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 Index: linux-5.4.11/drivers/usb/host/xhci-plat.c
  21 ===================================================================
  22 --- linux-5.4.11.orig/drivers/usb/host/xhci-plat.c
  23 +++ linux-5.4.11/drivers/usb/host/xhci-plat.c
  24 @@ -67,6 +67,8 @@ static int xhci_priv_resume_quirk(struct
  25  static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
  26  {
  27         struct xhci_plat_priv *priv = xhci_to_priv(xhci);
  28 +       struct platform_device*pdev = to_platform_device(dev);
  29 +       struct device_node *node = pdev->dev.of_node;
  30
  31         /*
  32          * As of now platform drivers don't provide MSI support so we ensure
  33 @@ -74,6 +76,9 @@ static void xhci_plat_quirks(struct devi
  34          * dev struct in order to setup MSI
  35          */
  36         xhci->quirks |= XHCI_PLAT | priv->quirks;
  37 +
  38 +       if (node && of_machine_is_compatible("brcm,bcm4708"))
  39 +               xhci->quirks |= XHCI_FAKE_DOORBELL;
  40  }
  41
  42  /* called during probe() after chip reset completes */
  43 Index: linux-5.4.11/drivers/usb/host/xhci.c
  44 ===================================================================
  45 --- linux-5.4.11.orig/drivers/usb/host/xhci.c
  46 +++ linux-5.4.11/drivers/usb/host/xhci.c
  47 @@ -156,6 +156,49 @@ int xhci_start(struct xhci_hcd *xhci)
  48         return ret;
  49  }
  50
  51 +/**
  52 + * xhci_fake_doorbell - Perform a fake doorbell on a specified slot
  53 + *
  54 + * Some controllers require a fake doorbell to start correctly. Without that
  55 + * they simply don't detect any devices.
  56 + */
  57 +static int xhci_fake_doorbell(struct xhci_hcd *xhci, int slot_id)
  58 +{
  59 +       u32 temp;
  60 +
  61 +       /* Alloc a virt device for that slot */
  62 +       if (!xhci_alloc_virt_device(xhci, slot_id, NULL, GFP_NOIO)) {
  63 +               xhci_warn(xhci, "Could not allocate xHCI USB device data structures\n");
  64 +               return -ENOMEM;
  65 +       }
  66 +
  67 +       /* Ring fake doorbell for slot_id ep 0 */
  68 +       xhci_ring_ep_doorbell(xhci, slot_id, 0, 0);
  69 +       usleep_range(1000, 1500);
  70 +
  71 +       /* Read the status to check if HSE is set or not */
  72 +       temp = readl(&xhci->op_regs->status);
  73 +
  74 +       /* Clear HSE if set */
  75 +       if (temp & STS_FATAL) {
  76 +               xhci_dbg(xhci, "HSE problem detected, status: 0x%08x\n", temp);
  77 +               temp &= ~0x1fff;
  78 +               temp |= STS_FATAL;
  79 +               writel(temp, &xhci->op_regs->status);
  80 +               usleep_range(1000, 1500);
  81 +               readl(&xhci->op_regs->status);
  82 +       }
  83 +
  84 +       /* Free virt device */
  85 +       xhci_free_virt_device(xhci, slot_id);
  86 +
  87 +       /* We're done if controller is already running */
  88 +       if (readl(&xhci->op_regs->command) & CMD_RUN)
  89 +               return 0;
  90 +
  91 +       return xhci_start(xhci);
  92 +}
  93 +
  94  /*
  95   * Reset a halted HC.
  96   *
  97 @@ -604,10 +647,20 @@ static int xhci_init(struct usb_hcd *hcd
  98
  99  static int xhci_run_finished(struct xhci_hcd *xhci)
 100  {
 101 -       if (xhci_start(xhci)) {
 102 -               xhci_halt(xhci);
 103 -               return -ENODEV;
 104 +       int err;
 105 +
 106 +       err = xhci_start(xhci);
 107 +       if (err) {
 108 +               err = -ENODEV;
 109 +               goto err_halt;
 110         }
 111 +
 112 +       if (xhci->quirks & XHCI_FAKE_DOORBELL) {
 113 +               err = xhci_fake_doorbell(xhci, 1);
 114 +               if (err)
 115 +                       goto err_halt;
 116 +       }
 117 +
 118         xhci->shared_hcd->state = HC_STATE_RUNNING;
 119         xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;
 120
 121 @@ -617,6 +670,10 @@ static int xhci_run_finished(struct xhci
 122         xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 123                         "Finished xhci_run for USB3 roothub");
 124         return 0;
 125 +
 126 +err_halt:
 127 +       xhci_halt(xhci);
 128 +       return err;
 129  }
 130
 131  /*
 132 Index: linux-5.4.11/drivers/usb/host/xhci.h
 133 ===================================================================
 134 --- linux-5.4.11.orig/drivers/usb/host/xhci.h
 135 +++ linux-5.4.11/drivers/usb/host/xhci.h
 136 @@ -1867,6 +1867,7 @@ struct xhci_hcd {
 137  #define XHCI_DEFAULT_PM_RUNTIME_ALLOW  BIT_ULL(33)
 138  #define XHCI_RESET_PLL_ON_DISCONNECT   BIT_ULL(34)
 139  #define XHCI_SNPS_BROKEN_SUSPEND    BIT_ULL(35)
 140 +#define XHCI_FAKE_DOORBELL     BIT_ULL(36)
 141
 142         unsigned int            num_active_eps;
 143         unsigned int            limit_active_eps;