On 09/24/2017 02:33 PM, Vignesh R wrote:
>
>
> 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 <[email protected]>
>>
>> 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.
OK, let's go with that then. I didn't observe any stability issues with
SoCFPGA, but I didn't run the flash at 100s of MHz either. At what kind
of frequencies does the quirk become relevant ?
>>
>>> ---
>>>
>>> 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 */ }
>>> };
>>>
>>>
>>
>>
--
Best regards,
Marek Vasut
