[PATCH AUTOSEL 4.14 08/12] i2c: rcar: avoid race when unregistering slave client

[PATCH AUTOSEL 4.14 08/12] i2c: rcar: avoid race when unregistering slave client

[Sasha Levin]

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

[ Upstream commit 7b814d852af6944657c2961039f404c4490771c0 ]

After we disabled interrupts, there might still be an active one
running. Sync before clearing the pointer to the slave device.

Fixes: de20d1857dd6 ("i2c: rcar: add slave support")
Reported-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-rcar.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 3415733a93645..132c4a405bf83 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -144,6 +144,7 @@ struct rcar_i2c_priv {
 	enum dma_data_direction dma_direction;
 
 	struct reset_control *rstc;
+	int irq;
 };
 
 #define rcar_i2c_priv_to_dev(p)		((p)->adap.dev.parent)
@@ -813,9 +814,11 @@ static int rcar_unreg_slave(struct i2c_client *slave)
 
 	WARN_ON(!priv->slave);
 
+	/* disable irqs and ensure none is running before clearing ptr */
 	rcar_i2c_write(priv, ICSIER, 0);
 	rcar_i2c_write(priv, ICSCR, 0);
 
+	synchronize_irq(priv->irq);
 	priv->slave = NULL;
 
 	pm_runtime_put(rcar_i2c_priv_to_dev(priv));
@@ -866,7 +869,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 	struct i2c_adapter *adap;
 	struct device *dev = &pdev->dev;
 	struct i2c_timings i2c_t;
-	int irq, ret;
+	int ret;
 
 	priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL);
 	if (!priv)
@@ -927,10 +930,10 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 		pm_runtime_put(dev);
 
 
-	irq = platform_get_irq(pdev, 0);
-	ret = devm_request_irq(dev, irq, rcar_i2c_irq, 0, dev_name(dev), priv);
+	priv->irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(dev, priv->irq, rcar_i2c_irq, 0, dev_name(dev), priv);
 	if (ret < 0) {
-		dev_err(dev, "cannot get irq %d\n", irq);
+		dev_err(dev, "cannot get irq %d\n", priv->irq);
 		goto out_pm_disable;
 	}
 
-- 
2.20.1

[PATCH AUTOSEL 4.14 09/12] i2c: emev2: avoid race when unregistering slave client

[Sasha Levin]

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

[ Upstream commit d7437fc0d8291181debe032671a289b6bd93f46f ]

After we disabled interrupts, there might still be an active one
running. Sync before clearing the pointer to the slave device.

Fixes: c31d0a00021d ("i2c: emev2: add slave support")
Reported-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-emev2.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-emev2.c b/drivers/i2c/busses/i2c-emev2.c
index d2e84480fbe96..dd97e5d9f49a2 100644
--- a/drivers/i2c/busses/i2c-emev2.c
+++ b/drivers/i2c/busses/i2c-emev2.c
@@ -72,6 +72,7 @@ struct em_i2c_device {
 	struct completion msg_done;
 	struct clk *sclk;
 	struct i2c_client *slave;
+	int irq;
 };
 
 static inline void em_clear_set_bit(struct em_i2c_device *priv, u8 clear, u8 set, u8 reg)
@@ -342,6 +343,12 @@ static int em_i2c_unreg_slave(struct i2c_client *slave)
 
 	writeb(0, priv->base + I2C_OFS_SVA0);
 
+	/*
+	 * Wait for interrupt to finish. New slave irqs cannot happen because we
+	 * cleared the slave address and, thus, only extension codes will be
+	 * detected which do not use the slave ptr.
+	 */
+	synchronize_irq(priv->irq);
 	priv->slave = NULL;
 
 	return 0;
@@ -358,7 +365,7 @@ static int em_i2c_probe(struct platform_device *pdev)
 {
 	struct em_i2c_device *priv;
 	struct resource *r;
-	int irq, ret;
+	int ret;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -393,8 +400,8 @@ static int em_i2c_probe(struct platform_device *pdev)
 
 	em_i2c_reset(&priv->adap);
 
-	irq = platform_get_irq(pdev, 0);
-	ret = devm_request_irq(&pdev->dev, irq, em_i2c_irq_handler, 0,
+	priv->irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(&pdev->dev, priv->irq, em_i2c_irq_handler, 0,
 				"em_i2c", priv);
 	if (ret)
 		goto err_clk;
@@ -404,7 +411,8 @@ static int em_i2c_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_clk;
 
-	dev_info(&pdev->dev, "Added i2c controller %d, irq %d\n", priv->adap.nr, irq);
+	dev_info(&pdev->dev, "Added i2c controller %d, irq %d\n", priv->adap.nr,
+		 priv->irq);
 
 	return 0;
 
-- 
2.20.1