Albert, > -----Original Message----- > From: Tom Warren [mailto:twarren.nvi...@gmail.com] > Sent: Thursday, February 16, 2012 12:46 PM > To: u-boot@lists.denx.de > Cc: twarren.nvi...@gmail.com; albert.u.b...@aribaud.net; w...@denx.de; > s...@chromium.org; Stephen Warren; Tom Warren > Subject: [PATCH] arm: Tegra2: Fix ELDK42 gcc failure with inline asm stack > pointer load > > The 4.2.2 gcc in the ELDK42 release doesn't like the direct SP load using a > constant in tegra2_start. Break it up into 4 loads using mov & orr. > > Tested on my Seaboard T20-A03, U-Boot loads and runs OK. Also compiled all > tegra2 builds with both gcc 4.2.2 and 4.4.1 OK. > > Signed-off-by: Tom Warren <twar...@nvidia.com> > --- > arch/arm/cpu/armv7/tegra2/ap20.c | 25 ++++++++++++++++++++----- > 1 files changed, 20 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/cpu/armv7/tegra2/ap20.c > b/arch/arm/cpu/armv7/tegra2/ap20.c > index 4c44bb3..d2bc0d5 100644 > --- a/arch/arm/cpu/armv7/tegra2/ap20.c > +++ b/arch/arm/cpu/armv7/tegra2/ap20.c > @@ -298,11 +298,26 @@ void tegra2_start(void) > writel(0xC0, &pmt->pmt_cfg_ctl); > > /* > - * If we are ARM7 - give it a different stack. We are about to > - * start up the A9 which will want to use this one. > - */ > - asm volatile("ldr sp, =%c0\n" > - : : "i"(AVP_EARLY_BOOT_STACK_LIMIT)); > + * If we are ARM7 - give it a different stack. We are about to > + * start up the A9 which will want to use this one. > + */ > + /* > + * Note that the 'ldr sp,CONSTANT' version, below, doesn't > + * work on gcc 4.2.2 (ELDK42), but does on gcc 4.4.1 and above. > + * The work-around is to use the (ugly) 4-pass mov/orr below. > + * > + * asm volatile("ldr sp, =%c0\n" : : > + * "i"(AVP_EARLY_BOOT_STACK_LIMIT)); > + */ > + > + asm volatile("mov sp, %0" > + : : "i"(AVP_EARLY_BOOT_STACK_LIMIT & 0xFF)); > + asm volatile("orr sp, %0" > + : : "i"(AVP_EARLY_BOOT_STACK_LIMIT & 0xFF00)); > + asm volatile("orr sp, %0" > + : : "i"(AVP_EARLY_BOOT_STACK_LIMIT & 0xFF0000)); > + asm volatile("orr sp, %0" > + : : "i"(AVP_EARLY_BOOT_STACK_LIMIT & 0xFF000000)); > > start_cpu((u32)_start); > halt_avp(); > -- > 1.7.7.1
This should fix the problem you had with compiling the 6 tegra2 builds w/ELDK42. I've also tested it with gcc 4.4.1 (the one I use every day) and gcc 4.6.1 (used internally @ NVIDIA for Chrome U-Boot builds, etc.). It's an ugly work-around, but it works. Thanks to Simon for the fix, BTW. Tom -- nvpublic _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
