ahci: avoton port-disable reset-quirk

commit dbfe8ef5599a5370abc441fcdbb382b656563eb4 upstream.

Avoton AHCI occasionally sees drive probe timeouts at driver load time.
When this happens SCR_STATUS indicates device detected, but no D2H FIS
reception.  Reset the internal link state machines by bouncing
port-enable in the PCS register when this occurs.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
[bwh: Backported to 3.2:
 - Adjust context
 - Call ahci_start_engine() directly]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 81f32e5..e2958aa 100644 (file)
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -67,6 +67,7 @@ enum board_ids {
        board_ahci_yes_fbs,
 
        /* board IDs for specific chipsets in alphabetical order */
+       board_ahci_avn,
        board_ahci_mcp65,
        board_ahci_mcp77,
        board_ahci_mcp89,
@@ -85,6 +86,8 @@ enum board_ids {
 static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);
 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,
+                             unsigned long deadline);
 static int ahci_p5wdh_hardreset(struct ata_link *link, unsigned int *class,
                                unsigned long deadline);
 #ifdef CONFIG_PM
@@ -108,6 +111,11 @@ static struct ata_port_operations ahci_p5wdh_ops = {
 
 #define AHCI_HFLAGS(flags)     .private_data   = (void *)(flags)
 
+static struct ata_port_operations ahci_avn_ops = {
+       .inherits               = &ahci_ops,
+       .hardreset              = ahci_avn_hardreset,
+};
+
 static const struct ata_port_info ahci_port_info[] = {
        /* by features */
        [board_ahci] =
@@ -156,6 +164,12 @@ static const struct ata_port_info ahci_port_info[] = {
                .port_ops       = &ahci_ops,
        },
        /* by chipsets */
+       [board_ahci_avn] = {
+               .flags          = AHCI_FLAG_COMMON,
+               .pio_mask       = ATA_PIO4,
+               .udma_mask      = ATA_UDMA6,
+               .port_ops       = &ahci_avn_ops,
+       },
        [board_ahci_mcp65] =
        {
                AHCI_HFLAGS     (AHCI_HFLAG_NO_FPDMA_AA | AHCI_HFLAG_NO_PMP |
@@ -302,14 +316,14 @@ static const struct pci_device_id ahci_pci_tbl[] = {
        { PCI_VDEVICE(INTEL, 0x1f27), board_ahci }, /* Avoton RAID */
        { PCI_VDEVICE(INTEL, 0x1f2e), board_ahci }, /* Avoton RAID */
        { PCI_VDEVICE(INTEL, 0x1f2f), board_ahci }, /* Avoton RAID */
-       { PCI_VDEVICE(INTEL, 0x1f32), board_ahci }, /* Avoton AHCI */
-       { PCI_VDEVICE(INTEL, 0x1f33), board_ahci }, /* Avoton AHCI */
-       { PCI_VDEVICE(INTEL, 0x1f34), board_ahci }, /* Avoton RAID */
-       { PCI_VDEVICE(INTEL, 0x1f35), board_ahci }, /* Avoton RAID */
-       { PCI_VDEVICE(INTEL, 0x1f36), board_ahci }, /* Avoton RAID */
-       { PCI_VDEVICE(INTEL, 0x1f37), board_ahci }, /* Avoton RAID */
-       { PCI_VDEVICE(INTEL, 0x1f3e), board_ahci }, /* Avoton RAID */
-       { PCI_VDEVICE(INTEL, 0x1f3f), board_ahci }, /* Avoton RAID */
+       { PCI_VDEVICE(INTEL, 0x1f32), board_ahci_avn }, /* Avoton AHCI */
+       { PCI_VDEVICE(INTEL, 0x1f33), board_ahci_avn }, /* Avoton AHCI */
+       { PCI_VDEVICE(INTEL, 0x1f34), board_ahci_avn }, /* Avoton RAID */
+       { PCI_VDEVICE(INTEL, 0x1f35), board_ahci_avn }, /* Avoton RAID */
+       { PCI_VDEVICE(INTEL, 0x1f36), board_ahci_avn }, /* Avoton RAID */
+       { PCI_VDEVICE(INTEL, 0x1f37), board_ahci_avn }, /* Avoton RAID */
+       { PCI_VDEVICE(INTEL, 0x1f3e), board_ahci_avn }, /* Avoton RAID */
+       { PCI_VDEVICE(INTEL, 0x1f3f), board_ahci_avn }, /* Avoton RAID */
        { PCI_VDEVICE(INTEL, 0x8d02), board_ahci }, /* Wellsburg AHCI */
        { PCI_VDEVICE(INTEL, 0x8d04), board_ahci }, /* Wellsburg RAID */
        { PCI_VDEVICE(INTEL, 0x8d06), board_ahci }, /* Wellsburg RAID */
@@ -680,6 +694,78 @@ static int ahci_p5wdh_hardreset(struct ata_link *link, unsigned int *class,
        return rc;
 }
 
+/*
+ * ahci_avn_hardreset - attempt more aggressive recovery of Avoton ports.
+ *
+ * It has been observed with some SSDs that the timing of events in the
+ * link synchronization phase can leave the port in a state that can not
+ * be recovered by a SATA-hard-reset alone.  The failing signature is
+ * SStatus.DET stuck at 1 ("Device presence detected but Phy
+ * communication not established").  It was found that unloading and
+ * reloading the driver when this problem occurs allows the drive
+ * connection to be recovered (DET advanced to 0x3).  The critical
+ * component of reloading the driver is that the port state machines are
+ * reset by bouncing "port enable" in the AHCI PCS configuration
+ * register.  So, reproduce that effect by bouncing a port whenever we
+ * see DET==1 after a reset.
+ */
+static int ahci_avn_hardreset(struct ata_link *link, unsigned int *class,
+                             unsigned long deadline)
+{
+       const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context);
+       struct ata_port *ap = link->ap;
+       struct ahci_port_priv *pp = ap->private_data;
+       u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
+       unsigned long tmo = deadline - jiffies;
+       struct ata_taskfile tf;
+       bool online;
+       int rc, i;
+
+       DPRINTK("ENTER\n");
+
+       ahci_stop_engine(ap);
+
+       for (i = 0; i < 2; i++) {
+               u16 val;
+               u32 sstatus;
+               int port = ap->port_no;
+               struct ata_host *host = ap->host;
+               struct pci_dev *pdev = to_pci_dev(host->dev);
+
+               /* clear D2H reception area to properly wait for D2H FIS */
+               ata_tf_init(link->device, &tf);
+               tf.command = ATA_BUSY;
+               ata_tf_to_fis(&tf, 0, 0, d2h_fis);
+
+               rc = sata_link_hardreset(link, timing, deadline, &online,
+                               ahci_check_ready);
+
+               if (sata_scr_read(link, SCR_STATUS, &sstatus) != 0 ||
+                               (sstatus & 0xf) != 1)
+                       break;
+
+               ata_link_printk(link, KERN_INFO, "avn bounce port%d\n",
+                               port);
+
+               pci_read_config_word(pdev, 0x92, &val);
+               val &= ~(1 << port);
+               pci_write_config_word(pdev, 0x92, val);
+               ata_msleep(ap, 1000);
+               val |= 1 << port;
+               pci_write_config_word(pdev, 0x92, val);
+               deadline += tmo;
+       }
+
+       ahci_start_engine(ap);
+
+       if (online)
+               *class = ahci_dev_classify(ap);
+
+       DPRINTK("EXIT, rc=%d, class=%u\n", rc, *class);
+       return rc;
+}
+
+
 #ifdef CONFIG_PM
 static int ahci_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg)
 {