[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>

4 files changed, 165 insertions, 0 deletions

diff --git a/drivers/scsi/ata_piix.c b/drivers/scsi/ata_piix.c
index 0ea27873b9ff..f79630340028 100644
--- a/drivers/scsi/ata_piix.c
+++ b/drivers/scsi/ata_piix.c
@@ -166,6 +166,8 @@ static struct pci_driver piix_pci_driver = {
 	.id_table		= piix_pci_tbl,
 	.probe			= piix_init_one,
 	.remove			= ata_pci_remove_one,
+	.suspend		= ata_pci_device_suspend,
+	.resume			= ata_pci_device_resume,
 };
 
 static struct scsi_host_template piix_sht = {
@@ -186,6 +188,8 @@ static struct scsi_host_template piix_sht = {
 	.slave_configure	= ata_scsi_slave_config,
 	.bios_param		= ata_std_bios_param,
 	.ordered_flush		= 1,
+	.resume			= ata_scsi_device_resume,
+	.suspend		= ata_scsi_device_suspend,
 };
 
 static const struct ata_port_operations piix_pata_ops = {
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);
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index e0439be4b573..c1ebede14a48 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -396,6 +396,22 @@ void ata_dump_status(unsigned id, struct ata_taskfile *tf)
 	}
 }
 
+int ata_scsi_device_resume(struct scsi_device *sdev)
+{
+	struct ata_port *ap = (struct ata_port *) &sdev->host->hostdata[0];
+	struct ata_device *dev = &ap->device[sdev->id];
+
+	return ata_device_resume(ap, dev);
+}
+
+int ata_scsi_device_suspend(struct scsi_device *sdev)
+{
+	struct ata_port *ap = (struct ata_port *) &sdev->host->hostdata[0];
+	struct ata_device *dev = &ap->device[sdev->id];
+
+	return ata_device_suspend(ap, dev);
+}
+
 /**
  *	ata_to_sense_error - convert ATA error to SCSI error
  *	@id: ATA device number
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 15842b1f0f4a..ea7f3a433572 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -263,9 +263,40 @@ static int scsi_bus_match(struct device *dev, struct device_driver *gendrv)
 	return (sdp->inq_periph_qual == SCSI_INQ_PQ_CON)? 1: 0;
 }
 
+static int scsi_bus_suspend(struct device * dev, pm_message_t state)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_host_template *sht = sdev->host->hostt;
+	int err;
+
+	err = scsi_device_quiesce(sdev);
+	if (err)
+		return err;
+
+	if (sht->suspend)
+		err = sht->suspend(sdev);
+
+	return err;
+}
+
+static int scsi_bus_resume(struct device * dev)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_host_template *sht = sdev->host->hostt;
+	int err = 0;
+
+	if (sht->resume)
+		err = sht->resume(sdev);
+
+	scsi_device_resume(sdev);
+	return err;
+}
+
 struct bus_type scsi_bus_type = {
         .name		= "scsi",
         .match		= scsi_bus_match,
+	.suspend	= scsi_bus_suspend,
+	.resume		= scsi_bus_resume,
 };
 
 int scsi_sysfs_register(void)