root/arch/arm/mach-imx/cpu-imx5.c

DEFINITIONS

1. imx5_read_srev_reg
2. get_mx51_srev
3. mx51_revision
4. mx51_neon_fixup
5. get_mx53_srev
6. mx53_revision
7. imx5_pmu_init

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2008-2010 Freescale Semiconductor, Inc. All Rights Reserved.
   4  *
   5  * This file contains the CPU initialization code.
   6  */
   7 
   8 #include <linux/types.h>
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/io.h>
  13 #include <linux/of.h>
  14 #include <linux/of_address.h>
  15 
  16 #include "hardware.h"
  17 #include "common.h"
  18 
  19 static int mx5_cpu_rev = -1;
  20 
  21 #define IIM_SREV 0x24
  22 
  23 static u32 imx5_read_srev_reg(const char *compat)
  24 {
  25         void __iomem *iim_base;
  26         struct device_node *np;
  27         u32 srev;
  28 
  29         np = of_find_compatible_node(NULL, NULL, compat);
  30         iim_base = of_iomap(np, 0);
  31         WARN_ON(!iim_base);
  32 
  33         srev = readl(iim_base + IIM_SREV) & 0xff;
  34 
  35         iounmap(iim_base);
  36 
  37         return srev;
  38 }
  39 
  40 static int get_mx51_srev(void)
  41 {
  42         u32 rev = imx5_read_srev_reg("fsl,imx51-iim");
  43 
  44         switch (rev) {
  45         case 0x0:
  46                 return IMX_CHIP_REVISION_2_0;
  47         case 0x10:
  48                 return IMX_CHIP_REVISION_3_0;
  49         default:
  50                 return IMX_CHIP_REVISION_UNKNOWN;
  51         }
  52 }
  53 
  54 /*
  55  * Returns:
  56  *      the silicon revision of the cpu
  57  */
  58 int mx51_revision(void)
  59 {
  60         if (mx5_cpu_rev == -1)
  61                 mx5_cpu_rev = get_mx51_srev();
  62 
  63         return mx5_cpu_rev;
  64 }
  65 EXPORT_SYMBOL(mx51_revision);
  66 
  67 #ifdef CONFIG_NEON
  68 
  69 /*
  70  * All versions of the silicon before Rev. 3 have broken NEON implementations.
  71  * Dependent on link order - so the assumption is that vfp_init is called
  72  * before us.
  73  */
  74 int __init mx51_neon_fixup(void)
  75 {
  76         if (mx51_revision() < IMX_CHIP_REVISION_3_0 &&
  77                         (elf_hwcap & HWCAP_NEON)) {
  78                 elf_hwcap &= ~HWCAP_NEON;
  79                 pr_info("Turning off NEON support, detected broken NEON implementation\n");
  80         }
  81         return 0;
  82 }
  83 
  84 #endif
  85 
  86 static int get_mx53_srev(void)
  87 {
  88         u32 rev = imx5_read_srev_reg("fsl,imx53-iim");
  89 
  90         switch (rev) {
  91         case 0x0:
  92                 return IMX_CHIP_REVISION_1_0;
  93         case 0x2:
  94                 return IMX_CHIP_REVISION_2_0;
  95         case 0x3:
  96                 return IMX_CHIP_REVISION_2_1;
  97         default:
  98                 return IMX_CHIP_REVISION_UNKNOWN;
  99         }
 100 }
 101 
 102 /*
 103  * Returns:
 104  *      the silicon revision of the cpu
 105  */
 106 int mx53_revision(void)
 107 {
 108         if (mx5_cpu_rev == -1)
 109                 mx5_cpu_rev = get_mx53_srev();
 110 
 111         return mx5_cpu_rev;
 112 }
 113 EXPORT_SYMBOL(mx53_revision);
 114 
 115 #define ARM_GPC         0x4
 116 #define DBGEN           BIT(16)
 117 
 118 /*
 119  * This enables the DBGEN bit in ARM_GPC register, which is
 120  * required for accessing some performance counter features.
 121  * Technically it is only required while perf is used, but to
 122  * keep the source code simple we just enable it all the time
 123  * when the kernel configuration allows using the feature.
 124  */
 125 void __init imx5_pmu_init(void)
 126 {
 127         void __iomem *tigerp_base;
 128         struct device_node *np;
 129         u32 gpc;
 130 
 131         if (!IS_ENABLED(CONFIG_ARM_PMU))
 132                 return;
 133 
 134         np = of_find_compatible_node(NULL, NULL, "arm,cortex-a8-pmu");
 135         if (!np)
 136                 return;
 137 
 138         if (!of_property_read_bool(np, "secure-reg-access"))
 139                 goto exit;
 140 
 141         of_node_put(np);
 142 
 143         np = of_find_compatible_node(NULL, NULL, "fsl,imx51-tigerp");
 144         if (!np)
 145                 return;
 146 
 147         tigerp_base = of_iomap(np, 0);
 148         if (!tigerp_base)
 149                 goto exit;
 150 
 151         gpc = readl_relaxed(tigerp_base + ARM_GPC);
 152         gpc |= DBGEN;
 153         writel_relaxed(gpc, tigerp_base + ARM_GPC);
 154         iounmap(tigerp_base);
 155 exit:
 156         of_node_put(np);
 157 
 158 }