target/linux/brcm2708/patches-4.4/0257-clk-bcm2835-add-locking-to-pll-_on-off-methods.patch

   1 From 39c3c0d0a8d038a692b95cc13e7d6acf2d04cf14 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: [PATCH 257/304] clk: bcm2835: add locking to pll*_on/off methods
   5
   6 Add missing locking to:
   7 * bcm2835_pll_divider_on
   8 * bcm2835_pll_divider_off
   9 to protect the read modify write cycle for the
  10 register access protecting both cm_reg and a2w_reg
  11 registers.
  12
  13 Fixes: 41691b8862e2 ("clk: bcm2835: Add support for programming the
  14 audio domain clocks")
  15
  16 Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
  17 Signed-off-by: Eric Anholt <eric@anholt.net>
  18 Reviewed-by: Eric Anholt <eric@anholt.net>
  19 (cherry picked from commit ec36a5c6682fdd5328abf15c3c67281bed0241d7)
  20 ---
  21  drivers/clk/bcm/clk-bcm2835.c | 4 ++++
  22  1 file changed, 4 insertions(+)
  23
  24 --- a/drivers/clk/bcm/clk-bcm2835.c
  25 +++ b/drivers/clk/bcm/clk-bcm2835.c
  26 @@ -1097,10 +1097,12 @@ static void bcm2835_pll_divider_off(stru
  27         struct bcm2835_cprman *cprman = divider->cprman;
  28         const struct bcm2835_pll_divider_data *data = divider->data;
  29
  30 +       spin_lock(&cprman->regs_lock);
  31         cprman_write(cprman, data->cm_reg,
  32                      (cprman_read(cprman, data->cm_reg) &
  33                       ~data->load_mask) | data->hold_mask);
  34         cprman_write(cprman, data->a2w_reg, A2W_PLL_CHANNEL_DISABLE);
  35 +       spin_unlock(&cprman->regs_lock);
  36  }
  37
  38  static int bcm2835_pll_divider_on(struct clk_hw *hw)
  39 @@ -1109,12 +1111,14 @@ static int bcm2835_pll_divider_on(struct
  40         struct bcm2835_cprman *cprman = divider->cprman;
  41         const struct bcm2835_pll_divider_data *data = divider->data;
  42
  43 +       spin_lock(&cprman->regs_lock);
  44         cprman_write(cprman, data->a2w_reg,
  45                      cprman_read(cprman, data->a2w_reg) &
  46                      ~A2W_PLL_CHANNEL_DISABLE);
  47
  48         cprman_write(cprman, data->cm_reg,
  49                      cprman_read(cprman, data->cm_reg) & ~data->hold_mask);
  50 +       spin_unlock(&cprman->regs_lock);
  51
  52         return 0;
  53  }