Suspending/resuming with an HDMI dongle attached leads to crashes from an audio regmap.

Unable to handle kernel paging request at virtual address ffffffc018068000 Mem abort info: ESR = 0x96000047 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000047 CM = 0, WnR = 1 swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000081b12000 [ffffffc018068000] pgd=0000000275d14003, pud=0000000275d14003, pmd=000000026365d003, pte=0000000000000000 Internal error: Oops: 96000047 [#1] PREEMPT SMP Call trace: regmap_mmio_write32le+0x2c/0x40 regmap_mmio_write+0x48/0x6c _regmap_bus_reg_write+0x34/0x44 _regmap_write+0x100/0x150 regcache_default_sync+0xc0/0x138 regcache_sync+0x188/0x26c lpass_platform_pcmops_resume+0x48/0x54 [snd_soc_lpass_platform] snd_soc_component_resume+0x28/0x40 soc_resume_deferred+0x6c/0x178 process_one_work+0x208/0x3c8 worker_thread+0x23c/0x3e8 kthread+0x144/0x178 ret_from_fork+0x10/0x18 Code: d503201f d50332bf f94002a8 8b344108 (b9000113)

I can reliably reproduce this problem by running 'tail' on the registers file in debugfs for the hdmi regmap.

# tail /sys/kernel/debug/regmap/62d87000.lpass-lpass_hdmi/registers [ 84.658733] Unable to handle kernel paging request at virtual address ffffffd0128e800c

This crash happens because we're trying to read registers from the regmap beyond the length of the mapping created by ioremap().

The number of hdmi_rdma_channels determines the size of the regmap via this code in sound/soc/qcom/lpass-cpu.c:

lpass_hdmi_regmap_config.max_register = LPAIF_HDMI_RDMAPER_REG(variant, variant->hdmi_rdma_channels);

According to debugfs the size of the regmap is 0x68010 but according to the DTS file posted in [1] the size is only 0x68000 (see the first reg property of the lpass_cpu node). Let's change the number of channels to be 3 instead of 4 so the math works out to have a max register of 0x67010, nicely fitting inside of the region size of 0x68000.

Note: I tried to bump up the size of the register region to the next page to include the 0x68010 register but then the tail command caused SErrors with an async abort, implying that the register region doesn't exist or it isn't clocked because the bus is telling us that the register read failed. I reduce the number of channels and played audio through the HDMI channel and it kept working so I think this is correct.

Fixes: 2ad63dc8df6b ("ASoC: qcom: sc7180: Add support for audio over DP") Link: https://lore.kernel.org/r/1601448168-18396-2-git-send-email-srivasam@codeaur... [1] Cc: V Sujith Kumar Reddy vsujithk@codeaurora.org Cc: Srinivasa Rao srivasam@codeaurora.org Cc: Srinivas Kandagatla srinivas.kandagatla@linaro.org Cc: Cheng-Yi Chiang cychiang@chromium.org Signed-off-by: Stephen Boyd swboyd@chromium.org --- sound/soc/qcom/lpass-sc7180.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/qcom/lpass-sc7180.c b/sound/soc/qcom/lpass-sc7180.c index 85db650c2169..3127b6022ea3 100644 --- a/sound/soc/qcom/lpass-sc7180.c +++ b/sound/soc/qcom/lpass-sc7180.c @@ -174,7 +174,7 @@ static struct lpass_variant sc7180_data = { .rdma_channels = 5, .hdmi_rdma_reg_base = 0x64000, .hdmi_rdma_reg_stride = 0x1000, - .hdmi_rdma_channels = 4, + .hdmi_rdma_channels = 3, .dmactl_audif_start = 1, .wrdma_reg_base = 0x18000, .wrdma_reg_stride = 0x1000,

base-commit: 5c8fe583cce542aa0b84adc939ce85293de36e5e