[PATCH] ata: ahci: Add shutdown to freeze hardware resources of ahci

[Prabhakar Kushwaha <pkushwaha@marvell.com>]

device_shutdown() called from reboot/power_shutdown expect all
devices to be shutdown. Same is true for ahci pci driver.
As no shutdown function was implemented ata subsystem remains
always alive and DMA/interrupt still active.

It creates problem during kexec, here "M" bit is cleared to stop
DMA usage. Any further DMA transaction may cause instability and
the hard-disk may even not get detected for second kernel.
One of possible case is periodic file system sync.

So defining ahci pci driver shutdown to freeze hardware (mask
interrupt, stop DMA engine and free DMA resources).

Signed-off-by: Prabhakar Kushwaha <pkushwaha@marvell.com>
---
 drivers/ata/ahci.c        |  8 ++++++++
 drivers/ata/libata-core.c | 21 +++++++++++++++++++++
 include/linux/libata.h    |  1 +
 3 files changed, 30 insertions(+)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 4bfd1b14b390..31fc934740b6 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -81,6 +81,7 @@ enum board_ids {
 
 static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);
 static void ahci_remove_one(struct pci_dev *dev);
+static void ahci_shutdown_one(struct pci_dev *dev);
 static int ahci_vt8251_hardreset(struct ata_link *link, unsigned int *class,
 				 unsigned long deadline);
 static int ahci_avn_hardreset(struct ata_link *link, unsigned int *class,
@@ -606,6 +607,7 @@ static struct pci_driver ahci_pci_driver = {
 	.id_table		= ahci_pci_tbl,
 	.probe			= ahci_init_one,
 	.remove			= ahci_remove_one,
+	.shutdown		= ahci_shutdown_one,
 	.driver = {
 		.pm		= &ahci_pci_pm_ops,
 	},
@@ -626,6 +628,7 @@ MODULE_PARM_DESC(mobile_lpm_policy, "Default LPM policy for mobile chipsets");
 static void ahci_pci_save_initial_config(struct pci_dev *pdev,
 					 struct ahci_host_priv *hpriv)
 {
+
 	if (pdev->vendor == PCI_VENDOR_ID_JMICRON && pdev->device == 0x2361) {
 		dev_info(&pdev->dev, "JMB361 has only one port\n");
 		hpriv->force_port_map = 1;
@@ -1877,6 +1880,11 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	return 0;
 }
 
+static void ahci_shutdown_one(struct pci_dev *pdev)
+{
+	ata_pci_shutdown_one(pdev);
+}
+
 static void ahci_remove_one(struct pci_dev *pdev)
 {
 	pm_runtime_get_noresume(&pdev->dev);
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 6f4ab5c5b52d..42c8728f6117 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6767,6 +6767,26 @@ void ata_pci_remove_one(struct pci_dev *pdev)
 	ata_host_detach(host);
 }
 
+void ata_pci_shutdown_one(struct pci_dev *pdev)
+{
+	struct ata_host *host = pci_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < host->n_ports; i++) {
+		struct ata_port *ap = host->ports[i];
+
+		ap->pflags |= ATA_PFLAG_FROZEN;
+
+		/* Disable port interrupts */
+		if (ap->ops->freeze)
+			ap->ops->freeze(ap);
+
+		/* Stop the port DMA engines */
+		if (ap->ops->port_stop)
+			ap->ops->port_stop(ap);
+	}
+}
+
 /* move to PCI subsystem */
 int pci_test_config_bits(struct pci_dev *pdev, const struct pci_bits *bits)
 {
@@ -7387,6 +7407,7 @@ EXPORT_SYMBOL_GPL(ata_timing_cycle2mode);
 
 #ifdef CONFIG_PCI
 EXPORT_SYMBOL_GPL(pci_test_config_bits);
+EXPORT_SYMBOL_GPL(ata_pci_shutdown_one);
 EXPORT_SYMBOL_GPL(ata_pci_remove_one);
 #ifdef CONFIG_PM
 EXPORT_SYMBOL_GPL(ata_pci_device_do_suspend);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 2dbde119721d..bff539918d82 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1221,6 +1221,7 @@ struct pci_bits {
 };
 
 extern int pci_test_config_bits(struct pci_dev *pdev, const struct pci_bits *bits);
+extern void ata_pci_shutdown_one(struct pci_dev *pdev);
 extern void ata_pci_remove_one(struct pci_dev *pdev);
 
 #ifdef CONFIG_PM
-- 
2.17.1