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

[Manivannan Sadhasivam <mani@kernel.org>]

On Mon, Aug 07, 2023 at 03:59:52PM +0800, Qiang Yu wrote:
> From: Mayank Rana <quic_mrana@quicinc.com>
> 

Subject prefix should be: "bus: mhi:..."

> Some devices (e.g. WLAN chips) are unable to handle the non-standard ELF
> format of the FBC image and thus need special handling of the FBC image.
> 

Which WLAN chip? Is the driver for the chip already upstreamed?

> Add standard_elf_image flag which makes decision in terms of how FBC image
> based AMSS image is being downloaded with connected endpoint.
> FBC image is having two image combine: SBL image + AMSS image.
> 1. FBC image download using legacy single ELF header image format:
> - SBL image: 512KB of FBC image is downloaded using BHI.
> - AMSS image: full FBC image is downloaded using BHIe.
> 2. FBC image download using separate ELF header image format:
> - SBL image: 512 KB of FBC image is downloaded using BHI.
> - AMSS image: 512 KB onward FBC image is downloaded using BHIe.
> There is no change for SBL image download. Although AMSS image start
> address is end address of SBL image while using separate ELF header format.
> 
> Signed-off-by: Mayank Rana <quic_mrana@quicinc.com>
> [quic_qianyu@quicinc.com: Update commit message, minor updates]
> Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com>
> ---
> v1->v2: modify commit message
> 	correct author
> 	rebase on latest mhi-next branch, resolve conflicts
> 
>  drivers/bus/mhi/host/boot.c | 7 +++++++
>  include/linux/mhi.h         | 2 ++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/drivers/bus/mhi/host/boot.c b/drivers/bus/mhi/host/boot.c
> index edc0ec5..586d551 100644
> --- a/drivers/bus/mhi/host/boot.c
> +++ b/drivers/bus/mhi/host/boot.c
> @@ -495,6 +495,13 @@ void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl)
>  	 * device transitioning into MHI READY state
>  	 */
>  	if (mhi_cntrl->fbc_download) {
> +		dev_dbg(dev, "standard_elf_image: %s\n",
> +				(mhi_cntrl->standard_elf_image ? "True" : "False"));
> +		if (mhi_cntrl->standard_elf_image) {

Commit message is saying that the devices cannot handle non-standard ELF image.
But this check is for standard ELF image. I'm confused.

> +			fw_data = firmware->data + mhi_cntrl->sbl_size;
> +			fw_sz = 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 039943e..e065101 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -310,6 +310,7 @@ struct mhi_controller_config {
>   * @reg_len: Length of the MHI MMIO region (required)
>   * @fbc_image: Points to firmware image buffer
>   * @rddm_image: Points to RAM dump buffer
> + * @standard_elf_image: Flag to make decision about firmware download start address (optional)
>   * @mhi_chan: Points to the channel configuration table
>   * @lpm_chans: List of channels that require LPM notifications
>   * @irq: base irq # to request (required)
> @@ -456,6 +457,7 @@ struct mhi_controller {
>  	bool bounce_buf;
>  	bool fbc_download;
>  	bool wake_set;
> +	bool standard_elf_image;

Which driver is making use of this flag?

- Mani

>  	unsigned long irq_flags;
>  	u32 mru;
>  };
> -- 
> 2.7.4
> 
> 

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