dsp: add workqueue for audio_prm and pinctrl_lpi

GPR will deregister and register to audio notifier during
SSR. When ADSP up notification comes to pinctrl LPI before
GPR is registered to audio notifier. Pinctrl LPI will
reset core vote clks however GPR is not masked as up yet
which will causes audio hold clk mutex_lock for long time
and cause kernel panic.
Add workqueue for audio_prm and pinctrl_lpi to avoid hold
clk mutex_lock for long time to resolve this issue.

Change-Id: Idcd7c7d18709dbd5ae85e19eb2abfbed009ffab1
Signed-off-by: Meng Wang <[email protected]>

dsp/audio_prm.c

@@ -1,13 +1,6 @@
-/* Copyright (c) 2019-2020, The Linux Foundation. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 and
- * only version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019-2021, The Linux Foundation. All rights reserved.
  */
 
 #include <linux/slab.h>
@@ -37,6 +30,7 @@ struct audio_prm {
 	atomic_t state;
 	atomic_t status;
 	bool is_adsp_up;
+	struct work_struct reset_work;
 };
 
 static struct audio_prm g_prm;
@@ -313,6 +307,13 @@ int audio_prm_set_lpass_clk_cfg (struct clk_cfg *clk, uint8_t enable)
 }
 EXPORT_SYMBOL(audio_prm_set_lpass_clk_cfg);
 
+static void audio_prm_adsp_work(struct work_struct *work)
+{
+	mutex_lock(&g_prm.lock);
+	g_prm.is_adsp_up = true;
+	mutex_unlock(&g_prm.lock);
+}
+
 static int audio_prm_service_cb(struct notifier_block *this,
 				unsigned long opcode, void *data)
 {
@@ -327,9 +328,7 @@ static int audio_prm_service_cb(struct notifier_block *this,
 		mutex_unlock(&g_prm.lock);
 		break;
 	case AUDIO_NOTIFIER_SERVICE_UP:
-		mutex_lock(&g_prm.lock);
-		g_prm.is_adsp_up = true;
-		mutex_unlock(&g_prm.lock);
+		schedule_work(&g_prm.reset_work);
 		break;
 	default:
 		break;
@@ -362,6 +361,7 @@ static int audio_prm_probe(struct gpr_device *adev)
 
 	init_waitqueue_head(&g_prm.wait);
 	g_prm.is_adsp_up = true;
+	INIT_WORK(&g_prm.reset_work, audio_prm_adsp_work);
 	pr_err("%s: prm probe success\n", __func__);
 	return ret;
 }
@@ -374,6 +374,9 @@ static int audio_prm_remove(struct gpr_device *adev)
 	mutex_lock(&g_prm.lock);
 	g_prm.is_adsp_up = false;
 	g_prm.adev = NULL;
+	flush_work(&g_prm.reset_work);
+	cancel_work_sync(&g_prm.reset_work);
+	INIT_WORK(&g_prm.reset_work, NULL);
 	mutex_unlock(&g_prm.lock);
 	return ret;
 }

soc/pinctrl-lpi.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2016-2020, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2016-2021, The Linux Foundation. All rights reserved.
  */
 
 #include <linux/gpio.h>
@@ -119,6 +119,7 @@ struct lpi_gpio_state {
 	struct mutex         slew_access_lock;
 	bool core_hw_vote_status;
 	struct mutex        core_hw_vote_lock;
+	struct work_struct reset_work;
 };
 
 static const char *const lpi_gpio_groups[] = {
@@ -471,6 +472,18 @@ static void lpi_gpio_set(struct gpio_chip *chip, unsigned int pin, int value)
 	lpi_config_set(state->ctrl, pin, &config, 1);
 }
 
+static void lpi_clk_reset(struct work_struct *work)
+{
+	struct lpi_gpio_state *state = dev_get_drvdata(lpi_dev);
+
+	if (state->lpass_core_hw_vote)
+		digital_cdc_rsc_mgr_hw_vote_reset(
+			state->lpass_core_hw_vote);
+	if (state->lpass_audio_hw_vote)
+		digital_cdc_rsc_mgr_hw_vote_reset(
+			state->lpass_audio_hw_vote);
+}
+
 static int lpi_notifier_service_cb(struct notifier_block *this,
 				   unsigned long opcode, void *ptr)
 {
@@ -496,12 +509,7 @@ static int lpi_notifier_service_cb(struct notifier_block *this,
 		if (!lpi_dev_up) {
 			/* Add 100ms sleep to ensure AVS is up after SSR */
 			msleep(100);
-			if (state->lpass_core_hw_vote)
-				digital_cdc_rsc_mgr_hw_vote_reset(
-					state->lpass_core_hw_vote);
-			if (state->lpass_audio_hw_vote)
-				digital_cdc_rsc_mgr_hw_vote_reset(
-					state->lpass_audio_hw_vote);
+			schedule_work(&state->reset_work);
 		}
 
 		lpi_dev_up = true;
@@ -742,6 +750,7 @@ static int lpi_pinctrl_probe(struct platform_device *pdev)
 	}
 
 	state->base = lpi_base;
+	INIT_WORK(&state->reset_work, lpi_clk_reset);
 
 	for (i = 0; i < npins; i++, pindesc++) {
 		pad = &pads[i];