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I have to make it work, old or new ;-) So I've been trying to apply your patch to 2.6.18 in a way that makes sense in uClinux-2.4.x.
The patch consists three parts and, besides the one I tried, there are (I patched and diff'ed them)
87a88,91 > if (buf[i].name[0] == 0xff) { > i = numslots; > break; > }
and
127c131
< continue;
---
> break;
It appears to me that 0xff is significant in both parts. What does it mean? I haven't been able to figure out how either will enable writing.
As my node starts up, I saw in the sequence 0x003e0000-0x003ff000 : "FIS directory"
mtd: partition "FIS directory" doesn't end on an erase block -- force read-only
0x003ff000-0x00400000 : "RedBoot config"
mtd: partition "RedBoot config" doesn't start on an erase block boundary -- force
read-only
can I remove the code that forced read-only (in mtdpart.c) at start up as an alternative to applying your patch?
Thanks! Wei
In addition, I found this piece of code in redboot.c confusing. #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY if (!memcmp(names, "RedBoot", 8) || !memcmp(names, "RedBoot config", 15) || !memcmp(names, "FIS directory", 14)) { parts[i].mask_flags = MTD_WRITEABLE; }
That is, if CONFIG_MTD_REDBOOT_PARTS_READONLY is defined, the partitions, "RedBoot", "RedBoot config", and "FIS directory", are set writeable! Can you shed some light?
#ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY #endif
image for the FIS partition back to /dev/mtd4I still get cat: Write Error: Read-only file systemYou missed the part of the patch that allows the FIS directory to be writable even if you have combined FIS & FCONFIG. I don't have such an old system, so you'll need to figure out how to get that code in.
--- Gary Thomas <gary@mlbassoc.com> wrote:
Weiguang Shi wrote:Gary,
I'm at the point to flash the modified partition back but can't erase the FIS partition /dev/mtd4
# cat /proc/mtd dev: size erasesize name mtd0: 00080000 00020000 "RedBoot" mtd1: 00100000 00020000 "kernel" mtd2: 00200000 00020000 "ramdisk" mtd3: 00020000 00020000 "kiyon_config" mtd4: 0001f000 00020000 "FIS directory" mtd5: 00001000 00020000 "RedBoot config" # eraseall /dev/mtd4 eraseall: /dev/mtd4: Permission denied
I realized that I may need to "unlock" it but both my attempts to do that
in RedBoot and Linux failed. In the former, "fis unlock" worked fine in Redboot but after Linux boots up I still get the same "Permission denied"
error. In linux, my unlock resulted in # unlock /dev/mtd4
Could not open mtd device: /dev/mtd4
# unlock /dev/mtd5
Could not open mtd device: /dev/mtd5
Any ideas on how shall I proceed?The problem is that if you use combined FIS directory and FCONFIG data (which you are based on the map above), then the MTD layer makes both of those images read only. The attached patch can let you override this. It's based on the public 2.6.18 kernel.
Note: you need to be careful doing these changes to your FLASH. If you simply erase the partition, RedBoot will lose everything. MTD is pretty cool and if you simply open /dev/mtd4 read/write, read the current contents, update them and then rewrite them, the MTD layer will take care of erasing and updating the appropriate portions.
--- Gary Thomas <gary@mlbassoc.com> wrote:
Weiguang Shi wrote:That's even better and was the solution that I was looking for.<redboot/fis.h>
The question is how, from the OS, can I update the FIS. Obviously
I need to know the structure of the "FIS directory" partition and
find the offset of that checksum and insert a '0' there by - reading the whole partition into ram, - changing the bit, erasing the partition on the flash, - and finally flashing the modified partition in the ram back.
Any suggestions as to where to start?
Also, drivers/mtd has some RedBoot FIS parsing code in it. You could look at it for pointers.
--- Gary Thomas <gary@mlbassoc.com> wrote:
Note: you don't really need to change RedBoot. Just update the FIS [directory] entry for the image you are changing, either with the corrected checksum, or the value 0. RedBoot ignores the checksum when the stored value is 0.-- ------------------------------------------------------------ Gary Thomas | Consulting for the MLB Associates | Embedded world ------------------------------------------------------------diff -ubNr --exclude=.gitignore linux-2.6.18/drivers/mtd/redboot.c/tmp/fc_base/opt/amltd/develop/linuxppc-2.6/drivers/mtd/redboot.c
--- linux-2.6.18/drivers/mtd/redboot.c 2006-09-19 21:42:06.000000000 -0600
+++ /tmp/fc_base/opt/amltd/develop/linuxppc-2.6/drivers/mtd/redboot.c 2006-10-24
11:59:32.000000000 -0600
@@ -85,6 +85,10 @@
numslots = (master->erasesize / sizeof(struct fis_image_desc));
for (i = 0; i < numslots; i++) {
+ if (buf[i].name[0] == 0xff) {
+ i = numslots;
+ break;
+ }
if (!memcmp(buf[i].name, "FIS directory", 14)) {
/* This is apparently the FIS directory entry for the
* FIS directory itself. The FIS directory size is
@@ -124,7 +128,7 @@
struct fis_list *new_fl, **prev;
if (buf[i].name[0] == 0xff)
- continue;
+ break;
if (!redboot_checksum(&buf[i]))
break;
@@ -196,14 +200,22 @@
parts[i].size = fl->img->size;
parts[i].offset = fl->img->flash_base;
parts[i].name = names;
-
strcpy(names, fl->img->name);
+
#ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
if (!memcmp(names, "RedBoot", 8) ||
!memcmp(names, "RedBoot config", 15) ||
!memcmp(names, "FIS directory", 14)) {
parts[i].mask_flags = MTD_WRITEABLE;
}
+#else
+ if (!memcmp(names, "FIS directory", 14)) {
+ // Special hack to let directory be read/write
+ if ((fl->img->size & (master->erasesize - 1)) != 0) {
+ parts[i].size = (fl->img->size + (master->erasesize - 1)) &
~(master->erasesize - 1);
+ }
+ }
+
#endif
names += strlen(names)+1;
-- ------------------------------------------------------------ Gary Thomas | Consulting for the MLB Associates | Embedded world ------------------------------------------------------------
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