Re: [PATCH v2] mhi: host: Add standard elf image download functionality

[Baochen Qiang <quic_bqiang@quicinc.com>]

On 6/3/2025 5:05 PM, Qiang Yu wrote:
> From: Mayank Rana <mayank.rana@oss.qualcomm.com>
> 
> Currently, the FBC image is a non-standard ELF file that contains a single
> ELF header, followed by segments for SBL, RDDM, and AMSS. Some devices are
> unable to process this non-standard ELF format and therefore require
> special handling during image loading.
> 
> Add standard_elf_image flag to determine whether the device can process
> the non-standard ELF format. If this flag is set, a standard ELF image
> must be loaded, meaning the first 512 KB of the FBC image should be
> skipped when loading the AMSS image over the BHIe interface. Note that
> this flag does not affect the SBL image download process.
> 
> Signed-off-by: Mayank Rana <mayank.rana@oss.qualcomm.com>
> Co-developed-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
> Signed-off-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
> ---
> Changes in v2:
> - V1 patch is paused because of no user. WLAN team plan to add support for
>   new WLAN chip that requires this patch, so send v2.
> - Change author and SOB with new mail address.
> - Reword commit message.
> - Place standard_elf_image flag after wake_set in struct mhi_controller
> - Link to v1: https://lore.kernel.org/mhi/1689907189-21844-1-git-send-email-quic_qianyu@quicinc.com/
> ---
>  drivers/bus/mhi/host/boot.c | 7 +++++++
>  include/linux/mhi.h         | 4 ++++
>  2 files changed, 11 insertions(+)
> 
> diff --git a/drivers/bus/mhi/host/boot.c b/drivers/bus/mhi/host/boot.c
> index efa3b6dddf4d2f937535243bd8e8ed32109150a4..f1686a8e0681d49f778838820b44f4c845ddbd1f 100644
> --- a/drivers/bus/mhi/host/boot.c
> +++ b/drivers/bus/mhi/host/boot.c
> @@ -584,6 +584,13 @@ void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl)
>  	 * device transitioning into MHI READY state
>  	 */
>  	if (fw_load_type == MHI_FW_LOAD_FBC) {
> +		dev_dbg(dev, "standard_elf_image:%s\n",
> +			(mhi_cntrl->standard_elf_image ? "True" : "False"));
> +		if (mhi_cntrl->standard_elf_image) {
> +			fw_data += mhi_cntrl->sbl_size;
> +			fw_sz -= mhi_cntrl->sbl_size;
> +		}
> +
>  		ret = mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->fbc_image, fw_sz);
>  		if (ret) {
>  			release_firmware(firmware);
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index dd372b0123a6da5107b807ff8fe940c567eb2030..48f2b50038519111aed2075f01d0704adfc8989e 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -360,6 +360,9 @@ struct mhi_controller_config {
>   * @bounce_buf: Use of bounce buffer
>   * @fbc_download: MHI host needs to do complete image transfer (optional)
>   * @wake_set: Device wakeup set flag
> + * @standard_elf_image: Flag to determine whether the first 512 KB of the FBC
> + *                      image need to be skipped when loading AMSS image over
> + *                      BHIe interface (optional)
>   * @irq_flags: irq flags passed to request_irq (optional)
>   * @mru: the default MRU for the MHI device
>   *
> @@ -445,6 +448,7 @@ struct mhi_controller {
>  	bool bounce_buf;
>  	bool fbc_download;
>  	bool wake_set;
> +	bool standard_elf_image;
>  	unsigned long irq_flags;
>  	u32 mru;
>  };
> 
> ---
> base-commit: 6348f62ef7ecc5855b710a7d4ea682425c38bb80
> change-id: 20250603-standard_elf_image_load_support-da9a2c649411
> 
> Best regards,

Reviewed-by: Baochen Qiang <quic_bqiang@quicinc.com>