[PATCH 2/2] SPI: SAMSUNG: Bug fix for SPI with different FIFO level

padma venkat padma.kvr at gmail.com
Fri Jul 1 01:59:02 EDT 2011

Hi Jassi,

On Fri, Jul 1, 2011 at 11:22 AM, Jassi Brar <jassisinghbrar at gmail.com> wrote:
> On Fri, Jul 1, 2011 at 11:16 AM, padma venkat <padma.kvr at gmail.com> wrote:
>> Hi Tony,
>> On Thu, Jun 30, 2011 at 4:30 PM, Tony Nadackal <tonykn at gmail.com> wrote:
>>> Hi Padma,
>>> With regards to your patch, even though one can check the tx done status
>>> using the TX_DONE bit, the present macro itself would work perfectly fine if
>>> the 'fifo_lvl_mask' is set properly.
>>> For example in 6450 channel 1, the fifo_lvl_mask should be 0x1ff (for 9bits,
>>> 15:23), while even in your patch, it is wrongly set as 0x7f(only 7bits).
>>> Thus, if this fifo_lvl_mask was defined correctly, the existing macro would
>>> itself have worked.
>> Thanks for your comment.
>> I considered changing to the fifo_lvl_mask to 1ff as you mentioned.
>> But I  think that the fifo_lvl_mask reflects the actual FIFO capacity
>> in the SPI driver.
>> For the failing channels the FIFO trigger level is 64 bytes and so i
>> retained that value.
>> In the driver it polls till the FIFO capacity level otherwise it goes
>> for DMA.So if we keep
>> the FIFO level as 1ff when the actual capacity is 7f then it fails.
>> Jassi what do you think about this?
> 'fifo_lvl_mask' is h/w specific and can't be set for convenience.
> I don't have access to post-s3c64xx datasheets.
> Please check and reply if TX_DONE bit is at same offset for all
> channels of an SoC, because
> I suspect it's otherwise.
Yes. The TX_DONE bit is at the same offset for all the channels of an SoC.
in S5P64X0,S5PV210 and S5PV310 it is at offset 25.

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