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

[Mukesh Savaliya <mukesh.savaliya@oss.qualcomm.com>]

On 6/30/2026 3:36 PM, Pengyu Luo wrote:
> On Tue, Jun 30, 2026 at 5:52 PM Mukesh Savaliya
> <mukesh.savaliya@oss.qualcomm.com> wrote:
>>
>>
>>
>> On 6/29/2026 1:33 PM, Pengyu Luo wrote:
>>> On Mon, Jun 29, 2026 at 1:36 PM Mukesh Savaliya
>>> <mukesh.savaliya@oss.qualcomm.com> 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.
> 
Thanks  ! if GSI is already enabled, then why do you need forced gsi ?
My point here - SW should only decide mode based on register read, not 
enforce by DT flag. As such it's not a SOC exposed, can't be overridden 
by user.
>>>
>>>>>
>>>>> 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@gmail.com>
>>>>>> ---
>>>>>>     drivers/spi/spi-geni-qcom.c | 7 +++++++
>>>>>>     1 file changed, 7 insertions(+)
>>>>>>
>>>>>
>>>>
>>