ahci_xgene: Implement the xgene_ahci_poll_reg_val to support PMP.
This patch implements the function xgene_ahci_poll_reg_val
to poll PxCI for multiple IDENTIFY DEVICE commands to finish before
restarting the DMA engine.
Signed-off-by: Suman Tripathi <stripathi@apm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/ata/ahci_xgene.c b/drivers/ata/ahci_xgene.c
index cbcd208..afa9c03 100644
--- a/drivers/ata/ahci_xgene.c
+++ b/drivers/ata/ahci_xgene.c
@@ -105,17 +105,69 @@
}
/**
+ * xgene_ahci_poll_reg_val- Poll a register on a specific value.
+ * @ap : ATA port of interest.
+ * @reg : Register of interest.
+ * @val : Value to be attained.
+ * @interval : waiting interval for polling.
+ * @timeout : timeout for achieving the value.
+ */
+static int xgene_ahci_poll_reg_val(struct ata_port *ap,
+ void __iomem *reg, unsigned
+ int val, unsigned long interval,
+ unsigned long timeout)
+{
+ unsigned long deadline;
+ unsigned int tmp;
+
+ tmp = ioread32(reg);
+ deadline = ata_deadline(jiffies, timeout);
+
+ while (tmp != val && time_before(jiffies, deadline)) {
+ ata_msleep(ap, interval);
+ tmp = ioread32(reg);
+ }
+
+ return tmp;
+}
+
+/**
* xgene_ahci_restart_engine - Restart the dma engine.
* @ap : ATA port of interest
*
- * Restarts the dma engine inside the controller.
+ * Waits for completion of multiple commands and 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;
+ struct ahci_port_priv *pp = ap->private_data;
+ void __iomem *port_mmio = ahci_port_base(ap);
+ u32 fbs;
+
+ /*
+ * In case of PMP multiple IDENTIFY DEVICE commands can be
+ * issued inside PxCI. So need to poll PxCI for the
+ * completion of outstanding IDENTIFY DEVICE commands before
+ * we restart the DMA engine.
+ */
+ if (xgene_ahci_poll_reg_val(ap, port_mmio +
+ PORT_CMD_ISSUE, 0x0, 1, 100))
+ return -EBUSY;
ahci_stop_engine(ap);
ahci_start_fis_rx(ap);
+
+ /*
+ * Enable the PxFBS.FBS_EN bit as it
+ * gets cleared due to stopping the engine.
+ */
+ if (pp->fbs_supported) {
+ fbs = readl(port_mmio + PORT_FBS);
+ writel(fbs | PORT_FBS_EN, port_mmio + PORT_FBS);
+ fbs = readl(port_mmio + PORT_FBS);
+ }
+
hpriv->start_engine(ap);
return 0;
@@ -374,7 +426,7 @@
};
static const struct ata_port_info xgene_ahci_port_info = {
- .flags = AHCI_FLAG_COMMON,
+ .flags = AHCI_FLAG_COMMON | ATA_FLAG_PMP,
.pio_mask = ATA_PIO4,
.udma_mask = ATA_UDMA6,
.port_ops = &xgene_ahci_ops,