNING "%s: lost interrupt\n", + drive->name); + startstop = handler(drive); + } else { + if (drive->waiting_for_dma) + startstop = ide_dma_timeout_retry(drive, wait); + else + startstop = ide_error(drive, "irq timeout", + hwif->tp_ops->read_status(hwif)); + } + /* Disable interrupts again, `handler' might have enabled it */ + spin_lock_irq(&hwif->lock); + enable_irq(hwif->irq); + if (startstop == ide_stopped && hwif->polling == 0) { + rq_in_flight = hwif->rq; + hwif->rq = NULL; + ide_unlock_port(hwif); + plug_device = 1; + } + } + spin_unlock_irqrestore(&hwif->lock, flags); + + if (plug_device) { + ide_unlock_host(hwif->host); + ide_requeue_and_plug(drive, rq_in_flight); + } +} + +/** + * unexpected_intr - handle an unexpected IDE interrupt + * @irq: interrupt line + * @hwif: port being processed + * + * There's nothing really useful we can do with an unexpected interrupt, + * other than reading the status register (to clear it), and logging it. + * There should be no way that an irq can happen before we're ready for it, + * so we needn't worry much about losing an "important" interrupt here. + * + * On laptops (and "green" PCs), an unexpected interrupt occurs whenever + * the drive enters "idle", "standby", or "sleep" mode, so if the status + * looks "good", we just ignore the interrupt completely. + * + * This routine assumes __cli() is in effect when called. + * + * If an unexpected interrupt happens on irq15 while we are handling irq14 + * and if the two interfaces are "serialized" (CMD640), then it looks like + * we could screw up by interfering with a new request being set up for + * irq15. + * + * In reality, this is a non-issue. The new command is not sent unless + * the drive is ready to accept one, in which case we know the drive is + * not trying to interrupt us. And ide_set_handler() is always invoked + * before completing the issuance of any new drive command, so we will not + * be accidentally invoked as a result of any valid command completion + * interrupt. + */ + +static void unexpected_intr(int irq, ide_hwif_t *hwif) +{ + u8 stat = hwif->tp_ops->read_status(hwif); + + if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) { + /* Try to not flood the console with msgs */ + static unsigned long last_msgtime, count; + ++count; + + if (time_after(jiffies, last_msgtime + HZ)) { + last_msgtime = jiffies; + printk(KERN_ERR "%s: unexpected interrupt, " + "status=0x%02x, count=%ld\n", + hwif->name, stat, count); + } + } +} + +/** + * ide_intr - default IDE interrupt handler + * @irq: interrupt number + * @dev_id: hwif + * @regs: unused weirdness from the kernel irq layer + * + * This is the default IRQ handler for the IDE layer. You should + * not need to override it. If you do be aware it is subtle in + * places + * + * hwif is the interface in the group currently performing + * a command. hwif->cur_dev is the drive and hwif->handler is + * the IRQ handler to call. As we issue a command the handlers + * step through multiple states, reassigning the handler to the + * next step in the process. Unlike a smart SCSI controller IDE + * expects the main processor to sequence the various transfer + * stages. We also manage a poll timer to catch up with most + * timeout situations. There are still a few where the handlers + * don't ever decide to give up. + * + * The handler eventually returns ide_stopped to indicate the + * request completed. At this point we issue the next request + * on the port and the process begins again. + */ + +irqreturn_t ide_intr (int irq, void *dev_id) +{ + ide_hwif_t *hwif = (ide_hwif_t *)dev_id; + struct ide_host *host = hwif->host; + ide_drive_t *drive; + ide_handler_t *handler; + unsigned long flags; + ide_startstop_t startstop; + irqreturn_t irq_ret = IRQ_NONE; + int plug_device = 0; + struct request *rq_in_flight; + + if (host->host_flags & IDE_HFLAG_SERIALIZE) { + if (hwif != host->cur_port) + goto out_early; + } + + spin_lock_irqsave(&hwif->lock, flags); + + if (hwif->port_ops && hwif->port_ops->test_irq && + hwif->port_ops->test_irq(hwif) == 0) + goto out; + + handler = hwif->handler; + + if (handler == NULL || hwif->polling) { + /* + * Not expecting an interrupt from this drive. + * That means this could be: + * (1) an interrupt from another PCI device + * sharing the same PCI INT# as us. + * or (2) a drive just entered sleep or standby mode, + * and is interrupting to let us know. + * or (3) a spurious interrupt of unknown origin. + * + * For PCI, we cannot tell the difference, + * so in that case we just ignore it and hope it goes away. + */ + if ((host->irq_flags & IRQF_SHARED) == 0) { + /* + * Probably not a shared PCI interrupt, + * so we can safely try to do something about it: + */ + unexpected_intr(irq, hwif); + } else { + /* + * Whack the status register, just in case + * we have a leftover pending IRQ. + */ + (void)hwif->tp_ops->read_status(hwif); + } + goto out; + } + + drive = hwif->cur_dev; + + if (!drive_is_ready(drive)) + /* + * This happens regularly when we share a PCI IRQ with + * another device. Unfortunately, it can also happen + * with some buggy drives that trigger the IRQ before + * their status register is up to date. Hopefully we have + * enough advance overhead that the latter isn't a problem. + */ + goto out; + + hwif->handler = NULL; + hwif->expiry = NULL; + hwif->req_gen++; + del_timer(&hwif->timer); + spin_unlock(&hwif->lock); + + if (hwif->port_ops && hwif->port_ops->clear_irq) + hwif->port_ops->clear_irq(drive); + + if (drive->dev_flags & IDE_DFLAG_UNMASK) + local_irq_enable_in_hardirq(); + + /* service this interrupt, may set handler for next interrupt */ + startstop = handler(drive); + + spin_lock_irq(&hwif->lock); + /* + * Note that handler() may have set things up for another + * interrupt to occur soon, but it cannot happen until + * we exit from this routine, because it will be the + * same irq as is currently being serviced here, and Linux + * won't allow another of the same (on any CPU) until we return. + */ + if (startstop == ide_stopped && hwif->polling == 0) { + BUG_ON(hwif->handler); + rq_in_flight = hwif->rq; + hwif->rq = NULL; + ide_unlock_port(hwif); + plug_device = 1; + } + irq_ret = IRQ_HANDLED; +out: + spin_unlock_irqrestore(&hwif->lock, flags); +out_early: + if (plug_device) { + ide_unlock_host(hwif->host); + ide_requeue_and_plug(drive, rq_in_flight); + } + + return irq_ret; +} +EXPORT_SYMBOL_GPL(ide_intr); + +void ide_pad_transfer(ide_drive_t *drive, int write, int len) +{ + ide_hwif_t *hwif = drive->hwif; + u8 buf[4] = { 0 }; + + while (len > 0) { + if (write) + hwif->tp_ops->output_data(drive, NULL, buf, min(4, len)); + else + hwif->tp_ops->input_data(drive, NULL, buf, min(4, len)); + len -= 4; + } +} +EXPORT_SYMBOL_GPL(ide_pad_transfer); + +void ide_insert_request_head(ide_drive_t *drive, struct request *rq) +{ + drive->sense_rq_active = true; + list_add_tail(&rq->queuelist, &drive->rq_list); + kblockd_schedule_work(&drive->rq_work); +} +EXPORT_SYMBOL_GPL(ide_insert_request_head); |