[RESEND PATCH V6 0/2] Implement Shutdown callback for geni-i2c

[RESEND PATCH V6 0/2] Implement Shutdown callback for geni-i2c

[Roja Rani Yarubandi]

Hi,

Below patch is picked:
[V6,1/3] soc: qcom: geni: Remove "iova" check

Resending below patches for review:
[V6,2/3] i2c: i2c-qcom-geni: Store DMA mapping data in geni_i2c_dev struct
[V6,3/3] i2c: i2c-qcom-geni: Add shutdown callback for i2c

Thanks,
Roja

Roja Rani Yarubandi (2):
  i2c: i2c-qcom-geni: Store DMA mapping data in geni_i2c_dev struct
  i2c: i2c-qcom-geni: Add shutdown callback for i2c

 drivers/i2c/busses/i2c-qcom-geni.c | 104 ++++++++++++++++++++++++-----
 1 file changed, 88 insertions(+), 16 deletions(-)

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

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

[Roja Rani Yarubandi]

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);
+		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;
 }
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

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

[Akash Asthana]

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

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

[rojay]

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;
>>   }

[RESEND PATCH V6 2/2] i2c: i2c-qcom-geni: Add shutdown callback for i2c

[Roja Rani Yarubandi]

If the hardware is still accessing memory after SMMU translation
is disabled (as part of smmu shutdown callback), then the
IOVAs (I/O virtual address) which it was using will go on the bus
as the physical addresses which will result in unknown crashes
like NoC/interconnect errors.

So, implement shutdown callback to i2c driver to stop on-going transfer
and unmap DMA mappings during system "reboot" or "shutdown".

Fixes: 37692de5d523 ("i2c: i2c-qcom-geni: Add bus driver for the Qualcomm GENI I2C controller")
Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
---
Changes in V2:
 - As per Stephen's comments added seperate function for stop transfer,
   fixed minor nitpicks.
 - As per Stephen's comments, changed commit text.

Changes in V3:
 - As per Stephen's comments, squashed patch 1 into patch 2, added Fixes tag.
 - As per Akash's comments, included FIFO case in stop_xfer, fixed minor nitpicks.

Changes in V4:
 - As per Stephen's comments cleaned up geni_i2c_stop_xfer function,
   added dma_buf in geni_i2c_dev struct to call i2c_put_dma_safe_msg_buf()
   from other functions, removed "iova" check in geni_se_rx_dma_unprep()
   and geni_se_tx_dma_unprep() functions.
 - Added two helper functions geni_i2c_rx_one_msg_done() and
   geni_i2c_tx_one_msg_done() 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. Updated commit text accordingly.
 - Checking whether it is tx/rx transfer using I2C_M_RD which is valid for both
   FIFO and DMA cases, so dropped DMA_RX_ACTIVE and DMA_TX_ACTIVE bit checking

Changes in V5:
 - As per Stephen's comments, added spin_lock_irqsave & spin_unlock_irqsave in
   geni_i2c_stop_xfer() function.

Changes in V6:
 - As per Stephen's comments, taken care of unsafe lock order in
   geni_i2c_stop_xfer().
 - Moved spin_lock/unlock to geni_i2c_rx_msg_cleanup() and
   geni_i2c_tx_msg_cleanup() functions.

 drivers/i2c/busses/i2c-qcom-geni.c | 35 ++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index bfbc80f65006..9a6bd7a0a56f 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -385,6 +385,33 @@ static void geni_i2c_tx_msg_cleanup(struct geni_i2c_dev *gi2c,
 	spin_unlock_irqrestore(&gi2c->lock, flags);
 }
 
+static void geni_i2c_stop_xfer(struct geni_i2c_dev *gi2c)
+{
+	int ret;
+	u32 geni_status;
+	struct i2c_msg *cur;
+
+	/* Resume device, as runtime suspend can happen anytime during transfer */
+	ret = pm_runtime_get_sync(gi2c->se.dev);
+	if (ret < 0) {
+		dev_err(gi2c->se.dev, "Failed to resume device: %d\n", ret);
+		return;
+	}
+
+	geni_status = readl_relaxed(gi2c->se.base + SE_GENI_STATUS);
+	if (!(geni_status & M_GENI_CMD_ACTIVE))
+		goto out;
+
+	cur = gi2c->cur;
+	geni_i2c_abort_xfer(gi2c);
+	if (cur->flags & I2C_M_RD)
+		geni_i2c_rx_msg_cleanup(gi2c, cur);
+	else
+		geni_i2c_tx_msg_cleanup(gi2c, cur);
+out:
+	pm_runtime_put_sync_suspend(gi2c->se.dev);
+}
+
 static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 				u32 m_param)
 {
@@ -664,6 +691,13 @@ static int geni_i2c_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static void  geni_i2c_shutdown(struct platform_device *pdev)
+{
+	struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
+
+	geni_i2c_stop_xfer(gi2c);
+}
+
 static int __maybe_unused geni_i2c_runtime_suspend(struct device *dev)
 {
 	int ret;
@@ -728,6 +762,7 @@ MODULE_DEVICE_TABLE(of, geni_i2c_dt_match);
 static struct platform_driver geni_i2c_driver = {
 	.probe  = geni_i2c_probe,
 	.remove = geni_i2c_remove,
+	.shutdown = geni_i2c_shutdown,
 	.driver = {
 		.name = "geni_i2c",
 		.pm = &geni_i2c_pm_ops,
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation