On 9/24/2017 5:29 PM, Marek Vasut wrote:
> On 09/24/2017 12:59 PM, Vignesh R wrote:
>> As per 66AK2G02 TRM[1] SPRUHY8F section 11.15.5.3 Indirect Access
>> Controller programming sequence, a delay equal to couple of QSPI master
>> clock(~5ns) is required after setting CQSPI_REG_INDIRECTWR_START bit and
>> writing data to the flash. Introduce a quirk flag CQSPI_NEEDS_WR_DELAY
>> to handle this and set this flag for TI 66AK2G SoC.
>>
>> [1]http://www.ti.com/lit/ug/spruhy8f/spruhy8f.pdf
>>
>> Signed-off-by: Vignesh R <vigne...@ti.com>
>
> Is this TI specific or is this controller property ? I wouldn't be
> surprised of the later ...
I am not sure, there is no generic public documentation by cadence for
this IP. TI TRM clearly states this delay is required and I have
verified it practically that this delay is indeed needed.
But current user of this IP, socfpga does not seem to mention anything
about it. So, I guess its TI specific quirk.
>
>> ---
>>
>> v3:
>> Fix build warnings reported by kbuild test bot.
>>
>> drivers/mtd/spi-nor/cadence-quadspi.c | 27 ++++++++++++++++++++++++++-
>> 1 file changed, 26 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c
>> b/drivers/mtd/spi-nor/cadence-quadspi.c
>> index 53c7d8e0327a..5cd5d6f7303f 100644
>> --- a/drivers/mtd/spi-nor/cadence-quadspi.c
>> +++ b/drivers/mtd/spi-nor/cadence-quadspi.c
>> @@ -38,6 +38,9 @@
>> #define CQSPI_NAME "cadence-qspi"
>> #define CQSPI_MAX_CHIPSELECT 16
>>
>> +/* Quirks */
>> +#define CQSPI_NEEDS_WR_DELAY BIT(0)
>> +
>> struct cqspi_st;
>>
>> struct cqspi_flash_pdata {
>> @@ -76,6 +79,7 @@ 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 +612,15 @@ 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.
>> + */
>> + if (cqspi->wr_delay)
>> + ndelay(cqspi->wr_delay);
>>
>> while (remaining > 0) {
>> write_bytes = remaining > page_size ? page_size : remaining;
>> @@ -1156,6 +1169,7 @@ static int cqspi_probe(struct platform_device *pdev)
>> struct cqspi_st *cqspi;
>> struct resource *res;
>> struct resource *res_ahb;
>> + unsigned long data;
>> int ret;
>> int irq;
>>
>> @@ -1213,6 +1227,10 @@ static int cqspi_probe(struct platform_device *pdev)
>> }
>>
>> cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk);
>> + data = (unsigned long)of_device_get_match_data(dev);
>> + if (data & CQSPI_NEEDS_WR_DELAY)
>> + 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);
>> @@ -1284,7 +1302,14 @@ static const struct dev_pm_ops cqspi__dev_pm_ops = {
>> #endif
>>
>> static const struct of_device_id cqspi_dt_ids[] = {
>> - {.compatible = "cdns,qspi-nor",},
>> + {
>> + .compatible = "cdns,qspi-nor",
>> + .data = (void *)0,
>> + },
>> + {
>> + .compatible = "ti,k2g-qspi",
>> + .data = (void *)CQSPI_NEEDS_WR_DELAY,
>> + },
>> { /* end of table */ }
>> };
>>
>>
>
>
