Re: [PATCH v4 5/9] bus: mhi: Add QDU100 variant and image_id firmware fallback

On 3/19/2026 12:31 AM, 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 an image_id based
> firmware lookup fallback for cases where an image does not have an explicit
> table entry. This allows required images to be provisioned by the platform
> without requiring device specific client drivers or additional registration
> mechanisms.
> 
> This change only affects devices matched on the SAHARA channel and does not
> change behavior for existing AIC100 and AIC200 devices.
> 
> Signed-off-by: Kishore Batta <[email protected]>
> ---
>   drivers/bus/mhi/sahara/sahara.c | 77 ++++++++++++++++++++++++++++++++++++++---
>   1 file changed, 72 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/bus/mhi/sahara/sahara.c b/drivers/bus/mhi/sahara/sahara.c
> index 8f1c0d72066c0cf80c09d78bfc51df2e482133b9..4ea14c57774f51a778289d7409372a6ab21fea60 100644
> --- a/drivers/bus/mhi/sahara/sahara.c
> +++ b/drivers/bus/mhi/sahara/sahara.c
> @@ -234,6 +234,36 @@ static const char * const aic200_image_table[] = {
>   	[78] = "qcom/aic200/pvs.bin",
>   };
>   
> +static const char * const qdu100_image_table[] = {
> +	[5] = "qcom/qdu100/uefi.elf",
> +	[8] = "qcom/qdu100/qdsp6sw.mbn",
> +	[16] = "qcom/qdu100/efs1.bin",
> +	[17] = "qcom/qdu100/efs2.bin",
> +	[20] = "qcom/qdu100/efs3.bin",
> +	[23] = "qcom/qdu100/aop.mbn",
> +	[25] = "qcom/qdu100/tz.mbn",
> +	[29] = "qcom/qdu100/zeros_1sector.bin",
> +	[33] = "qcom/qdu100/hypvm.mbn",
> +	[34] = "qcom/qdu100/mdmddr.mbn",
> +	[36] = "qcom/qdu100/multi_image_qti.mbn",
> +	[37] = "qcom/qdu100/multi_image.mbn",
> +	[38] = "qcom/qdu100/xbl_config.elf",
> +	[39] = "qcom/qdu100/abl_userdebug.elf",
> +	[40] = "qcom/qdu100/zeros_1sector.bin",
> +	[41] = "qcom/qdu100/devcfg.mbn",
> +	[42] = "qcom/qdu100/zeros_1sector.bin",
> +	[45] = "qcom/qdu100/tools_l.elf",
> +	[46] = "qcom/qdu100/Quantum.elf",
> +	[47] = "qcom/qdu100/quest.elf",
> +	[48] = "qcom/qdu100/xbl_ramdump.elf",
> +	[49] = "qcom/qdu100/shrm.elf",
> +	[50] = "qcom/qdu100/cpucp.elf",
> +	[51] = "qcom/qdu100/aop_devcfg.mbn",
> +	[52] = "qcom/qdu100/fw_csm_gsi_3.0.elf",
> +	[53] = "qcom/qdu100/qdsp6sw_dtbs.elf",
> +	[54] = "qcom/qdu100/qupv3fw.elf",
> +};
> +
>   static const struct sahara_variant sahara_variants[] = {
>   	{
>   		.match = "AIC100",
> @@ -250,6 +280,14 @@ static const struct sahara_variant sahara_variants[] = {
>   		.table_size = ARRAY_SIZE(aic200_image_table),
>   		.fw_folder = "aic200",
>   		.non_streaming = false,
> +	},
> +	{
> +		.match = "SAHARA",
> +		.match_is_chan = true,

Theres a half dozen non-QDU100 devices in pci_generic.c which expose 
"SAHARA" channels. Considering those as valid usecases, I don't see this 
mechanism working. Everything non-AIC is now going to be treated as QDU100.

> +		.image_table = qdu100_image_table,
> +		.table_size = ARRAY_SIZE(qdu100_image_table),
> +		.fw_folder = "qdu100",
> +		.non_streaming = false,
>   	}
>   };
>   
> @@ -278,8 +316,21 @@ static const struct sahara_variant *sahara_select_variant(struct mhi_device *mhi
>   	return NULL;
>   }
>   
> +static int sahara_request_fw(struct sahara_context *context, const char *path)
> +{
> +	int ret;
> +
> +	ret = firmware_request_nowarn(&context->firmware, path,
> +				      &context->mhi_dev->dev);
> +	if (ret)
> +		dev_dbg(&context->mhi_dev->dev,
> +			"Request for file %s failed %d\n", path, ret);
> +	return ret;
> +}

This is a pointless change. Drop it.

> +
>   static int sahara_find_image(struct sahara_context *context, u32 image_id)
>   {
> +	char *fw_path;
>   	int ret;
>   
>   	if (image_id == context->active_image_id)
> @@ -292,8 +343,26 @@ 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/image_%u.elf",
> +				    context->fw_folder, image_id);
> +		if (!fw_path)
> +			return -ENOMEM;
> +
> +		ret = sahara_request_fw(context, fw_path);
> +		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;

I don't see a usecase for this fw path search functionality, and I think 
it breaks the documented firmware loading guidelines.

>   	}
>   
>   	/*
> @@ -301,9 +370,7 @@ static int sahara_find_image(struct sahara_context *context, u32 image_id)
>   	 * Only the device knows. Suppress error messages that could suggest an
>   	 * a problem when we were actually able to continue.
>   	 */
> -	ret = firmware_request_nowarn(&context->firmware,
> -				      context->image_table[image_id],
> -				      &context->mhi_dev->dev);
> +	ret = sahara_request_fw(context, context->image_table[image_id]);
>   	if (ret) {
>   		dev_dbg(&context->mhi_dev->dev, "request for image id %d / file %s failed %d\n",
>   			image_id, context->image_table[image_id], ret);
>