[PATCH 4.4 72/86] clk: bcm2835: add locking to pll*_on/off methods

Greg Kroah-Hartman
2016-05-30T20:50:42Z

From: Martin Sperl <kernel@martin.sperl.org>

commit ec36a5c6682fdd5328abf15c3c67281bed0241d7 upstream.

Add missing locking to:
* bcm2835_pll_divider_on
* bcm2835_pll_divider_off
to protect the read modify write cycle for the
register access protecting both cm_reg and a2w_reg
registers.

Fixes: 41691b8862e2 ("clk: bcm2835: Add support for programming the
audio domain clocks")

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/clk/bcm/clk-bcm2835.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1068,10 +1068,12 @@ static void bcm2835_pll_divider_off(stru
struct bcm2835_cprman *cprman = divider->cprman;
const struct bcm2835_pll_divider_data *data = divider->data;

+ spin_lock(&cprman->regs_lock);
cprman_write(cprman, data->cm_reg,
(cprman_read(cprman, data->cm_reg) &
~data->load_mask) | data->hold_mask);
cprman_write(cprman, data->a2w_reg, A2W_PLL_CHANNEL_DISABLE);
+ spin_unlock(&cprman->regs_lock);
}

static int bcm2835_pll_divider_on(struct clk_hw *hw)
@@ -1080,12 +1082,14 @@ static int bcm2835_pll_divider_on(struct
struct bcm2835_cprman *cprman = divider->cprman;
const struct bcm2835_pll_divider_data *data = divider->data;

+ spin_lock(&cprman->regs_lock);
cprman_write(cprman, data->a2w_reg,
cprman_read(cprman, data->a2w_reg) &
~A2W_PLL_CHANNEL_DISABLE);

cprman_write(cprman, data->cm_reg,
cprman_read(cprman, data->cm_reg) & ~data->hold_mask);
+ spin_unlock(&cprman->regs_lock);

return 0;
}