releases/4.6.1/clk-bcm2835-add-locking-to-pll-_on-off-methods.patch

   1 From ec36a5c6682fdd5328abf15c3c67281bed0241d7 Mon Sep 17 00:00:00 2001
   2 From: Martin Sperl <kernel@martin.sperl.org>
   3 Date: Mon, 29 Feb 2016 11:39:18 +0000
   4 Subject: clk: bcm2835: add locking to pll*_on/off methods
   5
   6 From: Martin Sperl <kernel@martin.sperl.org>
   7
   8 commit ec36a5c6682fdd5328abf15c3c67281bed0241d7 upstream.
   9
  10 Add missing locking to:
  11 * bcm2835_pll_divider_on
  12 * bcm2835_pll_divider_off
  13 to protect the read modify write cycle for the
  14 register access protecting both cm_reg and a2w_reg
  15 registers.
  16
  17 Fixes: 41691b8862e2 ("clk: bcm2835: Add support for programming the
  18 audio domain clocks")
  19
  20 Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
  21 Signed-off-by: Eric Anholt <eric@anholt.net>
  22 Reviewed-by: Eric Anholt <eric@anholt.net>
  23 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  24
  25 ---
  26  drivers/clk/bcm/clk-bcm2835.c |    4 ++++
  27  1 file changed, 4 insertions(+)
  28
  29 --- a/drivers/clk/bcm/clk-bcm2835.c
  30 +++ b/drivers/clk/bcm/clk-bcm2835.c
  31 @@ -1079,10 +1079,12 @@ static void bcm2835_pll_divider_off(stru
  32         struct bcm2835_cprman *cprman = divider->cprman;
  33         const struct bcm2835_pll_divider_data *data = divider->data;
  34
  35 +       spin_lock(&cprman->regs_lock);
  36         cprman_write(cprman, data->cm_reg,
  37                      (cprman_read(cprman, data->cm_reg) &
  38                       ~data->load_mask) | data->hold_mask);
  39         cprman_write(cprman, data->a2w_reg, A2W_PLL_CHANNEL_DISABLE);
  40 +       spin_unlock(&cprman->regs_lock);
  41  }
  42
  43  static int bcm2835_pll_divider_on(struct clk_hw *hw)
  44 @@ -1091,12 +1093,14 @@ static int bcm2835_pll_divider_on(struct
  45         struct bcm2835_cprman *cprman = divider->cprman;
  46         const struct bcm2835_pll_divider_data *data = divider->data;
  47
  48 +       spin_lock(&cprman->regs_lock);
  49         cprman_write(cprman, data->a2w_reg,
  50                      cprman_read(cprman, data->a2w_reg) &
  51                      ~A2W_PLL_CHANNEL_DISABLE);
  52
  53         cprman_write(cprman, data->cm_reg,
  54                      cprman_read(cprman, data->cm_reg) & ~data->hold_mask);
  55 +       spin_unlock(&cprman->regs_lock);
  56
  57         return 0;
  58  }