i2c: emev2: avoid race when unregistering slave client
[ 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>
diff --git a/drivers/i2c/busses/i2c-emev2.c b/drivers/i2c/busses/i2c-emev2.c
index 96bb4e7..0218ba6 100644
--- a/drivers/i2c/busses/i2c-emev2.c
+++ b/drivers/i2c/busses/i2c-emev2.c
@@ -72,6 +72,7 @@
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 @@
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 @@
{
struct em_i2c_device *priv;
struct resource *r;
- int irq, ret;
+ int ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
@@ -391,8 +398,8 @@
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;
@@ -402,7 +409,8 @@
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;