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cpu.c

/*
 * Copyright 2008-2010 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 IIM_SREV 0x24

static int get_mx51_srev(void)
{
      void __iomem *iim_base = MX51_IO_ADDRESS(MX51_IIM_BASE_ADDR);
      u32 rev = readl(iim_base + IIM_SREV) & 0xff;

      if (rev == 0x0)
            return IMX_CHIP_REVISION_2_0;
      else if (rev == 0x10)
            return IMX_CHIP_REVISION_3_0;
      return 0;
}

/*
 * 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)
            cpu_silicon_rev = get_mx51_srev();

      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 (!cpu_is_mx51())
            return 0;

      if (mx51_revision() < IMX_CHIP_REVISION_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 get_mx53_srev(void)
{
      void __iomem *iim_base = MX51_IO_ADDRESS(MX53_IIM_BASE_ADDR);
      u32 rev = readl(iim_base + IIM_SREV) & 0xff;

      if (rev == 0x0)
            return IMX_CHIP_REVISION_1_0;
      else if (rev == 0x10)
            return IMX_CHIP_REVISION_2_0;
      return 0;
}

/*
 * Returns:
 *    the silicon revision of the cpu
 *    -EINVAL - not a mx53
 */
int mx53_revision(void)
{
      if (!cpu_is_mx53())
            return -EINVAL;

      if (cpu_silicon_rev == -1)
            cpu_silicon_rev = get_mx53_srev();

      return cpu_silicon_rev;
}
EXPORT_SYMBOL(mx53_revision);

static int __init post_cpu_init(void)
{
      unsigned int reg;
      void __iomem *base;

      if (cpu_is_mx51() || cpu_is_mx53()) {
            if (cpu_is_mx51())
                  base = MX51_IO_ADDRESS(MX51_AIPS1_BASE_ADDR);
            else
                  base = MX53_IO_ADDRESS(MX53_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);

            if (cpu_is_mx51())
                  base = MX51_IO_ADDRESS(MX51_AIPS2_BASE_ADDR);
            else
                  base = MX53_IO_ADDRESS(MX53_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);

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