[PATCH 5.4 12/85] clk: stm32f4: fix post divisor setup for I2S/SAI PLLs

Greg Kroah-Hartman
2021-08-10T17:34:48Z

From: Dario Binacchi <dariobin@libero.it>

[ Upstream commit 24b5b1978cd5a80db58e2a19db2f9c36fe8d4f7a ]

Enabling the framebuffer leads to a system hang. Running, as a debug
hack, the store_pan() function in drivers/video/fbdev/core/fbsysfs.c
without taking the console_lock, allows to see the crash backtrace on
the serial line.

~ # echo 0 0 > /sys/class/graphics/fb0/pan

[ 9.719414] Unhandled exception: IPSR = 00000005 LR = fffffff1
[ 9.726937] CPU: 0 PID: 49 Comm: sh Not tainted 5.13.0-rc5 #9
[ 9.733008] Hardware name: STM32 (Device Tree Support)
[ 9.738296] PC is at clk_gate_is_enabled+0x0/0x28
[ 9.743426] LR is at stm32f4_pll_div_set_rate+0xf/0x38
[ 9.748857] pc : [<0011e4be>] lr : [<0011f9e3>] psr: 0100000b
[ 9.755373] sp : 00bc7be0 ip : 00000000 fp : 001f3ac4
[ 9.760812] r10: 002610d0 r9 : 01efe920 r8 : 00540560
[ 9.766269] r7 : 02e7ddb0 r6 : 0173eed8 r5 : 00000000 r4 : 004027c0
[ 9.773081] r3 : 0011e4bf r2 : 02e7ddb0 r1 : 0173eed8 r0 : 1d3267b8
[ 9.779911] xPSR: 0100000b
[ 9.782719] CPU: 0 PID: 49 Comm: sh Not tainted 5.13.0-rc5 #9
[ 9.788791] Hardware name: STM32 (Device Tree Support)
[ 9.794120] [<0000afa1>] (unwind_backtrace) from [<0000a33f>] (show_stack+0xb/0xc)
[ 9.802421] [<0000a33f>] (show_stack) from [<0000a8df>] (__invalid_entry+0x4b/0x4c)

The `pll_num' field in the post_div_data configuration contained a wrong
value which also referenced an uninitialized hardware clock when
clk_register_pll_div() was called.

Fixes: 517633ef630e ("clk: stm32f4: Add post divisor for I2S & SAI PLLs")
Signed-off-by: Dario Binacchi <dariobin@libero.it>
Reviewed-by: Gabriel Fernandez <gabriel.fernandez@st.com>
Link: https://lore.kernel.org/r/20210725160725.10788-1-dariobin@libero.it
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/clk/clk-stm32f4.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c
index 18117ce5ff85..5c75e3d906c2 100644
--- a/drivers/clk/clk-stm32f4.c
+++ b/drivers/clk/clk-stm32f4.c
@@ -526,7 +526,7 @@ struct stm32f4_pll {

struct stm32f4_pll_post_div_data {
int idx;
- u8 pll_num;
+ int pll_idx;
const char *name;
const char *parent;
u8 flag;
@@ -557,13 +557,13 @@ static const struct clk_div_table post_divr_table[] = {

#define MAX_POST_DIV 3
static const struct stm32f4_pll_post_div_data post_div_data[MAX_POST_DIV] = {
- { CLK_I2SQ_PDIV, PLL_I2S, "plli2s-q-div", "plli2s-q",
+ { CLK_I2SQ_PDIV, PLL_VCO_I2S, "plli2s-q-div", "plli2s-q",
CLK_SET_RATE_PARENT, STM32F4_RCC_DCKCFGR, 0, 5, 0, NULL},

- { CLK_SAIQ_PDIV, PLL_SAI, "pllsai-q-div", "pllsai-q",
+ { CLK_SAIQ_PDIV, PLL_VCO_SAI, "pllsai-q-div", "pllsai-q",
CLK_SET_RATE_PARENT, STM32F4_RCC_DCKCFGR, 8, 5, 0, NULL },

- { NO_IDX, PLL_SAI, "pllsai-r-div", "pllsai-r", CLK_SET_RATE_PARENT,
+ { NO_IDX, PLL_VCO_SAI, "pllsai-r-div", "pllsai-r", CLK_SET_RATE_PARENT,
STM32F4_RCC_DCKCFGR, 16, 2, 0, post_divr_table },
};

@@ -1774,7 +1774,7 @@ static void __init stm32f4_rcc_init(struct device_node *np)
post_div->width,
post_div->flag_div,
post_div->div_table,
- clks[post_div->pll_num],
+ clks[post_div->pll_idx],
&stm32f4_clk_lock);

if (post_div->idx != NO_IDX)
--
2.30.2