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 d94da1f..ad397dc 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);