arch/arm/mach-imx/cpu-imx5.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 <linux/io.h>
  19
  20 #include "hardware.h"
  21 #include "common.h"
  22
  23 static int mx5_cpu_rev = -1;
  24
  25 #define IIM_SREV 0x24
  26
  27 static int get_mx51_srev(void)
  28 {
  29         void __iomem *iim_base = MX51_IO_ADDRESS(MX51_IIM_BASE_ADDR);
  30         u32 rev = readl(iim_base + IIM_SREV) & 0xff;
  31
  32         switch (rev) {
  33         case 0x0:
  34                 return IMX_CHIP_REVISION_2_0;
  35         case 0x10:
  36                 return IMX_CHIP_REVISION_3_0;
  37         default:
  38                 return IMX_CHIP_REVISION_UNKNOWN;
  39         }
  40 }
  41
  42 /*
  43  * Returns:
  44  *      the silicon revision of the cpu
  45  *      -EINVAL - not a mx51
  46  */
  47 int mx51_revision(void)
  48 {
  49         if (!cpu_is_mx51())
  50                 return -EINVAL;
  51
  52         if (mx5_cpu_rev == -1)
  53                 mx5_cpu_rev = get_mx51_srev();
  54
  55         return mx5_cpu_rev;
  56 }
  57 EXPORT_SYMBOL(mx51_revision);
  58
  59 #ifdef CONFIG_NEON
  60
  61 /*
  62  * All versions of the silicon before Rev. 3 have broken NEON implementations.
  63  * Dependent on link order - so the assumption is that vfp_init is called
  64  * before us.
  65  */
  66 int __init mx51_neon_fixup(void)
  67 {
  68         if (mx51_revision() < IMX_CHIP_REVISION_3_0 &&
  69                         (elf_hwcap & HWCAP_NEON)) {
  70                 elf_hwcap &= ~HWCAP_NEON;
  71                 pr_info("Turning off NEON support, detected broken NEON implementation\n");
  72         }
  73         return 0;
  74 }
  75
  76 #endif
  77
  78 static int get_mx53_srev(void)
  79 {
  80         void __iomem *iim_base = MX51_IO_ADDRESS(MX53_IIM_BASE_ADDR);
  81         u32 rev = readl(iim_base + IIM_SREV) & 0xff;
  82
  83         switch (rev) {
  84         case 0x0:
  85                 return IMX_CHIP_REVISION_1_0;
  86         case 0x2:
  87                 return IMX_CHIP_REVISION_2_0;
  88         case 0x3:
  89                 return IMX_CHIP_REVISION_2_1;
  90         default:
  91                 return IMX_CHIP_REVISION_UNKNOWN;
  92         }
  93 }
  94
  95 /*
  96  * Returns:
  97  *      the silicon revision of the cpu
  98  *      -EINVAL - not a mx53
  99  */
 100 int mx53_revision(void)
 101 {
 102         if (!cpu_is_mx53())
 103                 return -EINVAL;
 104
 105         if (mx5_cpu_rev == -1)
 106                 mx5_cpu_rev = get_mx53_srev();
 107
 108         return mx5_cpu_rev;
 109 }
 110 EXPORT_SYMBOL(mx53_revision);