iface clock is shared with other drivers, which may reconfigure this before the serial driver comes up. This may lead to crashes like the one below where GCC_BLSP1_AHB_CLK is same across multiple drivers like bam dma. <0>[ 3.164471] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP <4>[ 3.164479] Modules linked in: <4>[ 3.164495] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc8-00008-ge033b9909fff-dirty #175 <4>[ 3.164501] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) <4>[ 3.164508] pstate: 40000085 (nZcv daIf -PAN -UAO) <4>[ 3.164514] pc : msm_read.isra.2+0x20/0x50 <4>[ 3.164520] lr : msm_read.isra.2+0x1c/0x50 <4>[ 3.164526] sp : ffff000008033a50 <4>[ 3.164531] x29: ffff000008033a50 x28: ffff000009486018 <4>[ 3.164548] x27: 0000000000000001 x26: ffff7dfffe7ff070 <4>[ 3.164565] x25: 0000000000000034 x24: ffff000009486000 <4>[ 3.164582] x23: 0000000000000000 x22: ffff00000978e190 <4>[ 3.164599] x21: ffff0000095e8228 x20: 0000000000000034 <4>[ 3.164616] x19: ffff7dfffe7ff008 x18: ffffffffffffffff <4>[ 3.164632] x17: 0000000000000000 x16: 0000000000000000 <4>[ 3.164649] x15: ffff0000094a96c8 x14: ffff00008978e6bf <4>[ 3.164666] x13: ffff00000978e6cd x12: 0000000000000038 <4>[ 3.164683] x11: ffff0000094c6000 x10: 0000000000000c24 <4>[ 3.164699] x9 : ffff80003c89b400 x8 : ffff000008033970 <4>[ 3.164716] x7 : ffff80000eb04100 x6 : 00000000000af304 <4>[ 3.164732] x5 : 0000000000000c40 x4 : ffff80003c06f000 <4>[ 3.164750] x3 : ffff80003c89b498 x2 : 0000000000000000 <4>[ 3.164766] x1 : ffff80003ca68000 x0 : 0000000000000800 <0>[ 3.164785] Process swapper/0 (pid: 1, stack limit = 0x(____ptrval____)) <4>[ 3.164791] Call trace: <4>[ 3.164797] msm_read.isra.2+0x20/0x50 <4>[ 3.164804] msm_reset_dm_count+0x44/0x80 <4>[ 3.164810] __msm_console_write+0x1c8/0x1d0 <4>[ 3.164816] msm_serial_early_write_dm+0x3c/0x50 <4>[ 3.164823] console_unlock.part.6+0x468/0x528 <4>[ 3.164829] vprintk_emit+0x210/0x218 <4>[ 3.164835] vprintk_default+0x48/0x58 <4>[ 3.164841] vprintk_func+0xf0/0x1c0 <4>[ 3.164847] printk+0x74/0x94 <4>[ 3.164853] sci_init+0x24/0x3c <4>[ 3.164859] do_one_initcall+0x54/0x248 <4>[ 3.164866] kernel_init_freeable+0x210/0x378 <4>[ 3.164872] kernel_init+0x18/0x118 <4>[ 3.164878] ret_from_fork+0x10/0x1c <0>[ 3.164884] Code: aa1e03e0 8b214273 97e616f7 d503201f (b9400260) Link: https://lore.kernel.org/lkml/1cae8f10-55f5-20ce-9105-30af6f88bd6e@xxxxxxxxxxxxxx/ Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx> --- This is purely dependent on boot constraint subsystem by Viresh. Link: https://lore.kernel.org/lkml/cover.1519380923.git.viresh.kumar@xxxxxxxxxx/ --- drivers/soc/qcom/boot_constraint.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/soc/qcom/boot_constraint.c b/drivers/soc/qcom/boot_constraint.c index ca01eb50d9a9..c4e580a118f0 100644 --- a/drivers/soc/qcom/boot_constraint.c +++ b/drivers/soc/qcom/boot_constraint.c @@ -49,6 +49,10 @@ static struct dev_boot_constraint_supply_info vddio_info = { .name = "vddio" }; +static struct dev_boot_constraint_clk_info uart_iface_clk_info = { + .name = "iface", +}; + static struct dev_boot_constraint constraints_mdss[] = { { .type = DEV_BOOT_CONSTRAINT_PM, @@ -92,6 +96,13 @@ static struct dev_boot_constraint constraints_dsi[] = { }, }; +static struct dev_boot_constraint constraints_uart[] = { + { + .type = DEV_BOOT_CONSTRAINT_CLK, + .data = &uart_iface_clk_info, + }, +}; + static struct dev_boot_constraint_of constraints[] = { { .compat = "qcom,mdss", @@ -105,6 +116,10 @@ static struct dev_boot_constraint_of constraints[] = { .compat = "qcom,mdss-dsi-ctrl", .constraints = constraints_dsi, .count = ARRAY_SIZE(constraints_dsi), + }, { + .compat = "qcom,msm-uartdm-v1.4", + .constraints = constraints_uart, + .count = ARRAY_SIZE(constraints_uart), }, }; -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
