target/linux/lantiq/patches-3.7/0112-MTD-lantiq-xway-fix-NAND-reset-timeout-handling.patch

   1 From d8d9b9055d704d6f84ef6346d6826b8a9640f209 Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Mon, 22 Oct 2012 10:25:39 +0200
   4 Subject: [PATCH 112/123] MTD: lantiq: xway: fix NAND reset timeout handling
   5
   6 Fixes a possible deadlock in the code that resets the NAND flash.
   7
   8 http://lists.infradead.org/pipermail/linux-mtd/2012-September/044240.html
   9
  10 Signed-off-by: John Crispin <blogic@openwrt.org>
  11 ---
  12  drivers/mtd/nand/xway_nand.c |   12 ++++++++++--
  13  1 file changed, 10 insertions(+), 2 deletions(-)
  14
  15 --- a/drivers/mtd/nand/xway_nand.c
  16 +++ b/drivers/mtd/nand/xway_nand.c
  17 @@ -58,15 +58,23 @@ static void xway_reset_chip(struct nand_
  18  {
  19         unsigned long nandaddr = (unsigned long) chip->IO_ADDR_W;
  20         unsigned long flags;
  21 +       unsigned long timeout;
  22
  23         nandaddr &= ~NAND_WRITE_ADDR;
  24         nandaddr |= NAND_WRITE_CMD;
  25
  26         /* finish with a reset */
  27 +       timeout = jiffies + msecs_to_jiffies(200);
  28 +
  29         spin_lock_irqsave(&ebu_lock, flags);
  30 +
  31         writeb(NAND_WRITE_CMD_RESET, (void __iomem *) nandaddr);
  32 -       while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
  33 -               ;
  34 +       do {
  35 +               if ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
  36 +                       break;
  37 +               cond_resched();
  38 +       } while (!time_after_eq(jiffies, timeout));
  39 +
  40         spin_unlock_irqrestore(&ebu_lock, flags);
  41  }
  42