ARM: 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>
Tested-by: Dave Martin <dave.martin@linaro.org>
Tested-by: Jason Hui <jason.hui@linaro.org>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>

diff --git a/arch/arm/mach-mx5/cpu.c b/arch/arm/mach-mx5/cpu.c
index 2d37785..eaacb6e 100644 (file)
--- 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 && (elf_hwcap & HWCAP_NEON)) {
+               elf_hwcap &= ~HWCAP_NEON;
+               pr_info("Turning off NEON support, detected broken NEON implementation\n");
+       }
+       return 0;
+}
+
+late_initcall(mx51_neon_fixup);
+#endif
+
 static int __init post_cpu_init(void)
 {
        unsigned int reg;