Merge branch 'for-3.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata into for-3.17

The scheduled ahci platform patches depend on change in
for-3.16-fixes.  Pull it into for-3.17.

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 47 insertions, 13 deletions

diff --git a/drivers/ata/ahci_xgene.c b/drivers/ata/ahci_xgene.c
index 997b4178249a..1cfbdca638d2 100644
--- a/drivers/ata/ahci_xgene.c
+++ b/drivers/ata/ahci_xgene.c
@@ -81,6 +81,7 @@
 struct xgene_ahci_context {
         struct ahci_host_priv *hpriv;
         struct device *dev;
+        u8 last_cmd[MAX_AHCI_CHN_PERCTR]; /* tracking the last command issued*/
         void __iomem *csr_core;         /* Core CSR address of IP */
         void __iomem *csr_diag;         /* Diag CSR address of IP */
         void __iomem *csr_axi;          /* AXI CSR address of IP */
@@ -101,20 +102,62 @@ static int xgene_ahci_init_memram(struct xgene_ahci_context *ctx)
 }
 
 /**
+ * xgene_ahci_restart_engine - Restart the dma engine.
+ * @ap : ATA port of interest
+ *
+ * Restarts the dma engine inside the controller.
+ */
+static int xgene_ahci_restart_engine(struct ata_port *ap)
+{
+        struct ahci_host_priv *hpriv = ap->host->private_data;
+
+        ahci_stop_engine(ap);
+        ahci_start_fis_rx(ap);
+        hpriv->start_engine(ap);
+
+        return 0;
+}
+
+/**
+ * xgene_ahci_qc_issue - Issue commands to the device
+ * @qc: Command to issue
+ *
+ * Due to Hardware errata for IDENTIFY DEVICE command, the controller cannot
+ * clear the BSY bit after receiving the PIO setup FIS. This results in the dma
+ * state machine goes into the CMFatalErrorUpdate state and locks up. By
+ * restarting the dma engine, it removes the controller out of lock up state.
+ */
+static unsigned int xgene_ahci_qc_issue(struct ata_queued_cmd *qc)
+{
+        struct ata_port *ap = qc->ap;
+        struct ahci_host_priv *hpriv = ap->host->private_data;
+        struct xgene_ahci_context *ctx = hpriv->plat_data;
+        int rc = 0;
+
+        if (unlikely(ctx->last_cmd[ap->port_no] == ATA_CMD_ID_ATA))
+                xgene_ahci_restart_engine(ap);
+
+        rc = ahci_qc_issue(qc);
+
+        /* Save the last command issued */
+        ctx->last_cmd[ap->port_no] = qc->tf.command;
+
+        return rc;
+}
+
+/**
  * xgene_ahci_read_id - Read ID data from the specified device
  * @dev: device
  * @tf: proposed taskfile
  * @id: data buffer
  *
  * This custom read ID function is required due to the fact that the HW
- * does not support DEVSLP and the controller state machine may get stuck
- * after processing the ID query command.
+ * does not support DEVSLP.
  */
 static unsigned int xgene_ahci_read_id(struct ata_device *dev,
                                        struct ata_taskfile *tf, u16 *id)
 {
         u32 err_mask;
-        void __iomem *port_mmio = ahci_port_base(dev->link->ap);
 
         err_mask = ata_do_dev_read_id(dev, tf, id);
         if (err_mask)
@@ -136,16 +179,6 @@ static unsigned int xgene_ahci_read_id(struct ata_device *dev,
          */
         id[ATA_ID_FEATURE_SUPP] &= ~(1 << 8);
 
-        /*
-         * Due to HW errata, restart the port if no other command active.
-         * Otherwise the controller may get stuck.
-         */
-        if (!readl(port_mmio + PORT_CMD_ISSUE)) {
-                writel(PORT_CMD_FIS_RX, port_mmio + PORT_CMD);
-                readl(port_mmio + PORT_CMD);    /* Force a barrier */
-                writel(PORT_CMD_FIS_RX | PORT_CMD_START, port_mmio + PORT_CMD);
-                readl(port_mmio + PORT_CMD);    /* Force a barrier */
-        }
         return 0;
 }
 
@@ -307,6 +340,7 @@ static struct ata_port_operations xgene_ahci_ops = {
         .host_stop = xgene_ahci_host_stop,
         .hardreset = xgene_ahci_hardreset,
         .read_id = xgene_ahci_read_id,
+        .qc_issue = xgene_ahci_qc_issue,
 };
 
 static const struct ata_port_info xgene_ahci_port_info = {