[PATCH] Suspend support for libata

This patch adds suspend patch to libata, and ata_piix in particular. For
most low level drivers, they should just need to add the 4 hooks to
work. As I can only test ata_piix, I didn't enable it for more
though.

Suspend support is the single most important feature on a notebook, and
most new notebooks have sata drives. It's quite embarrassing that we
_still_ do not support this. Right now, it's perfectly possible to
suspend the drive in mid-transfer.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 114 insertions, 0 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 9ea102587914..9c66d4059399 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -4154,6 +4154,96 @@ err_out:
  *      Inherited from caller.
  */
 
+/*
+ * Execute a 'simple' command, that only consists of the opcode 'cmd' itself,
+ * without filling any other registers
+ */
+static int ata_do_simple_cmd(struct ata_port *ap, struct ata_device *dev,
+                             u8 cmd)
+{
+        struct ata_taskfile tf;
+        int err;
+
+        ata_tf_init(ap, &tf, dev->devno);
+
+        tf.command = cmd;
+        tf.flags |= ATA_TFLAG_DEVICE;
+        tf.protocol = ATA_PROT_NODATA;
+
+        err = ata_exec_internal(ap, dev, &tf, DMA_NONE, NULL, 0);
+        if (err)
+                printk(KERN_ERR "%s: ata command failed: %d\n",
+                                __FUNCTION__, err);
+
+        return err;
+}
+
+static int ata_flush_cache(struct ata_port *ap, struct ata_device *dev)
+{
+        u8 cmd;
+
+        if (!ata_try_flush_cache(dev))
+                return 0;
+
+        if (ata_id_has_flush_ext(dev->id))
+                cmd = ATA_CMD_FLUSH_EXT;
+        else
+                cmd = ATA_CMD_FLUSH;
+
+        return ata_do_simple_cmd(ap, dev, cmd);
+}
+
+static int ata_standby_drive(struct ata_port *ap, struct ata_device *dev)
+{
+        return ata_do_simple_cmd(ap, dev, ATA_CMD_STANDBYNOW1);
+}
+
+static int ata_start_drive(struct ata_port *ap, struct ata_device *dev)
+{
+        return ata_do_simple_cmd(ap, dev, ATA_CMD_IDLEIMMEDIATE);
+}
+
+/**
+ *      ata_device_resume - wakeup a previously suspended devices
+ *
+ *      Kick the drive back into action, by sending it an idle immediate
+ *      command and making sure its transfer mode matches between drive
+ *      and host.
+ *
+ */
+int ata_device_resume(struct ata_port *ap, struct ata_device *dev)
+{
+        if (ap->flags & ATA_FLAG_SUSPENDED) {
+                ap->flags &= ~ATA_FLAG_SUSPENDED;
+                ata_set_mode(ap);
+        }
+        if (!ata_dev_present(dev))
+                return 0;
+        if (dev->class == ATA_DEV_ATA)
+                ata_start_drive(ap, dev);
+
+        return 0;
+}
+
+/**
+ *      ata_device_suspend - prepare a device for suspend
+ *
+ *      Flush the cache on the drive, if appropriate, then issue a
+ *      standbynow command.
+ *
+ */
+int ata_device_suspend(struct ata_port *ap, struct ata_device *dev)
+{
+        if (!ata_dev_present(dev))
+                return 0;
+        if (dev->class == ATA_DEV_ATA)
+                ata_flush_cache(ap, dev);
+
+        ata_standby_drive(ap, dev);
+        ap->flags |= ATA_FLAG_SUSPENDED;
+        return 0;
+}
+
 int ata_port_start (struct ata_port *ap)
 {
         struct device *dev = ap->host_set->dev;
@@ -4902,6 +4992,23 @@ int pci_test_config_bits(struct pci_dev *pdev, const struct pci_bits *bits)
 
         return (tmp == bits->val) ? 1 : 0;
 }
+
+int ata_pci_device_suspend(struct pci_dev *pdev, pm_message_t state)
+{
+        pci_save_state(pdev);
+        pci_disable_device(pdev);
+        pci_set_power_state(pdev, PCI_D3hot);
+        return 0;
+}
+
+int ata_pci_device_resume(struct pci_dev *pdev)
+{
+        pci_set_power_state(pdev, PCI_D0);
+        pci_restore_state(pdev);
+        pci_enable_device(pdev);
+        pci_set_master(pdev);
+        return 0;
+}
 #endif /* CONFIG_PCI */
 
 
@@ -5005,4 +5112,11 @@ EXPORT_SYMBOL_GPL(ata_pci_host_stop);
 EXPORT_SYMBOL_GPL(ata_pci_init_native_mode);
 EXPORT_SYMBOL_GPL(ata_pci_init_one);
 EXPORT_SYMBOL_GPL(ata_pci_remove_one);
+EXPORT_SYMBOL_GPL(ata_pci_device_suspend);
+EXPORT_SYMBOL_GPL(ata_pci_device_resume);
 #endif /* CONFIG_PCI */
+
+EXPORT_SYMBOL_GPL(ata_device_suspend);
+EXPORT_SYMBOL_GPL(ata_device_resume);
+EXPORT_SYMBOL_GPL(ata_scsi_device_suspend);
+EXPORT_SYMBOL_GPL(ata_scsi_device_resume);