18.06.2019 7:29, Bitan Biswas пишет:
> The usage of BUG() macro is generally discouraged in kernel, unless
> it's a problem that results in a physical damage or loss of data.
> This patch removes unnecessary BUG() macros and replaces the rest
> with warning.
>
> Signed-off-by: Bitan Biswas <bbiswas@xxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-tegra.c | 49 +++++++++++++++++++++++++++++++++++-------
> 1 file changed, 41 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 4dfb4c1..6fb545e 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_RX_BUFFER_OVERFLOW BIT(3)
>
> #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28
> #define PACKET_HEADER0_PACKET_ID_SHIFT 16
> @@ -489,6 +490,13 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
> size_t buf_remaining = i2c_dev->msg_buf_remaining;
> int words_to_transfer;
>
> + /*
> + * Catch overflow due to message fully sent before
> + * check for RX FIFO availability.
> + */
> + if (WARN_ON_ONCE(!(i2c_dev->msg_buf_remaining)))
> + return -EINVAL;
> +
> if (i2c_dev->hw->has_mst_fifo) {
> val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS);
> rx_fifo_avail = (val & I2C_MST_FIFO_STATUS_RX_MASK) >>
> @@ -515,7 +523,11 @@ 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);
> + /*
> + * buf_remaining > 3 check not needed as rx_fifo_avail == 0
> + * when (words_to_transfer was > rx_fifo_avail) earlier
> + * in this function.
> + */
> val = i2c_readl(i2c_dev, I2C_RX_FIFO);
> val = cpu_to_le32(val);
> memcpy(buf, &val, buf_remaining);
> @@ -523,7 +535,12 @@ 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);
> + /*
> + * RX FIFO must be drained in Overflow case.
> + */
> + if (WARN_ON_ONCE(rx_fifo_avail))
> + return -EINVAL;
> +
The comment is incorrect because RX FIFO is *not* drained in a case of overflow. Also,
please use a single-line comment style if multi-line is
not needed.
Let's change it to:
/* RX FIFO must be drained, otherwise it's an Overflow case */
if (WARN_ON_ONCE(rx_fifo_avail))
return -EINVAL;
Otherwise looking good to me. Please address this minor comment and it should be done.
Looking forward to v9!
