drivers/soc/samsung/exynos-srom.c

   1 /*
   2  * Copyright (c) 2015 Samsung Electronics Co., Ltd.
   3  *            http://www.samsung.com/
   4  *
   5  * EXYNOS - SROM Controller support
   6  * Author: Pankaj Dubey <pankaj.dubey@samsung.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/io.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/of_address.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/slab.h>
  19
  20 #include "exynos-srom.h"
  21
  22 static const unsigned long exynos_srom_offsets[] = {
  23         /* SROM side */
  24         EXYNOS_SROM_BW,
  25         EXYNOS_SROM_BC0,
  26         EXYNOS_SROM_BC1,
  27         EXYNOS_SROM_BC2,
  28         EXYNOS_SROM_BC3,
  29 };
  30
  31 /**
  32  * struct exynos_srom_reg_dump: register dump of SROM Controller registers.
  33  * @offset: srom register offset from the controller base address.
  34  * @value: the value of register under the offset.
  35  */
  36 struct exynos_srom_reg_dump {
  37         u32     offset;
  38         u32     value;
  39 };
  40
  41 /**
  42  * struct exynos_srom: platform data for exynos srom controller driver.
  43  * @dev: platform device pointer
  44  * @reg_base: srom base address
  45  * @reg_offset: exynos_srom_reg_dump pointer to hold offset and its value.
  46  */
  47 struct exynos_srom {
  48         struct device *dev;
  49         void __iomem *reg_base;
  50         struct exynos_srom_reg_dump *reg_offset;
  51 };
  52
  53 static struct exynos_srom_reg_dump *exynos_srom_alloc_reg_dump(
  54                 const unsigned long *rdump,
  55                 unsigned long nr_rdump)
  56 {
  57         struct exynos_srom_reg_dump *rd;
  58         unsigned int i;
  59
  60         rd = kcalloc(nr_rdump, sizeof(*rd), GFP_KERNEL);
  61         if (!rd)
  62                 return NULL;
  63
  64         for (i = 0; i < nr_rdump; ++i)
  65                 rd[i].offset = rdump[i];
  66
  67         return rd;
  68 }
  69
  70 static int exynos_srom_probe(struct platform_device *pdev)
  71 {
  72         struct device_node *np;
  73         struct exynos_srom *srom;
  74         struct device *dev = &pdev->dev;
  75
  76         np = dev->of_node;
  77         if (!np) {
  78                 dev_err(&pdev->dev, "could not find device info\n");
  79                 return -EINVAL;
  80         }
  81
  82         srom = devm_kzalloc(&pdev->dev,
  83                         sizeof(struct exynos_srom), GFP_KERNEL);
  84         if (!srom)
  85                 return -ENOMEM;
  86
  87         srom->dev = dev;
  88         srom->reg_base = of_iomap(np, 0);
  89         if (!srom->reg_base) {
  90                 dev_err(&pdev->dev, "iomap of exynos srom controller failed\n");
  91                 return -ENOMEM;
  92         }
  93
  94         platform_set_drvdata(pdev, srom);
  95
  96         srom->reg_offset = exynos_srom_alloc_reg_dump(exynos_srom_offsets,
  97                         sizeof(exynos_srom_offsets));
  98         if (!srom->reg_offset) {
  99                 iounmap(srom->reg_base);
 100                 return -ENOMEM;
 101         }
 102
 103         return 0;
 104 }
 105
 106 static int exynos_srom_remove(struct platform_device *pdev)
 107 {
 108         struct exynos_srom *srom = platform_get_drvdata(pdev);
 109
 110         kfree(srom->reg_offset);
 111         iounmap(srom->reg_base);
 112
 113         return 0;
 114 }
 115
 116 #ifdef CONFIG_PM_SLEEP
 117 static void exynos_srom_save(void __iomem *base,
 118                                     struct exynos_srom_reg_dump *rd,
 119                                     unsigned int num_regs)
 120 {
 121         for (; num_regs > 0; --num_regs, ++rd)
 122                 rd->value = readl(base + rd->offset);
 123 }
 124
 125 static void exynos_srom_restore(void __iomem *base,
 126                                       const struct exynos_srom_reg_dump *rd,
 127                                       unsigned int num_regs)
 128 {
 129         for (; num_regs > 0; --num_regs, ++rd)
 130                 writel(rd->value, base + rd->offset);
 131 }
 132
 133 static int exynos_srom_suspend(struct device *dev)
 134 {
 135         struct exynos_srom *srom = dev_get_drvdata(dev);
 136
 137         exynos_srom_save(srom->reg_base, srom->reg_offset,
 138                                 ARRAY_SIZE(exynos_srom_offsets));
 139         return 0;
 140 }
 141
 142 static int exynos_srom_resume(struct device *dev)
 143 {
 144         struct exynos_srom *srom = dev_get_drvdata(dev);
 145
 146         exynos_srom_restore(srom->reg_base, srom->reg_offset,
 147                                 ARRAY_SIZE(exynos_srom_offsets));
 148         return 0;
 149 }
 150 #endif
 151
 152 static const struct of_device_id of_exynos_srom_ids[] = {
 153         {
 154                 .compatible     = "samsung,exynos-srom",
 155         },
 156         {},
 157 };
 158 MODULE_DEVICE_TABLE(of, of_exynos_srom_ids);
 159
 160 static SIMPLE_DEV_PM_OPS(exynos_srom_pm_ops, exynos_srom_suspend, exynos_srom_resume);
 161
 162 static struct platform_driver exynos_srom_driver = {
 163         .probe = exynos_srom_probe,
 164         .remove = exynos_srom_remove,
 165         .driver = {
 166                 .name = "exynos-srom",
 167                 .of_match_table = of_exynos_srom_ids,
 168                 .pm = &exynos_srom_pm_ops,
 169         },
 170 };
 171 module_platform_driver(exynos_srom_driver);
 172
 173 MODULE_AUTHOR("Pankaj Dubey <pankaj.dubey@samsung.com>");
 174 MODULE_DESCRIPTION("Exynos SROM Controller Driver");
 175 MODULE_LICENSE("GPL");