Re: [PATCH 2/2] spi: qcom-geni: Add property to force GSI mode

[Pengyu Luo]

On Tue, Jun 30, 2026 at 5:52 PM Mukesh Savaliya
<mukesh.savaliya@xxxxxxxxxxxxxxxx> wrote:
>
>
>
> On 6/29/2026 1:33 PM, Pengyu Luo wrote:
> > On Mon, Jun 29, 2026 at 1:36 PM Mukesh Savaliya
> > <mukesh.savaliya@xxxxxxxxxxxxxxxx> wrote:
> >>
> >> Hi Pengyu,
> >>
> >> On 6/15/2026 2:48 AM, Dmitry Baryshkov wrote:
> >>> On Sun, Jun 14, 2026 at 04:34:24PM +0800, Pengyu Luo wrote:
> >>>> Some devices (such as gaokun3) do not disable FIFO mode, causing the
> >>>> driver to fallback to FIFO mode by default. However, these platforms
> >>>> also support GSI mode, which is highly preferred for certain
> >>>> peripherals like SPI touchscreens to improve performance.
> >>>>
> >>>> Introduce the "qcom,force-gsi-mode" device property to hint and force
> >>>> the controller into GSI mode during initialization.
> >> Why to force ? You can directly configure in GSI mode. Note there are
> >> some configuration done prior to Linux bootup too.
> >
> > Sorry, I don't get it. how? I know there may be a qupfw, but it is
> > impossible for a normal user like me to generate one with GSI
> > preferred.
> >
> If firmware doesn't program in GSI, you can't have this working in GSI
> mode, its going to fail (and work with fallback). if it's programmed in
> GSI, anyway this will run in GSI mode. So why to add extra things
> without any usage ?
>

What I can confirm is that fifo is not disabled on my device, and gsi
is definitely enabled (under windows, check the register
SE_GENI_DMA_MODE_EN), forcing the device to enable GSI mode on linux
works well.

Best wishes,
Pengyu

> > Best wishes,
> > Pengyu
> >
> >>>
> >>> Ideally, this should be decided by the SPI controller based on the
> >>> requirements. Another option would be to prefer GSI for all transfers if
> >>> it is available, ignoring the FIFO even if it is not disabled.
> >>>
> >> Yes, it should be decided in advance and configured accordingly for GSI
> >> vs non GSI mode. Because there would be limited set of GSI pipes, which
> >> will actually make must have GSI mode device run with FIFO mode.
> >>
> >> Why don't you decide prior and configure for GSI mode ? We don't need to
> >> change the current logic of deciding FIFO vs GSI.
> >>>>
> >>>> Signed-off-by: Pengyu Luo <mitltlatltl@xxxxxxxxx>
> >>>> ---
> >>>>    drivers/spi/spi-geni-qcom.c | 7 +++++++
> >>>>    1 file changed, 7 insertions(+)
> >>>>
> >>>
> >>
>