ahci: Optimise AHCI controller reset and start-up

The existing code waits a whole second for the AHCI controller to reset.
Instead, let's poll the status register to see if the reset has
succeeded and return earlier if possible. This brings down the time for
AHCI probing from 1s to 20ms.

Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/block/ahci.c b/drivers/block/ahci.c
index d94da1f05a2fc4027e0a6c4ebb6a9480fd8bb7f3..ad397dcb6a1a3fa92c3efad710a8851dfb286a3d 100644 (file)
--- a/drivers/block/ahci.c
+++ b/drivers/block/ahci.c
@@ -110,13 +110,15 @@ static int ahci_host_init(struct ahci_probe_ent *probe_ent)
        /* reset must complete within 1 second, or
         * the hardware should be considered fried.
         */
-       ssleep(1);
-
-       tmp = readl(mmio + HOST_CTL);
-       if (tmp & HOST_RESET) {
-               debug("controller reset failed (0x%x)\n", tmp);
-               return -1;
-       }
+       i = 1000;
+       do {
+               udelay(1000);
+               tmp = readl(mmio + HOST_CTL);
+               if (!i--) {
+                       debug("controller reset failed (0x%x)\n", tmp);
+                       return -1;
+               }
+       } while (tmp & HOST_RESET);
 
        writel_with_flush(HOST_AHCI_EN, mmio + HOST_CTL);
        writel(cap_save, mmio + HOST_CAP);
@@ -164,13 +166,17 @@ static int ahci_host_init(struct ahci_probe_ent *probe_ent)
                writel(PORT_CMD_SPIN_UP, port_mmio + PORT_CMD);
 
                j = 0;
-               while (j < 100) {
-                       msleep(10);
+               while (j < 1000) {
                        tmp = readl(port_mmio + PORT_SCR_STAT);
                        if ((tmp & 0xf) == 0x3)
                                break;
+                       udelay(1000);
                        j++;
                }
+               if (j == 1000)
+                       debug("timeout.\n");
+               else
+                       debug("ok.\n");
 
                tmp = readl(port_mmio + PORT_SCR_ERR);
                debug("PORT_SCR_ERR 0x%x\n", tmp);