linux/arch/arm/mach-mx5/cpu.c
Amit Kucheria 33d7c5c1c8 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>
2010-10-01 22:26:38 -04:00

120 lines
2.5 KiB
C

/*
* Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*
* This file contains the CPU initialization code.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <mach/hardware.h>
#include <asm/io.h>
static int cpu_silicon_rev = -1;
#define SI_REV 0x48
static void query_silicon_parameter(void)
{
void __iomem *rom = ioremap(MX51_IROM_BASE_ADDR, MX51_IROM_SIZE);
u32 rev;
if (!rom) {
cpu_silicon_rev = -EINVAL;
return;
}
rev = readl(rom + SI_REV);
switch (rev) {
case 0x1:
cpu_silicon_rev = MX51_CHIP_REV_1_0;
break;
case 0x2:
cpu_silicon_rev = MX51_CHIP_REV_1_1;
break;
case 0x10:
cpu_silicon_rev = MX51_CHIP_REV_2_0;
break;
case 0x20:
cpu_silicon_rev = MX51_CHIP_REV_3_0;
break;
default:
cpu_silicon_rev = 0;
}
iounmap(rom);
}
/*
* Returns:
* the silicon revision of the cpu
* -EINVAL - not a mx51
*/
int mx51_revision(void)
{
if (!cpu_is_mx51())
return -EINVAL;
if (cpu_silicon_rev == -1)
query_silicon_parameter();
return cpu_silicon_rev;
}
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;
void __iomem *base;
if (!cpu_is_mx51())
return 0;
base = MX51_IO_ADDRESS(MX51_AIPS1_BASE_ADDR);
__raw_writel(0x0, base + 0x40);
__raw_writel(0x0, base + 0x44);
__raw_writel(0x0, base + 0x48);
__raw_writel(0x0, base + 0x4C);
reg = __raw_readl(base + 0x50) & 0x00FFFFFF;
__raw_writel(reg, base + 0x50);
base = MX51_IO_ADDRESS(MX51_AIPS2_BASE_ADDR);
__raw_writel(0x0, base + 0x40);
__raw_writel(0x0, base + 0x44);
__raw_writel(0x0, base + 0x48);
__raw_writel(0x0, base + 0x4C);
reg = __raw_readl(base + 0x50) & 0x00FFFFFF;
__raw_writel(reg, base + 0x50);
return 0;
}
postcore_initcall(post_cpu_init);