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

[Jagan Teki]

On Wed, Oct 19, 2016 at 8:18 PM, Marek Vasut <marex at denx.de> wrote:
> On 10/19/2016 04:41 PM, Jagan Teki wrote:
>> On Wed, Oct 19, 2016 at 10:10 AM, Vignesh R <vigneshr at ti.com> 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.
>>>
>>> With above change, can I have your Acked-by/Reviewed-by?
>>
>> Also try to get the 'sf update' data before and after and append it on
>> commit message.
>
> Why? Seems useless to me.

Since it's a performance improvement patch better to have that
numbers, no harm getting that data.

thanks!
-- 
Jagan Teki
Free Software Engineer | www.openedev.com
U-Boot, Linux | Upstream Maintainer
Hyderabad, India.