From: Atsushi Nemoto atsushi.nemoto@sord.co.jp
[ Upstream commit 5d4c7977499a736f3f80826bdc9744344ad55589 ]
Use a mutex to protect access to idev->msg_len, idev->buf, etc. which are modified by both altr_i2c_xfer_msg() and altr_i2c_isr().
This is the minimal fix for easy backporting. A cleanup to remove the spinlock will be added later.
Signed-off-by: Atsushi Nemoto atsushi.nemoto@sord.co.jp Acked-by: Thor Thayer thor.thayer@linux.intel.com [wsa: updated commit message] Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/i2c/busses/i2c-altera.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c index 92d2c706c2a7..a60042431370 100644 --- a/drivers/i2c/busses/i2c-altera.c +++ b/drivers/i2c/busses/i2c-altera.c @@ -70,6 +70,7 @@ * @isr_mask: cached copy of local ISR enables. * @isr_status: cached copy of local ISR status. * @lock: spinlock for IRQ synchronization. + * @isr_mutex: mutex for IRQ thread. */ struct altr_i2c_dev { void __iomem *base; @@ -86,6 +87,7 @@ struct altr_i2c_dev { u32 isr_mask; u32 isr_status; spinlock_t lock; /* IRQ synchronization */ + struct mutex isr_mutex; };
static void @@ -245,10 +247,11 @@ static irqreturn_t altr_i2c_isr(int irq, void *_dev) struct altr_i2c_dev *idev = _dev; u32 status = idev->isr_status;
+ mutex_lock(&idev->isr_mutex); if (!idev->msg) { dev_warn(idev->dev, "unexpected interrupt\n"); altr_i2c_int_clear(idev, ALTR_I2C_ALL_IRQ); - return IRQ_HANDLED; + goto out; } read = (idev->msg->flags & I2C_M_RD) != 0;
@@ -301,6 +304,8 @@ static irqreturn_t altr_i2c_isr(int irq, void *_dev) complete(&idev->msg_complete); dev_dbg(idev->dev, "Message Complete\n"); } +out: + mutex_unlock(&idev->isr_mutex);
return IRQ_HANDLED; } @@ -312,6 +317,7 @@ static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg) u32 value; u8 addr = i2c_8bit_addr_from_msg(msg);
+ mutex_lock(&idev->isr_mutex); idev->msg = msg; idev->msg_len = msg->len; idev->buf = msg->buf; @@ -336,6 +342,7 @@ static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg) altr_i2c_int_enable(idev, imask, true); altr_i2c_fill_tx_fifo(idev); } + mutex_unlock(&idev->isr_mutex);
time_left = wait_for_completion_timeout(&idev->msg_complete, ALTR_I2C_XFER_TIMEOUT); @@ -409,6 +416,7 @@ static int altr_i2c_probe(struct platform_device *pdev) idev->dev = &pdev->dev; init_completion(&idev->msg_complete); spin_lock_init(&idev->lock); + mutex_init(&idev->isr_mutex);
ret = device_property_read_u32(idev->dev, "fifo-size", &idev->fifo_size);