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 #include <linux/of.h>
  20 #include <linux/of_address.h>
  21
  22 #include "hardware.h"
  23 #include "common.h"
  24
  25 static int mx5_cpu_rev = -1;
  26
  27 #define IIM_SREV 0x24
  28
  29 static u32 imx5_read_srev_reg(const char *compat)
  30 {
  31         void __iomem *iim_base;
  32         struct device_node *np;
  33         u32 srev;
  34
  35         np = of_find_compatible_node(NULL, NULL, compat);
  36         iim_base = of_iomap(np, 0);
  37         WARN_ON(!iim_base);
  38
  39         srev = readl(iim_base + IIM_SREV) & 0xff;
  40
  41         iounmap(iim_base);
  42
  43         return srev;
  44 }
  45
  46 static int get_mx51_srev(void)
  47 {
  48         u32 rev = imx5_read_srev_reg("fsl,imx51-iim");
  49
  50         switch (rev) {
  51         case 0x0:
  52                 return IMX_CHIP_REVISION_2_0;
  53         case 0x10:
  54                 return IMX_CHIP_REVISION_3_0;
  55         default:
  56                 return IMX_CHIP_REVISION_UNKNOWN;
  57         }
  58 }
  59
  60 /*
  61  * Returns:
  62  *      the silicon revision of the cpu
  63  *      -EINVAL - not a mx51
  64  */
  65 int mx51_revision(void)
  66 {
  67         if (!cpu_is_mx51())
  68                 return -EINVAL;
  69
  70         if (mx5_cpu_rev == -1)
  71                 mx5_cpu_rev = get_mx51_srev();
  72
  73         return mx5_cpu_rev;
  74 }
  75 EXPORT_SYMBOL(mx51_revision);
  76
  77 #ifdef CONFIG_NEON
  78
  79 /*
  80  * All versions of the silicon before Rev. 3 have broken NEON implementations.
  81  * Dependent on link order - so the assumption is that vfp_init is called
  82  * before us.
  83  */
  84 int __init mx51_neon_fixup(void)
  85 {
  86         if (mx51_revision() < IMX_CHIP_REVISION_3_0 &&
  87                         (elf_hwcap & HWCAP_NEON)) {
  88                 elf_hwcap &= ~HWCAP_NEON;
  89                 pr_info("Turning off NEON support, detected broken NEON implementation\n");
  90         }
  91         return 0;
  92 }
  93
  94 #endif
  95
  96 static int get_mx53_srev(void)
  97 {
  98         u32 rev = imx5_read_srev_reg("fsl,imx53-iim");
  99
 100         switch (rev) {
 101         case 0x0:
 102                 return IMX_CHIP_REVISION_1_0;
 103         case 0x2:
 104                 return IMX_CHIP_REVISION_2_0;
 105         case 0x3:
 106                 return IMX_CHIP_REVISION_2_1;
 107         default:
 108                 return IMX_CHIP_REVISION_UNKNOWN;
 109         }
 110 }
 111
 112 /*
 113  * Returns:
 114  *      the silicon revision of the cpu
 115  *      -EINVAL - not a mx53
 116  */
 117 int mx53_revision(void)
 118 {
 119         if (!cpu_is_mx53())
 120                 return -EINVAL;
 121
 122         if (mx5_cpu_rev == -1)
 123                 mx5_cpu_rev = get_mx53_srev();
 124
 125         return mx5_cpu_rev;
 126 }
 127 EXPORT_SYMBOL(mx53_revision);