[PATCH] ahci: Add support for EEH error recovery

[wenxiong@linux.vnet.ibm.com]

From: Wen Xiong <wenxiong@linux.vnet.ibm.com>

This patch adds the callback functions to support EEH error
recovery in ahci driver. Also adds the code in ahci_error_handler
to issue an MMIO load then check if it is in EEH. If it is in EEH,
ahci_error_handler will wait until EEH recovery is completed.

Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
---
 drivers/ata/ahci.c    |   70 +++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/ata/ahci.h    |    3 ++
 drivers/ata/libahci.c |   11 +++++++
 3 files changed, 84 insertions(+), 0 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 65ee944..0184677 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -96,6 +96,10 @@ static int ahci_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg);
 static int ahci_pci_device_resume(struct pci_dev *pdev);
 #endif
 
+static pci_ers_result_t ahci_pci_error_detected(struct pci_dev *pdev,
+					       pci_channel_state_t state);
+static pci_ers_result_t ahci_pci_slot_reset(struct pci_dev *pdev);
+
 static struct scsi_host_template ahci_sht = {
 	AHCI_SHT("ahci"),
 };
@@ -520,6 +524,10 @@ static const struct pci_device_id ahci_pci_tbl[] = {
 	{ }	/* terminate list */
 };
 
+static const struct pci_error_handlers ahci_err_handler = {
+	.error_detected = ahci_pci_error_detected,
+	.slot_reset = ahci_pci_slot_reset,
+};
 
 static struct pci_driver ahci_pci_driver = {
 	.name			= DRV_NAME,
@@ -530,6 +538,7 @@ static struct pci_driver ahci_pci_driver = {
 	.suspend		= ahci_pci_device_suspend,
 	.resume			= ahci_pci_device_resume,
 #endif
+	.err_handler		= &ahci_err_handler,
 };
 
 #if defined(CONFIG_PATA_MARVELL) || defined(CONFIG_PATA_MARVELL_MODULE)
@@ -813,6 +822,64 @@ static int ahci_pci_device_resume(struct pci_dev *pdev)
 }
 #endif
 
+/**
+ * ahci_pci_error_detected - Called when a PCI error is detected.
+ * @pdev:	PCI device struct
+ * @state:	PCI channel state
+ *
+ * Description: Called when a PCI error is detected.
+ *
+ * Return value:
+ * PCI_ERS_RESULT_NEED_RESET or PCI_ERS_RESULT_DISCONNECT
+ */
+static pci_ers_result_t ahci_pci_error_detected(struct pci_dev *pdev,
+					       pci_channel_state_t state)
+{
+	struct ata_host *host = pci_get_drvdata(pdev);
+	int i;
+
+	if (state == pci_channel_io_perm_failure)
+		return PCI_ERS_RESULT_DISCONNECT;
+
+	for (i = 0; i < host->n_ports; i++)
+		scsi_block_requests(host->ports[i]->scsi_host);
+
+	return PCI_ERS_RESULT_NEED_RESET;
+
+}
+
+/**
+ * ahci_pci_slot_reset - Called when PCI slot has been reset.
+ * @pdev:	PCI device struct
+ *
+ * Description: This routine is called by the pci error recovery
+ * code after the PCI slot has been reset, just before we
+ * should resume normal operations.
+ */
+static pci_ers_result_t ahci_pci_slot_reset(struct pci_dev *pdev)
+{
+	struct ata_host *host = pci_get_drvdata(pdev);
+	struct ahci_host_priv *hpriv = host->private_data;
+	int i, rc;
+
+	pci_restore_state(pdev);
+
+	pci_save_state(pdev);
+
+	rc = ahci_pci_reset_controller(host);
+	if (rc)
+		return PCI_ERS_RESULT_DISCONNECT;
+
+	ahci_pci_init_controller(host);
+
+	for (i = 0; i < host->n_ports; i++)
+		scsi_unblock_requests(host->ports[i]->scsi_host);
+
+	wake_up_all(&hpriv->eeh_wait_q);
+
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
 static int ahci_configure_dma_masks(struct pci_dev *pdev, int using_dac)
 {
 	int rc;
@@ -1439,6 +1506,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar];
 
+	init_waitqueue_head(&hpriv->eeh_wait_q);
 	/* must set flag prior to save config in order to take effect */
 	if (ahci_broken_devslp(pdev))
 		hpriv->flags |= AHCI_HFLAG_NO_DEVSLP;
@@ -1549,6 +1617,8 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	pci_set_master(pdev);
 
+	pci_save_state(pdev);
+
 	return ahci_host_activate(host, pdev->irq, &ahci_sht);
 }
 
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 71262e0..6bbf747 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -51,6 +51,8 @@
 #define EM_MSG_LED_VALUE_OFF          0xfff80000
 #define EM_MSG_LED_VALUE_ON           0x00010000
 
+#define AHCI_PCI_ERROR_RECOVERY_TIMEOUT	(120 * HZ)
+
 enum {
 	AHCI_MAX_PORTS		= 32,
 	AHCI_MAX_CLKS		= 5,
@@ -341,6 +343,7 @@ struct ahci_host_priv {
 	struct phy		**phys;
 	unsigned		nports;		/* Number of ports */
 	void			*plat_data;	/* Other platform data */
+	wait_queue_head_t	eeh_wait_q;
 	/*
 	 * Optional ahci_start_engine override, if not set this gets set to the
 	 * default ahci_start_engine during ahci_save_initial_config, this can
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 287c4ba..bd7422a 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -43,6 +43,7 @@
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_cmnd.h>
 #include <linux/libata.h>
+#include <linux/pci.h>
 #include "ahci.h"
 #include "libata.h"
 
@@ -1968,6 +1969,16 @@ static void ahci_thaw(struct ata_port *ap)
 void ahci_error_handler(struct ata_port *ap)
 {
 	struct ahci_host_priv *hpriv = ap->host->private_data;
+	void __iomem *mmio = hpriv->mmio;
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	u32 irq_stat;
+
+	irq_stat = readl(mmio + HOST_IRQ_STAT);
+
+	if (pci_channel_offline(pdev))
+		wait_event_timeout(hpriv->eeh_wait_q,
+				!pci_channel_offline(pdev),
+				AHCI_PCI_ERROR_RECOVERY_TIMEOUT);
 
 	if (!(ap->pflags & ATA_PFLAG_FROZEN)) {
 		/* restart engine */
-- 
1.7.1