[PATCH v2] libata: disable runtime pm for hotpluggable port

[Lin Ming]

Currently, hotplug doesn't work if port is already runtime suspended.
For now, we simply disable runtime pm for hotpluggable port.
Later, we should add runtime pm support for hotpluggable port too.

Bug report:
https://lkml.org/lkml/2012/2/19/70

v2:
- Use bit 2 and 3 for flags ATA_FLAG_EXTERNAL and ATA_FLAG_PLUGGABLE.

TODO: add similar hotpluggable port check for controllers other than
AHCI.

Reported-and-tested-by: Jiri Slaby <jslaby@xxxxxxx>
Reported-and-tested-by: cwillu@xxxxxxxxxx
Reported-and-tested-by: jackdachef@xxxxxxxxx
Signed-off-by: Lin Ming <ming.m.lin@xxxxxxxxx>
---
 drivers/ata/ahci.c             |    3 +++
 drivers/ata/ahci.h             |    3 +++
 drivers/ata/libahci.c          |   20 ++++++++++++++++++++
 drivers/ata/libata-transport.c |    6 ++++--
 include/linux/libata.h         |    2 ++
 5 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index d07bf03..02e93ff 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1145,6 +1145,9 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (hpriv->cap & HOST_CAP_PMP)
 		pi.flags |= ATA_FLAG_PMP;
 
+	if (hpriv->cap & HOST_CAP_SXS)
+		pi.flags |= ATA_FLAG_EXTERNAL;
+
 	ahci_set_em_messages(hpriv, &pi);
 
 	if (ahci_broken_system_poweroff(pdev)) {
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index b175000..92f7172 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -172,6 +172,9 @@ enum {
 	PORT_CMD_ALPE		= (1 << 26), /* Aggressive Link PM enable */
 	PORT_CMD_ATAPI		= (1 << 24), /* Device is ATAPI */
 	PORT_CMD_FBSCP		= (1 << 22), /* FBS Capable Port */
+	PORT_CMD_ESP		= (1 << 21), /* External SATA Port */
+	PORT_CMD_MPSP		= (1 << 19), /* Mechanical Presence Switch Attached to Port */
+	PORT_CMD_HPCP		= (1 << 18), /* Hot Plug Capable Port */
 	PORT_CMD_PMP		= (1 << 17), /* PMP attached */
 	PORT_CMD_LIST_ON	= (1 << 15), /* cmd list DMA engine running */
 	PORT_CMD_FIS_ON		= (1 << 14), /* FIS DMA engine running */
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index a72bfd0..7d72d3c 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1097,6 +1097,23 @@ static void ahci_port_init(struct device *dev, struct ata_port *ap,
 	writel(1 << port_no, mmio + HOST_IRQ_STAT);
 }
 
+static bool ahci_port_pluggable(struct ata_port *ap)
+{
+	void __iomem *port_mmio = ahci_port_base(ap);
+	u32 cmd;
+
+	cmd = readl(port_mmio + PORT_CMD);
+
+	if ((ap->flags & ATA_FLAG_EXTERNAL) &&
+	    (cmd & PORT_CMD_ESP))
+		return true;
+
+	if (cmd & (PORT_CMD_MPSP | PORT_CMD_HPCP))
+		return true;
+
+	return false;
+}
+
 void ahci_init_controller(struct ata_host *host)
 {
 	struct ahci_host_priv *hpriv = host->private_data;
@@ -1112,6 +1129,9 @@ void ahci_init_controller(struct ata_host *host)
 		if (ata_port_is_dummy(ap))
 			continue;
 
+		if (ahci_port_pluggable(ap))
+			ap->flags |= ATA_FLAG_PLUGGABLE;
+
 		ahci_port_init(host->dev, ap, i, mmio, port_mmio);
 	}
 
diff --git a/drivers/ata/libata-transport.c b/drivers/ata/libata-transport.c
index 74aaee3..a7166b9 100644
--- a/drivers/ata/libata-transport.c
+++ b/drivers/ata/libata-transport.c
@@ -292,8 +292,10 @@ int ata_tport_add(struct device *parent,
 	}
 
 	device_enable_async_suspend(dev);
-	pm_runtime_set_active(dev);
-	pm_runtime_enable(dev);
+	if (!(ap->flags & ATA_FLAG_PLUGGABLE)) {
+		pm_runtime_set_active(dev);
+		pm_runtime_enable(dev);
+	}
 
 	transport_add_device(dev);
 	transport_configure_device(dev);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index cafc09a..f46961d 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -187,6 +187,8 @@ enum {
 	ATA_FLAG_SLAVE_POSS	= (1 << 0), /* host supports slave dev */
 					    /* (doesn't imply presence) */
 	ATA_FLAG_SATA		= (1 << 1),
+	ATA_FLAG_EXTERNAL	= (1 << 2), /* Controller supports external SATA */
+	ATA_FLAG_PLUGGABLE	= (1 << 3), /* Port is hotpluggable */
 	ATA_FLAG_NO_ATAPI	= (1 << 6), /* No ATAPI support */
 	ATA_FLAG_PIO_DMA	= (1 << 7), /* PIO cmds via DMA */
 	ATA_FLAG_PIO_LBA48	= (1 << 8), /* Host DMA engine is LBA28 only */
-- 
1.7.2.5



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