Re: [PATCH v6 4/7] bus: mhi: Add QDU100 Sahara variant and firmware fallback

[Kishore Batta]

On 7/13/2026 10:41 PM, Manivannan Sadhasivam wrote:
> On Mon, Jul 13, 2026 at 12:55:52PM +0530, Kishore Batta wrote:
> > On 7/9/2026 11:49 AM, Manivannan Sadhasivam wrote:
> > > On Wed, Jul 01, 2026 at 04:07:38PM +0530, Kishore Batta wrote:
> > > > The Sahara driver currently selects a firmware image table based on the
> > > > attached device, but it does not recognize QDU100 devices that expose the
> > > > protocol on the SAHARA MHI channel. As a result, the host cannot associate
> > > > QDU100 devices with the correct firmware namespace during image transfer.
> > > >
> > > > Extend the probe time variant selection to match the SAHARA MHI channel and
> > > > associate it with the QDU100 firmware folder. Add a firmware lookup
> > > > fallback for cases where an image does not have an explicit entry in the
> > > > device's firmware table. This allows required images to be provisioned by
> > > > the platform.
> > > >
> > > > This change only affects devices matched on the SAHARA MHI channel and
> > > > does not change behavior for existing AIC100 and AIC200 devices.
> > > >
> > > > Signed-off-by: Kishore Batta <kishore.batta@xxxxxxxxxxxxxxxx>
> > > > ---
> > > >    drivers/bus/mhi/host/clients/sahara/sahara.c | 27 +++++++++++++++--
> > > >    drivers/bus/mhi/host/pci_generic.c           | 45 ++++++++++++++++++++++++++++
> > > >    2 files changed, 70 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/bus/mhi/host/clients/sahara/sahara.c b/drivers/bus/mhi/host/clients/sahara/sahara.c
> > > > index e339c67e236af271645ca81cc517efd9eead87e4..9adbd84859073d8024ba2a5fcfa33897439d6759 100644
> > > > --- a/drivers/bus/mhi/host/clients/sahara/sahara.c
> > > > +++ b/drivers/bus/mhi/host/clients/sahara/sahara.c
> > > > @@ -189,6 +189,7 @@ static bool is_streaming(struct sahara_context *context)
> > > >    static int sahara_find_image(struct sahara_context *context, u32 image_id)
> > > >    {
> > > > +	char *fw_path;
> > > >    	int ret;
> > > >    	if (image_id == context->active_image_id)
> > > > @@ -201,8 +202,28 @@ static int sahara_find_image(struct sahara_context *context, u32 image_id)
> > > >    	}
> > > >    	if (image_id >= context->table_size || !context->image_table[image_id]) {
> > > > -		dev_err(&context->mhi_dev->dev, "request for unknown image: %d\n", image_id);
> > > > -		return -EINVAL;
> > > > +		if (!context->fw_folder) {
> > > > +			dev_err(&context->mhi_dev->dev,
> > > > +				"Request for unknown image: %u (no fw folder)\n", image_id);
> > > > +			return -EINVAL;
> > > > +		}
> > > > +
> > > > +		fw_path = kasprintf(GFP_KERNEL, "qcom/%s/%u",
> > > > +				    context->fw_folder, image_id);
> > > > +		if (!fw_path)
> > > > +			return -ENOMEM;
> > > > +
> > > > +		ret = firmware_request_nowarn(&context->firmware,
> > > > +					      fw_path,
> > > > +					      &context->mhi_dev->dev);
> > > > +		kfree(fw_path);
> > > > +		if (ret) {
> > > > +			dev_err(&context->mhi_dev->dev,
> > > > +				"request for unknown image: %d\n", image_id);
> > > > +			return -EINVAL;
> > > > +		}
> > > > +		context->active_image_id = image_id;
> > > > +		return 0;
> > > >    	}
> > > >    	/*
> > > > @@ -870,8 +891,10 @@ static void sahara_mhi_dl_xfer_cb(struct mhi_device *mhi_dev, struct mhi_result
> > > >    static const struct mhi_device_id sahara_mhi_match_table[] = {
> > > >    	{ .chan = "QAIC_SAHARA", },
> > > > +	{ .chan = "SAHARA"},
> > > >    	{},
> > > >    };
> > > > +MODULE_DEVICE_TABLE(mhi, sahara_mhi_match_table);
> > > This change should belong to a separate patch.
> > There was a review comment from Jeff(v4, patch 3) to move to this change to
> > the patch which adds QDU100 support so that it doesn't break bisect. Please
> > let me know if i need to move it to a separate patch altogether ?
> Since it is a new device support for Sahara, bisect is not really a problem. But
> I do see a value in keeping everything in a single patch.
>
> - Mani
Sure. I am keeping this change in the same patch.