MLK-24132: ASoC: fsl_micfil: Fix kernel panic when hwvad is disabled

The reason is that we access the register when power is disabled

reproduce command:
echo 8 > /sys/devices/platform/soc@0/30c00000.bus/30c00000.spba-bus/30ca0000.micfil/hwvad/enable

[  332.838518] SError Interrupt on CPU2, code 0xbf000002 -- SError
[  332.838521] CPU: 2 PID: 1383 Comm: sh Tainted: G           O      5.4.24-2.1.0+g2ad925d15481 #1
[  332.838523] Hardware name: NXP i.MX8MPlus EVK board (DT)
[  332.838525] pstate: 20000085 (nzCv daIf -PAN -UAO)
[  332.838526] pc : regcache_sync_block+0x7c/0x258
[  332.838528] lr : regcache_sync_block+0xf0/0x258
[  332.838531] sp : ffff800012bf3be0
[  332.838532] x29: ffff800012bf3be0 x28: 0000000000000000
[  332.838535] x27: 0000000000000000 x26: 0000000000000001
[  332.838541] x25: ffff00017753ed00 x24: 0000000000000000
[  332.838546] x23: ffff00017706d400 x22: 000000000000002b
[  332.838550] x21: ffff00017753f100 x20: ffff000177538c00
[  332.838554] x19: 0000000000000001 x18: 0000000000000000
[  332.838559] x17: 0000000000000000 x16: 0000000000000000
[  332.838564] x15: 0000000000000000 x14: 0000000000000000
[  332.838567] x13: 0000000000000000 x12: 0000000000000000
[  332.838572] x11: ffff800012bf3d50 x10: ffff000173c0e900
[  332.838577] x9 : ffff00017706d870 x8 : 0000000000000000
[  332.838582] x7 : 00000000000000a8 x6 : 0000000000000000
[  332.838587] x5 : 0000000000000000 x4 : ffff800010769d88
[  332.838592] x3 : ffff80001076d278 x2 : 0000000008000000
[  332.838597] x1 : ffff800023c10000 x0 : 0000000000000000
[  332.838603] Kernel panic - not syncing: Asynchronous SError Interrupt
[  332.838605] CPU: 2 PID: 1383 Comm: sh Tainted: G           O      5.4.24-2.1.0+g2ad925d15481 #1
[  332.838606] Hardware name: NXP i.MX8MPlus EVK board (DT)
[  332.838608] Call trace:
[  332.838609]  dump_backtrace+0x0/0x140
[  332.838612]  show_stack+0x14/0x20
[  332.838613]  dump_stack+0xb4/0xf8
[  332.838617]  panic+0x158/0x324
[  332.838618]  nmi_panic+0x84/0x88
[  332.838621]  arm64_serror_panic+0x74/0x80
[  332.838622]  do_serror+0x80/0x138
[  332.838623]  el1_error+0x84/0xf8
[  332.838627]  regcache_sync_block+0x7c/0x258
[  332.838628]  regcache_rbtree_sync+0x60/0xb0
[  332.838629]  regcache_sync+0xac/0x140
[  332.838633]  disable_hwvad+0x3c/0x1f0
[  332.838634]  micfil_hwvad_handler+0x78/0x170
[  332.838635]  kobj_attr_store+0x14/0x28
[  332.838637]  sysfs_kf_write+0x40/0x50
[  332.838640]  kernfs_fop_write+0xf8/0x210
[  332.838641]  __vfs_write+0x18/0x40
[  332.838642]  vfs_write+0xdc/0x1c8
[  332.838646]  ksys_write+0x68/0xf0
[  332.838647]  __arm64_sys_write+0x18/0x20
[  332.838648]  el0_svc_common.constprop.0+0x68/0x160
[  332.838651]  el0_svc_handler+0x20/0x80
[  332.838653]  el0_svc+0x8/0xc
[  332.838972] SMP: stopping secondary CPUs
[  332.838974] Kernel Offset: disabled
[  332.838975] CPU features: 0x0002,2000200c
[  332.838976] Memory Limit: none

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Viorel Suman <viorel.suman@nxp.com>

1 files changed, 10 insertions, 11 deletions

diff --git a/sound/soc/fsl/fsl_micfil.c b/sound/soc/fsl/fsl_micfil.c
index 97187737d1a3..a04376768832 100644
--- a/sound/soc/fsl/fsl_micfil.c
+++ b/sound/soc/fsl/fsl_micfil.c
@@ -2066,14 +2066,6 @@ static int disable_hwvad(struct device *dev, bool sync)
 	int ret = 0;
 	u32 state;
 
-	/* This is required because if an arecord was done,
-	 * suspend function will mark regmap as cache only
-	 * and reads/writes in volatile regs will fail
-	 */
-	regcache_cache_only(micfil->regmap, false);
-	regcache_mark_dirty(micfil->regmap);
-	regcache_sync(micfil->regmap);
-
 	/* disable is called with sync = false only from
 	 * system suspend and in this case, you should not
 	 * change the hwvad_state so we know at system_resume
@@ -2087,6 +2079,14 @@ static int disable_hwvad(struct device *dev, bool sync)
 		state = atomic_read(&micfil->hwvad_state);
 
 	if (state == MICFIL_HWVAD_ON) {
+		/* This is required because if an arecord was done,
+		 * suspend function will mark regmap as cache only
+		 * and reads/writes in volatile regs will fail
+		 */
+		regcache_cache_only(micfil->regmap, false);
+		regcache_mark_dirty(micfil->regmap);
+		regcache_sync(micfil->regmap);
+
 		/* Voice Activity Detector Reset */
 		ret |= regmap_update_bits(micfil->regmap,
 					  REG_MICFIL_VAD0_CTRL1,
@@ -2135,14 +2135,13 @@ static int disable_hwvad(struct device *dev, bool sync)
 						  0);
 		}
 
+		if (sync)
+			pm_runtime_put_sync(dev);
 	} else {
 		ret = -EPERM;
 		dev_err(dev, "HWVAD is not enabled %d\n", ret);
 	}
 
-	if (sync)
-		pm_runtime_put_sync(dev);
-
 	return ret;
 }