target/linux/bcm53xx/patches-4.4/180-usb-xhci-add-support-for-performing-fake-doorbell.patch

   1 From 37df205cdb69d17d5e815385fc1af3c97d1fe20b Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   3 Date: Sat, 1 Oct 2016 22:54:48 +0200
   4 Subject: [PATCH] usb: xhci: add support for performing fake doorbell
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Broadcom's Northstar XHCI controllers seem to need a special start
  10 procedure to work correctly. There isn't any official documentation on
  11 this, the problem is that controller doesn't detect any connected
  12 devices with default setup. Moreover connecting USB device to controller
  13 that doesn't run properly can cause SoC's watchdog issues.
  14
  15 A workaround that was successfully tested on multiple devices is to
  16 perform a fake doorbell. This patch adds code for doing that and a DT
  17 binding enabling it.
  18
  19 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  20 ---
  21  Documentation/devicetree/bindings/usb/usb-xhci.txt |  2 +
  22  drivers/usb/host/xhci-plat.c                       |  6 +++
  23  drivers/usb/host/xhci.c                            | 63 ++++++++++++++++++++--
  24  drivers/usb/host/xhci.h                            |  1 +
  25  4 files changed, 69 insertions(+), 3 deletions(-)
  26
  27 --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
  28 +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
  29 @@ -12,6 +12,8 @@ Required properties:
  30  Optional properties:
  31    - clocks: reference to a clock
  32    - usb3-lpm-capable: determines if platform is USB3 LPM capable
  33 +  - usb3-fake-doorbell: determines if controller requires a fake doorbell when
  34 +                       starting it
  35
  36  Example:
  37         usb@f0931000 {
  38 --- a/drivers/usb/host/xhci-plat.c
  39 +++ b/drivers/usb/host/xhci-plat.c
  40 @@ -38,12 +38,18 @@ static const struct xhci_driver_override
  41
  42  static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
  43  {
  44 +       struct platform_device  *pdev = to_platform_device(dev);
  45 +       struct device_node      *node = pdev->dev.of_node;
  46 +
  47         /*
  48          * As of now platform drivers don't provide MSI support so we ensure
  49          * here that the generic code does not try to make a pci_dev from our
  50          * dev struct in order to setup MSI
  51          */
  52         xhci->quirks |= XHCI_PLAT;
  53 +
  54 +       if (node && of_property_read_bool(node, "usb3-fake-doorbell"))
  55 +               xhci->quirks |= XHCI_FAKE_DOORBELL;
  56  }
  57
  58  /* called during probe() after chip reset completes */
  59 --- a/drivers/usb/host/xhci.c
  60 +++ b/drivers/usb/host/xhci.c
  61 @@ -152,6 +152,49 @@ static int xhci_start(struct xhci_hcd *x
  62         return ret;
  63  }
  64
  65 +/**
  66 + * xhci_fake_doorbell - Perform a fake doorbell on a specified slot
  67 + *
  68 + * Some controllers require a fake doorbell to start correctly. Without that
  69 + * they simply don't detect any devices.
  70 + */
  71 +static int xhci_fake_doorbell(struct xhci_hcd *xhci, int slot_id)
  72 +{
  73 +       u32 temp;
  74 +
  75 +       /* Alloc a virt device for that slot */
  76 +       if (!xhci_alloc_virt_device(xhci, slot_id, NULL, GFP_NOIO)) {
  77 +               xhci_warn(xhci, "Could not allocate xHCI USB device data structures\n");
  78 +               return -ENOMEM;
  79 +       }
  80 +
  81 +       /* Ring fake doorbell for slot_id ep 0 */
  82 +       xhci_ring_ep_doorbell(xhci, slot_id, 0, 0);
  83 +       usleep_range(1000, 1500);
  84 +
  85 +       /* Read the status to check if HSE is set or not */
  86 +       temp = readl(&xhci->op_regs->status);
  87 +
  88 +       /* Clear HSE if set */
  89 +       if (temp & STS_FATAL) {
  90 +               xhci_dbg(xhci, "HSE problem detected, status: 0x%08x\n", temp);
  91 +               temp &= ~0x1fff;
  92 +               temp |= STS_FATAL;
  93 +               writel(temp, &xhci->op_regs->status);
  94 +               usleep_range(1000, 1500);
  95 +               readl(&xhci->op_regs->status);
  96 +       }
  97 +
  98 +       /* Free virt device */
  99 +       xhci_free_virt_device(xhci, slot_id);
 100 +
 101 +       /* We're done if controller is already running */
 102 +       if (readl(&xhci->op_regs->command) & CMD_RUN)
 103 +               return 0;
 104 +
 105 +       return xhci_start(xhci);
 106 +}
 107 +
 108  /*
 109   * Reset a halted HC.
 110   *
 111 @@ -568,10 +611,20 @@ int xhci_init(struct usb_hcd *hcd)
 112
 113  static int xhci_run_finished(struct xhci_hcd *xhci)
 114  {
 115 -       if (xhci_start(xhci)) {
 116 -               xhci_halt(xhci);
 117 -               return -ENODEV;
 118 +       int err;
 119 +
 120 +       err = xhci_start(xhci);
 121 +       if (err) {
 122 +               err = -ENODEV;
 123 +               goto err_halt;
 124 +       }
 125 +
 126 +       if (xhci->quirks & XHCI_FAKE_DOORBELL) {
 127 +               err = xhci_fake_doorbell(xhci, 1);
 128 +               if (err)
 129 +                       goto err_halt;
 130         }
 131 +
 132         xhci->shared_hcd->state = HC_STATE_RUNNING;
 133         xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;
 134
 135 @@ -581,6 +634,10 @@ static int xhci_run_finished(struct xhci
 136         xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 137                         "Finished xhci_run for USB3 roothub");
 138         return 0;
 139 +
 140 +err_halt:
 141 +       xhci_halt(xhci);
 142 +       return err;
 143  }
 144
 145  /*
 146 --- a/drivers/usb/host/xhci.h
 147 +++ b/drivers/usb/host/xhci.h
 148 @@ -1631,6 +1631,7 @@ struct xhci_hcd {
 149  /* For controllers with a broken beyond repair streams implementation */
 150  #define XHCI_BROKEN_STREAMS    (1 << 19)
 151  #define XHCI_PME_STUCK_QUIRK   (1 << 20)
 152 +#define XHCI_FAKE_DOORBELL     (1 << 24)
 153         unsigned int            num_active_eps;
 154         unsigned int            limit_active_eps;
 155         /* There are two roothubs to keep track of bus suspend info for */