Re: [PATCH v4] mhi: host: Add support for dual ELF image format

On Tue, Dec 23, 2025 at 01:16:46AM -0800, Qiang Yu wrote:
> From: Mayank Rana <[email protected]>
> 
> Currently, the FBC image contains a single ELF header followed by segments
> for both SBL and WLAN FW. However, TME-L (Trust Management Engine Lite)
> supported devices (e.g., QCC2072) require separate ELF headers for SBL and
> WLAN FW segments due to TME-L image authentication requirements.
> 
> Current image format contains two sections in a single binary:
> - First 512KB: ELF header + SBL segments
> - Remaining: WLAN FW segments (raw data)
> 
> The TME-L supported image format contains two complete ELF files in a
> single binary:
> - First 512KB: Complete SBL ELF file (ELF header + SBL segments)
> - Remaining: Complete WLAN FW ELF file (ELF header + WLAN FW segments)
> 
> Download behavior:
> - Legacy: 1. First 512KB via BHI (ELF header + SBL)
>           2. Full image via BHIe
> 
> - TME-L: 1. First 512KB via BHI (SBL ELF file)
>          2. Remaining via BHIe (WLAN FW ELF file only)
> 
> Add runtime detection to automatically identify the image format by
> checking for the presence of a second ELF header at the 512KB boundary.
> When detected, MHI skips the first 512KB during WLAN FW download over BHIe
> as it is loaded in BHI phase.
> 
> Reviewed-by: Baochen Qiang <[email protected]>
> Signed-off-by: Mayank Rana <[email protected]>
> Co-developed-by: Qiang Yu <[email protected]>
> Signed-off-by: Qiang Yu <[email protected]>

This version is not anyway close to the previous one. So all the tags from
Mayank and Baochen are irrelevant.

- Mani

> ---
> Changes in v4:
> - Detect image format runtime by checking second ELF header instead of using a flag.
> - Link to v3: https://lore.kernel.org/r/20251201-wlan_image_load_skip_512k-v3-1-bedb5498a58a@oss.qualcomm.com
> 
> Changes in v3:
> - Reword commit message.
> - Reword comments of standard_elf_image flag
> - Add reviewed-by tag.
> - Link to v2: https://lore.kernel.org/mhi/20250603-standard_elf_image_load_support-v2-1-cce97644e99e@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/[email protected]/
> ---
>  drivers/bus/mhi/host/boot.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/bus/mhi/host/boot.c b/drivers/bus/mhi/host/boot.c
> index 205d83ac069f15a19ab2d66a63692e5d60334d4c..6ba0f16854d3a839e987f19d782600467b5f9836 100644
> --- a/drivers/bus/mhi/host/boot.c
> +++ b/drivers/bus/mhi/host/boot.c
> @@ -584,6 +584,17 @@ void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl)
>  	 * device transitioning into MHI READY state
>  	 */
>  	if (fw_load_type == MHI_FW_LOAD_FBC) {
> +
> +		/*
> +		 * Some FW combine two separate ELF images (SBL + WLAN FW) in a single
> +		 * file. Hence, check for the existence of the second ELF header after
> +		 * SBL. If present, load the second image separately.
> +		 */
> +		if (!memcmp(fw_data + mhi_cntrl->sbl_size, ELFMAG, SELFMAG)) {
> +			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);
> 
> ---
> base-commit: ac35e04f8000aaaf98635792464647e7a6f3422e
> change-id: 20251129-wlan_image_load_skip_512k-ddcfe49db8e3
> 
> Best regards,
> -- 
> Qiang Yu <[email protected]>
> 

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