diff mbox series

[V3,6/6] i2c: tegra: remove BUG, BUG_ON

Message ID 1560143324-21754-6-git-send-email-bbiswas@nvidia.com
State Superseded
Headers show
Series [V3,1/6] i2c: tegra: clean up macros | expand

Commit Message

Bitan Biswas June 10, 2019, 5:08 a.m. UTC 
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@nvidia.com>
---
 drivers/i2c/busses/i2c-tegra.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

Comments

Dmitry Osipenko June 10, 2019, 10:30 a.m. UTC | #1 
10.06.2019 8:08, 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@nvidia.com>
> ---
>  drivers/i2c/busses/i2c-tegra.c | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 4dfb4c1..d9e99b4 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 +877,10 @@ 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);
> +		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;
> 

It looks nearly ideal now, although there is still one thing that could
be improved. We're going to print a error message in a case of RX and
spew a warning on a similar case of TX, this makes code inconsistent.
Let's switch to either a error message or just a warning in both places.
Bitan Biswas June 10, 2019, 10:58 a.m. UTC | #2 
On 6/10/19 3:30 AM, Dmitry Osipenko wrote:
> 10.06.2019 8:08, 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@nvidia.com>
>> ---
>>   drivers/i2c/busses/i2c-tegra.c | 18 +++++++++++-------
>>   1 file changed, 11 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
>> index 4dfb4c1..d9e99b4 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 +877,10 @@ 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);
>> +		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;
>>
> 
> It looks nearly ideal now, although there is still one thing that could
> be improved. We're going to print a error message in a case of RX and
> spew a warning on a similar case of TX, this makes code inconsistent.
> Let's switch to either a error message or just a warning in both places.
> 
Agree. I shall share the updated patch.

-Thanks,
  Bitan
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 4dfb4c1..d9e99b4 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 +877,10 @@  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);
+		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;