linux-kernel - Re: [RESEND: PATCH v4 2/4] remoteproc: qcom: refactor mss fw image loading sequence

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Date:   Thu, 25 May 2017 12:13:23 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Avaneesh Kumar Dwivedi <akdwived@...eaurora.org>
Cc:     sboyd@...eaurora.org, agross@...eaurora.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-remoteproc@...r.kernel.org
Subject: Re: [RESEND: PATCH v4 2/4] remoteproc: qcom: refactor mss fw image
 loading sequence

On Tue 16 May 11:02 PDT 2017, Avaneesh Kumar Dwivedi wrote:

> This patch refactor code to first load all firmware blobs
> and then update modem proc to authenticate and boot fw.

Nice, I like this! Just some style details below.

> Also make a trivial change in a error log.
> 
> Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@...eaurora.org>
> ---
>  drivers/remoteproc/qcom_q6v5_pil.c | 25 ++++++++++++-------------
>  1 file changed, 12 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/remoteproc/qcom_q6v5_pil.c b/drivers/remoteproc/qcom_q6v5_pil.c
> index 8fd697a..2626954 100644
> --- a/drivers/remoteproc/qcom_q6v5_pil.c
> +++ b/drivers/remoteproc/qcom_q6v5_pil.c
> @@ -466,9 +466,10 @@ static int q6v5_mpss_init_image(struct q6v5 *qproc, const struct firmware *fw)
>  
>  	ret = q6v5_rmb_mba_wait(qproc, RMB_MBA_META_DATA_AUTH_SUCCESS, 1000);
>  	if (ret == -ETIMEDOUT)
> -		dev_err(qproc->dev, "MPSS header authentication timed out\n");
> +		dev_err(qproc->dev, "metadata authentication timed out\n");
>  	else if (ret < 0)
> -		dev_err(qproc->dev, "MPSS header authentication failed: %d\n", ret);
> +		dev_err(qproc->dev,
> +			"metadata authentication failed: %d\n", ret);

I'm happy to accept these changes if they better describe the errors,
but please send them in a separate patch in that case - and please don't
line break that second print.

>  
>  	dma_free_attrs(qproc->dev, fw->size, ptr, phys, dma_attrs);
>  
> @@ -503,7 +504,7 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>  	bool relocate = false;
>  	char seg_name[10];
>  	ssize_t offset;
> -	size_t size;
> +	size_t size = 0;
>  	void *ptr;
>  	int ret;
>  	int i;
> @@ -541,7 +542,9 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>  	}
>  
>  	mpss_reloc = relocate ? min_addr : qproc->mpss_phys;
> -
> +	/* Load firmware completely before letting mss to start
> +	 * authentication and then boot firmware
> +	 */

/*
 * The first line of a multi-line comment should be empty.
 */

Also your comment tend to tell the story of your change, that's what the
commit message is for, the comment should describe the code regardless
of history;

I think it makes sense to have a comment in the lines of:

/* Load the firmware segments */

>  	for (i = 0; i < ehdr->e_phnum; i++) {
>  		phdr = &phdrs[i];
>  
> @@ -574,17 +577,13 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>  			memset(ptr + phdr->p_filesz, 0,
>  			       phdr->p_memsz - phdr->p_filesz);
>  		}
> -
> -		size = readl(qproc->rmb_base + RMB_PMI_CODE_LENGTH_REG);
> -		if (!size) {
> -			boot_addr = relocate ? qproc->mpss_phys : min_addr;
> -			writel(boot_addr, qproc->rmb_base + RMB_PMI_CODE_START_REG);
> -			writel(RMB_CMD_LOAD_READY, qproc->rmb_base + RMB_MBA_COMMAND_REG);
> -		}
> -
>  		size += phdr->p_memsz;
> -		writel(size, qproc->rmb_base + RMB_PMI_CODE_LENGTH_REG);
>  	}

Please put a blank line here, to separate the steps like "paragraphs".

> +	/* Transfer ownership of modem region with modem fw */
> +	boot_addr = relocate ? qproc->mpss_phys : min_addr;
> +	writel(boot_addr, qproc->rmb_base + RMB_PMI_CODE_START_REG);
> +	writel(RMB_CMD_LOAD_READY, qproc->rmb_base + RMB_MBA_COMMAND_REG);
> +	writel(size, qproc->rmb_base + RMB_PMI_CODE_LENGTH_REG);

I originally did something similar, but ran into some issue - so I will
test this on 8974 and 8916 as soon as my devboards are back online.

Regards,
Bjorn