target/linux/bcm53xx/patches-6.6/180-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 @@ -77,8 +77,13 @@ 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         xhci->quirks |= priv->quirks;
  30 +
  31 +       if (node && of_machine_is_compatible("brcm,bcm4708"))
  32 +               xhci->quirks |= XHCI_FAKE_DOORBELL;
  33  }
  34
  35  /* called during probe() after chip reset completes */
  36 --- a/drivers/usb/host/xhci.c
  37 +++ b/drivers/usb/host/xhci.c
  38 @@ -161,6 +161,49 @@ int xhci_start(struct xhci_hcd *xhci)
  39         return ret;
  40  }
  41
  42 +/**
  43 + * xhci_fake_doorbell - Perform a fake doorbell on a specified slot
  44 + *
  45 + * Some controllers require a fake doorbell to start correctly. Without that
  46 + * they simply don't detect any devices.
  47 + */
  48 +static int xhci_fake_doorbell(struct xhci_hcd *xhci, int slot_id)
  49 +{
  50 +       u32 temp;
  51 +
  52 +       /* Alloc a virt device for that slot */
  53 +       if (!xhci_alloc_virt_device(xhci, slot_id, NULL, GFP_NOIO)) {
  54 +               xhci_warn(xhci, "Could not allocate xHCI USB device data structures\n");
  55 +               return -ENOMEM;
  56 +       }
  57 +
  58 +       /* Ring fake doorbell for slot_id ep 0 */
  59 +       xhci_ring_ep_doorbell(xhci, slot_id, 0, 0);
  60 +       usleep_range(1000, 1500);
  61 +
  62 +       /* Read the status to check if HSE is set or not */
  63 +       temp = readl(&xhci->op_regs->status);
  64 +
  65 +       /* Clear HSE if set */
  66 +       if (temp & STS_FATAL) {
  67 +               xhci_dbg(xhci, "HSE problem detected, status: 0x%08x\n", temp);
  68 +               temp &= ~0x1fff;
  69 +               temp |= STS_FATAL;
  70 +               writel(temp, &xhci->op_regs->status);
  71 +               usleep_range(1000, 1500);
  72 +               readl(&xhci->op_regs->status);
  73 +       }
  74 +
  75 +       /* Free virt device */
  76 +       xhci_free_virt_device(xhci, slot_id);
  77 +
  78 +       /* We're done if controller is already running */
  79 +       if (readl(&xhci->op_regs->command) & CMD_RUN)
  80 +               return 0;
  81 +
  82 +       return xhci_start(xhci);
  83 +}
  84 +
  85  /*
  86   * Reset a halted HC.
  87   *
  88 @@ -480,6 +523,15 @@ static int xhci_run_finished(struct xhci
  89                 return -ENODEV;
  90         }
  91
  92 +       if (xhci->quirks & XHCI_FAKE_DOORBELL) {
  93 +               int err = xhci_fake_doorbell(xhci, 1);
  94 +               if (err) {
  95 +                       xhci_halt(xhci);
  96 +                       spin_unlock_irqrestore(&xhci->lock, flags);
  97 +                       return err;
  98 +               }
  99 +       }
 100 +
 101         xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;
 102
 103         if (xhci->quirks & XHCI_NEC_HOST)
 104 --- a/drivers/usb/host/xhci.h
 105 +++ b/drivers/usb/host/xhci.h
 106 @@ -1912,6 +1912,7 @@ struct xhci_hcd {
 107  #define XHCI_RESET_TO_DEFAULT  BIT_ULL(44)
 108  #define XHCI_ZHAOXIN_TRB_FETCH BIT_ULL(45)
 109  #define XHCI_ZHAOXIN_HOST      BIT_ULL(46)
 110 +#define XHCI_FAKE_DOORBELL     BIT_ULL(47)
 111
 112         unsigned int            num_active_eps;
 113         unsigned int            limit_active_eps;