target/linux/bcm53xx/patches-5.4/180-usb-xhci-add-support-for-performing-fake-doorbell.patch

   1 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   2 Date: Sat, 1 Oct 2016 22:54:48 +0200
   3 Subject: [PATCH] usb: xhci: add support for performing fake doorbell
   4
   5 Broadcom's Northstar XHCI controllers seem to need a special start
   6 procedure to work correctly. There isn't any official documentation of
   7 this, the problem is that controller doesn't detect any connected
   8 devices with default setup. Moreover connecting USB device to controller
   9 that doesn't run properly can cause SoC's watchdog issues.
  10
  11 A workaround that was successfully tested on multiple devices is to
  12 perform a fake doorbell. This patch adds code for doing this and enables
  13 it on BCM4708 family.
  14 ---
  15  drivers/usb/host/xhci-plat.c |  6 +++++
  16  drivers/usb/host/xhci.c      | 63 +++++++++++++++++++++++++++++++++++++++++---
  17  drivers/usb/host/xhci.h      |  1 +
  18  3 files changed, 67 insertions(+), 3 deletions(-)
  19
  20 --- a/drivers/usb/host/xhci-plat.c
  21 +++ b/drivers/usb/host/xhci-plat.c
  22 @@ -67,6 +67,8 @@ static int xhci_priv_resume_quirk(struct
  23  static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
  24  {
  25         struct xhci_plat_priv *priv = xhci_to_priv(xhci);
  26 +       struct platform_device*pdev = to_platform_device(dev);
  27 +       struct device_node *node = pdev->dev.of_node;
  28
  29         /*
  30          * As of now platform drivers don't provide MSI support so we ensure
  31 @@ -74,6 +76,9 @@ static void xhci_plat_quirks(struct devi
  32          * dev struct in order to setup MSI
  33          */
  34         xhci->quirks |= XHCI_PLAT | priv->quirks;
  35 +
  36 +       if (node && of_machine_is_compatible("brcm,bcm4708"))
  37 +               xhci->quirks |= XHCI_FAKE_DOORBELL;
  38  }
  39
  40  /* called during probe() after chip reset completes */
  41 --- a/drivers/usb/host/xhci.c
  42 +++ b/drivers/usb/host/xhci.c
  43 @@ -156,6 +156,49 @@ int xhci_start(struct xhci_hcd *xhci)
  44         return ret;
  45  }
  46
  47 +/**
  48 + * xhci_fake_doorbell - Perform a fake doorbell on a specified slot
  49 + *
  50 + * Some controllers require a fake doorbell to start correctly. Without that
  51 + * they simply don't detect any devices.
  52 + */
  53 +static int xhci_fake_doorbell(struct xhci_hcd *xhci, int slot_id)
  54 +{
  55 +       u32 temp;
  56 +
  57 +       /* Alloc a virt device for that slot */
  58 +       if (!xhci_alloc_virt_device(xhci, slot_id, NULL, GFP_NOIO)) {
  59 +               xhci_warn(xhci, "Could not allocate xHCI USB device data structures\n");
  60 +               return -ENOMEM;
  61 +       }
  62 +
  63 +       /* Ring fake doorbell for slot_id ep 0 */
  64 +       xhci_ring_ep_doorbell(xhci, slot_id, 0, 0);
  65 +       usleep_range(1000, 1500);
  66 +
  67 +       /* Read the status to check if HSE is set or not */
  68 +       temp = readl(&xhci->op_regs->status);
  69 +
  70 +       /* Clear HSE if set */
  71 +       if (temp & STS_FATAL) {
  72 +               xhci_dbg(xhci, "HSE problem detected, status: 0x%08x\n", temp);
  73 +               temp &= ~0x1fff;
  74 +               temp |= STS_FATAL;
  75 +               writel(temp, &xhci->op_regs->status);
  76 +               usleep_range(1000, 1500);
  77 +               readl(&xhci->op_regs->status);
  78 +       }
  79 +
  80 +       /* Free virt device */
  81 +       xhci_free_virt_device(xhci, slot_id);
  82 +
  83 +       /* We're done if controller is already running */
  84 +       if (readl(&xhci->op_regs->command) & CMD_RUN)
  85 +               return 0;
  86 +
  87 +       return xhci_start(xhci);
  88 +}
  89 +
  90  /*
  91   * Reset a halted HC.
  92   *
  93 @@ -604,10 +647,20 @@ static int xhci_init(struct usb_hcd *hcd
  94
  95  static int xhci_run_finished(struct xhci_hcd *xhci)
  96  {
  97 -       if (xhci_start(xhci)) {
  98 -               xhci_halt(xhci);
  99 -               return -ENODEV;
 100 +       int err;
 101 +
 102 +       err = xhci_start(xhci);
 103 +       if (err) {
 104 +               err = -ENODEV;
 105 +               goto err_halt;
 106         }
 107 +
 108 +       if (xhci->quirks & XHCI_FAKE_DOORBELL) {
 109 +               err = xhci_fake_doorbell(xhci, 1);
 110 +               if (err)
 111 +                       goto err_halt;
 112 +       }
 113 +
 114         xhci->shared_hcd->state = HC_STATE_RUNNING;
 115         xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;
 116
 117 @@ -617,6 +670,10 @@ static int xhci_run_finished(struct xhci
 118         xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 119                         "Finished xhci_run for USB3 roothub");
 120         return 0;
 121 +
 122 +err_halt:
 123 +       xhci_halt(xhci);
 124 +       return err;
 125  }
 126
 127  /*
 128 --- a/drivers/usb/host/xhci.h
 129 +++ b/drivers/usb/host/xhci.h
 130 @@ -1872,6 +1872,7 @@ struct xhci_hcd {
 131  #define XHCI_DEFAULT_PM_RUNTIME_ALLOW  BIT_ULL(33)
 132  #define XHCI_RESET_PLL_ON_DISCONNECT   BIT_ULL(34)
 133  #define XHCI_SNPS_BROKEN_SUSPEND    BIT_ULL(35)
 134 +#define XHCI_FAKE_DOORBELL     BIT_ULL(36)
 135
 136         unsigned int            num_active_eps;
 137         unsigned int            limit_active_eps;