[PATCH V2 0/2] Implement Shutdown callback for i2c

[PATCH V2 0/2] Implement Shutdown callback for i2c

[Roja Rani Yarubandi]

Store DMA mapping data in geni_i2c_dev struct.
Implement Shutdown callback for geni i2c driver.

Changes in V2:
 - Changed commit text.
 - As per Stephen's comments added separate function for stop transfer.

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 | 50 ++++++++++++++++++++++++++++++
 include/linux/qcom-geni-se.h       |  5 +++
 2 files changed, 55 insertions(+)

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

[PATCH V2 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.

Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
---
Changes in V2:
 - As per Stephen's comments, changed commit text, fixed minor nitpicks.

 drivers/i2c/busses/i2c-qcom-geni.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index 7f130829bf01..1fda5c7c2cfc 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;
+	dma_addr_t tx_dma;
+	dma_addr_t rx_dma;
+	size_t xfer_len;
 };
 
 struct geni_i2c_err_log {
@@ -358,6 +361,7 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 	struct geni_se *se = &gi2c->se;
 	size_t len = msg->len;
 
+	gi2c->xfer_len = msg->len;
 	if (!of_machine_is_compatible("lenovo,yoga-c630"))
 		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
 
@@ -384,6 +388,7 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 	if (dma_buf) {
 		if (gi2c->err)
 			geni_i2c_rx_fsm_rst(gi2c);
+		gi2c->rx_dma = rx_dma;
 		geni_se_rx_dma_unprep(se, rx_dma, len);
 		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
 	}
@@ -400,6 +405,7 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 	struct geni_se *se = &gi2c->se;
 	size_t len = msg->len;
 
+	gi2c->xfer_len = msg->len;
 	if (!of_machine_is_compatible("lenovo,yoga-c630"))
 		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
 
@@ -429,6 +435,7 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
 	if (dma_buf) {
 		if (gi2c->err)
 			geni_i2c_tx_fsm_rst(gi2c);
+		gi2c->tx_dma = tx_dma;
 		geni_se_tx_dma_unprep(se, tx_dma, len);
 		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
 	}
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH V2 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 unmap DMA mappings
during system "reboot" or "shutdown".

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.

 drivers/i2c/busses/i2c-qcom-geni.c | 43 ++++++++++++++++++++++++++++++
 include/linux/qcom-geni-se.h       |  5 ++++
 2 files changed, 48 insertions(+)

diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index 1fda5c7c2cfc..d07f2f33bb75 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -486,6 +486,28 @@ static int geni_i2c_xfer(struct i2c_adapter *adap,
 	return ret;
 }
 
+static void geni_i2c_stop_xfer(struct geni_i2c_dev *gi2c)
+{
+	u32 val;
+	struct geni_se *se = &gi2c->se;
+
+	val = readl_relaxed(gi2c->se.base + SE_DMA_DEBUG_REG0);
+	if (val & DMA_TX_ACTIVE) {
+		geni_i2c_abort_xfer(gi2c);
+		gi2c->cur_wr = 0;
+		if (gi2c->err)
+			geni_i2c_tx_fsm_rst(gi2c);
+		geni_se_tx_dma_unprep(se, gi2c->tx_dma, gi2c->xfer_len);
+	}
+	if (val & DMA_RX_ACTIVE) {
+		geni_i2c_abort_xfer(gi2c);
+		gi2c->cur_rd = 0;
+		if (gi2c->err)
+			geni_i2c_rx_fsm_rst(gi2c);
+		geni_se_rx_dma_unprep(se, gi2c->rx_dma, gi2c->xfer_len);
+	}
+}
+
 static u32 geni_i2c_func(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
@@ -617,6 +639,26 @@ static int geni_i2c_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static void geni_i2c_shutdown(struct platform_device *pdev)
+{
+	int ret;
+	u32 dma;
+	struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
+	struct geni_se *se = &gi2c->se;
+
+	ret = pm_runtime_get_sync(gi2c->se.dev);
+	if (ret < 0) {
+		dev_err(gi2c->se.dev, "Failed to resume device: %d\n", ret);
+		return;
+	}
+
+	dma = readl_relaxed(se->base + SE_GENI_DMA_MODE_EN);
+	if (dma)
+		geni_i2c_stop_xfer(gi2c);
+
+	pm_runtime_put_sync_suspend(gi2c->se.dev);
+}
+
 static int __maybe_unused geni_i2c_runtime_suspend(struct device *dev)
 {
 	int ret;
@@ -677,6 +719,7 @@ 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,
diff --git a/include/linux/qcom-geni-se.h b/include/linux/qcom-geni-se.h
index dd464943f717..c3c016496d98 100644
--- a/include/linux/qcom-geni-se.h
+++ b/include/linux/qcom-geni-se.h
@@ -77,6 +77,7 @@ struct geni_se {
 #define SE_DMA_RX_FSM_RST		0xd58
 #define SE_HW_PARAM_0			0xe24
 #define SE_HW_PARAM_1			0xe28
+#define SE_DMA_DEBUG_REG0		0xe40
 
 /* GENI_FORCE_DEFAULT_REG fields */
 #define FORCE_DEFAULT	BIT(0)
@@ -207,6 +208,10 @@ struct geni_se {
 #define RX_GENI_CANCEL_IRQ		BIT(11)
 #define RX_GENI_GP_IRQ_EXT		GENMASK(13, 12)
 
+/* SE_DMA_DEBUG_REG0 Register fields */
+#define DMA_TX_ACTIVE			BIT(0)
+#define DMA_RX_ACTIVE			BIT(1)
+
 /* SE_HW_PARAM_0 fields */
 #define TX_FIFO_WIDTH_MSK		GENMASK(29, 24)
 #define TX_FIFO_WIDTH_SHFT		24
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH V2 1/2] i2c: i2c-qcom-geni: Store DMA mapping data in geni_i2c_dev struct

[Stephen Boyd]

Quoting Roja Rani Yarubandi (2020-08-20 03:35:21)
> 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.
> 
> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
> ---

Can this be squashed with the next patch? I don't see how this stands on
its own.

Re: [PATCH V2 2/2] i2c: i2c-qcom-geni: Add shutdown callback for i2c

[Stephen Boyd]

Quoting Roja Rani Yarubandi (2020-08-20 03:35:22)
> 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 unmap DMA mappings
> during system "reboot" or "shutdown".
> 
> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
> ---

I'd still put a Fixes tag because it's fixing the driver when someone
runs shutdown.

> Changes in V2:
>  - As per Stephen's comments added seperate function for stop transfer,
>    fixed minor nitpicks.
> 
>  drivers/i2c/busses/i2c-qcom-geni.c | 43 ++++++++++++++++++++++++++++++
>  include/linux/qcom-geni-se.h       |  5 ++++
>  2 files changed, 48 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
> index 1fda5c7c2cfc..d07f2f33bb75 100644
> --- a/drivers/i2c/busses/i2c-qcom-geni.c
> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> @@ -486,6 +486,28 @@ static int geni_i2c_xfer(struct i2c_adapter *adap,
>         return ret;
>  }
>  
> +static void geni_i2c_stop_xfer(struct geni_i2c_dev *gi2c)
> +{
> +       u32 val;
> +       struct geni_se *se = &gi2c->se;
> +
> +       val = readl_relaxed(gi2c->se.base + SE_DMA_DEBUG_REG0);
> +       if (val & DMA_TX_ACTIVE) {
> +               geni_i2c_abort_xfer(gi2c);
> +               gi2c->cur_wr = 0;
> +               if (gi2c->err)
> +                       geni_i2c_tx_fsm_rst(gi2c);
> +               geni_se_tx_dma_unprep(se, gi2c->tx_dma, gi2c->xfer_len);
> +       }
> +       if (val & DMA_RX_ACTIVE) {
> +               geni_i2c_abort_xfer(gi2c);
> +               gi2c->cur_rd = 0;
> +               if (gi2c->err)
> +                       geni_i2c_rx_fsm_rst(gi2c);
> +               geni_se_rx_dma_unprep(se, gi2c->rx_dma, gi2c->xfer_len);
> +       }
> +}
> +
>  static u32 geni_i2c_func(struct i2c_adapter *adap)
>  {
>         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
> @@ -617,6 +639,26 @@ static int geni_i2c_remove(struct platform_device *pdev)
>         return 0;
>  }
>  
> +static void geni_i2c_shutdown(struct platform_device *pdev)
> +{
> +       int ret;
> +       u32 dma;
> +       struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
> +       struct geni_se *se = &gi2c->se;
> +
> +       ret = pm_runtime_get_sync(gi2c->se.dev);
> +       if (ret < 0) {
> +               dev_err(gi2c->se.dev, "Failed to resume device: %d\n", ret);
> +               return;
> +       }
> +
> +       dma = readl_relaxed(se->base + SE_GENI_DMA_MODE_EN);
> +       if (dma)
> +               geni_i2c_stop_xfer(gi2c);

Any reason the if (dma) check isn't inside geni_i2c_stop_xfer()?
Checking for dma and then bailing out early should work and keep the
logic in one function. Then the pm_runtime_sync() call could go in there
too and if (!dma) goto out. This assumes that we're going to call
geni_i2c_stop_xfer() from somewhere else, like if a transfer times out
or something?

> +
> +       pm_runtime_put_sync_suspend(gi2c->se.dev);
> +}
> +
>  static int __maybe_unused geni_i2c_runtime_suspend(struct device *dev)
>  {
>         int ret;

Re: [PATCH V2 1/2] i2c: i2c-qcom-geni: Store DMA mapping data in geni_i2c_dev struct

[Akash Asthana]

Hi Roja,

On 8/20/2020 4:05 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.
>
> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
> ---
> Changes in V2:
>   - As per Stephen's comments, changed commit text, fixed minor nitpicks.
>
>   drivers/i2c/busses/i2c-qcom-geni.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
> index 7f130829bf01..1fda5c7c2cfc 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;
> +	dma_addr_t tx_dma;
> +	dma_addr_t rx_dma;
> +	size_t xfer_len;
>   };
>   
>   struct geni_i2c_err_log {
> @@ -358,6 +361,7 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
>   	struct geni_se *se = &gi2c->se;
>   	size_t len = msg->len;
>   
> +	gi2c->xfer_len = msg->len;

nit: gi2c->xfer = len, for tx_one_msg as well.

Regards,

Akash

>   	if (!of_machine_is_compatible("lenovo,yoga-c630"))
>   		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
>   
> @@ -384,6 +388,7 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
>   	if (dma_buf) {
>   		if (gi2c->err)
>   			geni_i2c_rx_fsm_rst(gi2c);
> +		gi2c->rx_dma = rx_dma;
>   		geni_se_rx_dma_unprep(se, rx_dma, len);
>   		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
>   	}
> @@ -400,6 +405,7 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
>   	struct geni_se *se = &gi2c->se;
>   	size_t len = msg->len;
>   
> +	gi2c->xfer_len = msg->len;
>   	if (!of_machine_is_compatible("lenovo,yoga-c630"))
>   		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
>   
> @@ -429,6 +435,7 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
>   	if (dma_buf) {
>   		if (gi2c->err)
>   			geni_i2c_tx_fsm_rst(gi2c);
> +		gi2c->tx_dma = tx_dma;
>   		geni_se_tx_dma_unprep(se, tx_dma, len);
>   		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
>   	}

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project

Re: [PATCH V2 2/2] i2c: i2c-qcom-geni: Add shutdown callback for i2c

[Akash Asthana]

Hi Roja,

On 8/20/2020 4:05 PM, Roja Rani Yarubandi wrote:
> 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 unmap DMA mappings
> during system "reboot" or "shutdown".
>
> 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.
>
>   drivers/i2c/busses/i2c-qcom-geni.c | 43 ++++++++++++++++++++++++++++++
>   include/linux/qcom-geni-se.h       |  5 ++++
>   2 files changed, 48 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
> index 1fda5c7c2cfc..d07f2f33bb75 100644
> --- a/drivers/i2c/busses/i2c-qcom-geni.c
> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> @@ -486,6 +486,28 @@ static int geni_i2c_xfer(struct i2c_adapter *adap,
>   	return ret;
>   }
>   
> +static void geni_i2c_stop_xfer(struct geni_i2c_dev *gi2c)
> +{
> +	u32 val;
> +	struct geni_se *se = &gi2c->se;
> +
> +	val = readl_relaxed(gi2c->se.base + SE_DMA_DEBUG_REG0);
> +	if (val & DMA_TX_ACTIVE) {
> +		geni_i2c_abort_xfer(gi2c);
> +		gi2c->cur_wr = 0;
> +		if (gi2c->err)
> +			geni_i2c_tx_fsm_rst(gi2c);
> +		geni_se_tx_dma_unprep(se, gi2c->tx_dma, gi2c->xfer_len);
> +	}
should be 'else if', because TX and RX can't happen parallel.
> +	if (val & DMA_RX_ACTIVE) {
> +		geni_i2c_abort_xfer(gi2c);
> +		gi2c->cur_rd = 0;
> +		if (gi2c->err)
> +			geni_i2c_rx_fsm_rst(gi2c);
> +		geni_se_rx_dma_unprep(se, gi2c->rx_dma, gi2c->xfer_len);
> +	}
> +}
> +
>   static u32 geni_i2c_func(struct i2c_adapter *adap)
>   {
>   	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
> @@ -617,6 +639,26 @@ static int geni_i2c_remove(struct platform_device *pdev)
>   	return 0;
>   }
>   
> +static void geni_i2c_shutdown(struct platform_device *pdev)
> +{
> +	int ret;
> +	u32 dma;
> +	struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
> +	struct geni_se *se = &gi2c->se;
> +
> +	ret = pm_runtime_get_sync(gi2c->se.dev);
> +	if (ret < 0) {
> +		dev_err(gi2c->se.dev, "Failed to resume device: %d\n", ret);
> +		return;
> +	}
> +
> +	dma = readl_relaxed(se->base + SE_GENI_DMA_MODE_EN);

Wrt to current issue context it may be suffice to stop just DMA mode 
transfers but why not stop all mode of active transfer during shutdown 
in a generic way.

Regards,

Akash

> +	if (dma)
> +		geni_i2c_stop_xfer(gi2c);
> +
> +	pm_runtime_put_sync_suspend(gi2c->se.dev);
> +}
> +
>   static int __maybe_unused geni_i2c_runtime_suspend(struct device *dev)
>   {
>   	int ret;
> @@ -677,6 +719,7 @@ 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,
> diff --git a/include/linux/qcom-geni-se.h b/include/linux/qcom-geni-se.h
> index dd464943f717..c3c016496d98 100644
> --- a/include/linux/qcom-geni-se.h
> +++ b/include/linux/qcom-geni-se.h
> @@ -77,6 +77,7 @@ struct geni_se {
>   #define SE_DMA_RX_FSM_RST		0xd58
>   #define SE_HW_PARAM_0			0xe24
>   #define SE_HW_PARAM_1			0xe28
> +#define SE_DMA_DEBUG_REG0		0xe40
>   
>   /* GENI_FORCE_DEFAULT_REG fields */
>   #define FORCE_DEFAULT	BIT(0)
> @@ -207,6 +208,10 @@ struct geni_se {
>   #define RX_GENI_CANCEL_IRQ		BIT(11)
>   #define RX_GENI_GP_IRQ_EXT		GENMASK(13, 12)
>   
> +/* SE_DMA_DEBUG_REG0 Register fields */
> +#define DMA_TX_ACTIVE			BIT(0)
> +#define DMA_RX_ACTIVE			BIT(1)
> +
>   /* SE_HW_PARAM_0 fields */
>   #define TX_FIFO_WIDTH_MSK		GENMASK(29, 24)
>   #define TX_FIFO_WIDTH_SHFT		24

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project

Re: [PATCH V2 1/2] i2c: i2c-qcom-geni: Store DMA mapping data in geni_i2c_dev struct

[rojay]

On 2020-08-21 05:48, Stephen Boyd wrote:
> Quoting Roja Rani Yarubandi (2020-08-20 03:35:21)
>> 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.
>> 
>> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
>> ---
> 
> Can this be squashed with the next patch? I don't see how this stands 
> on
> its own.

Okay.

Re: [PATCH V2 2/2] i2c: i2c-qcom-geni: Add shutdown callback for i2c

[rojay]

On 2020-08-21 05:52, Stephen Boyd wrote:
> Quoting Roja Rani Yarubandi (2020-08-20 03:35:22)
>> 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 unmap DMA mappings
>> during system "reboot" or "shutdown".
>> 
>> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
>> ---
> 
> I'd still put a Fixes tag because it's fixing the driver when someone
> runs shutdown.
> 

Okay, will add fixes tag.

>> Changes in V2:
>>  - As per Stephen's comments added seperate function for stop 
>> transfer,
>>    fixed minor nitpicks.
>> 
>>  drivers/i2c/busses/i2c-qcom-geni.c | 43 
>> ++++++++++++++++++++++++++++++
>>  include/linux/qcom-geni-se.h       |  5 ++++
>>  2 files changed, 48 insertions(+)
>> 
>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c 
>> b/drivers/i2c/busses/i2c-qcom-geni.c
>> index 1fda5c7c2cfc..d07f2f33bb75 100644
>> --- a/drivers/i2c/busses/i2c-qcom-geni.c
>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
>> @@ -486,6 +486,28 @@ static int geni_i2c_xfer(struct i2c_adapter 
>> *adap,
>>         return ret;
>>  }
>> 
>> +static void geni_i2c_stop_xfer(struct geni_i2c_dev *gi2c)
>> +{
>> +       u32 val;
>> +       struct geni_se *se = &gi2c->se;
>> +
>> +       val = readl_relaxed(gi2c->se.base + SE_DMA_DEBUG_REG0);
>> +       if (val & DMA_TX_ACTIVE) {
>> +               geni_i2c_abort_xfer(gi2c);
>> +               gi2c->cur_wr = 0;
>> +               if (gi2c->err)
>> +                       geni_i2c_tx_fsm_rst(gi2c);
>> +               geni_se_tx_dma_unprep(se, gi2c->tx_dma, 
>> gi2c->xfer_len);
>> +       }
>> +       if (val & DMA_RX_ACTIVE) {
>> +               geni_i2c_abort_xfer(gi2c);
>> +               gi2c->cur_rd = 0;
>> +               if (gi2c->err)
>> +                       geni_i2c_rx_fsm_rst(gi2c);
>> +               geni_se_rx_dma_unprep(se, gi2c->rx_dma, 
>> gi2c->xfer_len);
>> +       }
>> +}
>> +
>>  static u32 geni_i2c_func(struct i2c_adapter *adap)
>>  {
>>         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & 
>> ~I2C_FUNC_SMBUS_QUICK);
>> @@ -617,6 +639,26 @@ static int geni_i2c_remove(struct platform_device 
>> *pdev)
>>         return 0;
>>  }
>> 
>> +static void geni_i2c_shutdown(struct platform_device *pdev)
>> +{
>> +       int ret;
>> +       u32 dma;
>> +       struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
>> +       struct geni_se *se = &gi2c->se;
>> +
>> +       ret = pm_runtime_get_sync(gi2c->se.dev);
>> +       if (ret < 0) {
>> +               dev_err(gi2c->se.dev, "Failed to resume device: %d\n", 
>> ret);
>> +               return;
>> +       }
>> +
>> +       dma = readl_relaxed(se->base + SE_GENI_DMA_MODE_EN);
>> +       if (dma)
>> +               geni_i2c_stop_xfer(gi2c);
> 
> Any reason the if (dma) check isn't inside geni_i2c_stop_xfer()?
> Checking for dma and then bailing out early should work and keep the
> logic in one function. Then the pm_runtime_sync() call could go in 
> there
> too and if (!dma) goto out. This assumes that we're going to call
> geni_i2c_stop_xfer() from somewhere else, like if a transfer times out
> or something?
> 

Okay, will do the changes.

>> +
>> +       pm_runtime_put_sync_suspend(gi2c->se.dev);
>> +}
>> +
>>  static int __maybe_unused geni_i2c_runtime_suspend(struct device 
>> *dev)
>>  {
>>         int ret;

Re: [PATCH V2 1/2] i2c: i2c-qcom-geni: Store DMA mapping data in geni_i2c_dev struct

[rojay]

On 2020-08-26 17:25, Akash Asthana wrote:
> Hi Roja,
> 
> On 8/20/2020 4:05 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.
>> 
>> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
>> ---
>> Changes in V2:
>>   - As per Stephen's comments, changed commit text, fixed minor 
>> nitpicks.
>> 
>>   drivers/i2c/busses/i2c-qcom-geni.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>> 
>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c 
>> b/drivers/i2c/busses/i2c-qcom-geni.c
>> index 7f130829bf01..1fda5c7c2cfc 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;
>> +	dma_addr_t tx_dma;
>> +	dma_addr_t rx_dma;
>> +	size_t xfer_len;
>>   };
>>     struct geni_i2c_err_log {
>> @@ -358,6 +361,7 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev 
>> *gi2c, struct i2c_msg *msg,
>>   	struct geni_se *se = &gi2c->se;
>>   	size_t len = msg->len;
>>   +	gi2c->xfer_len = msg->len;
> 
> nit: gi2c->xfer = len, for tx_one_msg as well.
> 
> Regards,
> 
> Akash
> 

Okay

>>   	if (!of_machine_is_compatible("lenovo,yoga-c630"))
>>   		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
>>   @@ -384,6 +388,7 @@ static int geni_i2c_rx_one_msg(struct 
>> geni_i2c_dev *gi2c, struct i2c_msg *msg,
>>   	if (dma_buf) {
>>   		if (gi2c->err)
>>   			geni_i2c_rx_fsm_rst(gi2c);
>> +		gi2c->rx_dma = rx_dma;
>>   		geni_se_rx_dma_unprep(se, rx_dma, len);
>>   		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
>>   	}
>> @@ -400,6 +405,7 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev 
>> *gi2c, struct i2c_msg *msg,
>>   	struct geni_se *se = &gi2c->se;
>>   	size_t len = msg->len;
>>   +	gi2c->xfer_len = msg->len;
>>   	if (!of_machine_is_compatible("lenovo,yoga-c630"))
>>   		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
>>   @@ -429,6 +435,7 @@ static int geni_i2c_tx_one_msg(struct 
>> geni_i2c_dev *gi2c, struct i2c_msg *msg,
>>   	if (dma_buf) {
>>   		if (gi2c->err)
>>   			geni_i2c_tx_fsm_rst(gi2c);
>> +		gi2c->tx_dma = tx_dma;
>>   		geni_se_tx_dma_unprep(se, tx_dma, len);
>>   		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
>>   	}

Re: [PATCH V2 2/2] i2c: i2c-qcom-geni: Add shutdown callback for i2c

[rojay]

On 2020-08-26 17:26, Akash Asthana wrote:
> Hi Roja,
> 
> On 8/20/2020 4:05 PM, Roja Rani Yarubandi wrote:
>> 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 unmap DMA mappings
>> during system "reboot" or "shutdown".
>> 
>> 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.
>> 
>>   drivers/i2c/busses/i2c-qcom-geni.c | 43 
>> ++++++++++++++++++++++++++++++
>>   include/linux/qcom-geni-se.h       |  5 ++++
>>   2 files changed, 48 insertions(+)
>> 
>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c 
>> b/drivers/i2c/busses/i2c-qcom-geni.c
>> index 1fda5c7c2cfc..d07f2f33bb75 100644
>> --- a/drivers/i2c/busses/i2c-qcom-geni.c
>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
>> @@ -486,6 +486,28 @@ static int geni_i2c_xfer(struct i2c_adapter 
>> *adap,
>>   	return ret;
>>   }
>>   +static void geni_i2c_stop_xfer(struct geni_i2c_dev *gi2c)
>> +{
>> +	u32 val;
>> +	struct geni_se *se = &gi2c->se;
>> +
>> +	val = readl_relaxed(gi2c->se.base + SE_DMA_DEBUG_REG0);
>> +	if (val & DMA_TX_ACTIVE) {
>> +		geni_i2c_abort_xfer(gi2c);
>> +		gi2c->cur_wr = 0;
>> +		if (gi2c->err)
>> +			geni_i2c_tx_fsm_rst(gi2c);
>> +		geni_se_tx_dma_unprep(se, gi2c->tx_dma, gi2c->xfer_len);
>> +	}
> should be 'else if', because TX and RX can't happen parallel.
>> +	if (val & DMA_RX_ACTIVE) {
>> +		geni_i2c_abort_xfer(gi2c);
>> +		gi2c->cur_rd = 0;
>> +		if (gi2c->err)
>> +			geni_i2c_rx_fsm_rst(gi2c);
>> +		geni_se_rx_dma_unprep(se, gi2c->rx_dma, gi2c->xfer_len);
>> +	}
>> +}
>> +
>>   static u32 geni_i2c_func(struct i2c_adapter *adap)
>>   {
>>   	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & 
>> ~I2C_FUNC_SMBUS_QUICK);
>> @@ -617,6 +639,26 @@ static int geni_i2c_remove(struct platform_device 
>> *pdev)
>>   	return 0;
>>   }
>>   +static void geni_i2c_shutdown(struct platform_device *pdev)
>> +{
>> +	int ret;
>> +	u32 dma;
>> +	struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
>> +	struct geni_se *se = &gi2c->se;
>> +
>> +	ret = pm_runtime_get_sync(gi2c->se.dev);
>> +	if (ret < 0) {
>> +		dev_err(gi2c->se.dev, "Failed to resume device: %d\n", ret);
>> +		return;
>> +	}
>> +
>> +	dma = readl_relaxed(se->base + SE_GENI_DMA_MODE_EN);
> 
> Wrt to current issue context it may be suffice to stop just DMA mode
> transfers but why not stop all mode of active transfer during shutdown
> in a generic way.
> 
> Regards,
> 
> Akash
> 

Okay, I will include FIFO transfer case also in stop_xfer

>> +	if (dma)
>> +		geni_i2c_stop_xfer(gi2c);
>> +
>> +	pm_runtime_put_sync_suspend(gi2c->se.dev);
>> +}
>> +
>>   static int __maybe_unused geni_i2c_runtime_suspend(struct device 
>> *dev)
>>   {
>>   	int ret;
>> @@ -677,6 +719,7 @@ 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,
>> diff --git a/include/linux/qcom-geni-se.h 
>> b/include/linux/qcom-geni-se.h
>> index dd464943f717..c3c016496d98 100644
>> --- a/include/linux/qcom-geni-se.h
>> +++ b/include/linux/qcom-geni-se.h
>> @@ -77,6 +77,7 @@ struct geni_se {
>>   #define SE_DMA_RX_FSM_RST		0xd58
>>   #define SE_HW_PARAM_0			0xe24
>>   #define SE_HW_PARAM_1			0xe28
>> +#define SE_DMA_DEBUG_REG0		0xe40
>>     /* GENI_FORCE_DEFAULT_REG fields */
>>   #define FORCE_DEFAULT	BIT(0)
>> @@ -207,6 +208,10 @@ struct geni_se {
>>   #define RX_GENI_CANCEL_IRQ		BIT(11)
>>   #define RX_GENI_GP_IRQ_EXT		GENMASK(13, 12)
>>   +/* SE_DMA_DEBUG_REG0 Register fields */
>> +#define DMA_TX_ACTIVE			BIT(0)
>> +#define DMA_RX_ACTIVE			BIT(1)
>> +
>>   /* SE_HW_PARAM_0 fields */
>>   #define TX_FIFO_WIDTH_MSK		GENMASK(29, 24)
>>   #define TX_FIFO_WIDTH_SHFT		24