target/linux/brcm2708/patches-4.1/0110-mailbox-bcm2835-Fix-mailbox-full-detection.patch

   1 From 38a0a5c357245cfe2b359277bc38509fa05c268d Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Wed, 13 May 2015 13:10:32 -0700
   4 Subject: [PATCH 110/148] mailbox/bcm2835: Fix mailbox full detection.
   5
   6 With the VC reader blocked and the ARM writing, MAIL0_STA reads empty
   7 permanently while MAIL1_STA goes from empty (0x40000000) to non-empty
   8 (0x00000001-0x00000007) to full (0x80000008).
   9
  10 This bug ended up having no effect on us, because all of our
  11 transactions in the client driver were synchronous and under a mutex.
  12
  13 Suggested-by: Phil Elwell <phil@raspberrypi.org>
  14 Signed-off-by: Eric Anholt <eric@anholt.net>
  15 Acked-by: Stephen Warren <swarren@wwwdotorg.org>
  16 Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
  17 ---
  18  drivers/mailbox/bcm2835-mailbox.c | 3 ++-
  19  1 file changed, 2 insertions(+), 1 deletion(-)
  20
  21 --- a/drivers/mailbox/bcm2835-mailbox.c
  22 +++ b/drivers/mailbox/bcm2835-mailbox.c
  23 @@ -49,6 +49,7 @@
  24  #define MAIL0_STA      (ARM_0_MAIL0 + 0x18)
  25  #define MAIL0_CNF      (ARM_0_MAIL0 + 0x1C)
  26  #define MAIL1_WRT      (ARM_0_MAIL1 + 0x00)
  27 +#define MAIL1_STA      (ARM_0_MAIL1 + 0x18)
  28
  29  /* Status register: FIFO state. */
  30  #define ARM_MS_FULL            BIT(31)
  31 @@ -117,7 +118,7 @@ static bool bcm2835_last_tx_done(struct
  32         bool ret;
  33
  34         spin_lock(&mbox->lock);
  35 -       ret = !(readl(mbox->regs + MAIL0_STA) & ARM_MS_FULL);
  36 +       ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL);
  37         spin_unlock(&mbox->lock);
  38         return ret;
  39  }