07.06.2019 15:12, Dmitry Osipenko пишет:
> 07.06.2019 15:08, Dmitry Osipenko пишет:
>> 07.06.2019 14:55, Bitan Biswas пишет:
>>> Remove redundant BUG_ON calls or replace with WARN_ON_ONCE
>>> as needed. Replace BUG() with error handling code.
>>> Define I2C_ERR_UNEXPECTED_STATUS for error handling.
>>>
>>> Signed-off-by: Bitan Biswas <bbiswas@xxxxxxxxxx>
>>> ---
>>> drivers/i2c/busses/i2c-tegra.c | 15 ++++++++-------
>>> 1 file changed, 8 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
>>> index 4dfb4c1..c407bd7 100644
>>> --- a/drivers/i2c/busses/i2c-tegra.c
>>> +++ b/drivers/i2c/busses/i2c-tegra.c
>>> @@ -73,6 +73,7 @@
>>> #define I2C_ERR_NO_ACK BIT(0)
>>> #define I2C_ERR_ARBITRATION_LOST BIT(1)
>>> #define I2C_ERR_UNKNOWN_INTERRUPT BIT(2)
>>> +#define I2C_ERR_UNEXPECTED_STATUS BIT(3)
>>>
>>> #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28
>>> #define PACKET_HEADER0_PACKET_ID_SHIFT 16
>>> @@ -515,7 +516,6 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
>>> * prevent overwriting past the end of buf
>>> */
>>> if (rx_fifo_avail > 0 && buf_remaining > 0) {
>>> - BUG_ON(buf_remaining > 3);
>>> val = i2c_readl(i2c_dev, I2C_RX_FIFO);
>>> val = cpu_to_le32(val);
>>> memcpy(buf, &val, buf_remaining);
>>> @@ -523,7 +523,6 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
>>> rx_fifo_avail--;
>>> }
>>>
>>> - BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0);
>>> i2c_dev->msg_buf_remaining = buf_remaining;
>>> i2c_dev->msg_buf = buf;
>>>
>>> @@ -581,7 +580,6 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
>>> * boundary and fault.
>>> */
>>> if (tx_fifo_avail > 0 && buf_remaining > 0) {
>>> - BUG_ON(buf_remaining > 3);
>>> memcpy(&val, buf, buf_remaining);
>>> val = le32_to_cpu(val);
>>>
>>> @@ -847,10 +845,13 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
>>>
>>> if (!i2c_dev->is_curr_dma_xfer) {
>>> if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) {
>>> - if (i2c_dev->msg_buf_remaining)
>>> + if (i2c_dev->msg_buf_remaining) {
>>> tegra_i2c_empty_rx_fifo(i2c_dev);
>>> - else
>>> - BUG();
>>> + } else {
>>> + dev_err(i2c_dev->dev, "unexpected rx data request\n");
>>> + i2c_dev->msg_err |= I2C_ERR_UNEXPECTED_STATUS;
>>> + goto err;
>>> + }
>>> }
>>>
>>> if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) {
>>> @@ -876,7 +877,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
>>> if (status & I2C_INT_PACKET_XFER_COMPLETE) {
>>> if (i2c_dev->is_curr_dma_xfer)
>>> i2c_dev->msg_buf_remaining = 0;
>>> - BUG_ON(i2c_dev->msg_buf_remaining);
>>> + WARN_ON_ONCE(i2c_dev->msg_buf_remaining);
>>> complete(&i2c_dev->msg_complete);
>>> }
>>> goto done;
>>>
>>
>> Very nice, thank you very much! BTW, I think it may worth to add another
>> patch that will reset hardware state in a case of the warning since we
>> know that something gone wrong.
>>
>> Reviewed-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>>
>
> Something like that:
>
> complete(&i2c_dev->msg_complete);
>
> if (WARN_ON_ONCE(i2c_dev->msg_buf_remaining))
> goto err;
>
Ah, that's inside the ISR, so maybe will make sense to just not complete
the transfer and let it timeout:
if (!WARN_ON_ONCE(i2c_dev->msg_buf_remaining))
complete(&i2c_dev->msg_complete);
