USB: ehci-dbgp: Execute early BIOS hand off

The PCI quirk code executes a BIOS hand off to obtain full control of
the EHCI host controller, the self contained ehci-dbgp driver must do
the same thing using the early PCI API, else the BIOS can cause a
fatal fault.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: dbrownell@users.sourceforge.net
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 49 insertions, 0 deletions

diff --git a/drivers/usb/early/ehci-dbgp.c b/drivers/usb/early/ehci-dbgp.c
index 8de709ac0f55..7deae97fe50f 100644
--- a/drivers/usb/early/ehci-dbgp.c
+++ b/drivers/usb/early/ehci-dbgp.c
@@ -435,6 +435,53 @@ static void __init detect_set_debug_port(void)
         }
 }
 
+/* The code in early_ehci_bios_handoff() is derived from the usb pci
+ * quirk initialization, but altered so as to use the early PCI
+ * routines. */
+#define EHCI_USBLEGSUP_BIOS     (1 << 16)       /* BIOS semaphore */
+#define EHCI_USBLEGCTLSTS       4               /* legacy control/status */
+static void __init early_ehci_bios_handoff(void)
+{
+        u32 hcc_params = readl(&ehci_caps->hcc_params);
+        int offset = (hcc_params >> 8) & 0xff;
+        u32 cap;
+        int msec;
+
+        if (!offset)
+                return;
+
+        cap = read_pci_config(ehci_dev.bus, ehci_dev.slot,
+                              ehci_dev.func, offset);
+        dbgp_printk("dbgp: ehci BIOS state %08x\n", cap);
+
+        if ((cap & 0xff) == 1 && (cap & EHCI_USBLEGSUP_BIOS)) {
+                dbgp_printk("dbgp: BIOS handoff\n");
+                write_pci_config_byte(ehci_dev.bus, ehci_dev.slot,
+                                      ehci_dev.func, offset + 3, 1);
+        }
+
+        /* if boot firmware now owns EHCI, spin till it hands it over. */
+        msec = 1000;
+        while ((cap & EHCI_USBLEGSUP_BIOS) && (msec > 0)) {
+                mdelay(10);
+                msec -= 10;
+                cap = read_pci_config(ehci_dev.bus, ehci_dev.slot,
+                                      ehci_dev.func, offset);
+        }
+
+        if (cap & EHCI_USBLEGSUP_BIOS) {
+                /* well, possibly buggy BIOS... try to shut it down,
+                 * and hope nothing goes too wrong */
+                dbgp_printk("dbgp: BIOS handoff failed: %08x\n", cap);
+                write_pci_config_byte(ehci_dev.bus, ehci_dev.slot,
+                                      ehci_dev.func, offset + 2, 0);
+        }
+
+        /* just in case, always disable EHCI SMIs */
+        write_pci_config_byte(ehci_dev.bus, ehci_dev.slot, ehci_dev.func,
+                              offset + EHCI_USBLEGCTLSTS, 0);
+}
+
 static int __init ehci_setup(void)
 {
         struct usb_debug_descriptor dbgp_desc;
@@ -446,6 +493,8 @@ static int __init ehci_setup(void)
         int port_map_tried;
         int playtimes = 3;
 
+        early_ehci_bios_handoff();
+
 try_next_time:
         port_map_tried = 0;