On 10 Sep 02, Nicolas Pitre wrote:
On Thu, 2 Sep 2010, Amit Kucheria wrote:
Instead of having this empty mx51_neon_fixup() in the #else part...
@@ -98,3 +120,4 @@ static int __init post_cpu_init(void) } postcore_initcall(post_cpu_init); +late_initcall(mx51_neon_fixup);
... why don't you move this late_initcall() _inside_ the #ifdef CONFIG_NEON ?
Elegant. Please find patch attached. If someone with a TO2 board can test this, there is a uImage with this patch and Nico's at http://people.canonical.com/~amitk/imx5/uImage
Regards, Amit
From ee41c96eb92a1561cbbde6bafffa87ba11c7544d Mon Sep 17 00:00:00 2001
Message-Id: ee41c96eb92a1561cbbde6bafffa87ba11c7544d.1283442320.git.amit.kucheria@linaro.org From: Amit Kucheria amit.kucheria@verdurent.com 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.kucheria@linaro.org --- arch/arm/mach-mx5/cpu.c | 19 +++++++++++++++++++ 1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-mx5/cpu.c b/arch/arm/mach-mx5/cpu.c index 2d37785..06e1717 100644 --- a/arch/arm/mach-mx5/cpu.c +++ b/arch/arm/mach-mx5/cpu.c @@ -70,6 +70,25 @@ int mx51_revision(void) } EXPORT_SYMBOL(mx51_revision);
+#ifdef CONFIG_NEON + +/* All versions of the silicon before Rev. 3 have broken NEON implementations. + * Dependent on link order - so the assumption is that vfp_init is called before us + */ +static int __init 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"); + } + } + return 0; +} + +late_initcall(mx51_neon_fixup); +#endif + static int __init post_cpu_init(void) { unsigned int reg;