diff mbox series

[RESEND,V6,1/2] i2c: i2c-qcom-geni: Store DMA mapping data in geni_i2c_dev struct

Message ID 20201203103156.32595-2-rojay@codeaurora.org
State New
Headers show
Series Implement Shutdown callback for geni-i2c | expand

Commit Message

Roja Rani Yarubandi Dec. 3, 2020, 10:31 a.m. UTC 
Store DMA mapping data in geni_i2c_dev struct to enhance DMA mapping
data scope. For example during shutdown callback to unmap DMA mapping,
this stored DMA mapping data can be used to call geni_se_tx_dma_unprep
and geni_se_rx_dma_unprep functions.

Add two helper functions geni_i2c_rx_msg_cleanup and
geni_i2c_tx_msg_cleanup to unwrap the things after rx/tx FIFO/DMA
transfers, so that the same can be used in geni_i2c_stop_xfer()
function during shutdown callback.

Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
---
Changes in V5:
 - As per Stephen's comments separated this patch from shutdown
   callback patch, gi2c->cur = NULL is not removed from
   geni_i2c_abort_xfer(), and made a copy of gi2c->cur and passed
   to cleanup functions.

Changes in V6:
 - Added spin_lock/unlock in geni_i2c_rx_msg_cleanup() and
   geni_i2c_tx_msg_cleanup() functions.

 drivers/i2c/busses/i2c-qcom-geni.c | 69 +++++++++++++++++++++++-------
 1 file changed, 53 insertions(+), 16 deletions(-)

Comments

Akash Asthana Dec. 9, 2020, 12:59 p.m. UTC | #1 
Hi Roja,

On 12/3/2020 4:01 PM, Roja Rani Yarubandi wrote:
> Store DMA mapping data in geni_i2c_dev struct to enhance DMA mapping

> data scope. For example during shutdown callback to unmap DMA mapping,

> this stored DMA mapping data can be used to call geni_se_tx_dma_unprep

> and geni_se_rx_dma_unprep functions.

>

> Add two helper functions geni_i2c_rx_msg_cleanup and

> geni_i2c_tx_msg_cleanup to unwrap the things after rx/tx FIFO/DMA

> transfers, so that the same can be used in geni_i2c_stop_xfer()

> function during shutdown callback.

>

> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>

> ---

> Changes in V5:

>   - As per Stephen's comments separated this patch from shutdown

>     callback patch, gi2c->cur = NULL is not removed from

>     geni_i2c_abort_xfer(), and made a copy of gi2c->cur and passed

>     to cleanup functions.

>

> Changes in V6:

>   - Added spin_lock/unlock in geni_i2c_rx_msg_cleanup() and

>     geni_i2c_tx_msg_cleanup() functions.

>

>   drivers/i2c/busses/i2c-qcom-geni.c | 69 +++++++++++++++++++++++-------

>   1 file changed, 53 insertions(+), 16 deletions(-)

>

> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c

> index dce75b85253c..bfbc80f65006 100644

> --- a/drivers/i2c/busses/i2c-qcom-geni.c

> +++ b/drivers/i2c/busses/i2c-qcom-geni.c

> @@ -86,6 +86,9 @@ struct geni_i2c_dev {

>   	u32 clk_freq_out;

>   	const struct geni_i2c_clk_fld *clk_fld;

>   	int suspended;

> +	void *dma_buf;

> +	size_t xfer_len;

> +	dma_addr_t dma_addr;

>   };

>   

>   struct geni_i2c_err_log {

> @@ -348,14 +351,49 @@ static void geni_i2c_tx_fsm_rst(struct geni_i2c_dev *gi2c)

>   		dev_err(gi2c->se.dev, "Timeout resetting TX_FSM\n");

>   }

>   

> +static void geni_i2c_rx_msg_cleanup(struct geni_i2c_dev *gi2c,

> +				     struct i2c_msg *cur)

> +{

> +	struct geni_se *se = &gi2c->se;

> +	unsigned long flags;

> +

> +	spin_lock_irqsave(&gi2c->lock, flags);

> +	gi2c->cur_rd = 0;

> +	if (gi2c->dma_buf) {

> +		if (gi2c->err)

> +			geni_i2c_rx_fsm_rst(gi2c);


Which race we are trying to avoid here by holding spinlock?

We cannot call any sleeping API by holding spinlock, geni_i2c_rx_fsm_rst 
calls *wait-for-completion*, which is a sleeping call.

> +		geni_se_rx_dma_unprep(se, gi2c->dma_addr, gi2c->xfer_len);

> +		i2c_put_dma_safe_msg_buf(gi2c->dma_buf, cur, !gi2c->err);

> +	}

> +	spin_unlock_irqrestore(&gi2c->lock, flags);

> +}

> +

> +static void geni_i2c_tx_msg_cleanup(struct geni_i2c_dev *gi2c,

> +				     struct i2c_msg *cur)

> +{

> +	struct geni_se *se = &gi2c->se;

> +	unsigned long flags;

> +

> +	spin_lock_irqsave(&gi2c->lock, flags);

> +	gi2c->cur_wr = 0;

> +	if (gi2c->dma_buf) {

> +		if (gi2c->err)

> +			geni_i2c_tx_fsm_rst(gi2c);


Same here

Regards,

Akash

> +		geni_se_tx_dma_unprep(se, gi2c->dma_addr, gi2c->xfer_len);

> +		i2c_put_dma_safe_msg_buf(gi2c->dma_buf, cur, !gi2c->err);

> +	}

> +	spin_unlock_irqrestore(&gi2c->lock, flags);

> +}

> +

>   static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,

>   				u32 m_param)

>   {

> -	dma_addr_t rx_dma;

> +	dma_addr_t rx_dma = 0;

>   	unsigned long time_left;

>   	void *dma_buf = NULL;

>   	struct geni_se *se = &gi2c->se;

>   	size_t len = msg->len;

> +	struct i2c_msg *cur;

>   

>   	if (!of_machine_is_compatible("lenovo,yoga-c630"))

>   		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);

> @@ -372,19 +410,18 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,

>   		geni_se_select_mode(se, GENI_SE_FIFO);

>   		i2c_put_dma_safe_msg_buf(dma_buf, msg, false);

>   		dma_buf = NULL;

> +	} else {

> +		gi2c->xfer_len = len;

> +		gi2c->dma_addr = rx_dma;

> +		gi2c->dma_buf = dma_buf;

>   	}

>   

> +	cur = gi2c->cur;

>   	time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);

>   	if (!time_left)

>   		geni_i2c_abort_xfer(gi2c);

>   

> -	gi2c->cur_rd = 0;

> -	if (dma_buf) {

> -		if (gi2c->err)

> -			geni_i2c_rx_fsm_rst(gi2c);

> -		geni_se_rx_dma_unprep(se, rx_dma, len);

> -		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);

> -	}

> +	geni_i2c_rx_msg_cleanup(gi2c, cur);

>   

>   	return gi2c->err;

>   }

> @@ -392,11 +429,12 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,

>   static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,

>   				u32 m_param)

>   {

> -	dma_addr_t tx_dma;

> +	dma_addr_t tx_dma = 0;

>   	unsigned long time_left;

>   	void *dma_buf = NULL;

>   	struct geni_se *se = &gi2c->se;

>   	size_t len = msg->len;

> +	struct i2c_msg *cur;

>   

>   	if (!of_machine_is_compatible("lenovo,yoga-c630"))

>   		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);

> @@ -413,22 +451,21 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,

>   		geni_se_select_mode(se, GENI_SE_FIFO);

>   		i2c_put_dma_safe_msg_buf(dma_buf, msg, false);

>   		dma_buf = NULL;

> +	} else {

> +		gi2c->xfer_len = len;

> +		gi2c->dma_addr = tx_dma;

> +		gi2c->dma_buf = dma_buf;

>   	}

>   

>   	if (!dma_buf) /* Get FIFO IRQ */

>   		writel_relaxed(1, se->base + SE_GENI_TX_WATERMARK_REG);

>   

> +	cur = gi2c->cur;

>   	time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);

>   	if (!time_left)

>   		geni_i2c_abort_xfer(gi2c);

>   

> -	gi2c->cur_wr = 0;

> -	if (dma_buf) {

> -		if (gi2c->err)

> -			geni_i2c_tx_fsm_rst(gi2c);

> -		geni_se_tx_dma_unprep(se, tx_dma, len);

> -		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);

> -	}

> +	geni_i2c_tx_msg_cleanup(gi2c, cur);

>   

>   	return gi2c->err;

>   }


-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project
Roja Rani Yarubandi Dec. 21, 2020, 12:34 p.m. UTC | #2 
On 2020-12-09 18:29, Akash Asthana wrote:
> Hi Roja,
> 
> On 12/3/2020 4:01 PM, Roja Rani Yarubandi wrote:
>> Store DMA mapping data in geni_i2c_dev struct to enhance DMA mapping
>> data scope. For example during shutdown callback to unmap DMA mapping,
>> this stored DMA mapping data can be used to call geni_se_tx_dma_unprep
>> and geni_se_rx_dma_unprep functions.
>> 
>> Add two helper functions geni_i2c_rx_msg_cleanup and
>> geni_i2c_tx_msg_cleanup to unwrap the things after rx/tx FIFO/DMA
>> transfers, so that the same can be used in geni_i2c_stop_xfer()
>> function during shutdown callback.
>> 
>> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
>> ---
>> Changes in V5:
>>   - As per Stephen's comments separated this patch from shutdown
>>     callback patch, gi2c->cur = NULL is not removed from
>>     geni_i2c_abort_xfer(), and made a copy of gi2c->cur and passed
>>     to cleanup functions.
>> 
>> Changes in V6:
>>   - Added spin_lock/unlock in geni_i2c_rx_msg_cleanup() and
>>     geni_i2c_tx_msg_cleanup() functions.
>> 
>>   drivers/i2c/busses/i2c-qcom-geni.c | 69 
>> +++++++++++++++++++++++-------
>>   1 file changed, 53 insertions(+), 16 deletions(-)
>> 
>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c 
>> b/drivers/i2c/busses/i2c-qcom-geni.c
>> index dce75b85253c..bfbc80f65006 100644
>> --- a/drivers/i2c/busses/i2c-qcom-geni.c
>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
>> @@ -86,6 +86,9 @@ struct geni_i2c_dev {
>>   	u32 clk_freq_out;
>>   	const struct geni_i2c_clk_fld *clk_fld;
>>   	int suspended;
>> +	void *dma_buf;
>> +	size_t xfer_len;
>> +	dma_addr_t dma_addr;
>>   };
>>     struct geni_i2c_err_log {
>> @@ -348,14 +351,49 @@ static void geni_i2c_tx_fsm_rst(struct 
>> geni_i2c_dev *gi2c)
>>   		dev_err(gi2c->se.dev, "Timeout resetting TX_FSM\n");
>>   }
>>   +static void geni_i2c_rx_msg_cleanup(struct geni_i2c_dev *gi2c,
>> +				     struct i2c_msg *cur)
>> +{
>> +	struct geni_se *se = &gi2c->se;
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&gi2c->lock, flags);
>> +	gi2c->cur_rd = 0;
>> +	if (gi2c->dma_buf) {
>> +		if (gi2c->err)
>> +			geni_i2c_rx_fsm_rst(gi2c);
> 
> Which race we are trying to avoid here by holding spinlock?
> 

Thought that race might occur with "cur" here.

> We cannot call any sleeping API by holding spinlock,
> geni_i2c_rx_fsm_rst calls *wait-for-completion*, which is a sleeping
> call.
> 

Fixed this.

>> +		geni_se_rx_dma_unprep(se, gi2c->dma_addr, gi2c->xfer_len);
>> +		i2c_put_dma_safe_msg_buf(gi2c->dma_buf, cur, !gi2c->err);
>> +	}
>> +	spin_unlock_irqrestore(&gi2c->lock, flags);
>> +}
>> +
>> +static void geni_i2c_tx_msg_cleanup(struct geni_i2c_dev *gi2c,
>> +				     struct i2c_msg *cur)
>> +{
>> +	struct geni_se *se = &gi2c->se;
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&gi2c->lock, flags);
>> +	gi2c->cur_wr = 0;
>> +	if (gi2c->dma_buf) {
>> +		if (gi2c->err)
>> +			geni_i2c_tx_fsm_rst(gi2c);
> 
> Same here
> 
> Regards,
> 
> Akash
> 
>> +		geni_se_tx_dma_unprep(se, gi2c->dma_addr, gi2c->xfer_len);
>> +		i2c_put_dma_safe_msg_buf(gi2c->dma_buf, cur, !gi2c->err);
>> +	}
>> +	spin_unlock_irqrestore(&gi2c->lock, flags);
>> +}
>> +
>>   static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct 
>> i2c_msg *msg,
>>   				u32 m_param)
>>   {
>> -	dma_addr_t rx_dma;
>> +	dma_addr_t rx_dma = 0;
>>   	unsigned long time_left;
>>   	void *dma_buf = NULL;
>>   	struct geni_se *se = &gi2c->se;
>>   	size_t len = msg->len;
>> +	struct i2c_msg *cur;
>>     	if (!of_machine_is_compatible("lenovo,yoga-c630"))
>>   		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
>> @@ -372,19 +410,18 @@ static int geni_i2c_rx_one_msg(struct 
>> geni_i2c_dev *gi2c, struct i2c_msg *msg,
>>   		geni_se_select_mode(se, GENI_SE_FIFO);
>>   		i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
>>   		dma_buf = NULL;
>> +	} else {
>> +		gi2c->xfer_len = len;
>> +		gi2c->dma_addr = rx_dma;
>> +		gi2c->dma_buf = dma_buf;
>>   	}
>>   +	cur = gi2c->cur;
>>   	time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
>>   	if (!time_left)
>>   		geni_i2c_abort_xfer(gi2c);
>>   -	gi2c->cur_rd = 0;
>> -	if (dma_buf) {
>> -		if (gi2c->err)
>> -			geni_i2c_rx_fsm_rst(gi2c);
>> -		geni_se_rx_dma_unprep(se, rx_dma, len);
>> -		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
>> -	}
>> +	geni_i2c_rx_msg_cleanup(gi2c, cur);
>>     	return gi2c->err;
>>   }
>> @@ -392,11 +429,12 @@ static int geni_i2c_rx_one_msg(struct 
>> geni_i2c_dev *gi2c, struct i2c_msg *msg,
>>   static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct 
>> i2c_msg *msg,
>>   				u32 m_param)
>>   {
>> -	dma_addr_t tx_dma;
>> +	dma_addr_t tx_dma = 0;
>>   	unsigned long time_left;
>>   	void *dma_buf = NULL;
>>   	struct geni_se *se = &gi2c->se;
>>   	size_t len = msg->len;
>> +	struct i2c_msg *cur;
>>     	if (!of_machine_is_compatible("lenovo,yoga-c630"))
>>   		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
>> @@ -413,22 +451,21 @@ static int geni_i2c_tx_one_msg(struct 
>> geni_i2c_dev *gi2c, struct i2c_msg *msg,
>>   		geni_se_select_mode(se, GENI_SE_FIFO);
>>   		i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
>>   		dma_buf = NULL;
>> +	} else {
>> +		gi2c->xfer_len = len;
>> +		gi2c->dma_addr = tx_dma;
>> +		gi2c->dma_buf = dma_buf;
>>   	}
>>     	if (!dma_buf) /* Get FIFO IRQ */
>>   		writel_relaxed(1, se->base + SE_GENI_TX_WATERMARK_REG);
>>   +	cur = gi2c->cur;
>>   	time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
>>   	if (!time_left)
>>   		geni_i2c_abort_xfer(gi2c);
>>   -	gi2c->cur_wr = 0;
>> -	if (dma_buf) {
>> -		if (gi2c->err)
>> -			geni_i2c_tx_fsm_rst(gi2c);
>> -		geni_se_tx_dma_unprep(se, tx_dma, len);
>> -		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
>> -	}
>> +	geni_i2c_tx_msg_cleanup(gi2c, cur);
>>     	return gi2c->err;
>>   }
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index dce75b85253c..bfbc80f65006 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -86,6 +86,9 @@  struct geni_i2c_dev {
 	u32 clk_freq_out;
 	const struct geni_i2c_clk_fld *clk_fld;
 	int suspended;
+	void *dma_buf;
+	size_t xfer_len;
+	dma_addr_t dma_addr;
 };
 
 struct geni_i2c_err_log {
@@ -348,14 +351,49 @@  static void geni_i2c_tx_fsm_rst(struct geni_i2c_dev *gi2c)
 		dev_err(gi2c->se.dev, "Timeout resetting TX_FSM\n");
 }
 
+static void geni_i2c_rx_msg_cleanup(struct geni_i2c_dev *gi2c,
+				     struct i2c_msg *cur)
+{
+	struct geni_se *se = &gi2c->se;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gi2c->lock, flags);
+	gi2c->cur_rd = 0;
+	if (gi2c->dma_buf) {
+		if (gi2c->err)
+			geni_i2c_rx_fsm_rst(gi2c);
+		geni_se_rx_dma_unprep(se, gi2c->dma_addr, gi2c->xfer_len);
+		i2c_put_dma_safe_msg_buf(gi2c->dma_buf, cur, !gi2c->err);
+	}
+	spin_unlock_irqrestore(&gi2c->lock, flags);
+}
+
+static void geni_i2c_tx_msg_cleanup(struct geni_i2c_dev *gi2c,
+				     struct i2c_msg *cur)
+{
+	struct geni_se *se = &gi2c->se;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gi2c->lock, flags);
+	gi2c->cur_wr = 0;
+	if (gi2c->dma_buf) {
+		if (gi2c->err)
+			geni_i2c_tx_fsm_rst(gi2c);
+		geni_se_tx_dma_unprep(se, gi2c->dma_addr, gi2c->xfer_len);
+		i2c_put_dma_safe_msg_buf(gi2c->dma_buf, cur, !gi2c->err);
+	}
+	spin_unlock_irqrestore(&gi2c->lock, flags);
+}
+
 static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 				u32 m_param)
 {
-	dma_addr_t rx_dma;
+	dma_addr_t rx_dma = 0;
 	unsigned long time_left;
 	void *dma_buf = NULL;
 	struct geni_se *se = &gi2c->se;
 	size_t len = msg->len;
+	struct i2c_msg *cur;
 
 	if (!of_machine_is_compatible("lenovo,yoga-c630"))
 		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
@@ -372,19 +410,18 @@  static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 		geni_se_select_mode(se, GENI_SE_FIFO);
 		i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
 		dma_buf = NULL;
+	} else {
+		gi2c->xfer_len = len;
+		gi2c->dma_addr = rx_dma;
+		gi2c->dma_buf = dma_buf;
 	}
 
+	cur = gi2c->cur;
 	time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
 	if (!time_left)
 		geni_i2c_abort_xfer(gi2c);
 
-	gi2c->cur_rd = 0;
-	if (dma_buf) {
-		if (gi2c->err)
-			geni_i2c_rx_fsm_rst(gi2c);
-		geni_se_rx_dma_unprep(se, rx_dma, len);
-		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
-	}
+	geni_i2c_rx_msg_cleanup(gi2c, cur);
 
 	return gi2c->err;
 }
@@ -392,11 +429,12 @@  static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 				u32 m_param)
 {
-	dma_addr_t tx_dma;
+	dma_addr_t tx_dma = 0;
 	unsigned long time_left;
 	void *dma_buf = NULL;
 	struct geni_se *se = &gi2c->se;
 	size_t len = msg->len;
+	struct i2c_msg *cur;
 
 	if (!of_machine_is_compatible("lenovo,yoga-c630"))
 		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
@@ -413,22 +451,21 @@  static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 		geni_se_select_mode(se, GENI_SE_FIFO);
 		i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
 		dma_buf = NULL;
+	} else {
+		gi2c->xfer_len = len;
+		gi2c->dma_addr = tx_dma;
+		gi2c->dma_buf = dma_buf;
 	}
 
 	if (!dma_buf) /* Get FIFO IRQ */
 		writel_relaxed(1, se->base + SE_GENI_TX_WATERMARK_REG);
 
+	cur = gi2c->cur;
 	time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
 	if (!time_left)
 		geni_i2c_abort_xfer(gi2c);
 
-	gi2c->cur_wr = 0;
-	if (dma_buf) {
-		if (gi2c->err)
-			geni_i2c_tx_fsm_rst(gi2c);
-		geni_se_tx_dma_unprep(se, tx_dma, len);
-		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
-	}
+	geni_i2c_tx_msg_cleanup(gi2c, cur);
 
 	return gi2c->err;
 }