Hello Michal:
> I tried to connect a SPI NOR flash to my sunxi board and due to the
current
> sunxi SPI driver limitations it does not work.
>
> The SPI driver returns an error when more than 64 bytes are
> transferred at once
> due to lack of DMA support.
Wouldn't it be easier to fix the SPI driver to handle transfers larger
than 64 bytes, filling and draining the FIFO multiple times if neccessary?
(As far as I can tell, most SPI drivers do this.)
Just asking,
Thomas
On 30 April 2015 at 18:30, <[email protected]> wrote:
> Hello Michal:
>
>> I tried to connect a SPI NOR flash to my sunxi board and due to the
> current
>> sunxi SPI driver limitations it does not work.
>>
>> The SPI driver returns an error when more than 64 bytes are
>> transferred at once
>> due to lack of DMA support.
>
> Wouldn't it be easier to fix the SPI driver to handle transfers larger
> than 64 bytes, filling and draining the FIFO multiple times if neccessary?
> (As far as I can tell, most SPI drivers do this.)
>
Yes, the intent is to fix this by adding dma support to the driver, eventually.
The patch might be still useful for other hardware with developing SPI support.
Thanks
Michal
On Thursday, April 30, 2015 at 06:56:18 PM, Michal Suchanek wrote:
> On 30 April 2015 at 18:30, <[email protected]> wrote:
> > Hello Michal:
> >> I tried to connect a SPI NOR flash to my sunxi board and due to the
> >
> > current
> >
> >> sunxi SPI driver limitations it does not work.
> >>
> >> The SPI driver returns an error when more than 64 bytes are
> >> transferred at once
> >> due to lack of DMA support.
> >
> > Wouldn't it be easier to fix the SPI driver to handle transfers larger
> > than 64 bytes, filling and draining the FIFO multiple times if
> > neccessary? (As far as I can tell, most SPI drivers do this.)
>
> Yes, the intent is to fix this by adding dma support to the driver,
> eventually.
>
> The patch might be still useful for other hardware with developing SPI
> support.
Please just fix the controller driver to correctly handle arbitrary transfer
lengths.
Best regards,
Marek Vasut
On Thu, Apr 30, 2015 at 08:34:36PM +0200, Marek Vasut wrote:
> On Thursday, April 30, 2015 at 06:56:18 PM, Michal Suchanek wrote:
> > On 30 April 2015 at 18:30, <[email protected]> wrote:
> > > Hello Michal:
> > >> I tried to connect a SPI NOR flash to my sunxi board and due to the
> > >
> > > current
> > >
> > >> sunxi SPI driver limitations it does not work.
> > >>
> > >> The SPI driver returns an error when more than 64 bytes are
> > >> transferred at once
> > >> due to lack of DMA support.
> > >
> > > Wouldn't it be easier to fix the SPI driver to handle transfers larger
> > > than 64 bytes, filling and draining the FIFO multiple times if
> > > neccessary? (As far as I can tell, most SPI drivers do this.)
> >
> > Yes, the intent is to fix this by adding dma support to the driver,
> > eventually.
> >
> > The patch might be still useful for other hardware with developing SPI
> > support.
>
> Please just fix the controller driver to correctly handle arbitrary transfer
> lengths.
Just noticed this. Yes, that would definitely be a better option!
Brian