From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Date: Mon, 4 Jul 2011 17:24:07 -0400 Subject: [U-Boot] [PATCH 5/5] Warn when the machine ID isn't passed to an ARM kernel and u-boot is compiled in debug mode. The kernel cannot boot without it. In-Reply-To: <20110704203235.GI3016@harvey-pc.matrox.com> References: <20110704174541.GF3016@harvey-pc.matrox.com> <20110704180844.GC30477@titan.lakedaemon.net> <20110704185554.GH3016@harvey-pc.matrox.com> <20110704201349.GD30477@titan.lakedaemon.net> <20110704203235.GI3016@harvey-pc.matrox.com> Message-ID: <20110704212407.GE30477@titan.lakedaemon.net> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Mon, Jul 04, 2011 at 04:32:35PM -0400, Christopher Harvey wrote: > On Mon, Jul 04, 2011 at 04:13:49PM -0400, Jason wrote: > > On Mon, Jul 04, 2011 at 02:55:54PM -0400, Christopher Harvey wrote: > > > On Mon, Jul 04, 2011 at 02:08:44PM -0400, Jason wrote: > > > > On Mon, Jul 04, 2011 at 01:45:41PM -0400, Christopher Harvey wrote: > > > > > + Hopefully there will never be this many machines. > > > > > + Can't use 0 since 0 is already used as a mach-type. */ > > > > > + gd->bd->bi_arch_number = 0xffffffff; > > > > > > > > > > gd->bd->bi_baudrate = gd->baudrate; > > > > > /* Ram ist board specific, so move it to board code ... */ > > > > > diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c > > > > > index 802e833..70b3b76 100644 > > > > > --- a/arch/arm/lib/bootm.c > > > > > +++ b/arch/arm/lib/bootm.c > > > > > @@ -113,6 +113,12 @@ int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images) > > > > > printf ("Using machid 0x%x from environment\n", machid); > > > > > } > > > > > > > > > > +#ifdef DEBUG > > > > > + if(machid==0xffffffff) { > > > > > + debug("\nWarning: machid not set! Linux will not finish booting.\n\n"); > > > > > > > > s/finish/start/ ;-) > > > > > > > I'll have to disagree here. Linux will decompress and some functions > > > will run but it will eventually stop, hence will not finish. > > > > On further investigation, you're right, it doesn't finish > > starting/booting. Sorry for the noise. > > > > > > Also, shouldn't the compile fail in this case (#error)? Or, at least #warn? > > > > > > > The compiler can't know what machid will be at runtime. Maybe a "would > > > you like to continue?" prompt could work. > > > > Since the kernel throws a nice fat error message when the MACH_TYPE > > doesn't match what it was compiled for, I don't see the point to adding > > another message at the same point in the development process. > > I didn't see that message. Do you know what lines of code in the > kernel print it? Or maybe just the message itself? In init/main.c start_kernel() calls setup_arch() In arch/arm/kernel/setup.c setup_arch() calls setup_machine_tags() which calls dump_machine_table() when the value in r1 doesn't match any of the mach-types the kernel was compiled for. > If the kernel can check the value why would it need to be passed > in the first place? Because the kernel has no way of easily determining which arm board it's running on without this feature. hth, Jason.