Re: [PATCH] scripts: imx-usb-loader: simplify code flow for file size calculations

[Sascha Hauer <sha@pengutronix.de>]

On Wed, Jun 15, 2022 at 02:38:37PM +0200, Uwe Kleine-König wrote:
> This change contains several changes that make the code flow easier to
> understand (in my eyes at least):
> 
>  - Rename max_length to fststage_length
>    In some cases the image is loaded in two stages: First the PBL which
>    is started after the PBL is loaded completely and then the whole
>    image. So the size of the first stage isn't about some maximum.

When not reading this note I think it's not clear that "fst" is an
abbreviation for "first". Can you rename to "firststage_length"?
If you care about variable name length then you could maybe rather
drop the last three letters ;)

Sascha

> 
>  - Drop unintuitive total_size variable
>    This variable used to be 0 in the one stage case and the filesize
>    otherwise. Just use fststage_length for the first stage and use the
>    filesize for the second stage (if needed).
> 
>  - Don't call the first stage size "fsize" in the debug output.
> 
>  - Add offset for second stage to debug output.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  scripts/imx/imx-usb-loader.c | 37 ++++++++++++++++--------------------
>  1 file changed, 16 insertions(+), 21 deletions(-)
> 
> diff --git a/scripts/imx/imx-usb-loader.c b/scripts/imx/imx-usb-loader.c
> index 96d36fa0a85e..3676f87abb3a 100644
> --- a/scripts/imx/imx-usb-loader.c
> +++ b/scripts/imx/imx-usb-loader.c
> @@ -1213,7 +1213,7 @@ static int perform_dcd(unsigned char *p, const unsigned char *file_start,
>  }
>  
>  static int get_dl_start(const unsigned char *p, const unsigned char *file_start,
> -		unsigned cnt, unsigned *max_length, unsigned *plugin,
> +		unsigned cnt, size_t *fststage_length, unsigned *plugin,
>  		unsigned *header_addr)
>  {
>  	const unsigned char *file_end = file_start + cnt;
> @@ -1228,7 +1228,7 @@ static int get_dl_start(const unsigned char *p, const unsigned char *file_start,
>  		*header_addr = ohdr->dcd_ptr_ptr - offsetof(struct imx_flash_header, dcd);
>  		*plugin = 0;
>  		if (err >= 0)
> -			*max_length = dcd_end[0] | (dcd_end[1] << 8) | (dcd_end[2] << 16) | (dcd_end[3] << 24);
> +			*fststage_length = dcd_end[0] | (dcd_end[1] << 8) | (dcd_end[2] << 16) | (dcd_end[3] << 24);
>  
>  		break;
>  	}
> @@ -1244,7 +1244,7 @@ static int get_dl_start(const unsigned char *p, const unsigned char *file_start,
>  			return -1;
>  		}
>  
> -		*max_length = ((struct imx_boot_data *)bd)->size;
> +		*fststage_length = ((struct imx_boot_data *)bd)->size;
>  		*plugin = ((struct imx_boot_data *)bd)->plugin;
>  		((struct imx_boot_data *)bd)->plugin = 0;
>  
> @@ -1271,7 +1271,7 @@ static int get_payload_start(const unsigned char *p, uint32_t *ofs)
>  }
>  
>  static int process_header(struct usb_work *curr, unsigned char *buf, int cnt,
> -		unsigned *p_max_length, unsigned *p_plugin,
> +		size_t *p_fststage_length, unsigned *p_plugin,
>  		unsigned *p_header_addr)
>  {
>  	int ret;
> @@ -1286,7 +1286,7 @@ static int process_header(struct usb_work *curr, unsigned char *buf, int cnt,
>  		if (!is_header(p))
>  			continue;
>  
> -		ret = get_dl_start(p, buf, cnt, p_max_length, p_plugin, p_header_addr);
> +		ret = get_dl_start(p, buf, cnt, p_fststage_length, p_plugin, p_header_addr);
>  		if (ret < 0) {
>  			printf("!!get_dl_start returned %i\n", ret);
>  			return ret;
> @@ -1303,7 +1303,7 @@ static int process_header(struct usb_work *curr, unsigned char *buf, int cnt,
>  
>  		if (*p_plugin && (!curr->plug) && (!header_cnt)) {
>  			header_cnt++;
> -			header_max = header_offset + *p_max_length + 0x400;
> +			header_max = header_offset + *p_fststage_length + 0x400;
>  			if (header_max > cnt - 32)
>  				header_max = cnt - 32;
>  			printf("header_max=%x\n", header_max);
> @@ -1329,18 +1329,17 @@ static int do_irom_download(struct usb_work *curr, int verify)
>  	unsigned char *buf = NULL;
>  	unsigned char *image;
>  	unsigned char *verify_buffer = NULL;
> -	unsigned max_length;
> +	size_t fststage_length;
>  	unsigned plugin = 0;
>  	unsigned header_addr = 0;
> -	unsigned total_size = 0;
>  
>  	buf = read_file(curr->filename, &fsize);
>  	if (!buf)
>  		return -errno;
>  
> -	max_length = fsize;
> +	fststage_length = fsize;
>  
> -	ret = process_header(curr, buf, fsize, &max_length, &plugin, &header_addr);
> +	ret = process_header(curr, buf, fsize, &fststage_length, &plugin, &header_addr);
>  	if (ret < 0)
>  		goto cleanup;
>  
> @@ -1352,14 +1351,10 @@ static int do_irom_download(struct usb_work *curr, int verify)
>  		goto cleanup;
>  	}
>  
> +	/* skip over the imx-image-part */
>  	image = buf + header_offset;
>  	fsize -= header_offset;
>  
> -	if (fsize > max_length) {
> -		total_size = fsize;
> -		fsize = max_length;
> -	}
> -
>  	type = FT_APP;
>  
>  	if (verify) {
> @@ -1379,10 +1374,10 @@ static int do_irom_download(struct usb_work *curr, int verify)
>  		}
>  	}
>  
> -	printf("loading binary file(%s) to 0x%08x, fsize=%zu type=%d...\n",
> -			curr->filename, header_addr, fsize, type);
> +	printf("loading binary file(%s) to 0x%08x, fststage_length=%zu type=%d, hdroffset=%u...\n",
> +			curr->filename, header_addr, fststage_length, type, header_offset);
>  
> -	ret = load_file(image, fsize, header_addr, type, false);
> +	ret = load_file(image, fststage_length, header_addr, type, false);
>  	if (ret < 0)
>  		goto cleanup;
>  
> @@ -1420,7 +1415,7 @@ static int do_irom_download(struct usb_work *curr, int verify)
>  			return ret;
>  	}
>  
> -	if (total_size) {
> +	if (fststage_length < fsize) {
>  		uint32_t ofs;
>  
>  		ret = get_payload_start(image, &ofs);
> @@ -1428,9 +1423,9 @@ static int do_irom_download(struct usb_work *curr, int verify)
>  			printf("Cannot get offset of payload\n");
>  			goto cleanup;
>  		}
> -		printf("Loading full image\n");
> +		printf("Loading full image from offset %u\n", ofs);
>  		printf("Note: This needs board support on the other end\n");
> -		load_file(image + ofs, total_size - ofs, 0, 0, true);
> +		load_file(image + ofs, fsize - ofs, 0, 0, true);
>  	}
>  
>  	ret = 0;
> 
> base-commit: a91d44f25b0a279260d2c5710d7c8a7d7d0d1d78
> -- 
> 2.30.2
> 
> 
> 

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