target/linux/ipq806x/patches-4.4/714-spi-qup-properly-detect-extra-interrupts.patch

   1 From b69e5e855aaae2dd9f7fc6f4a40af8e6e0cf98ee Mon Sep 17 00:00:00 2001
   2 From: Matthew McClintock <mmcclint@codeaurora.org>
   3 Date: Thu, 10 Mar 2016 16:44:55 -0600
   4 Subject: [PATCH] spi: qup: properly detect extra interrupts
   5
   6 It's possible for a SPI transaction to complete and get another
   7 interrupt and have it processed on the same spi_transfer before the
   8 transfer_one can set it to NULL.
   9
  10 This masks unexpected interrupts, so let's set the spi_transfer to
  11 NULL in the interrupt once the transaction is done. So we can
  12 properly detect these bad interrupts and print warning messages.
  13
  14 Change-Id: I0e70ed59fb50e5c48a72a38f74bd178b17c9f24d
  15 Signed-off-by: Matthew McClintock <mmcclint@codeaurora.org>
  16 ---
  17  drivers/spi/spi-qup.c | 15 +++++++++------
  18  1 file changed, 9 insertions(+), 6 deletions(-)
  19
  20 --- a/drivers/spi/spi-qup.c
  21 +++ b/drivers/spi/spi-qup.c
  22 @@ -509,6 +509,7 @@ static irqreturn_t spi_qup_qup_irq(int i
  23         u32 opflags, qup_err, spi_err;
  24         unsigned long flags;
  25         int error = 0;
  26 +       bool done = 0;
  27
  28         spin_lock_irqsave(&controller->lock, flags);
  29         xfer = controller->xfer;
  30 @@ -567,16 +568,19 @@ static irqreturn_t spi_qup_qup_irq(int i
  31                         spi_qup_write(controller, xfer);
  32         }
  33
  34 -       spin_lock_irqsave(&controller->lock, flags);
  35 -       controller->error = error;
  36 -       controller->xfer = xfer;
  37 -       spin_unlock_irqrestore(&controller->lock, flags);
  38 -
  39         /* re-read opflags as flags may have changed due to actions above */
  40         opflags = readl_relaxed(controller->base + QUP_OPERATIONAL);
  41
  42         if ((controller->rx_bytes == xfer->len &&
  43                 (opflags & QUP_OP_MAX_INPUT_DONE_FLAG)) ||  error)
  44 +               done = true;
  45 +
  46 +       spin_lock_irqsave(&controller->lock, flags);
  47 +       controller->error = error;
  48 +       controller->xfer = done ? NULL : xfer;
  49 +       spin_unlock_irqrestore(&controller->lock, flags);
  50 +
  51 +       if (done)
  52                 complete(&controller->done);
  53
  54         return IRQ_HANDLED;
  55 @@ -769,7 +773,6 @@ static int spi_qup_transfer_one(struct s
  56  exit:
  57         spi_qup_set_state(controller, QUP_STATE_RESET);
  58         spin_lock_irqsave(&controller->lock, flags);
  59 -       controller->xfer = NULL;
  60         if (!ret)
  61                 ret = controller->error;
  62         spin_unlock_irqrestore(&controller->lock, flags);