arch/arm/mach-mx5/cpu.c

   1 /*
   2  * Copyright 2008-2010 Freescale Semiconductor, Inc. All Rights Reserved.
   3  *
   4  * The code contained herein is licensed under the GNU General Public
   5  * License. You may obtain a copy of the GNU General Public License
   6  * Version 2 or later at the following locations:
   7  *
   8  * http://www.opensource.org/licenses/gpl-license.html
   9  * http://www.gnu.org/copyleft/gpl.html
  10  *
  11  * This file contains the CPU initialization code.
  12  */
  13
  14 #include <linux/types.h>
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <mach/hardware.h>
  19 #include <asm/io.h>
  20
  21 static int cpu_silicon_rev = -1;
  22
  23 #define IIM_SREV 0x24
  24
  25 static int get_mx51_srev(void)
  26 {
  27         void __iomem *iim_base = MX51_IO_ADDRESS(MX51_IIM_BASE_ADDR);
  28         u32 rev = readl(iim_base + IIM_SREV) & 0xff;
  29
  30         if (rev == 0x0)
  31                 return IMX_CHIP_REVISION_2_0;
  32         else if (rev == 0x10)
  33                 return IMX_CHIP_REVISION_3_0;
  34         return 0;
  35 }
  36
  37 /*
  38  * Returns:
  39  *      the silicon revision of the cpu
  40  *      -EINVAL - not a mx51
  41  */
  42 int mx51_revision(void)
  43 {
  44         if (!cpu_is_mx51())
  45                 return -EINVAL;
  46
  47         if (cpu_silicon_rev == -1)
  48                 cpu_silicon_rev = get_mx51_srev();
  49
  50         return cpu_silicon_rev;
  51 }
  52 EXPORT_SYMBOL(mx51_revision);
  53
  54 #ifdef CONFIG_NEON
  55
  56 /*
  57  * All versions of the silicon before Rev. 3 have broken NEON implementations.
  58  * Dependent on link order - so the assumption is that vfp_init is called
  59  * before us.
  60  */
  61 static int __init mx51_neon_fixup(void)
  62 {
  63         if (!cpu_is_mx51())
  64                 return 0;
  65
  66         if (mx51_revision() < IMX_CHIP_REVISION_3_0 && (elf_hwcap & HWCAP_NEON)) {
  67                 elf_hwcap &= ~HWCAP_NEON;
  68                 pr_info("Turning off NEON support, detected broken NEON implementation\n");
  69         }
  70         return 0;
  71 }
  72
  73 late_initcall(mx51_neon_fixup);
  74 #endif
  75
  76 static int get_mx53_srev(void)
  77 {
  78         void __iomem *iim_base = MX51_IO_ADDRESS(MX53_IIM_BASE_ADDR);
  79         u32 rev = readl(iim_base + IIM_SREV) & 0xff;
  80
  81         if (rev == 0x0)
  82                 return IMX_CHIP_REVISION_1_0;
  83         else if (rev == 0x10)
  84                 return IMX_CHIP_REVISION_2_0;
  85         return 0;
  86 }
  87
  88 /*
  89  * Returns:
  90  *      the silicon revision of the cpu
  91  *      -EINVAL - not a mx53
  92  */
  93 int mx53_revision(void)
  94 {
  95         if (!cpu_is_mx53())
  96                 return -EINVAL;
  97
  98         if (cpu_silicon_rev == -1)
  99                 cpu_silicon_rev = get_mx53_srev();
 100
 101         return cpu_silicon_rev;
 102 }
 103 EXPORT_SYMBOL(mx53_revision);
 104
 105 static int __init post_cpu_init(void)
 106 {
 107         unsigned int reg;
 108         void __iomem *base;
 109
 110         if (cpu_is_mx51() || cpu_is_mx53()) {
 111                 if (cpu_is_mx51())
 112                         base = MX51_IO_ADDRESS(MX51_AIPS1_BASE_ADDR);
 113                 else
 114                         base = MX53_IO_ADDRESS(MX53_AIPS1_BASE_ADDR);
 115
 116                 __raw_writel(0x0, base + 0x40);
 117                 __raw_writel(0x0, base + 0x44);
 118                 __raw_writel(0x0, base + 0x48);
 119                 __raw_writel(0x0, base + 0x4C);
 120                 reg = __raw_readl(base + 0x50) & 0x00FFFFFF;
 121                 __raw_writel(reg, base + 0x50);
 122
 123                 if (cpu_is_mx51())
 124                         base = MX51_IO_ADDRESS(MX51_AIPS2_BASE_ADDR);
 125                 else
 126                         base = MX53_IO_ADDRESS(MX53_AIPS2_BASE_ADDR);
 127
 128                 __raw_writel(0x0, base + 0x40);
 129                 __raw_writel(0x0, base + 0x44);
 130                 __raw_writel(0x0, base + 0x48);
 131                 __raw_writel(0x0, base + 0x4C);
 132                 reg = __raw_readl(base + 0x50) & 0x00FFFFFF;
 133                 __raw_writel(reg, base + 0x50);
 134         }
 135
 136         return 0;
 137 }
 138
 139 postcore_initcall(post_cpu_init);