On Wed, Sep 21, 2011 at 8:25 AM, Nicolas Pitre <[email protected]> wrote: > On Wed, 21 Sep 2011, Dave P Martin wrote: > >> >> >> > -----Original Message----- >> > From: >> > [email protected] >> g [mailto:devicetree-discuss-> [email protected]] >> On Behalf Of >> > Grant Likely >> > Sent: 20 September 2011 21:11 >> > To: Olivier Martin >> > Cc: [email protected] >> > Subject: Re: Passing an initrd to a Linux kernel with Device Tree >> > >> > On Tue, Sep 20, 2011 at 06:46:22PM +0100, Olivier Martin wrote: >> > > Hello, >> > > >> > > I tried recently to add support in UEFI to pass an initrd >> > with FDT to >> > > a Linux kernel. I have searched the Internet but I did not find any >> > > information to do that. >> > > >> > > FYI, this is the way it is done in ATAG: >> > > typedef struct { >> > > UINT32 start; >> > > UINT32 size; >> > > } LINUX_ATAG_INITRD2; >> > > >> > > The boot loader loads the initrd in system memory and passes the >> > > memory region information through ATAG. >> > > >> > > >> > > Sorry, if it is the wrong mailing-list. In this case, can someone >> > > point me on the right forum for any Linux FDT oriented questions. >> > >> > Hmmm, it may not be documented (the binding was implemented a >> > long time ago before we got strict about documenting >> > bindings). The magic is two properties in the /chosen node; >> > "linux,initrd-start" and "linux,initrd-end". Each contains >> > the physical start and end addresses of the initrd. >> >> What does "end address" mean here? >> >> It could be read as meaning either: >> >> a) address of the the final byte of the image >> b) address of the first byte following the image (0 if the image ends at 4G) > > Looking at the code (remember this is always the ultimate > documentation), end_address = start_address + size. So (b) would be the > right answer.
Yes, (b) is correct. I lost 2 days of my life tracking down a bug last year that turned out to be that I incorrectly assumed (a). g. _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
