Re: [PATCH v4] pwrap: mediatek: fix FSM timeout issue

[Matthias Brugger <matthias.bgg@gmail.com>]

On 13/05/2022 05:43, Zhiyong Tao wrote:
> From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>
> 
> Fix pwrap FSM timeout issue which leads the system crash on GFX VSRAM
> power on.
> The crash log:
> [ 3986.543401] mediatek-drm-dp 1c500000.edp_tx: drm_helper_hpd_irq_event
> [ 3986.670756] vsram_others: is_enabled() failed: -ETIMEDOUT
> [ 3986.670765] mali 13000000.mali: Power on reg 1 failed error = -110
> [ 3986.670768] ------------[ cut here ]------------
> [ 3986.670770] unbalanced disables for vsram_others
> [ 3986.670783] WARNING: CPU: 7 PID: 4125 at drivers/regulator/core.c:2761 _regulator_disable+0x194/0x1a0
> [ 3986.670785] Modules linked in: rfcomm algif_hash algif_skcipher af_alg veth uinput btusb btmtk btintel btbcm btrtl xt_cgroup bluetooth uvcvideo videobuf2_vmalloc ecdh_generic ecc mtk_vcodec_dec mtk_vcodec_enc mtk_mdp3 v4l2_h264 mtk_vcodec_common videobuf2_dma_contig mtk_vpu videobuf2_memops v4l2_mem2mem xt_MASQUERADE videobuf2_v4l2 videobuf2_common cros_ec_rpmsg mtk_scp mtk_rpmsg rpmsg_core mtk_scp_ipi ip6table_nat fuse 8021q iio_trig_sysfs cros_ec_sensors cros_ec_lid_angle cros_ec_sensors_core industrialio_triggered_buffer kfifo_buf cros_ec_sensorhub mt7921e mt7921_common mt76_connac_lib lzo_rle mt76 lzo_compress mac80211 cfg80211 zram r8152 mii joydev
> [ 3986.670830] CPU: 7 PID: 4125 Comm: mali-cmar-backe Not tainted 5.10.78-CL2781499-v287 #1 b899b40a63da40d4767c6c0e96b6700d2f3eb242
> [ 3986.670832] Hardware name: MediaTek Tomato board (DT)
> [ 3986.670835] pstate: 60400009 (nZCv daif +PAN -UAO -TCO BTYPE=--)
> [ 3986.670838] pc : _regulator_disable+0x194/0x1a0
> [ 3986.670840] lr : _regulator_disable+0x194/0x1a0
> [ 3986.670842] sp : ffffffc016203a10
> [ 3986.670843] x29: ffffffc016203a10 x28: ffffffb7c3186b28
> [ 3986.670846] x27: 0000000000000002 x26: fffffffffffffdc8
> [ 3986.670848] x25: ffffffc017225000 x24: ffffffb7c0e94880
> [ 3986.670851] x23: ffffffb7c31840f0 x22: ffffffd6b4f3e275
> [ 3986.670853] x21: ffffffb7c3181a00 x20: ffffffb7c27e7800
> [ 3986.670855] x19: ffffffb7c27e7800 x18: 00000000ffff0a10
> [ 3986.670857] x17: 0000000000000020 x16: 00000000000000ec
> [ 3986.670860] x15: ffffffd6b44fa17c x14: 0000000000000003
> [ 3986.670862] x13: 0000000000000004 x12: 0000000000fd8318
> [ 3986.670864] x11: c000000100029ccd x10: 00000000ffffffff
> [ 3986.670866] x9 : 7dd6d080afd6f400 x8 : 7dd6d080afd6f400
> [ 3986.670868] x7 : 0000000000000000 x6 : ffffffd6b5459f0c
> [ 3986.670871] x5 : ffffffc016203a58 x4 : 0000000000000000
> [ 3986.670873] x3 : ffffffc016203668 x2 : ffffffc016203670
> [ 3986.670875] x1 : 0000000100029ccd x0 : 0000000000000024
> [ 3986.670878] Call trace:
> [ 3986.670880]  _regulator_disable+0x194/0x1a0
> [ 3986.670883]  regulator_disable+0x4c/0x8c
> 
> Add a usleep delay to avoid busy read for the H/W status.
> If (time_after()) be turn first, it maybe cause the system behavior
> crash problem like above. so we change it after sleep delay.
> 
> Fixes: 1f022d84bd19 ("soc: mediatek: Add PMIC wrapper for MT8135 and
> MT8173 SoCs")
> 
> Signed-off-by: Zhiyong.Tao <zhiyong.tao@mediatek.com>

I prefer the solution send by Angelo on this:
https://lore.kernel.org/linux-mediatek/a8bd608c-d94c-f4a2-e3b1-3381c9098caf@gmail.com/T/#m44170235be954f39bafc404b266d2c5b59dd4853

Please feel free to provide feedback on this.

Regards,
Matthias

> ---
>   drivers/soc/mediatek/mtk-pmic-wrap.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soc/mediatek/mtk-pmic-wrap.c b/drivers/soc/mediatek/mtk-pmic-wrap.c
> index 952bc554f443..f9e7c2f35157 100644
> --- a/drivers/soc/mediatek/mtk-pmic-wrap.c
> +++ b/drivers/soc/mediatek/mtk-pmic-wrap.c
> @@ -4,6 +4,7 @@
>    * Author: Flora Fu, MediaTek
>    */
>   #include <linux/clk.h>
> +#include <linux/delay.h>
>   #include <linux/interrupt.h>
>   #include <linux/io.h>
>   #include <linux/kernel.h>
> @@ -1197,10 +1198,13 @@ static int pwrap_wait_for_state(struct pmic_wrapper *wrp,
>   	timeout = jiffies + usecs_to_jiffies(10000);
>   
>   	do {
> -		if (time_after(jiffies, timeout))
> -			return fp(wrp) ? 0 : -ETIMEDOUT;
>   		if (fp(wrp))
>   			return 0;
> +
> +		usleep_range(10, 11);
> +
> +		if (time_after(jiffies, timeout))
> +			return fp(wrp) ? 0 : -ETIMEDOUT;
>   	} while (1);
>   }
>