drivers/nvmem/snvs_lpgpr.c

   1 /*
   2  * Copyright (c) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
   3  * Copyright (c) 2017 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2
   7  * as published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/mfd/syscon.h>
  11 #include <linux/module.h>
  12 #include <linux/nvmem-provider.h>
  13 #include <linux/of_device.h>
  14 #include <linux/regmap.h>
  15
  16 #define IMX6Q_SNVS_HPLR         0x00
  17 #define IMX6Q_SNVS_LPLR         0x34
  18 #define IMX6Q_SNVS_LPGPR        0x68
  19
  20 #define IMX7D_SNVS_HPLR         0x00
  21 #define IMX7D_SNVS_LPLR         0x34
  22 #define IMX7D_SNVS_LPGPR        0x90
  23
  24 #define IMX_GPR_SL              BIT(5)
  25 #define IMX_GPR_HL              BIT(5)
  26
  27 struct snvs_lpgpr_cfg {
  28         int offset;
  29         int offset_hplr;
  30         int offset_lplr;
  31         int size;
  32 };
  33
  34 struct snvs_lpgpr_priv {
  35         struct device_d                 *dev;
  36         struct regmap                   *regmap;
  37         struct nvmem_config             cfg;
  38         const struct snvs_lpgpr_cfg     *dcfg;
  39 };
  40
  41 static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = {
  42         .offset         = IMX6Q_SNVS_LPGPR,
  43         .offset_hplr    = IMX6Q_SNVS_HPLR,
  44         .offset_lplr    = IMX6Q_SNVS_LPLR,
  45         .size           = 4,
  46 };
  47
  48 static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx7d = {
  49         .offset         = IMX7D_SNVS_LPGPR,
  50         .offset_hplr    = IMX7D_SNVS_HPLR,
  51         .offset_lplr    = IMX7D_SNVS_LPLR,
  52         .size           = 16,
  53 };
  54
  55 static int snvs_lpgpr_write(void *context, unsigned int offset, void *val,
  56                             size_t bytes)
  57 {
  58         struct snvs_lpgpr_priv *priv = context;
  59         const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
  60         unsigned int lock_reg;
  61         int ret;
  62
  63         ret = regmap_read(priv->regmap, dcfg->offset_hplr, &lock_reg);
  64         if (ret < 0)
  65                 return ret;
  66
  67         if (lock_reg & IMX_GPR_SL)
  68                 return -EPERM;
  69
  70         ret = regmap_read(priv->regmap, dcfg->offset_lplr, &lock_reg);
  71         if (ret < 0)
  72                 return ret;
  73
  74         if (lock_reg & IMX_GPR_HL)
  75                 return -EPERM;
  76
  77         return regmap_bulk_write(priv->regmap, dcfg->offset + offset, val,
  78                                 bytes / 4);
  79 }
  80
  81 static int snvs_lpgpr_read(void *context, unsigned int offset, void *val,
  82                            size_t bytes)
  83 {
  84         struct snvs_lpgpr_priv *priv = context;
  85         const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
  86
  87         return regmap_bulk_read(priv->regmap, dcfg->offset + offset,
  88                                val, bytes / 4);
  89 }
  90
  91 static int snvs_lpgpr_probe(struct platform_device *pdev)
  92 {
  93         struct device *dev = &pdev->dev;
  94         struct device_node *node = dev->of_node;
  95         struct device_node *syscon_node;
  96         struct snvs_lpgpr_priv *priv;
  97         struct nvmem_config *cfg;
  98         struct nvmem_device *nvmem;
  99         const struct snvs_lpgpr_cfg *dcfg;
 100
 101         if (!node)
 102                 return -ENOENT;
 103
 104         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 105         if (!priv)
 106                 return -ENOMEM;
 107
 108         dcfg = of_device_get_match_data(dev);
 109         if (!dcfg)
 110                 return -EINVAL;
 111
 112         syscon_node = of_get_parent(node);
 113         if (!syscon_node)
 114                 return -ENODEV;
 115
 116         priv->regmap = syscon_node_to_regmap(syscon_node);
 117         of_node_put(syscon_node);
 118         if (IS_ERR(priv->regmap))
 119                 return PTR_ERR(priv->regmap);
 120
 121         priv->dcfg = dcfg;
 122
 123         cfg = &priv->cfg;
 124         cfg->priv = priv;
 125         cfg->name = dev_name(dev);
 126         cfg->dev = dev;
 127         cfg->stride = 4;
 128         cfg->word_size = 4;
 129         cfg->size = dcfg->size,
 130         cfg->owner = THIS_MODULE;
 131         cfg->reg_read  = snvs_lpgpr_read;
 132         cfg->reg_write = snvs_lpgpr_write;
 133
 134         nvmem = devm_nvmem_register(dev, cfg);
 135
 136         return PTR_ERR_OR_ZERO(nvmem);
 137 }
 138
 139 static const struct of_device_id snvs_lpgpr_dt_ids[] = {
 140         { .compatible = "fsl,imx6q-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx6q },
 141         { .compatible = "fsl,imx6ul-snvs-lpgpr",
 142           .data = &snvs_lpgpr_cfg_imx6q },
 143         { .compatible = "fsl,imx7d-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx7d },
 144         { },
 145 };
 146 MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids);
 147
 148 static struct platform_driver snvs_lpgpr_driver = {
 149         .probe  = snvs_lpgpr_probe,
 150         .driver = {
 151                 .name   = "snvs_lpgpr",
 152                 .of_match_table = snvs_lpgpr_dt_ids,
 153         },
 154 };
 155 module_platform_driver(snvs_lpgpr_driver);
 156
 157 MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
 158 MODULE_DESCRIPTION("Low Power General Purpose Register in i.MX6 and i.MX7 Secure Non-Volatile Storage");
 159 MODULE_LICENSE("GPL v2");