[xhci] Forcibly disable SMIs if BIOS fails to release ownership

If the BIOS fails to gracefully release ownership of the xHCI
controller, we can forcibly claim it by disabling all SMIs via the
USB legacy support control/status register.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/drivers/usb/xhci.c b/src/drivers/usb/xhci.c
index 34290774a93d83539d3e2157d7807c2e8d48e3ed..6306e158058d13a6c16ba18538cc51a3c2573dcf 100644 (file)
--- a/src/drivers/usb/xhci.c
+++ b/src/drivers/usb/xhci.c
@@ -556,16 +556,15 @@ static void xhci_legacy_init ( struct xhci_device *xhci ) {
  * Claim ownership from BIOS
  *
  * @v xhci             xHCI device
- * @ret rc             Return status code
  */
-static int xhci_legacy_claim ( struct xhci_device *xhci ) {
+static void xhci_legacy_claim ( struct xhci_device *xhci ) {
        uint32_t ctlsts;
        uint8_t bios;
        unsigned int i;
 
        /* Do nothing unless legacy support capability is present */
        if ( ! xhci->legacy )
-               return 0;
+               return;
 
        /* Claim ownership */
        writeb ( XHCI_USBLEGSUP_OS_OWNED,
@@ -585,16 +584,19 @@ static int xhci_legacy_claim ( struct xhci_device *xhci ) {
                                DBGC ( xhci, "XHCI %p warning: BIOS retained "
                                       "SMIs: %08x\n", xhci, ctlsts );
                        }
-                       return 0;
+                       return;
                }
 
                /* Delay */
                mdelay ( 1 );
        }
 
-       DBGC ( xhci, "XHCI %p timed out waiting for BIOS to release "
-              "ownership\n", xhci );
-       return -ETIMEDOUT;
+       /* BIOS did not release ownership.  Claim it forcibly by
+        * disabling all SMIs.
+        */
+       DBGC ( xhci, "XHCI %p could not claim ownership from BIOS: forcibly "
+              "disabling SMIs\n", xhci );
+       writel ( 0, xhci->cap + xhci->legacy + XHCI_USBLEGSUP_CTLSTS );
 }
 
 /**
@@ -3105,8 +3107,7 @@ static int xhci_probe ( struct pci_device *pci ) {
 
        /* Initialise USB legacy support and claim ownership */
        xhci_legacy_init ( xhci );
-       if ( ( rc = xhci_legacy_claim ( xhci ) ) != 0 )
-               goto err_legacy_claim;
+       xhci_legacy_claim ( xhci );
 
        /* Fix Intel PCH-specific quirks, if applicable */
        if ( pci->id->driver_data & XHCI_PCH )
@@ -3148,7 +3149,6 @@ static int xhci_probe ( struct pci_device *pci ) {
        if ( pci->id->driver_data & XHCI_PCH )
                xhci_pch_undo ( xhci, pci );
        xhci_legacy_release ( xhci );
- err_legacy_claim:
        iounmap ( xhci->regs );
  err_ioremap:
        free ( xhci );