drivers/reset/reset-intel-gw.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2019 Intel Corporation.
   4  * Lei Chuanhua <Chuanhua.lei@intel.com>
   5  */
   6
   7 #include <linux/bitfield.h>
   8 #include <linux/init.h>
   9 #include <linux/of.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/reboot.h>
  12 #include <linux/regmap.h>
  13 #include <linux/reset-controller.h>
  14
  15 #define RCU_RST_STAT    0x0024
  16 #define RCU_RST_REQ     0x0048
  17
  18 #define REG_OFFSET_MASK GENMASK(31, 16)
  19 #define BIT_OFFSET_MASK GENMASK(15, 8)
  20 #define STAT_BIT_OFFSET_MASK    GENMASK(7, 0)
  21
  22 #define to_reset_data(x)        container_of(x, struct intel_reset_data, rcdev)
  23
  24 struct intel_reset_soc {
  25         bool legacy;
  26         u32 reset_cell_count;
  27 };
  28
  29 struct intel_reset_data {
  30         struct reset_controller_dev rcdev;
  31         struct notifier_block restart_nb;
  32         const struct intel_reset_soc *soc_data;
  33         struct regmap *regmap;
  34         struct device *dev;
  35         u32 reboot_id;
  36 };
  37
  38 static const struct regmap_config intel_rcu_regmap_config = {
  39         .name =         "intel-reset",
  40         .reg_bits =     32,
  41         .reg_stride =   4,
  42         .val_bits =     32,
  43         .fast_io =      true,
  44 };
  45
  46 /*
  47  * Reset status register offset relative to
  48  * the reset control register(X) is X + 4
  49  */
  50 static u32 id_to_reg_and_bit_offsets(struct intel_reset_data *data,
  51                                      unsigned long id, u32 *rst_req,
  52                                      u32 *req_bit, u32 *stat_bit)
  53 {
  54         *rst_req = FIELD_GET(REG_OFFSET_MASK, id);
  55         *req_bit = FIELD_GET(BIT_OFFSET_MASK, id);
  56
  57         if (data->soc_data->legacy)
  58                 *stat_bit = FIELD_GET(STAT_BIT_OFFSET_MASK, id);
  59         else
  60                 *stat_bit = *req_bit;
  61
  62         if (data->soc_data->legacy && *rst_req == RCU_RST_REQ)
  63                 return RCU_RST_STAT;
  64         else
  65                 return *rst_req + 0x4;
  66 }
  67
  68 static int intel_set_clr_bits(struct intel_reset_data *data, unsigned long id,
  69                               bool set)
  70 {
  71         u32 rst_req, req_bit, rst_stat, stat_bit, val;
  72         int ret;
  73
  74         rst_stat = id_to_reg_and_bit_offsets(data, id, &rst_req,
  75                                              &req_bit, &stat_bit);
  76
  77         val = set ? BIT(req_bit) : 0;
  78         ret = regmap_update_bits(data->regmap, rst_req,  BIT(req_bit), val);
  79         if (ret)
  80                 return ret;
  81
  82         return regmap_read_poll_timeout(data->regmap, rst_stat, val,
  83                                         set == !!(val & BIT(stat_bit)), 20,
  84                                         200);
  85 }
  86
  87 static int intel_assert_device(struct reset_controller_dev *rcdev,
  88                                unsigned long id)
  89 {
  90         struct intel_reset_data *data = to_reset_data(rcdev);
  91         int ret;
  92
  93         ret = intel_set_clr_bits(data, id, true);
  94         if (ret)
  95                 dev_err(data->dev, "Reset assert failed %d\n", ret);
  96
  97         return ret;
  98 }
  99
 100 static int intel_deassert_device(struct reset_controller_dev *rcdev,
 101                                  unsigned long id)
 102 {
 103         struct intel_reset_data *data = to_reset_data(rcdev);
 104         int ret;
 105
 106         ret = intel_set_clr_bits(data, id, false);
 107         if (ret)
 108                 dev_err(data->dev, "Reset deassert failed %d\n", ret);
 109
 110         return ret;
 111 }
 112
 113 static int intel_reset_status(struct reset_controller_dev *rcdev,
 114                               unsigned long id)
 115 {
 116         struct intel_reset_data *data = to_reset_data(rcdev);
 117         u32 rst_req, req_bit, rst_stat, stat_bit, val;
 118         int ret;
 119
 120         rst_stat = id_to_reg_and_bit_offsets(data, id, &rst_req,
 121                                              &req_bit, &stat_bit);
 122         ret = regmap_read(data->regmap, rst_stat, &val);
 123         if (ret)
 124                 return ret;
 125
 126         return !!(val & BIT(stat_bit));
 127 }
 128
 129 static const struct reset_control_ops intel_reset_ops = {
 130         .assert =       intel_assert_device,
 131         .deassert =     intel_deassert_device,
 132         .status =       intel_reset_status,
 133 };
 134
 135 static int intel_reset_xlate(struct reset_controller_dev *rcdev,
 136                              const struct of_phandle_args *spec)
 137 {
 138         struct intel_reset_data *data = to_reset_data(rcdev);
 139         u32 id;
 140
 141         if (spec->args[1] > 31)
 142                 return -EINVAL;
 143
 144         id = FIELD_PREP(REG_OFFSET_MASK, spec->args[0]);
 145         id |= FIELD_PREP(BIT_OFFSET_MASK, spec->args[1]);
 146
 147         if (data->soc_data->legacy) {
 148                 if (spec->args[2] > 31)
 149                         return -EINVAL;
 150
 151                 id |= FIELD_PREP(STAT_BIT_OFFSET_MASK, spec->args[2]);
 152         }
 153
 154         return id;
 155 }
 156
 157 static int intel_reset_restart_handler(struct notifier_block *nb,
 158                                        unsigned long action, void *data)
 159 {
 160         struct intel_reset_data *reset_data;
 161
 162         reset_data = container_of(nb, struct intel_reset_data, restart_nb);
 163         intel_assert_device(&reset_data->rcdev, reset_data->reboot_id);
 164
 165         return NOTIFY_DONE;
 166 }
 167
 168 static int intel_reset_probe(struct platform_device *pdev)
 169 {
 170         struct device_node *np = pdev->dev.of_node;
 171         struct device *dev = &pdev->dev;
 172         struct intel_reset_data *data;
 173         void __iomem *base;
 174         u32 rb_id[3];
 175         int ret;
 176
 177         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 178         if (!data)
 179                 return -ENOMEM;
 180
 181         data->soc_data = of_device_get_match_data(dev);
 182         if (!data->soc_data)
 183                 return -ENODEV;
 184
 185         base = devm_platform_ioremap_resource(pdev, 0);
 186         if (IS_ERR(base))
 187                 return PTR_ERR(base);
 188
 189         data->regmap = devm_regmap_init_mmio(dev, base,
 190                                              &intel_rcu_regmap_config);
 191         if (IS_ERR(data->regmap)) {
 192                 dev_err(dev, "regmap initialization failed\n");
 193                 return PTR_ERR(data->regmap);
 194         }
 195
 196         ret = device_property_read_u32_array(dev, "intel,global-reset", rb_id,
 197                                              data->soc_data->reset_cell_count);
 198         if (ret) {
 199                 dev_err(dev, "Failed to get global reset offset!\n");
 200                 return ret;
 201         }
 202
 203         data->dev =                     dev;
 204         data->rcdev.of_node =           np;
 205         data->rcdev.owner =             dev->driver->owner;
 206         data->rcdev.ops =               &intel_reset_ops;
 207         data->rcdev.of_xlate =          intel_reset_xlate;
 208         data->rcdev.of_reset_n_cells =  data->soc_data->reset_cell_count;
 209         ret = devm_reset_controller_register(&pdev->dev, &data->rcdev);
 210         if (ret)
 211                 return ret;
 212
 213         data->reboot_id = FIELD_PREP(REG_OFFSET_MASK, rb_id[0]);
 214         data->reboot_id |= FIELD_PREP(BIT_OFFSET_MASK, rb_id[1]);
 215
 216         if (data->soc_data->legacy)
 217                 data->reboot_id |= FIELD_PREP(STAT_BIT_OFFSET_MASK, rb_id[2]);
 218
 219         data->restart_nb.notifier_call =        intel_reset_restart_handler;
 220         data->restart_nb.priority =             128;
 221         register_restart_handler(&data->restart_nb);
 222
 223         return 0;
 224 }
 225
 226 static const struct intel_reset_soc xrx200_data = {
 227         .legacy =               true,
 228         .reset_cell_count =     3,
 229 };
 230
 231 static const struct intel_reset_soc lgm_data = {
 232         .legacy =               false,
 233         .reset_cell_count =     2,
 234 };
 235
 236 static const struct of_device_id intel_reset_match[] = {
 237         { .compatible = "intel,rcu-lgm", .data = &lgm_data },
 238         { .compatible = "intel,rcu-xrx200", .data = &xrx200_data },
 239         {}
 240 };
 241
 242 static struct platform_driver intel_reset_driver = {
 243         .probe = intel_reset_probe,
 244         .driver = {
 245                 .name = "intel-reset",
 246                 .of_match_table = intel_reset_match,
 247         },
 248 };
 249
 250 static int __init intel_reset_init(void)
 251 {
 252         return platform_driver_register(&intel_reset_driver);
 253 }
 254
 255 /*
 256  * RCU is system core entity which is in Always On Domain whose clocks
 257  * or resource initialization happens in system core initialization.
 258  * Also, it is required for most of the platform or architecture
 259  * specific devices to perform reset operation as part of initialization.
 260  * So perform RCU as post core initialization.
 261  */
 262 postcore_initcall(intel_reset_init);