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| author | Atsushi Nemoto <atsushi.nemoto@sord.co.jp> | 2020-05-08 16:12:48 +0300 |
|---|---|---|
| committer | Wolfram Sang <wsa@kernel.org> | 2020-05-15 12:23:49 +0300 |
| commit | 5d4c7977499a736f3f80826bdc9744344ad55589 (patch) | |
| tree | 4524c52e9cb2888ab5568013795cb54a9b9252d9 | |
| parent | ab7cf7e53ccf1fecec6b72d1a3a13ff88193b490 (diff) | |
| download | linux-5d4c7977499a736f3f80826bdc9744344ad55589.tar.xz | |
i2c: altera: Fix race between xfer_msg and isr thread
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>
| -rw-r--r-- | drivers/i2c/busses/i2c-altera.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c index f5c00f903df3..16ddc26c00e6 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); |