[PATCH] mfd: qcom-pm8xxx: Switch to nested IRQ handler

[Linus Walleij <linus.walleij@linaro.org>]

After facing problems when using the chained interrupt for handling
the PM8xxx IRQs we solve the issue by simply requesting the IRQ
from the producer (in this case the TLMM) as any other IRQ, and
nesting any consumer IRQs.

Recently the driver is hanging during probe:
[    1.646990] ssbi 500000.qcom,ssbi: SSBI controller type: 'pmic-arbiter'
[    1.650901] pm8xxx_probe: PMIC revision 1: E3
[    1.655078] pm8xxx_probe: PMIC revision 2: 00
(...)
it just hangs after this.

I am unable to bisect down to what is causing this hang, but the
patch fixes the problem.

After this patch the DragonBoard APQ8060 boots to prompt without
problems.

Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: David Heidelberg <david@ixit.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/mfd/qcom-pm8xxx.c | 60 ++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 32 deletions(-)

diff --git a/drivers/mfd/qcom-pm8xxx.c b/drivers/mfd/qcom-pm8xxx.c
index acd172ddcbd6..223aed53aad8 100644
--- a/drivers/mfd/qcom-pm8xxx.c
+++ b/drivers/mfd/qcom-pm8xxx.c
@@ -65,7 +65,7 @@
 struct pm_irq_data {
 	int num_irqs;
 	struct irq_chip *irq_chip;
-	void (*irq_handler)(struct irq_desc *desc);
+	irqreturn_t (*irq_handler)(int irq, void *data);
 };
 
 struct pm_irq_chip {
@@ -140,7 +140,7 @@ static int pm8xxx_irq_block_handler(struct pm_irq_chip *chip, int block)
 		if (bits & (1 << i)) {
 			pmirq = block * 8 + i;
 			irq = irq_find_mapping(chip->irqdomain, pmirq);
-			generic_handle_irq(irq);
+			handle_nested_irq(irq);
 		}
 	}
 	return 0;
@@ -170,19 +170,16 @@ static int pm8xxx_irq_master_handler(struct pm_irq_chip *chip, int master)
 	return ret;
 }
 
-static void pm8xxx_irq_handler(struct irq_desc *desc)
+static irqreturn_t pm8xxx_irq_handler(int irq, void *data)
 {
-	struct pm_irq_chip *chip = irq_desc_get_handler_data(desc);
-	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
+	struct pm_irq_chip *chip = data;
 	unsigned int root;
 	int	i, ret, masters = 0;
 
-	chained_irq_enter(irq_chip, desc);
-
 	ret = regmap_read(chip->regmap, SSBI_REG_ADDR_IRQ_ROOT, &root);
 	if (ret) {
 		pr_err("Can't read root status ret=%d\n", ret);
-		return;
+		return IRQ_NONE;
 	}
 
 	/* on pm8xxx series masters start from bit 1 of the root */
@@ -193,7 +190,7 @@ static void pm8xxx_irq_handler(struct irq_desc *desc)
 		if (masters & (1 << i))
 			pm8xxx_irq_master_handler(chip, i);
 
-	chained_irq_exit(irq_chip, desc);
+	return IRQ_HANDLED;
 }
 
 static void pm8821_irq_block_handler(struct pm_irq_chip *chip,
@@ -217,7 +214,7 @@ static void pm8821_irq_block_handler(struct pm_irq_chip *chip,
 		if (bits & BIT(i)) {
 			pmirq = block * 8 + i;
 			irq = irq_find_mapping(chip->irqdomain, pmirq);
-			generic_handle_irq(irq);
+			handle_nested_irq(irq);
 		}
 	}
 }
@@ -232,19 +229,17 @@ static inline void pm8821_irq_master_handler(struct pm_irq_chip *chip,
 			pm8821_irq_block_handler(chip, master, block);
 }
 
-static void pm8821_irq_handler(struct irq_desc *desc)
+static irqreturn_t pm8821_irq_handler(int irq, void *data)
 {
-	struct pm_irq_chip *chip = irq_desc_get_handler_data(desc);
-	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
+	struct pm_irq_chip *chip = data;
 	unsigned int master;
 	int ret;
 
-	chained_irq_enter(irq_chip, desc);
 	ret = regmap_read(chip->regmap,
 			  PM8821_SSBI_REG_ADDR_IRQ_MASTER0, &master);
 	if (ret) {
 		pr_err("Failed to read master 0 ret=%d\n", ret);
-		goto done;
+		return IRQ_NONE;
 	}
 
 	/* bits 1 through 7 marks the first 7 blocks in master 0 */
@@ -253,19 +248,18 @@ static void pm8821_irq_handler(struct irq_desc *desc)
 
 	/* bit 0 marks if master 1 contains any bits */
 	if (!(master & BIT(0)))
-		goto done;
+		return IRQ_HANDLED;
 
 	ret = regmap_read(chip->regmap,
 			  PM8821_SSBI_REG_ADDR_IRQ_MASTER1, &master);
 	if (ret) {
 		pr_err("Failed to read master 1 ret=%d\n", ret);
-		goto done;
+		return IRQ_NONE;
 	}
 
 	pm8821_irq_master_handler(chip, 1, master);
 
-done:
-	chained_irq_exit(irq_chip, desc);
+	return IRQ_HANDLED;
 }
 
 static void pm8xxx_irq_mask_ack(struct irq_data *d)
@@ -516,15 +510,16 @@ MODULE_DEVICE_TABLE(of, pm8xxx_id_table);
 static int pm8xxx_probe(struct platform_device *pdev)
 {
 	const struct pm_irq_data *data;
+	struct device *dev = &pdev->dev;
 	struct regmap *regmap;
 	int irq, rc;
 	unsigned int val;
 	u32 rev;
 	struct pm_irq_chip *chip;
 
-	data = of_device_get_match_data(&pdev->dev);
+	data = of_device_get_match_data(dev);
 	if (!data) {
-		dev_err(&pdev->dev, "No matching driver data found\n");
+		dev_err(dev, "No matching driver data found\n");
 		return -EINVAL;
 	}
 
@@ -532,7 +527,7 @@ static int pm8xxx_probe(struct platform_device *pdev)
 	if (irq < 0)
 		return irq;
 
-	regmap = devm_regmap_init(&pdev->dev, NULL, pdev->dev.parent,
+	regmap = devm_regmap_init(dev, NULL, pdev->dev.parent,
 				  &ssbi_regmap_config);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
@@ -556,8 +551,7 @@ static int pm8xxx_probe(struct platform_device *pdev)
 	pr_info("PMIC revision 2: %02X\n", val);
 	rev |= val << BITS_PER_BYTE;
 
-	chip = devm_kzalloc(&pdev->dev,
-			    struct_size(chip, config, data->num_irqs),
+	chip = devm_kzalloc(dev, struct_size(chip, config, data->num_irqs),
 			    GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;
@@ -569,21 +563,25 @@ static int pm8xxx_probe(struct platform_device *pdev)
 	chip->pm_irq_data = data;
 	spin_lock_init(&chip->pm_irq_lock);
 
-	chip->irqdomain = irq_domain_add_linear(pdev->dev.of_node,
+	chip->irqdomain = irq_domain_add_linear(dev->of_node,
 						data->num_irqs,
 						&pm8xxx_irq_domain_ops,
 						chip);
 	if (!chip->irqdomain)
 		return -ENODEV;
 
-	irq_set_chained_handler_and_data(irq, data->irq_handler, chip);
+	rc = devm_request_irq(dev, irq, data->irq_handler,
+			      IRQF_SHARED, KBUILD_MODNAME, chip);
+	if (rc) {
+		dev_err(dev, "failed to request IRQ\n");
+		return rc;
+	}
+
 	irq_set_irq_wake(irq, 1);
 
-	rc = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
-	if (rc) {
-		irq_set_chained_handler_and_data(irq, NULL, NULL);
+	rc = of_platform_populate(pdev->dev.of_node, NULL, NULL, dev);
+	if (rc)
 		irq_domain_remove(chip->irqdomain);
-	}
 
 	return rc;
 }
@@ -596,11 +594,9 @@ static int pm8xxx_remove_child(struct device *dev, void *unused)
 
 static int pm8xxx_remove(struct platform_device *pdev)
 {
-	int irq = platform_get_irq(pdev, 0);
 	struct pm_irq_chip *chip = platform_get_drvdata(pdev);
 
 	device_for_each_child(&pdev->dev, NULL, pm8xxx_remove_child);
-	irq_set_chained_handler_and_data(irq, NULL, NULL);
 	irq_domain_remove(chip->irqdomain);
 
 	return 0;
-- 
2.31.1