Re: [PATCH v2] clk: stm32f4: fix post divisor setup for I2S/SAI PLLs

From: Gabriel FERNANDEZ
Date: Thu Jul 01 2021 - 02:46:40 EST


Hi Stephen,
it's ok for me, you can add my Reviewed-by: Gabriel Fernandez <gabriel.fernandez@xxxxxx>

Thank's
Gabriel
________________________________________
From: Stephen Boyd <sboyd@xxxxxxxxxx>
Sent: Wednesday, June 30, 2021 8:36 PM
To: Dario Binacchi; linux-clk@xxxxxxxxxxxxxxx
Cc: Dario Binacchi; Alexandre TORGUE - foss; Gabriel FERNANDEZ; Maxime Coquelin; Michael Turquette; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Subject: Re: [PATCH v2] clk: stm32f4: fix post divisor setup for I2S/SAI PLLs

Quoting Dario Binacchi (2021-06-23 14:00:39)
> 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@xxxxxxxxx>
>
> ---

Can someone from ST review this? Gabriel or Alexandre?

>
> Changes in v2:
> - Change 'u8 pll_num' from 'stm32f4_pll_post_div_data' structure into
> 'int pll_idx'.
>
> 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)