Messages in this thread | | | Subject | Re: [PATCH V6] i2c: tegra: remove BUG, BUG_ON | From | Bitan Biswas <> | Date | Mon, 17 Jun 2019 12:08:06 -0700 |
| |
On 6/14/19 10:51 AM, Dmitry Osipenko wrote: > 14.06.2019 18:50, Bitan Biswas пишет: >> Remove redundant BUG_ON calls or replace with WARN_ON_ONCE >> as needed. Remove BUG() and mask Rx interrupt similar as Tx >> for message fully sent case. Add WARN_ON_ONCE check >> for non-zero rx_fifo_avail in tegra_i2c_empty_rx_fifo() >> after all processing. Error handling in tegra_i2c_empty_rx_fifo >> caller is also added. >> >> Signed-off-by: Bitan Biswas <bbiswas@nvidia.com> >> --- >> drivers/i2c/busses/i2c-tegra.c | 46 ++++++++++++++++++++++++++++++++++-------- >> 1 file changed, 38 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c >> index 4dfb4c1..26a7c8c 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) > > What about I2C_ERR_RX_BUFFER_OVERFLOW? OK.
> >> #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28 >> #define PACKET_HEADER0_PACKET_ID_SHIFT 16 >> @@ -515,15 +516,23 @@ 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 >> + */ > > Please start all multiline comments with an empty "/*", it should be the correct > style. There are some places in the kernel where style like yours is used, but I > assume they are not very correct. Besides, yours variant is not consistent with the > style of the rest of comments in this source file. And put a dot in the end for > completeness. Same for the other comments in this patch. > OK
>> val = i2c_readl(i2c_dev, I2C_RX_FIFO); >> val = cpu_to_le32(val); >> memcpy(buf, &val, buf_remaining); >> buf_remaining = 0; >> rx_fifo_avail--; >> } > > Please add a newline here. All logical parts of the code should be separated to ease > reading and following. OK
> >> + if (WARN_ON_ONCE(rx_fifo_avail)) >> + return -EINVAL; >> >> - BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0); >> + /* buf_remaining > 0 at this point can only have rx_fifo_avail == 0 >> + * as this corresponds to (words_to_transfer was > rx_fifo_avail) >> + * case earlier in this function >> + */ >> i2c_dev->msg_buf_remaining = buf_remaining; >> i2c_dev->msg_buf = buf; >> >> @@ -581,7 +590,10 @@ 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); >> + /* buf_remaining > 3 check not needed as tx_fifo_avail == 0 >> + * when (words_to_transfer was > tx_fifo_avail) earlier >> + * in this function for non-zero words_to_transfer >> + */ >> memcpy(&val, buf, buf_remaining); >> val = le32_to_cpu(val); >> >> @@ -811,6 +823,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) >> u32 status; >> const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; >> struct tegra_i2c_dev *i2c_dev = dev_id; >> + int err_val; >> >> status = i2c_readl(i2c_dev, I2C_INT_STATUS); >> >> @@ -847,10 +860,21 @@ 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) >> - tegra_i2c_empty_rx_fifo(i2c_dev); >> - else >> - BUG(); >> + err_val = tegra_i2c_empty_rx_fifo(i2c_dev); >> + if ((!(i2c_dev->msg_buf_remaining)) && > > Let's move this check into tegra_i2c_empty_rx_fifo() and return -EINVAL for that case. > This will make code to look cleaner. OK.
> >> + (!(status & I2C_INT_PACKET_XFER_COMPLETE)) && > > It shouldn't matter that XFER_COMPLETE is set if RX FIFO isn't fully emptied because > it always shall be emptied. Hence this check is not needed and we should error out > regardless. OK
> >> + err_val) { >> + /* >> + * Overflow error condition: message fully sent, >> + * with no XFER_COMPLETE interrupt but hardware >> + * asks to transfer more. >> + */ >> + tegra_i2c_mask_irq(i2c_dev, >> + I2C_INT_RX_FIFO_DATA_REQ); > > No need to mask RX_FIFO_DATA_REQ here because all interrupts are masked on "goto > err:", hence just remove the tegra_i2c_mask_irq(). > >> + i2c_dev->msg_err |= >> + I2C_ERR_UNEXPECTED_STATUS; > > No need to split this into two lines because it's less than 80 chars, write this in a > single line. OK
> >> + goto err; >> + } >> } >> >> if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) { >> @@ -876,7 +900,13 @@ 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); >> + /* Underflow error condition: XFER_COMPLETE before message >> + * fully sent. >> + */ >> + if (WARN_ON_ONCE(i2c_dev->msg_buf_remaining)) { >> + i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT; >> + goto err; >> + } >> complete(&i2c_dev->msg_complete); >> } >> goto done; >> > > Please address comments in the next revision. >
Sorry for the delayed reply. I shared Patch V7 with above changes earlier today.
-regards, Bitan
| |