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"); 160