[1/7] mtd: spi-nor: cadence-quadspi: add a delay in write sequence

Submitted by Vignesh R on Aug. 1, 2017, 4:54 a.m.

Details

Message ID 20170801045434.8733-2-vigneshr@ti.com
State New
Delegated to: Cyrille Pitchen
Headers show

Commit Message

Vignesh R Aug. 1, 2017, 4:54 a.m.
As per 66AK2G02 TRM[1] SPRUHY8F section 11.15.5.3 Indirect Access
Controller programming sequence, a delay equal to couple QSPI master
clock(~5ns) is required after setting CQSPI_REG_INDIRECTWR_START bit and
writing data to the flash. Add a new compatible to handle the couple of
cycles of delay required in the indirect write sequence, since this
delay is specific to TI 66AK2G SoC.

[1]http://www.ti.com/lit/ug/spruhy8f/spruhy8f.pdf

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
 Documentation/devicetree/bindings/mtd/cadence-quadspi.txt |  1 +
 drivers/mtd/spi-nor/cadence-quadspi.c                     | 13 +++++++++++++
 2 files changed, 14 insertions(+)

Comments

Rob Herring Aug. 10, 2017, 12:05 a.m.
On Tue, Aug 01, 2017 at 10:24:28AM +0530, Vignesh R wrote:
> As per 66AK2G02 TRM[1] SPRUHY8F section 11.15.5.3 Indirect Access
> Controller programming sequence, a delay equal to couple QSPI master
> clock(~5ns) is required after setting CQSPI_REG_INDIRECTWR_START bit and
> writing data to the flash. Add a new compatible to handle the couple of
> cycles of delay required in the indirect write sequence, since this
> delay is specific to TI 66AK2G SoC.
> 
> [1]http://www.ti.com/lit/ug/spruhy8f/spruhy8f.pdf
> 
> Signed-off-by: Vignesh R <vigneshr@ti.com>
> ---
>  Documentation/devicetree/bindings/mtd/cadence-quadspi.txt |  1 +
>  drivers/mtd/spi-nor/cadence-quadspi.c                     | 13 +++++++++++++
>  2 files changed, 14 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
> index f248056da24c..fdd511a83511 100644
> --- a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
> +++ b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
> @@ -2,6 +2,7 @@
>  
>  Required properties:
>  - compatible : Should be "cdns,qspi-nor".
> +	       Should be "ti,k2g-qspi" for TI 66AK2G platform.
>  - reg : Contains two entries, each of which is a tuple consisting of a
>  	physical address and length. The first entry is the address and
>  	length of the controller register set. The second entry is the
> diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
> index 53c7d8e0327a..94571590371d 100644
> --- a/drivers/mtd/spi-nor/cadence-quadspi.c
> +++ b/drivers/mtd/spi-nor/cadence-quadspi.c
> @@ -76,6 +76,7 @@ struct cqspi_st {
>  	u32			fifo_depth;
>  	u32			fifo_width;
>  	u32			trigger_address;
> +	u32			wr_delay;
>  	struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
>  };
>  
> @@ -608,6 +609,14 @@ static int cqspi_indirect_write_execute(struct spi_nor *nor,
>  	reinit_completion(&cqspi->transfer_complete);
>  	writel(CQSPI_REG_INDIRECTWR_START_MASK,
>  	       reg_base + CQSPI_REG_INDIRECTWR);
> +	/*
> +	 * As per 66AK2G02 TRM SPRUHY8F section 11.15.5.3 Indirect Access
> +	 * Controller programming sequence, couple of cycles of
> +	 * QSPI_REF_CLK delay is required for the above bit to
> +	 * be internally synchronized by the QSPI module. Provide 5
> +	 * cycles of delay.
> +	 */
> +	ndelay(cqspi->wr_delay);
>  
>  	while (remaining > 0) {
>  		write_bytes = remaining > page_size ? page_size : remaining;
> @@ -1213,6 +1222,9 @@ static int cqspi_probe(struct platform_device *pdev)
>  	}
>  
>  	cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk);
> +	if (of_device_is_compatible(dev->of_node, "ti,k2g-qspi"))
> +		cqspi->wr_delay = 5 * DIV_ROUND_UP(NSEC_PER_SEC,
> +						   cqspi->master_ref_clk_hz);

Use the data pointer in the of_device_id table and put the delay value 
there.

>  
>  	ret = devm_request_irq(dev, irq, cqspi_irq_handler, 0,
>  			       pdev->name, cqspi);
> @@ -1285,6 +1297,7 @@ static const struct dev_pm_ops cqspi__dev_pm_ops = {
>  
>  static const struct of_device_id cqspi_dt_ids[] = {
>  	{.compatible = "cdns,qspi-nor",},
> +	{.compatible = "ti,k2g-qspi",},
>  	{ /* end of table */ }
>  };
>  
> -- 
> 2.13.3
>
Rob Herring Aug. 10, 2017, 12:08 a.m.
On Tue, Aug 01, 2017 at 10:24:28AM +0530, Vignesh R wrote:
> As per 66AK2G02 TRM[1] SPRUHY8F section 11.15.5.3 Indirect Access
> Controller programming sequence, a delay equal to couple QSPI master
> clock(~5ns) is required after setting CQSPI_REG_INDIRECTWR_START bit and
> writing data to the flash. Add a new compatible to handle the couple of
> cycles of delay required in the indirect write sequence, since this
> delay is specific to TI 66AK2G SoC.
> 
> [1]http://www.ti.com/lit/ug/spruhy8f/spruhy8f.pdf
> 
> Signed-off-by: Vignesh R <vigneshr@ti.com>
> ---
>  Documentation/devicetree/bindings/mtd/cadence-quadspi.txt |  1 +
>  drivers/mtd/spi-nor/cadence-quadspi.c                     | 13 +++++++++++++
>  2 files changed, 14 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
> index f248056da24c..fdd511a83511 100644
> --- a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
> +++ b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
> @@ -2,6 +2,7 @@
>  
>  Required properties:
>  - compatible : Should be "cdns,qspi-nor".
> +	       Should be "ti,k2g-qspi" for TI 66AK2G platform.

Also, this doesn't indicate that "cdns,qspi-nor" is a fallback as you 
have in the dts files. Reformat to 1 valid combination per line.

>  - reg : Contains two entries, each of which is a tuple consisting of a
>  	physical address and length. The first entry is the address and
>  	length of the controller register set. The second entry is the
Vignesh R Aug. 10, 2017, 5:24 a.m.
On Thursday 10 August 2017 05:35 AM, Rob Herring wrote:
> On Tue, Aug 01, 2017 at 10:24:28AM +0530, Vignesh R wrote:
>> As per 66AK2G02 TRM[1] SPRUHY8F section 11.15.5.3 Indirect Access
>> Controller programming sequence, a delay equal to couple QSPI master
>> clock(~5ns) is required after setting CQSPI_REG_INDIRECTWR_START bit and
>> writing data to the flash. Add a new compatible to handle the couple of
>> cycles of delay required in the indirect write sequence, since this
>> delay is specific to TI 66AK2G SoC.
>>
>> [1]http://www.ti.com/lit/ug/spruhy8f/spruhy8f.pdf
>>
[...]
>> +	/*
>> +	 * As per 66AK2G02 TRM SPRUHY8F section 11.15.5.3 Indirect Access
>> +	 * Controller programming sequence, couple of cycles of
>> +	 * QSPI_REF_CLK delay is required for the above bit to
>> +	 * be internally synchronized by the QSPI module. Provide 5
>> +	 * cycles of delay.
>> +	 */
>> +	ndelay(cqspi->wr_delay);
>>  
>>  	while (remaining > 0) {
>>  		write_bytes = remaining > page_size ? page_size : remaining;
>> @@ -1213,6 +1222,9 @@ static int cqspi_probe(struct platform_device *pdev)
>>  	}
>>  
>>  	cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk);
>> +	if (of_device_is_compatible(dev->of_node, "ti,k2g-qspi"))
>> +		cqspi->wr_delay = 5 * DIV_ROUND_UP(NSEC_PER_SEC,
>> +						   cqspi->master_ref_clk_hz);
> 
> Use the data pointer in the of_device_id table and put the delay value 
> there.
> 

I thought about this, but for a given SoC, delay value might vary
depending on what frequency QSPI master_ref_clk is set to. So hard
coding will not help. How about having a flag (CQSPI_NEEDS_WR_DELAY) in
data pointer and then using that to determine whether or not to
calculate and set delay here?

>>  
>>  	ret = devm_request_irq(dev, irq, cqspi_irq_handler, 0,
>>  			       pdev->name, cqspi);
>> @@ -1285,6 +1297,7 @@ static const struct dev_pm_ops cqspi__dev_pm_ops = {
>>  
>>  static const struct of_device_id cqspi_dt_ids[] = {
>>  	{.compatible = "cdns,qspi-nor",},
>> +	{.compatible = "ti,k2g-qspi",},
>>  	{ /* end of table */ }
>>  };
>>  
>> -- 
>> 2.13.3
>>
Vignesh R Aug. 10, 2017, 5:28 a.m.
On Thursday 10 August 2017 05:38 AM, Rob Herring wrote:
> On Tue, Aug 01, 2017 at 10:24:28AM +0530, Vignesh R wrote:
>> As per 66AK2G02 TRM[1] SPRUHY8F section 11.15.5.3 Indirect Access
>> Controller programming sequence, a delay equal to couple QSPI master
>> clock(~5ns) is required after setting CQSPI_REG_INDIRECTWR_START bit and
>> writing data to the flash. Add a new compatible to handle the couple of
>> cycles of delay required in the indirect write sequence, since this
>> delay is specific to TI 66AK2G SoC.
>>
>> [1]http://www.ti.com/lit/ug/spruhy8f/spruhy8f.pdf
>>
>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>> ---
>>  Documentation/devicetree/bindings/mtd/cadence-quadspi.txt |  1 +
>>  drivers/mtd/spi-nor/cadence-quadspi.c                     | 13 +++++++++++++
>>  2 files changed, 14 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
>> index f248056da24c..fdd511a83511 100644
>> --- a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
>> +++ b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
>> @@ -2,6 +2,7 @@
>>  
>>  Required properties:
>>  - compatible : Should be "cdns,qspi-nor".
>> +	       Should be "ti,k2g-qspi" for TI 66AK2G platform.
> 
> Also, this doesn't indicate that "cdns,qspi-nor" is a fallback as you 
> have in the dts files. Reformat to 1 valid combination per line.
> 

Agreed, will fix it in v2.

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diff --git a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
index f248056da24c..fdd511a83511 100644
--- a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
+++ b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
@@ -2,6 +2,7 @@ 
 
 Required properties:
 - compatible : Should be "cdns,qspi-nor".
+	       Should be "ti,k2g-qspi" for TI 66AK2G platform.
 - reg : Contains two entries, each of which is a tuple consisting of a
 	physical address and length. The first entry is the address and
 	length of the controller register set. The second entry is the
diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index 53c7d8e0327a..94571590371d 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -76,6 +76,7 @@  struct cqspi_st {
 	u32			fifo_depth;
 	u32			fifo_width;
 	u32			trigger_address;
+	u32			wr_delay;
 	struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
 };
 
@@ -608,6 +609,14 @@  static int cqspi_indirect_write_execute(struct spi_nor *nor,
 	reinit_completion(&cqspi->transfer_complete);
 	writel(CQSPI_REG_INDIRECTWR_START_MASK,
 	       reg_base + CQSPI_REG_INDIRECTWR);
+	/*
+	 * As per 66AK2G02 TRM SPRUHY8F section 11.15.5.3 Indirect Access
+	 * Controller programming sequence, couple of cycles of
+	 * QSPI_REF_CLK delay is required for the above bit to
+	 * be internally synchronized by the QSPI module. Provide 5
+	 * cycles of delay.
+	 */
+	ndelay(cqspi->wr_delay);
 
 	while (remaining > 0) {
 		write_bytes = remaining > page_size ? page_size : remaining;
@@ -1213,6 +1222,9 @@  static int cqspi_probe(struct platform_device *pdev)
 	}
 
 	cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk);
+	if (of_device_is_compatible(dev->of_node, "ti,k2g-qspi"))
+		cqspi->wr_delay = 5 * DIV_ROUND_UP(NSEC_PER_SEC,
+						   cqspi->master_ref_clk_hz);
 
 	ret = devm_request_irq(dev, irq, cqspi_irq_handler, 0,
 			       pdev->name, cqspi);
@@ -1285,6 +1297,7 @@  static const struct dev_pm_ops cqspi__dev_pm_ops = {
 
 static const struct of_device_id cqspi_dt_ids[] = {
 	{.compatible = "cdns,qspi-nor",},
+	{.compatible = "ti,k2g-qspi",},
 	{ /* end of table */ }
 };