drivers/memory/bt1-l2-ctl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
   4  *
   5  * Authors:
   6  *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
   7  *
   8  * Baikal-T1 CM2 L2-cache Control Block driver.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/bitfield.h>
  14 #include <linux/types.h>
  15 #include <linux/device.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/regmap.h>
  18 #include <linux/mfd/syscon.h>
  19 #include <linux/sysfs.h>
  20 #include <linux/of.h>
  21
  22 #define L2_CTL_REG                      0x028
  23 #define L2_CTL_DATA_STALL_FLD           0
  24 #define L2_CTL_DATA_STALL_MASK          GENMASK(1, L2_CTL_DATA_STALL_FLD)
  25 #define L2_CTL_TAG_STALL_FLD            2
  26 #define L2_CTL_TAG_STALL_MASK           GENMASK(3, L2_CTL_TAG_STALL_FLD)
  27 #define L2_CTL_WS_STALL_FLD             4
  28 #define L2_CTL_WS_STALL_MASK            GENMASK(5, L2_CTL_WS_STALL_FLD)
  29 #define L2_CTL_SET_CLKRATIO             BIT(13)
  30 #define L2_CTL_CLKRATIO_LOCK            BIT(31)
  31
  32 #define L2_CTL_STALL_MIN                0
  33 #define L2_CTL_STALL_MAX                3
  34 #define L2_CTL_STALL_SET_DELAY_US       1
  35 #define L2_CTL_STALL_SET_TOUT_US        1000
  36
  37 /*
  38  * struct l2_ctl - Baikal-T1 L2 Control block private data.
  39  * @dev: Pointer to the device structure.
  40  * @sys_regs: Baikal-T1 System Controller registers map.
  41  */
  42 struct l2_ctl {
  43         struct device *dev;
  44
  45         struct regmap *sys_regs;
  46 };
  47
  48 /*
  49  * enum l2_ctl_stall - Baikal-T1 L2-cache-RAM stall identifier.
  50  * @L2_WSSTALL: Way-select latency.
  51  * @L2_TAGSTALL: Tag latency.
  52  * @L2_DATASTALL: Data latency.
  53  */
  54 enum l2_ctl_stall {
  55         L2_WS_STALL,
  56         L2_TAG_STALL,
  57         L2_DATA_STALL
  58 };
  59
  60 /*
  61  * struct l2_ctl_device_attribute - Baikal-T1 L2-cache device attribute.
  62  * @dev_attr: Actual sysfs device attribute.
  63  * @id: L2-cache stall field identifier.
  64  */
  65 struct l2_ctl_device_attribute {
  66         struct device_attribute dev_attr;
  67         enum l2_ctl_stall id;
  68 };
  69
  70 #define to_l2_ctl_dev_attr(_dev_attr) \
  71         container_of(_dev_attr, struct l2_ctl_device_attribute, dev_attr)
  72
  73 #define L2_CTL_ATTR_RW(_name, _prefix, _id) \
  74         struct l2_ctl_device_attribute l2_ctl_attr_##_name = \
  75                 { __ATTR(_name, 0644, _prefix##_show, _prefix##_store), _id }
  76
  77 static int l2_ctl_get_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 *val)
  78 {
  79         u32 data = 0;
  80         int ret;
  81
  82         ret = regmap_read(l2->sys_regs, L2_CTL_REG, &data);
  83         if (ret)
  84                 return ret;
  85
  86         switch (id) {
  87         case L2_WS_STALL:
  88                 *val = FIELD_GET(L2_CTL_WS_STALL_MASK, data);
  89                 break;
  90         case L2_TAG_STALL:
  91                 *val = FIELD_GET(L2_CTL_TAG_STALL_MASK, data);
  92                 break;
  93         case L2_DATA_STALL:
  94                 *val = FIELD_GET(L2_CTL_DATA_STALL_MASK, data);
  95                 break;
  96         default:
  97                 return -EINVAL;
  98         }
  99
 100         return 0;
 101 }
 102
 103 static int l2_ctl_set_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 val)
 104 {
 105         u32 mask = 0, data = 0;
 106         int ret;
 107
 108         val = clamp_val(val, L2_CTL_STALL_MIN, L2_CTL_STALL_MAX);
 109
 110         switch (id) {
 111         case L2_WS_STALL:
 112                 data = FIELD_PREP(L2_CTL_WS_STALL_MASK, val);
 113                 mask = L2_CTL_WS_STALL_MASK;
 114                 break;
 115         case L2_TAG_STALL:
 116                 data = FIELD_PREP(L2_CTL_TAG_STALL_MASK, val);
 117                 mask = L2_CTL_TAG_STALL_MASK;
 118                 break;
 119         case L2_DATA_STALL:
 120                 data = FIELD_PREP(L2_CTL_DATA_STALL_MASK, val);
 121                 mask = L2_CTL_DATA_STALL_MASK;
 122                 break;
 123         default:
 124                 return -EINVAL;
 125         }
 126
 127         data |= L2_CTL_SET_CLKRATIO;
 128         mask |= L2_CTL_SET_CLKRATIO;
 129
 130         ret = regmap_update_bits(l2->sys_regs, L2_CTL_REG, mask, data);
 131         if (ret)
 132                 return ret;
 133
 134         return regmap_read_poll_timeout(l2->sys_regs, L2_CTL_REG, data,
 135                                         data & L2_CTL_CLKRATIO_LOCK,
 136                                         L2_CTL_STALL_SET_DELAY_US,
 137                                         L2_CTL_STALL_SET_TOUT_US);
 138 }
 139
 140 static void l2_ctl_clear_data(void *data)
 141 {
 142         struct l2_ctl *l2 = data;
 143         struct platform_device *pdev = to_platform_device(l2->dev);
 144
 145         platform_set_drvdata(pdev, NULL);
 146 }
 147
 148 static struct l2_ctl *l2_ctl_create_data(struct platform_device *pdev)
 149 {
 150         struct device *dev = &pdev->dev;
 151         struct l2_ctl *l2;
 152         int ret;
 153
 154         l2 = devm_kzalloc(dev, sizeof(*l2), GFP_KERNEL);
 155         if (!l2)
 156                 return ERR_PTR(-ENOMEM);
 157
 158         ret = devm_add_action(dev, l2_ctl_clear_data, l2);
 159         if (ret) {
 160                 dev_err(dev, "Can't add L2 CTL data clear action\n");
 161                 return ERR_PTR(ret);
 162         }
 163
 164         l2->dev = dev;
 165         platform_set_drvdata(pdev, l2);
 166
 167         return l2;
 168 }
 169
 170 static int l2_ctl_find_sys_regs(struct l2_ctl *l2)
 171 {
 172         l2->sys_regs = syscon_node_to_regmap(l2->dev->of_node->parent);
 173         if (IS_ERR(l2->sys_regs)) {
 174                 dev_err(l2->dev, "Couldn't get L2 CTL register map\n");
 175                 return PTR_ERR(l2->sys_regs);
 176         }
 177
 178         return 0;
 179 }
 180
 181 static int l2_ctl_of_parse_property(struct l2_ctl *l2, enum l2_ctl_stall id,
 182                                     const char *propname)
 183 {
 184         int ret = 0;
 185         u32 data;
 186
 187         if (!of_property_read_u32(l2->dev->of_node, propname, &data)) {
 188                 ret = l2_ctl_set_latency(l2, id, data);
 189                 if (ret)
 190                         dev_err(l2->dev, "Invalid value of '%s'\n", propname);
 191         }
 192
 193         return ret;
 194 }
 195
 196 static int l2_ctl_of_parse(struct l2_ctl *l2)
 197 {
 198         int ret;
 199
 200         ret = l2_ctl_of_parse_property(l2, L2_WS_STALL, "baikal,l2-ws-latency");
 201         if (ret)
 202                 return ret;
 203
 204         ret = l2_ctl_of_parse_property(l2, L2_TAG_STALL, "baikal,l2-tag-latency");
 205         if (ret)
 206                 return ret;
 207
 208         return l2_ctl_of_parse_property(l2, L2_DATA_STALL,
 209                                         "baikal,l2-data-latency");
 210 }
 211
 212 static ssize_t l2_ctl_latency_show(struct device *dev,
 213                                    struct device_attribute *attr,
 214                                    char *buf)
 215 {
 216         struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
 217         struct l2_ctl *l2 = dev_get_drvdata(dev);
 218         u32 data;
 219         int ret;
 220
 221         ret = l2_ctl_get_latency(l2, devattr->id, &data);
 222         if (ret)
 223                 return ret;
 224
 225         return scnprintf(buf, PAGE_SIZE, "%u\n", data);
 226 }
 227
 228 static ssize_t l2_ctl_latency_store(struct device *dev,
 229                                     struct device_attribute *attr,
 230                                     const char *buf, size_t count)
 231 {
 232         struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
 233         struct l2_ctl *l2 = dev_get_drvdata(dev);
 234         u32 data;
 235         int ret;
 236
 237         if (kstrtouint(buf, 0, &data) < 0)
 238                 return -EINVAL;
 239
 240         ret = l2_ctl_set_latency(l2, devattr->id, data);
 241         if (ret)
 242                 return ret;
 243
 244         return count;
 245 }
 246
 247 static L2_CTL_ATTR_RW(l2_ws_latency, l2_ctl_latency, L2_WS_STALL);
 248 static L2_CTL_ATTR_RW(l2_tag_latency, l2_ctl_latency, L2_TAG_STALL);
 249 static L2_CTL_ATTR_RW(l2_data_latency, l2_ctl_latency, L2_DATA_STALL);
 250
 251 static struct attribute *l2_ctl_sysfs_attrs[] = {
 252         &l2_ctl_attr_l2_ws_latency.dev_attr.attr,
 253         &l2_ctl_attr_l2_tag_latency.dev_attr.attr,
 254         &l2_ctl_attr_l2_data_latency.dev_attr.attr,
 255         NULL
 256 };
 257 ATTRIBUTE_GROUPS(l2_ctl_sysfs);
 258
 259 static void l2_ctl_remove_sysfs(void *data)
 260 {
 261         struct l2_ctl *l2 = data;
 262
 263         device_remove_groups(l2->dev, l2_ctl_sysfs_groups);
 264 }
 265
 266 static int l2_ctl_init_sysfs(struct l2_ctl *l2)
 267 {
 268         int ret;
 269
 270         ret = device_add_groups(l2->dev, l2_ctl_sysfs_groups);
 271         if (ret) {
 272                 dev_err(l2->dev, "Failed to create L2 CTL sysfs nodes\n");
 273                 return ret;
 274         }
 275
 276         ret = devm_add_action_or_reset(l2->dev, l2_ctl_remove_sysfs, l2);
 277         if (ret)
 278                 dev_err(l2->dev, "Can't add L2 CTL sysfs remove action\n");
 279
 280         return ret;
 281 }
 282
 283 static int l2_ctl_probe(struct platform_device *pdev)
 284 {
 285         struct l2_ctl *l2;
 286         int ret;
 287
 288         l2 = l2_ctl_create_data(pdev);
 289         if (IS_ERR(l2))
 290                 return PTR_ERR(l2);
 291
 292         ret = l2_ctl_find_sys_regs(l2);
 293         if (ret)
 294                 return ret;
 295
 296         ret = l2_ctl_of_parse(l2);
 297         if (ret)
 298                 return ret;
 299
 300         ret = l2_ctl_init_sysfs(l2);
 301         if (ret)
 302                 return ret;
 303
 304         return 0;
 305 }
 306
 307 static const struct of_device_id l2_ctl_of_match[] = {
 308         { .compatible = "baikal,bt1-l2-ctl" },
 309         { }
 310 };
 311 MODULE_DEVICE_TABLE(of, l2_ctl_of_match);
 312
 313 static struct platform_driver l2_ctl_driver = {
 314         .probe = l2_ctl_probe,
 315         .driver = {
 316                 .name = "bt1-l2-ctl",
 317                 .of_match_table = l2_ctl_of_match
 318         }
 319 };
 320 module_platform_driver(l2_ctl_driver);
 321
 322 MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
 323 MODULE_DESCRIPTION("Baikal-T1 L2-cache driver");
 324 MODULE_LICENSE("GPL v2");