[coreboot] flashrom: Can't mmap memory

Myles Watson mylesgw at gmail.com
Fri Feb 6 18:29:12 CET 2009

On Fri, Feb 6, 2009 at 10:19 AM, Myles Watson <mylesgw at gmail.com> wrote:
> On Thu, Feb 5, 2009 at 8:18 PM, Myles Watson <mylesgw at gmail.com> wrote:
>>> -----Original Message-----
>>> From: Carl-Daniel Hailfinger [mailto:c-d.hailfinger.devel.2006 at gmx.net]
>>> Sent: Thursday, February 05, 2009 4:19 PM
>>> To: Myles Watson
>>> Cc: Coreboot
>>> Subject: Re: [coreboot] flashrom: Can't mmap memory
>>> On 05.02.2009 21:26, Myles Watson wrote:
>>> > When I boot using the factory BIOS on my s2895 flashrom works.  When I
>>> > boot with Coreboot, I get the Error:
>>> >
>>> > Can't mmap memory using /dev/mem: Operation not permitted
>>> >
>>> > It shouldn't be kernel parameters since I'm using the same grub2 entry
>>> > to boot either way.
>>> >
>>> > This sounds a little too familiar, but I can't find a thread where
>>> > this isn't linked to a newer, more restrictive kernel.
>>> >
>>> Could be the memory map passed by cbtable or e820. A diff between dmesg
>>> for each configuration would probably reveal quite a bit of info.
>> Good idea.  Tomorrow I'll look at that.  The memory maps are quite
>> different, but in both cases the ROM is marked uncacheable.
> It turns out that flashrom is getting confused and trying to map
> 0xfff00000-0x10100000.  The factory BIOS doesn't boost memory up
> there, so it was fine.  If I specify the chip with -c SST49LF080A it
> succeeds.  I don't know why the size is different depending on whether
> you specify the chip or not.
> An added printf shows that flash->total_size = 0x800 when it fails,
> and 0x400 when it succeeds.

I should have used flashrom -V earlier.  Here it is:

Probing for SST SST49LF040, 512 KB: probe_jedec: id1 0xbf, id2 0x5b
Probing for SST SST49LF040B, 512 KB: probe_jedec: id1 0xbf, id2 0x5b
Probing for SST SST49LF080A, 1024 KB: probe_jedec: id1 0xbf, id2 0x5b
Found chip "SST SST49LF080A" (1024 KB) at physical address 0xfff00000.
Probing for SST SST49LF160C, 2048 KB: Error accessing flash chip,
0x200000 bytes at 0xfff00000
/dev/mem mmap failed: Operation not permitted

I don't know enough about flashrom to know if it should have stopped,
or if it should have figured out a better base address for the

Hopefully that's enough information to point in the right direction.


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