queue-4.14/xhci-convert-xhci_handshake-to-use-readl_poll_timeout_atomic.patch

   1 From f7fac17ca925faa03fc5eb854c081a24075f8bad Mon Sep 17 00:00:00 2001
   2 From: Andrey Smirnov <andrew.smirnov@gmail.com>
   3 Date: Wed, 22 May 2019 14:34:01 +0300
   4 Subject: xhci: Convert xhci_handshake() to use readl_poll_timeout_atomic()
   5
   6 From: Andrey Smirnov <andrew.smirnov@gmail.com>
   7
   8 commit f7fac17ca925faa03fc5eb854c081a24075f8bad upstream.
   9
  10 Xhci_handshake() implements the algorithm already captured by
  11 readl_poll_timeout_atomic(). Convert the former to use the latter to
  12 avoid repetition.
  13
  14 Turned out this patch also fixes a bug on the AMD Stoneyridge platform
  15 where usleep(1) sometimes takes over 10ms.
  16 This means a 5 second timeout can easily take over 15 seconds which will
  17 trigger the watchdog and reboot the system.
  18
  19 [Add info about patch fixing a bug to commit message -Mathias]
  20 Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
  21 Tested-by: Raul E Rangel <rrangel@chromium.org>
  22 Reviewed-by: Raul E Rangel <rrangel@chromium.org>
  23 Cc: <stable@vger.kernel.org>
  24 Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
  25 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  26
  27 ---
  28  drivers/usb/host/xhci.c |   22 ++++++++++------------
  29  1 file changed, 10 insertions(+), 12 deletions(-)
  30
  31 --- a/drivers/usb/host/xhci.c
  32 +++ b/drivers/usb/host/xhci.c
  33 @@ -21,6 +21,7 @@
  34   */
  35
  36  #include <linux/pci.h>
  37 +#include <linux/iopoll.h>
  38  #include <linux/irq.h>
  39  #include <linux/log2.h>
  40  #include <linux/module.h>
  41 @@ -62,7 +63,6 @@ static bool td_on_ring(struct xhci_td *t
  42         return false;
  43  }
  44
  45 -/* TODO: copied from ehci-hcd.c - can this be refactored? */
  46  /*
  47   * xhci_handshake - spin reading hc until handshake completes or fails
  48   * @ptr: address of hc register to be read
  49 @@ -79,18 +79,16 @@ static bool td_on_ring(struct xhci_td *t
  50  int xhci_handshake(void __iomem *ptr, u32 mask, u32 done, int usec)
  51  {
  52         u32     result;
  53 +       int     ret;
  54
  55 -       do {
  56 -               result = readl(ptr);
  57 -               if (result == ~(u32)0)          /* card removed */
  58 -                       return -ENODEV;
  59 -               result &= mask;
  60 -               if (result == done)
  61 -                       return 0;
  62 -               udelay(1);
  63 -               usec--;
  64 -       } while (usec > 0);
  65 -       return -ETIMEDOUT;
  66 +       ret = readl_poll_timeout_atomic(ptr, result,
  67 +                                       (result & mask) == done ||
  68 +                                       result == U32_MAX,
  69 +                                       1, usec);
  70 +       if (result == U32_MAX)          /* card removed */
  71 +               return -ENODEV;
  72 +
  73 +       return ret;
  74  }
  75
  76  /*