--- /dev/null
+/*
+ * 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 <asm/uaccess.h>
+#include <asm/io.h>
+
+int ide_end_rq(ide_drive_t *drive, struct request *rq, int 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);
+ }
+
+ return blk_end_request(rq, error, nr_bytes);
+}
+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 && rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
+ struct ide_cmd *orig_cmd = rq->special;
+
+ if (cmd->tf_flags & IDE_TFLAG_DYN)
+ kfree(orig_cmd);
+ else
+ memcpy(orig_cmd, cmd, sizeof(*cmd));
+ }
+}
+
+int ide_complete_rq(ide_drive_t *drive, int 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 <= 0)
+ 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 = (rq->cmd_type == REQ_TYPE_SPECIAL) && rq->rq_disk;
+ u8 media = drive->media;
+
+ drive->failed_pc = NULL;
+
+ if ((media == ide_floppy || media == ide_tape) && drv_req) {
+ rq->errors = 0;
+ } else {
+ if (media == ide_tape)
+ rq->errors = IDE_DRV_ERROR_GENERAL;
+ else if (rq->cmd_type != REQ_TYPE_FS && rq->errors == 0)
+ rq->errors = -EIO;
+ }
+
+ ide_complete_rq(drive, -EIO, 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;
+ struct request *rq = cmd->rq;
+
+ cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
+}
+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 = 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
+ rq->errors = 0;
+ ide_complete_rq(drive, 0, blk_rq_bytes(rq));
+
+ return ide_stopped;
+}
+
+static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
+{
+ u8 cmd = 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;
+
+ BUG_ON(!(rq->cmd_flags & REQ_STARTED));
+
+#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->cmd_flags |= REQ_FAILED;
+ goto kill_rq;
+ }
+
+ if (blk_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 (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
+ return execute_drive_cmd(drive, rq);
+ else if (blk_pm_request(rq)) {
+ struct request_pm_state *pm = 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 && rq->cmd_type == REQ_TYPE_SPECIAL)
+ /*
+ * 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);
+ }
+}
+
+static void __ide_requeue_and_plug(struct request_queue *q, struct request *rq)
+{
+ if (rq)
+ blk_requeue_request(q, rq);
+ if (rq || blk_peek_request(q)) {
+ /* Use 3ms as that was the old plug delay */
+ blk_delay_queue(q, 3);
+ }
+}
+
+void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
+{
+ struct request_queue *q = drive->queue;
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ __ide_requeue_and_plug(q, rq);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+/*
+ * Issue a new request to a device.
+ */
+void do_ide_request(struct request_queue *q)
+{
+ ide_drive_t *drive = q->queuedata;
+ ide_hwif_t *hwif = drive->hwif;
+ struct ide_host *host = hwif->host;
+ struct request *rq = NULL;
+ ide_startstop_t startstop;
+ unsigned long queue_run_ms = 3; /* old plug delay */
+
+ spin_unlock_irq(q->queue_lock);
+
+ /* HLD do_request() callback might sleep, make sure it's okay */
+ might_sleep();
+
+ if (ide_lock_host(host, hwif))
+ goto plug_device_2;
+
+ 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)) {
+ unsigned long left = jiffies - drive->sleep;
+
+ queue_run_ms = jiffies_to_msecs(left + 1);
+ 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);
+
+ spin_unlock_irq(&hwif->lock);
+ spin_lock_irq(q->queue_lock);
+ /*
+ * we know that the queue isn't empty, but this can happen
+ * if the q->prep_rq_fn() decides to kill a request
+ */
+ if (!rq)
+ rq = blk_fetch_request(drive->queue);
+
+ spin_unlock_irq(q->queue_lock);
+ spin_lock_irq(&hwif->lock);
+
+ if (!rq) {
+ ide_unlock_port(hwif);
+ goto out;
+ }
+
+ /*
+ * 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...
+ *
+ * We let requests forced at head of queue with ide-preempt
+ * though. I hope that doesn't happen too much, hopefully not
+ * unless the subdriver triggers such a thing in its own PM
+ * state machine.
+ */
+ if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
+ blk_pm_request(rq) == 0 &&
+ (rq->cmd_flags & REQ_PREEMPT) == 0) {
+ /* there should be no pending command at this point */
+ ide_unlock_port(hwif);
+ goto plug_device;
+ }
+
+ 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;
+ goto repeat;
+ }
+ } else
+ goto plug_device;
+out:
+ spin_unlock_irq(&hwif->lock);
+ if (rq == NULL)
+ ide_unlock_host(host);
+ spin_lock_irq(q->queue_lock);
+ return;
+
+plug_device:
+ spin_unlock_irq(&hwif->lock);
+ ide_unlock_host(host);
+plug_device_2:
+ spin_lock_irq(q->queue_lock);
+ __ide_requeue_and_plug(q, rq);
+}
+
+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 (unsigned long data)
+{
+ ide_hwif_t *hwif = (ide_hwif_t *)data;
+ ide_drive_t *uninitialized_var(drive);
+ ide_handler_t *handler;
+ unsigned long flags;
+ int wait = -1;
+ int plug_device = 0;
+ struct request *uninitialized_var(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);
+ /* local CPU only, as if we were handling an interrupt */
+ local_irq_disable_nort();
+ 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));
+ }
+ 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 *uninitialized_var(drive);
+ ide_handler_t *handler;
+ unsigned long flags;
+ ide_startstop_t startstop;
+ irqreturn_t irq_ret = IRQ_NONE;
+ int plug_device = 0;
+ struct request *uninitialized_var(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);
Code Review / kvmfornfv.git / blobdiff