On 10 Sep 01, Nicolas Pitre wrote:
> On Wed, 1 Sep 2010, Amit Kucheria wrote:
>
[snip]
> > Unfortunately, it seems after talking to Nicolas that mdesc->fixup() is
> > called too early.
> >
> > Nicolas suggested linking the i.MX5 code _after_ the VFP module :)
>
> Something like this patch:
>
> ----- >8
> From: Nicolas Pitre <nicolas.pi...@linaro.org>
> Date: Wed, 1 Sep 2010 09:37:05 -0400
> Subject: [PATCH] ARM: link board specific files after core files
>
> This allows for board specific issues to override decisions made in generic
> code that might not be suitable due to some errata or the like.
>
> Signed-off-by: Nicolas Pitre <nicolas.pi...@linaro.org>
>
> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> index df4ab3c..3e8e3d7 100644
> --- a/arch/arm/Makefile
> +++ b/arch/arm/Makefile
> @@ -243,13 +243,14 @@ ifeq ($(FASTFPE),$(wildcard $(FASTFPE)))
> FASTFPE_OBJ :=$(FASTFPE)/
> endif
>
> -# If we have a machine-specific directory, then include it in the build.
> -core-y += arch/arm/kernel/ arch/arm/mm/
> arch/arm/common/
> -core-y += $(machdirs) $(platdirs)
> core-$(CONFIG_FPE_NWFPE) += arch/arm/nwfpe/
> core-$(CONFIG_FPE_FASTFPE) += $(FASTFPE_OBJ)
> core-$(CONFIG_VFP) += arch/arm/vfp/
>
> +# If we have a machine-specific directory, then include it in the build.
> +core-y += arch/arm/kernel/ arch/arm/mm/
> arch/arm/common/
> +core-y += $(machdirs) $(platdirs)
> +
> drivers-$(CONFIG_OPROFILE) += arch/arm/oprofile/
>
> libs-y := arch/arm/lib/ $(libs-y)
> 8< -----
>
> Then, just add your fixup in a separate patch. Beware: the above patch
> is untested.
>
My fixup patch is attached. Compile-tested along with Nico's patch. But I
have no TO1/TO2 boards to test. Loic do know anybody that can test with
Nico's patch and this fixup?
>From caad712990cccb705b44414830d41142277538b8 Mon Sep 17 00:00:00 2001
Message-Id:
<caad712990cccb705b44414830d41142277538b8.1283370628.git.amit.kuche...@linaro.org>
From: Amit Kucheria <amit.kuche...@linaro.org>
Date: Wed, 1 Sep 2010 22:49:13 +0300
Subject: [PATCH] mxc: turn off HWCAP_NEON for older versions of imx51 silicon
Versions of silicon older than TO3 have broken NEON implementation. Turn off
NEON in such cases.
Signed-off-by: Amit Kucheria <amit.kuche...@linaro.org>
---
arch/arm/mach-mx5/board-mx51_babbage.c | 9 +++++++++
arch/arm/mach-mx5/cpu.c | 15 +++++++++++++++
2 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-mx5/board-mx51_babbage.c
b/arch/arm/mach-mx5/board-mx51_babbage.c
index 6e384d9..65d1d2c 100644
--- a/arch/arm/mach-mx5/board-mx51_babbage.c
+++ b/arch/arm/mach-mx5/board-mx51_babbage.c
@@ -45,6 +45,8 @@
#define MX51_USB_PLL_DIV_19_2_MHZ 0x01
#define MX51_USB_PLL_DIV_24_MHZ 0x02
+extern void mx51_neon_fixup(void);
+
static struct platform_device *devices[] __initdata = {
&mxc_fec_device,
};
@@ -240,6 +242,12 @@ static int __init babbage_otg_mode(char *options)
}
__setup("otg_mode=", babbage_otg_mode);
+static void __init fixup_mx51_babbage(struct machine_desc *desc,
+ struct tag *tags, char **cmdline, struct meminfo *mi)
+{
+ mx51_neon_fixup();
+}
+
/*
* Board specific initialization.
*/
@@ -284,6 +292,7 @@ MACHINE_START(MX51_BABBAGE, "Freescale MX51 Babbage Board")
.phys_io = MX51_AIPS1_BASE_ADDR,
.io_pg_offst = ((MX51_AIPS1_BASE_ADDR_VIRT) >> 18) & 0xfffc,
.boot_params = PHYS_OFFSET + 0x100,
+ .fixup = fixup_mx51_babbage,
.map_io = mx51_map_io,
.init_irq = mx51_init_irq,
.init_machine = mxc_board_init,
diff --git a/arch/arm/mach-mx5/cpu.c b/arch/arm/mach-mx5/cpu.c
index 2d37785..8d081c6 100644
--- a/arch/arm/mach-mx5/cpu.c
+++ b/arch/arm/mach-mx5/cpu.c
@@ -70,6 +70,21 @@ int mx51_revision(void)
}
EXPORT_SYMBOL(mx51_revision);
+#ifdef CONFIG_NEON
+/* All versions of the silicon before Rev. 3 have broken NEON implementations
*/
+void mx51_neon_fixup(void)
+{
+ if (mx51_revision() < MX51_CHIP_REV_3_0) {
+ if (elf_hwcap & HWCAP_NEON) {
+ elf_hwcap &= ~HWCAP_NEON;
+ pr_info("Turning off NEON support, detected broken NEON
implemention\n");
+ }
+ }
+}
+#else
+void mx51_neon_fixup(void) {}
+#endif
+
static int __init post_cpu_init(void)
{
unsigned int reg;
--
1.7.0.4
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