Re: [flashrom] [PATCH] RFC: enable flashrom to write images of arbitrary size

[Charlotte Plusplus]

Hello

That is very interesting. Do you have a way to automate that?

I am testing ram stuff with coreboot, I don't need to flash a full 8MB
image. I could just pass a -i of the cbfs content to only change the
ramstage, and do a manual md5 of the various parts contained to only target
the difference, but it seems a bit tedious.

It would be nice to do have a way to do kind of diff between the currenttly
flashed image and the desired image, and only flash the required changes.

Charlotte

On Tue, Nov 8, 2016 at 2:22 PM, David Hendricks via flashrom <
[e-mail]> wrote:
> Hi Peter,
> Thanks for the patch! However, I suspect this will not be accepted
> since the size check is an important safety measure for the general
> use case.
>
> In general layout files should be used for this sort of thing. The way
> we've gone about this in the chromium.org branch is to augment the -i
> syntax to allow the user to specify a region and corresponding file,
> and we also added a "--fast-verify" mode to only verify regions which
> were targeted. So for example you could do "flashrom -p <programmer>
> -l <layout_file> -i region:filename.bin --fast-verify --ignore-fmap
> -w" which will write filename.bin to the targeted region and verify
> only that region.
>
> Details here: https://www.chromium.org/chromium-os/packages/cros-
> flashrom#TOC-Partial-Reads-and-Writes
> . LMK if this is any help.
>
> On Mon, Nov 7, 2016 at 1:00 PM, Peter Mamonov  wrote:
> > Flashrom restricts an image size to be equal to a ROM capacity. This is
> > inconvenient in case of large and slow ROM chips, when only part of the
>
> ROM
> > should be updated. This patch removes this restriction in a
>
> quick-and-dirty
> > manner.
> > Signed-off-by: Peter Mamonov
> >
> > flashrom.c | 26 +++++++++++++++-----------
> >  1 file changed, 15 insertions(+), 11 deletions(-)
> >
> > diff --git a/flashrom.c b/flashrom.c
> > index d51a44c..f805e00 100644
> > --- a/flashrom.c
> > +++ b/flashrom.c
> > @@ -1255,30 +1255,30 @@ int read_buf_from_file(unsigned char *buf,
>
> unsigned long size,
> >     if ((image = fopen(filename, "rb")) == NULL) {
> >             msg_gerr("Error: opening file \"%s\" failed: %s\n",
>
> filename, strerror(errno));
> >           return 1;
> >           return -1;
> >   }
> >   if (fstat(fileno(image), &image_stat) != 0) {
> >           msg_gerr("Error: getting metadata of file \"%s\" failed:
>
> %s\n", filename, strerror(errno));
> >             fclose(image);
> >           return 1;
> >           return -1;
> >   }
> >   if (image_stat.st_size != size) {
> >   if (image_stat.st_size > size) {
> >           msg_gerr("Error: Image size (%jd B) doesn't match the
>
> flash chip's size (%lu B)!\n",
> >                      (intmax_t)image_stat.st_size, size);
> >           fclose(image);
> >           return 1;
> >           return -1;
> >   }
> >   size = image_stat.st_size;
> >   numbytes = fread(buf, 1, size, image);
> >   if (fclose(image)) {
> >           msg_gerr("Error: closing file \"%s\" failed: %s\n",
>
> filename, strerror(errno));
> >           return 1;
> >           return -1;
> >   }
> >   if (numbytes != size) {
> >           msg_gerr("Error: Failed to read complete file. Got %ld
>
> bytes, "
> >                      "wanted %ld!\n", numbytes, size);
> >           return 1;
> >           return -1;
> >   }
> >   return 0;
> >   return size;
> >
> > #endif
> >  }
> >
> > @@ -1481,7 +1481,10 @@ static int walk_eraseregions(struct flashctx
>
> *flash, int erasefunction,
> >              * members so the loop below won't be executed for them.
> >              */
> >             len = eraser.eraseblocks[i].size;
> >           for (j = 0; j < eraser.eraseblocks[i].count; j++) {
> >           for (j = 0;
> >                j < eraser.eraseblocks[i].count &&
> >                start + len <= flash->chip->total_size * 1024;
> >                j++) {
> >                   /* Print this for every block except the first
>
> one. */
> >                     if (i || j)
> >                             msg_cdbg(", ");
> >
> > @@ -1988,11 +1991,12 @@ int doit(struct flashctx *flash, int force,
>
> const char *filename, int read_it,
> >     }
> >
> >     if (write_it || verify_it) {
> >           if (read_buf_from_file(newcontents, size, filename)) {
> >           size = read_buf_from_file(newcontents, size, filename);
> >           if (size < 0) {
> >                   ret = 1;
> >                   goto out;
> >           }
> >           flash->chip->total_size = size / 1024; /* FIXME */
> >
> > #if CONFIG_INTERNAL == 1
> >                 if (programmer == PROGRAMMER_INTERNAL &&
>
> cb_check_image(newcontents, size) < 0) {
> >                     if (force_boardmismatch) {
> >
> > flashrom mailing list
> > [e-mail]
> > https://www.flashrom.org/mailman/listinfo/flashrom
>
> flashrom mailing list
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