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, 377 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
new file mode 100644
index 000000000000..64fcc22e9d59
--- /dev/null
+++ b/drivers/usb/host/xhci-hcd.c
@@ -0,0 +1,377 @@
+/*
+ * xHCI host controller driver
+ *
+ * Copyright (C) 2008 Intel Corp.
+ *
+ * Author: Sarah Sharp
+ * Some code borrowed from the Linux EHCI driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+
+#include "xhci.h"
+
+#define DRIVER_AUTHOR "Sarah Sharp"
+#define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver"
+
+/* TODO: copied from ehci-hcd.c - can this be refactored? */
+/*
+ * handshake - spin reading hc until handshake completes or fails
+ * @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
+ * @usec: timeout in microseconds
+ *
+ * Returns negative errno, or zero on success
+ *
+ * Success happens when the "mask" bits have the specified value (hardware
+ * handshake done).  There are two failure modes:  "usec" have passed (major
+ * hardware flakeout), or the register reads as all-ones (hardware removed).
+ */
+static int handshake(struct xhci_hcd *xhci, void __iomem *ptr,
+                      u32 mask, u32 done, int usec)
+{
+        u32     result;
+
+        do {
+                result = xhci_readl(xhci, ptr);
+                if (result == ~(u32)0)          /* card removed */
+                        return -ENODEV;
+                result &= mask;
+                if (result == done)
+                        return 0;
+                udelay(1);
+                usec--;
+        } while (usec > 0);
+        return -ETIMEDOUT;
+}
+
+/*
+ * Force HC into halt state.
+ *
+ * Disable any IRQs and clear the run/stop bit.
+ * HC will complete any current and actively pipelined transactions, and
+ * should halt within 16 microframes of the run/stop bit being cleared.
+ * Read HC Halted bit in the status register to see when the HC is finished.
+ * XXX: shouldn't we set HC_STATE_HALT here somewhere?
+ */
+int xhci_halt(struct xhci_hcd *xhci)
+{
+        u32 halted;
+        u32 cmd;
+        u32 mask;
+
+        xhci_dbg(xhci, "// Halt the HC\n");
+        /* Disable all interrupts from the host controller */
+        mask = ~(XHCI_IRQS);
+        halted = xhci_readl(xhci, &xhci->op_regs->status) & STS_HALT;
+        if (!halted)
+                mask &= ~CMD_RUN;
+
+        cmd = xhci_readl(xhci, &xhci->op_regs->command);
+        cmd &= mask;
+        xhci_writel(xhci, cmd, &xhci->op_regs->command);
+
+        return handshake(xhci, &xhci->op_regs->status,
+                        STS_HALT, STS_HALT, XHCI_MAX_HALT_USEC);
+}
+
+/*
+ * Reset a halted HC, and set the internal HC state to HC_STATE_HALT.
+ *
+ * This resets pipelines, timers, counters, state machines, etc.
+ * Transactions will be terminated immediately, and operational registers
+ * will be set to their defaults.
+ */
+int xhci_reset(struct xhci_hcd *xhci)
+{
+        u32 command;
+        u32 state;
+
+        state = xhci_readl(xhci, &xhci->op_regs->status);
+        BUG_ON((state & STS_HALT) == 0);
+
+        xhci_dbg(xhci, "// Reset the HC\n");
+        command = xhci_readl(xhci, &xhci->op_regs->command);
+        command |= CMD_RESET;
+        xhci_writel(xhci, command, &xhci->op_regs->command);
+        /* XXX: Why does EHCI set this here?  Shouldn't other code do this? */
+        xhci_to_hcd(xhci)->state = HC_STATE_HALT;
+
+        return handshake(xhci, &xhci->op_regs->command, CMD_RESET, 0, 250 * 1000);
+}
+
+/*
+ * Stop the HC from processing the endpoint queues.
+ */
+static void xhci_quiesce(struct xhci_hcd *xhci)
+{
+        /*
+         * Queues are per endpoint, so we need to disable an endpoint or slot.
+         *
+         * To disable a slot, we need to insert a disable slot command on the
+         * command ring and ring the doorbell.  This will also free any internal
+         * resources associated with the slot (which might not be what we want).
+         *
+         * A Release Endpoint command sounds better - doesn't free internal HC
+         * memory, but removes the endpoints from the schedule and releases the
+         * bandwidth, disables the doorbells, and clears the endpoint enable
+         * flag.  Usually used prior to a set interface command.
+         *
+         * TODO: Implement after command ring code is done.
+         */
+        BUG_ON(!HC_IS_RUNNING(xhci_to_hcd(xhci)->state));
+        xhci_dbg(xhci, "Finished quiescing -- code not written yet\n");
+}
+
+#if 0
+/* Set up MSI-X table for entry 0 (may claim other entries later) */
+static int xhci_setup_msix(struct xhci_hcd *xhci)
+{
+        int ret;
+        struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
+
+        xhci->msix_count = 0;
+        /* XXX: did I do this right?  ixgbe does kcalloc for more than one */
+        xhci->msix_entries = kmalloc(sizeof(struct msix_entry), GFP_KERNEL);
+        if (!xhci->msix_entries) {
+                xhci_err(xhci, "Failed to allocate MSI-X entries\n");
+                return -ENOMEM;
+        }
+        xhci->msix_entries[0].entry = 0;
+
+        ret = pci_enable_msix(pdev, xhci->msix_entries, xhci->msix_count);
+        if (ret) {
+                xhci_err(xhci, "Failed to enable MSI-X\n");
+                goto free_entries;
+        }
+
+        /*
+         * Pass the xhci pointer value as the request_irq "cookie".
+         * If more irqs are added, this will need to be unique for each one.
+         */
+        ret = request_irq(xhci->msix_entries[0].vector, &xhci_irq, 0,
+                        "xHCI", xhci_to_hcd(xhci));
+        if (ret) {
+                xhci_err(xhci, "Failed to allocate MSI-X interrupt\n");
+                goto disable_msix;
+        }
+        xhci_dbg(xhci, "Finished setting up MSI-X\n");
+        return 0;
+
+disable_msix:
+        pci_disable_msix(pdev);
+free_entries:
+        kfree(xhci->msix_entries);
+        xhci->msix_entries = NULL;
+        return ret;
+}
+
+/* XXX: code duplication; can xhci_setup_msix call this? */
+/* Free any IRQs and disable MSI-X */
+static void xhci_cleanup_msix(struct xhci_hcd *xhci)
+{
+        struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
+        if (!xhci->msix_entries)
+                return;
+
+        free_irq(xhci->msix_entries[0].vector, xhci);
+        pci_disable_msix(pdev);
+        kfree(xhci->msix_entries);
+        xhci->msix_entries = NULL;
+        xhci_dbg(xhci, "Finished cleaning up MSI-X\n");
+}
+#endif
+
+/*
+ * Initialize memory for HCD and xHC (one-time init).
+ *
+ * Program the PAGESIZE register, initialize the device context array, create
+ * device contexts (?), set up a command ring segment (or two?), create event
+ * ring (one for now).
+ */
+int xhci_init(struct usb_hcd *hcd)
+{
+        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+        int retval = 0;
+
+        xhci_dbg(xhci, "xhci_init\n");
+        spin_lock_init(&xhci->lock);
+        retval = xhci_mem_init(xhci, GFP_KERNEL);
+        xhci_dbg(xhci, "Finished xhci_init\n");
+
+        return retval;
+}
+
+/*
+ * Start the HC after it was halted.
+ *
+ * This function is called by the USB core when the HC driver is added.
+ * Its opposite is xhci_stop().
+ *
+ * xhci_init() must be called once before this function can be called.
+ * Reset the HC, enable device slot contexts, program DCBAAP, and
+ * set command ring pointer and event ring pointer.
+ *
+ * Setup MSI-X vectors and enable interrupts.
+ */
+int xhci_run(struct usb_hcd *hcd)
+{
+        u32 temp;
+        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+        xhci_dbg(xhci, "xhci_run\n");
+
+#if 0   /* FIXME: MSI not setup yet */
+        /* Do this at the very last minute */
+        ret = xhci_setup_msix(xhci);
+        if (!ret)
+                return ret;
+
+        return -ENOSYS;
+#endif
+        xhci_dbg(xhci, "// Set the interrupt modulation register\n");
+        temp = xhci_readl(xhci, &xhci->ir_set->irq_control);
+        temp &= 0xffff;
+        temp |= (u32) 160;
+        xhci_writel(xhci, temp, &xhci->ir_set->irq_control);
+
+        /* Set the HCD state before we enable the irqs */
+        hcd->state = HC_STATE_RUNNING;
+        temp = xhci_readl(xhci, &xhci->op_regs->command);
+        temp |= (CMD_EIE);
+        xhci_dbg(xhci, "// Enable interrupts, cmd = 0x%x.\n",
+                        temp);
+        xhci_writel(xhci, temp, &xhci->op_regs->command);
+
+        temp = xhci_readl(xhci, &xhci->ir_set->irq_pending);
+        xhci_dbg(xhci, "// Enabling event ring interrupter 0x%x"
+                        " by writing 0x%x to irq_pending\n",
+                        (unsigned int) xhci->ir_set,
+                        (unsigned int) ER_IRQ_ENABLE(temp));
+        xhci_writel(xhci, ER_IRQ_ENABLE(temp),
+                        &xhci->ir_set->irq_pending);
+        xhci_print_ir_set(xhci, xhci->ir_set, 0);
+
+        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);
+        xhci_dbg(xhci, "// @%x = 0x%x\n",
+                        (unsigned int) &xhci->op_regs->command, temp);
+
+        xhci_dbg(xhci, "Finished xhci_run\n");
+        return 0;
+}
+
+/*
+ * Stop xHCI driver.
+ *
+ * This function is called by the USB core when the HC driver is removed.
+ * Its opposite is xhci_run().
+ *
+ * Disable device contexts, disable IRQs, and quiesce the HC.
+ * Reset the HC, finish any completed transactions, and cleanup memory.
+ */
+void xhci_stop(struct usb_hcd *hcd)
+{
+        u32 temp;
+        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+
+        spin_lock_irq(&xhci->lock);
+        if (HC_IS_RUNNING(hcd->state))
+                xhci_quiesce(xhci);
+        xhci_halt(xhci);
+        xhci_reset(xhci);
+        spin_unlock_irq(&xhci->lock);
+
+#if 0   /* No MSI yet */
+        xhci_cleanup_msix(xhci);
+#endif
+        xhci_dbg(xhci, "// Disabling event ring interrupts\n");
+        temp = xhci_readl(xhci, &xhci->op_regs->status);
+        xhci_writel(xhci, temp & ~STS_EINT, &xhci->op_regs->status);
+        temp = xhci_readl(xhci, &xhci->ir_set->irq_pending);
+        xhci_writel(xhci, ER_IRQ_DISABLE(temp),
+                        &xhci->ir_set->irq_pending);
+        xhci_print_ir_set(xhci, xhci->ir_set, 0);
+
+        xhci_dbg(xhci, "cleaning up memory\n");
+        xhci_mem_cleanup(xhci);
+        xhci_dbg(xhci, "xhci_stop completed - status = %x\n",
+                    xhci_readl(xhci, &xhci->op_regs->status));
+}
+
+/*
+ * Shutdown HC (not bus-specific)
+ *
+ * This is called when the machine is rebooting or halting.  We assume that the
+ * machine will be powered off, and the HC's internal state will be reset.
+ * Don't bother to free memory.
+ */
+void xhci_shutdown(struct usb_hcd *hcd)
+{
+        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+
+        spin_lock_irq(&xhci->lock);
+        xhci_halt(xhci);
+        spin_unlock_irq(&xhci->lock);
+
+#if 0
+        xhci_cleanup_msix(xhci);
+#endif
+
+        xhci_dbg(xhci, "xhci_shutdown completed - status = %x\n",
+                    xhci_readl(xhci, &xhci->op_regs->status));
+}
+
+int xhci_get_frame(struct usb_hcd *hcd)
+{
+        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+        /* EHCI mods by the periodic size.  Why? */
+        return xhci_readl(xhci, &xhci->run_regs->microframe_index) >> 3;
+}
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_LICENSE("GPL");
+
+static int __init xhci_hcd_init(void)
+{
+#ifdef CONFIG_PCI
+        int retval = 0;
+
+        retval = xhci_register_pci();
+
+        if (retval < 0) {
+                printk(KERN_DEBUG "Problem registering PCI driver.");
+                return retval;
+        }
+#endif
+        return 0;
+}
+module_init(xhci_hcd_init);
+
+static void __exit xhci_hcd_cleanup(void)
+{
+#ifdef CONFIG_PCI
+        xhci_unregister_pci();
+#endif
+}
+module_exit(xhci_hcd_cleanup);