[U-Boot] [PATCH] spi: cadence_qspi_apb: Improve indirect write transaction

[Marek Vasut]

On 10/19/2016 06:40 AM, Vignesh R wrote:
> Hi,
> 
> On Tuesday 18 October 2016 05:15 PM, Marek Vasut wrote:
>> On 10/18/2016 10:23 AM, Vignesh R wrote:
>>>
>>>
>>> On Thursday 06 October 2016 04:49 PM, Vignesh R wrote:
>>>> If the write transaction size(write_bytes) is not a multiple of word
>>>> length, then issue word length writes till the we reach the dangling
>>>> bytes. On the final write, issue byte by byte write to complete the
>>>> transaction. This marginally improves write throughput when performing
>>>> random sized writes to the flash.
>>>>
>>>> Signed-off-by: Vignesh R <vigneshr at ti.com>
>>>> ---
>>>
>>> Gentle ping... Any comments?
>>>
>>>>
>>>> Tested on K2G GP EVM.
>>>>
>>>>  drivers/spi/cadence_qspi_apb.c | 10 ++++++++--
>>>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
>>>> index e285d3c1e761..4b891f227243 100644
>>>> --- a/drivers/spi/cadence_qspi_apb.c
>>>> +++ b/drivers/spi/cadence_qspi_apb.c
>>>> @@ -752,10 +752,16 @@ int cadence_qspi_apb_indirect_write_execute(struct cadence_spi_platdata *plat,
>>>>  	while (remaining > 0) {
>>>>  		write_bytes = remaining > page_size ? page_size : remaining;
>>>>  		/* Handle non-4-byte aligned access to avoid data abort. */
>>>> -		if (((uintptr_t)txbuf % 4) || (write_bytes % 4))
>>>> +		if ((uintptr_t)txbuf % 4) {
>>>>  			writesb(plat->ahbbase, txbuf, write_bytes);
>>>> -		else
>>>> +		} else {
>>>>  			writesl(plat->ahbbase, txbuf, write_bytes >> 2);
>>>> +			if (write_bytes % 4) {
>>>> +				writesb(plat->ahbbase,
>>>> +					txbuf + rounddown(write_bytes, 4),
>>>> +					write_bytes % 4);
>>>> +			}
>>
>> You can probably pull this block from the else branch.
> 
> Yeah, I guess writesb() can handle zero byte write request I believe.

Hmmmm, good point, in which case this is OK as-is.

> With above change, can I have your Acked-by/Reviewed-by?

Reviewed-by: Marek Vasut <marex at denx.de>


-- 
Best regards,
Marek Vasut