USB: xhci: BIOS handoff and HW initialization.

Add PCI initialization code to take control of the xHCI host controller
away from the BIOS, halt, and reset the host controller.  The xHCI spec
says that BIOSes must give up the host controller within 5 seconds.

Add some host controller glue functions to handle hardware initialization
and memory allocation for the host controller.  The current xHCI
prototypes use PCI interrupts, but the xHCI spec requires MSI-X
interrupts.  Add code to support MSI-X interrupts, but use the PCI
interrupts for now.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 123 insertions, 0 deletions

diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index 033c2846ce59..83b5f9cea85a 100644
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -15,6 +15,7 @@
 #include <linux/delay.h>
 #include <linux/acpi.h>
 #include "pci-quirks.h"
+#include "xhci-ext-caps.h"
 
 
 #define UHCI_USBLEGSUP          0xc0            /* legacy support */
@@ -341,7 +342,127 @@ static void __devinit quirk_usb_disable_ehci(struct pci_dev *pdev)
         return;
 }
 
+/*
+ * handshake - spin reading a register until handshake completes
+ * @ptr: address of hc register to be read
+ * @mask: bits to look at in result of read
+ * @done: value of those bits when handshake succeeds
+ * @wait_usec: timeout in microseconds
+ * @delay_usec: delay in microseconds to wait between polling
+ *
+ * Polls a register every delay_usec microseconds.
+ * Returns 0 when the mask bits have the value done.
+ * Returns -ETIMEDOUT if this condition is not true after
+ * wait_usec microseconds have passed.
+ */
+static int handshake(void __iomem *ptr, u32 mask, u32 done,
+                int wait_usec, int delay_usec)
+{
+        u32     result;
+
+        do {
+                result = readl(ptr);
+                result &= mask;
+                if (result == done)
+                        return 0;
+                udelay(delay_usec);
+                wait_usec -= delay_usec;
+        } while (wait_usec > 0);
+        return -ETIMEDOUT;
+}
+
+/**
+ * PCI Quirks for xHCI.
+ *
+ * Takes care of the handoff between the Pre-OS (i.e. BIOS) and the OS.
+ * It signals to the BIOS that the OS wants control of the host controller,
+ * and then waits 5 seconds for the BIOS to hand over control.
+ * If we timeout, assume the BIOS is broken and take control anyway.
+ */
+static void __devinit quirk_usb_handoff_xhci(struct pci_dev *pdev)
+{
+        void __iomem *base;
+        int ext_cap_offset;
+        void __iomem *op_reg_base;
+        u32 val;
+        int timeout;
+
+        if (!mmio_resource_enabled(pdev, 0))
+                return;
+
+        base = ioremap_nocache(pci_resource_start(pdev, 0),
+                                pci_resource_len(pdev, 0));
+        if (base == NULL)
+                return;
 
+        /*
+         * Find the Legacy Support Capability register -
+         * this is optional for xHCI host controllers.
+         */
+        ext_cap_offset = xhci_find_next_cap_offset(base, XHCI_HCC_PARAMS_OFFSET);
+        do {
+                if (!ext_cap_offset)
+                        /* We've reached the end of the extended capabilities */
+                        goto hc_init;
+                val = readl(base + ext_cap_offset);
+                if (XHCI_EXT_CAPS_ID(val) == XHCI_EXT_CAPS_LEGACY)
+                        break;
+                ext_cap_offset = xhci_find_next_cap_offset(base, ext_cap_offset);
+        } while (1);
+
+        /* If the BIOS owns the HC, signal that the OS wants it, and wait */
+        if (val & XHCI_HC_BIOS_OWNED) {
+                writel(val & XHCI_HC_OS_OWNED, base + ext_cap_offset);
+
+                /* Wait for 5 seconds with 10 microsecond polling interval */
+                timeout = handshake(base + ext_cap_offset, XHCI_HC_BIOS_OWNED,
+                                0, 5000, 10);
+
+                /* Assume a buggy BIOS and take HC ownership anyway */
+                if (timeout) {
+                        dev_warn(&pdev->dev, "xHCI BIOS handoff failed"
+                                        " (BIOS bug ?) %08x\n", val);
+                        writel(val & ~XHCI_HC_BIOS_OWNED, base + ext_cap_offset);
+                }
+        }
+
+        /* Disable any BIOS SMIs */
+        writel(XHCI_LEGACY_DISABLE_SMI,
+                        base + ext_cap_offset + XHCI_LEGACY_CONTROL_OFFSET);
+
+hc_init:
+        op_reg_base = base + XHCI_HC_LENGTH(readl(base));
+
+        /* Wait for the host controller to be ready before writing any
+         * operational or runtime registers.  Wait 5 seconds and no more.
+         */
+        timeout = handshake(op_reg_base + XHCI_STS_OFFSET, XHCI_STS_CNR, 0,
+                        5000, 10);
+        /* Assume a buggy HC and start HC initialization anyway */
+        if (timeout) {
+                val = readl(op_reg_base + XHCI_STS_OFFSET);
+                dev_warn(&pdev->dev,
+                                "xHCI HW not ready after 5 sec (HC bug?) "
+                                "status = 0x%x\n", val);
+        }
+
+        /* Send the halt and disable interrupts command */
+        val = readl(op_reg_base + XHCI_CMD_OFFSET);
+        val &= ~(XHCI_CMD_RUN | XHCI_IRQS);
+        writel(val, op_reg_base + XHCI_CMD_OFFSET);
+
+        /* Wait for the HC to halt - poll every 125 usec (one microframe). */
+        timeout = handshake(op_reg_base + XHCI_STS_OFFSET, XHCI_STS_HALT, 1,
+                        XHCI_MAX_HALT_USEC, 125);
+        if (timeout) {
+                val = readl(op_reg_base + XHCI_STS_OFFSET);
+                dev_warn(&pdev->dev,
+                                "xHCI HW did not halt within %d usec "
+                                "status = 0x%x\n", XHCI_MAX_HALT_USEC, val);
+        }
+
+        iounmap(base);
+}
 
 static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev)
 {
@@ -351,5 +472,7 @@ static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev)
                 quirk_usb_handoff_ohci(pdev);
         else if (pdev->class == PCI_CLASS_SERIAL_USB_EHCI)
                 quirk_usb_disable_ehci(pdev);
+        else if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI)
+                quirk_usb_handoff_xhci(pdev);
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, quirk_usb_early_handoff);