USB: xhci: Wait for host to start running.

When the run bit is set in the xHCI command register, it may take a few
microseconds for the host to start running.  We cannot ring any doorbells
until the host is actually running, so wait until the status register says
the host is running.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Reported-by: Shinya Saito <shinya.saito.sx@renesas.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 79ccfe5f8ad010d8159fe1011bb4055aa1c9e51f..8a49c6716b69e26c81ac7d86909eaac171d1a67e 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -105,6 +105,33 @@ int xhci_halt(struct xhci_hcd *xhci)
                        STS_HALT, STS_HALT, XHCI_MAX_HALT_USEC);
 }
 
+/*
+ * Set the run bit and wait for the host to be running.
+ */
+int xhci_start(struct xhci_hcd *xhci)
+{
+       u32 temp;
+       int ret;
+
+       temp = xhci_readl(xhci, &xhci->op_regs->command);
+       temp |= (CMD_RUN);
+       xhci_dbg(xhci, "// Turn on HC, cmd = 0x%x.\n",
+                       temp);
+       xhci_writel(xhci, temp, &xhci->op_regs->command);
+
+       /*
+        * Wait for the HCHalted Status bit to be 0 to indicate the host is
+        * running.
+        */
+       ret = handshake(xhci, &xhci->op_regs->status,
+                       STS_HALT, 0, XHCI_MAX_HALT_USEC);
+       if (ret == -ETIMEDOUT)
+               xhci_err(xhci, "Host took too long to start, "
+                               "waited %u microseconds.\n",
+                               XHCI_MAX_HALT_USEC);
+       return ret;
+}
+
 /*
  * Reset a halted HC, and set the internal HC state to HC_STATE_HALT.
  *
@@ -460,13 +487,11 @@ int xhci_run(struct usb_hcd *hcd)
        if (NUM_TEST_NOOPS > 0)
                doorbell = xhci_setup_one_noop(xhci);
 
-       temp = xhci_readl(xhci, &xhci->op_regs->command);
-       temp |= (CMD_RUN);
-       xhci_dbg(xhci, "// Turn on HC, cmd = 0x%x.\n",
-                       temp);
-       xhci_writel(xhci, temp, &xhci->op_regs->command);
-       /* Flush PCI posted writes */
-       temp = xhci_readl(xhci, &xhci->op_regs->command);
+       if (xhci_start(xhci)) {
+               xhci_halt(xhci);
+               return -ENODEV;
+       }
+
        xhci_dbg(xhci, "// @%p = 0x%x\n", &xhci->op_regs->command, temp);
        if (doorbell)
                (*doorbell)(xhci);