1 files changed, 81 insertions, 50 deletions

diff --git a/drivers/ata/sata_nv.c b/drivers/ata/sata_nv.c
index 6cda12ba8122..b2d11f300c39 100644
--- a/drivers/ata/sata_nv.c
+++ b/drivers/ata/sata_nv.c
@@ -305,8 +305,8 @@ static irqreturn_t nv_ck804_interrupt(int irq, void *dev_instance);
 static int nv_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val);
 static int nv_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val);
 
-static int nv_noclassify_hardreset(struct ata_link *link, unsigned int *class,
-                                   unsigned long deadline);
+static int nv_hardreset(struct ata_link *link, unsigned int *class,
+                        unsigned long deadline);
 static void nv_nf2_freeze(struct ata_port *ap);
 static void nv_nf2_thaw(struct ata_port *ap);
 static void nv_ck804_freeze(struct ata_port *ap);
@@ -406,49 +406,82 @@ static struct scsi_host_template nv_swncq_sht = {
         .slave_configure        = nv_swncq_slave_config,
 };
 
-static struct ata_port_operations nv_common_ops = {
+/*
+ * NV SATA controllers have various different problems with hardreset
+ * protocol depending on the specific controller and device.
+ *
+ * GENERIC:
+ *
+ *  bko11195 reports that link doesn't come online after hardreset on
+ *  generic nv's and there have been several other similar reports on
+ *  linux-ide.
+ *
+ *  bko12351#c23 reports that warmplug on MCP61 doesn't work with
+ *  softreset.
+ *
+ * NF2/3:
+ *
+ *  bko3352 reports nf2/3 controllers can't determine device signature
+ *  reliably after hardreset.  The following thread reports detection
+ *  failure on cold boot with the standard debouncing timing.
+ *
+ *  http://thread.gmane.org/gmane.linux.ide/34098
+ *
+ *  bko12176 reports that hardreset fails to bring up the link during
+ *  boot on nf2.
+ *
+ * CK804:
+ *
+ *  For initial probing after boot and hot plugging, hardreset mostly
+ *  works fine on CK804 but curiously, reprobing on the initial port
+ *  by rescanning or rmmod/insmod fails to acquire the initial D2H Reg
+ *  FIS in somewhat undeterministic way.
+ *
+ * SWNCQ:
+ *
+ *  bko12351 reports that when SWNCQ is enabled, for hotplug to work,
+ *  hardreset should be used and hardreset can't report proper
+ *  signature, which suggests that mcp5x is closer to nf2 as long as
+ *  reset quirkiness is concerned.
+ *
+ *  bko12703 reports that boot probing fails for intel SSD with
+ *  hardreset.  Link fails to come online.  Softreset works fine.
+ *
+ * The failures are varied but the following patterns seem true for
+ * all flavors.
+ *
+ * - Softreset during boot always works.
+ *
+ * - Hardreset during boot sometimes fails to bring up the link on
+ *   certain comibnations and device signature acquisition is
+ *   unreliable.
+ *
+ * - Hardreset is often necessary after hotplug.
+ *
+ * So, preferring softreset for boot probing and error handling (as
+ * hardreset might bring down the link) but using hardreset for
+ * post-boot probing should work around the above issues in most
+ * cases.  Define nv_hardreset() which only kicks in for post-boot
+ * probing and use it for all variants.
+ */
+static struct ata_port_operations nv_generic_ops = {
         .inherits               = &ata_bmdma_port_ops,
         .lost_interrupt         = ATA_OP_NULL,
         .scr_read               = nv_scr_read,
         .scr_write              = nv_scr_write,
+        .hardreset              = nv_hardreset,
 };
 
-/* OSDL bz11195 reports that link doesn't come online after hardreset
- * on generic nv's and there have been several other similar reports
- * on linux-ide.  Disable hardreset for generic nv's.
- */
-static struct ata_port_operations nv_generic_ops = {
-        .inherits               = &nv_common_ops,
-        .hardreset              = ATA_OP_NULL,
-};
-
-/* nf2 is ripe with hardreset related problems.
- *
- * kernel bz#3352 reports nf2/3 controllers can't determine device
- * signature reliably.  The following thread reports detection failure
- * on cold boot with the standard debouncing timing.
- *
- * http://thread.gmane.org/gmane.linux.ide/34098
- *
- * And bz#12176 reports that hardreset simply doesn't work on nf2.
- * Give up on it and just don't do hardreset.
- */
 static struct ata_port_operations nv_nf2_ops = {
         .inherits               = &nv_generic_ops,
         .freeze                 = nv_nf2_freeze,
         .thaw                   = nv_nf2_thaw,
 };
 
-/* For initial probing after boot and hot plugging, hardreset mostly
- * works fine on CK804 but curiously, reprobing on the initial port by
- * rescanning or rmmod/insmod fails to acquire the initial D2H Reg FIS
- * in somewhat undeterministic way.  Use noclassify hardreset.
- */
 static struct ata_port_operations nv_ck804_ops = {
-        .inherits               = &nv_common_ops,
+        .inherits               = &nv_generic_ops,
         .freeze                 = nv_ck804_freeze,
         .thaw                   = nv_ck804_thaw,
-        .hardreset              = nv_noclassify_hardreset,
         .host_stop              = nv_ck804_host_stop,
 };
 
@@ -476,19 +509,8 @@ static struct ata_port_operations nv_adma_ops = {
         .host_stop              = nv_adma_host_stop,
 };
 
-/* Kernel bz#12351 reports that when SWNCQ is enabled, for hotplug to
- * work, hardreset should be used and hardreset can't report proper
- * signature, which suggests that mcp5x is closer to nf2 as long as
- * reset quirkiness is concerned.  Define separate ops for mcp5x with
- * nv_noclassify_hardreset().
- */
-static struct ata_port_operations nv_mcp5x_ops = {
-        .inherits               = &nv_common_ops,
-        .hardreset              = nv_noclassify_hardreset,
-};
-
 static struct ata_port_operations nv_swncq_ops = {
-        .inherits               = &nv_mcp5x_ops,
+        .inherits               = &nv_generic_ops,
 
         .qc_defer               = ata_std_qc_defer,
         .qc_prep                = nv_swncq_qc_prep,
@@ -557,7 +579,7 @@ static const struct ata_port_info nv_port_info[] = {
                 .pio_mask       = NV_PIO_MASK,
                 .mwdma_mask     = NV_MWDMA_MASK,
                 .udma_mask      = NV_UDMA_MASK,
-                .port_ops       = &nv_mcp5x_ops,
+                .port_ops       = &nv_generic_ops,
                 .private_data   = NV_PI_PRIV(nv_generic_interrupt, &nv_sht),
         },
         /* SWNCQ */
@@ -1559,15 +1581,24 @@ static int nv_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val)
         return 0;
 }
 
-static int nv_noclassify_hardreset(struct ata_link *link, unsigned int *class,
-                                   unsigned long deadline)
+static int nv_hardreset(struct ata_link *link, unsigned int *class,
+                        unsigned long deadline)
 {
-        bool online;
-        int rc;
+        struct ata_eh_context *ehc = &link->eh_context;
 
-        rc = sata_link_hardreset(link, sata_deb_timing_hotplug, deadline,
-                                 &online, NULL);
-        return online ? -EAGAIN : rc;
+        /* Do hardreset iff it's post-boot probing, please read the
+         * comment above port ops for details.
+         */
+        if (!(link->ap->pflags & ATA_PFLAG_LOADING) &&
+            !ata_dev_enabled(link->device))
+                sata_link_hardreset(link, sata_deb_timing_hotplug, deadline,
+                                    NULL, NULL);
+        else if (!(ehc->i.flags & ATA_EHI_QUIET))
+                ata_link_printk(link, KERN_INFO,
+                                "nv: skipping hardreset on occupied port\n");
+
+        /* device signature acquisition is unreliable */
+        return -EAGAIN;
 }
 
 static void nv_nf2_freeze(struct ata_port *ap)