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 <[email protected]>
   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 #define to_l2_ctl_dev_attr(_dev_attr) \
  70         container_of(_dev_attr, struct l2_ctl_device_attribute, dev_attr)
  71
  72 #define L2_CTL_ATTR_RW(_name, _prefix, _id) \
  73         struct l2_ctl_device_attribute l2_ctl_attr_##_name = \
  74                 { __ATTR(_name, 0644, _prefix##_show, _prefix##_store), _id }
  75
  76 static int l2_ctl_get_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 *val)
  77 {
  78         u32 data = 0;
  79         int ret;
  80
  81         ret = regmap_read(l2->sys_regs, L2_CTL_REG, &data);
  82         if (ret)
  83                 return ret;
  84
  85         switch (id) {
  86         case L2_WS_STALL:
  87                 *val = FIELD_GET(L2_CTL_WS_STALL_MASK, data);
  88                 break;
  89         case L2_TAG_STALL:
  90                 *val = FIELD_GET(L2_CTL_TAG_STALL_MASK, data);
  91                 break;
  92         case L2_DATA_STALL:
  93                 *val = FIELD_GET(L2_CTL_DATA_STALL_MASK, data);
  94                 break;
  95         default:
  96                 return -EINVAL;
  97         }
  98
  99         return 0;
 100 }
 101
 102 static int l2_ctl_set_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 val)
 103 {
 104         u32 mask = 0, data = 0;
 105         int ret;
 106
 107         val = clamp_val(val, L2_CTL_STALL_MIN, L2_CTL_STALL_MAX);
 108
 109         switch (id) {
 110         case L2_WS_STALL:
 111                 data = FIELD_PREP(L2_CTL_WS_STALL_MASK, val);
 112                 mask = L2_CTL_WS_STALL_MASK;
 113                 break;
 114         case L2_TAG_STALL:
 115                 data = FIELD_PREP(L2_CTL_TAG_STALL_MASK, val);
 116                 mask = L2_CTL_TAG_STALL_MASK;
 117                 break;
 118         case L2_DATA_STALL:
 119                 data = FIELD_PREP(L2_CTL_DATA_STALL_MASK, val);
 120                 mask = L2_CTL_DATA_STALL_MASK;
 121                 break;
 122         default:
 123                 return -EINVAL;
 124         }
 125
 126         data |= L2_CTL_SET_CLKRATIO;
 127         mask |= L2_CTL_SET_CLKRATIO;
 128
 129         ret = regmap_update_bits(l2->sys_regs, L2_CTL_REG, mask, data);
 130         if (ret)
 131                 return ret;
 132
 133         return regmap_read_poll_timeout(l2->sys_regs, L2_CTL_REG, data,
 134                                         data & L2_CTL_CLKRATIO_LOCK,
 135                                         L2_CTL_STALL_SET_DELAY_US,
 136                                         L2_CTL_STALL_SET_TOUT_US);
 137 }
 138
 139 static void l2_ctl_clear_data(void *data)
 140 {
 141         struct l2_ctl *l2 = data;
 142         struct platform_device *pdev = to_platform_device(l2->dev);
 143
 144         platform_set_drvdata(pdev, NULL);
 145 }
 146
 147 static struct l2_ctl *l2_ctl_create_data(struct platform_device *pdev)
 148 {
 149         struct device *dev = &pdev->dev;
 150         struct l2_ctl *l2;
 151         int ret;
 152
 153         l2 = devm_kzalloc(dev, sizeof(*l2), GFP_KERNEL);
 154         if (!l2)
 155                 return ERR_PTR(-ENOMEM);
 156
 157         ret = devm_add_action(dev, l2_ctl_clear_data, l2);
 158         if (ret) {
 159                 dev_err(dev, "Can't add L2 CTL data clear action\n");
 160                 return ERR_PTR(ret);
 161         }
 162
 163         l2->dev = dev;
 164         platform_set_drvdata(pdev, l2);
 165
 166         return l2;
 167 }
 168
 169 static int l2_ctl_find_sys_regs(struct l2_ctl *l2)
 170 {
 171         l2->sys_regs = syscon_node_to_regmap(l2->dev->of_node->parent);
 172         if (IS_ERR(l2->sys_regs)) {
 173                 dev_err(l2->dev, "Couldn't get L2 CTL register map\n");
 174                 return PTR_ERR(l2->sys_regs);
 175         }
 176
 177         return 0;
 178 }
 179
 180 static int l2_ctl_of_parse_property(struct l2_ctl *l2, enum l2_ctl_stall id,
 181                                     const char *propname)
 182 {
 183         int ret = 0;
 184         u32 data;
 185
 186         if (!of_property_read_u32(l2->dev->of_node, propname, &data)) {
 187                 ret = l2_ctl_set_latency(l2, id, data);
 188                 if (ret)
 189                         dev_err(l2->dev, "Invalid value of '%s'\n", propname);
 190         }
 191
 192         return ret;
 193 }
 194
 195 static int l2_ctl_of_parse(struct l2_ctl *l2)
 196 {
 197         int ret;
 198
 199         ret = l2_ctl_of_parse_property(l2, L2_WS_STALL, "baikal,l2-ws-latency");
 200         if (ret)
 201                 return ret;
 202
 203         ret = l2_ctl_of_parse_property(l2, L2_TAG_STALL, "baikal,l2-tag-latency");
 204         if (ret)
 205                 return ret;
 206
 207         return l2_ctl_of_parse_property(l2, L2_DATA_STALL,
 208                                         "baikal,l2-data-latency");
 209 }
 210
 211 static ssize_t l2_ctl_latency_show(struct device *dev,
 212                                    struct device_attribute *attr,
 213                                    char *buf)
 214 {
 215         struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
 216         struct l2_ctl *l2 = dev_get_drvdata(dev);
 217         u32 data;
 218         int ret;
 219
 220         ret = l2_ctl_get_latency(l2, devattr->id, &data);
 221         if (ret)
 222                 return ret;
 223
 224         return scnprintf(buf, PAGE_SIZE, "%u\n", data);
 225 }
 226
 227 static ssize_t l2_ctl_latency_store(struct device *dev,
 228                                     struct device_attribute *attr,
 229                                     const char *buf, size_t count)
 230 {
 231         struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
 232         struct l2_ctl *l2 = dev_get_drvdata(dev);
 233         u32 data;
 234         int ret;
 235
 236         if (kstrtouint(buf, 0, &data) < 0)
 237                 return -EINVAL;
 238
 239         ret = l2_ctl_set_latency(l2, devattr->id, data);
 240         if (ret)
 241                 return ret;
 242
 243         return count;
 244 }
 245 static L2_CTL_ATTR_RW(l2_ws_latency, l2_ctl_latency, L2_WS_STALL);
 246 static L2_CTL_ATTR_RW(l2_tag_latency, l2_ctl_latency, L2_TAG_STALL);
 247 static L2_CTL_ATTR_RW(l2_data_latency, l2_ctl_latency, L2_DATA_STALL);
 248
 249 static struct attribute *l2_ctl_sysfs_attrs[] = {
 250         &l2_ctl_attr_l2_ws_latency.dev_attr.attr,
 251         &l2_ctl_attr_l2_tag_latency.dev_attr.attr,
 252         &l2_ctl_attr_l2_data_latency.dev_attr.attr,
 253         NULL
 254 };
 255 ATTRIBUTE_GROUPS(l2_ctl_sysfs);
 256
 257 static void l2_ctl_remove_sysfs(void *data)
 258 {
 259         struct l2_ctl *l2 = data;
 260
 261         device_remove_groups(l2->dev, l2_ctl_sysfs_groups);
 262 }
 263
 264 static int l2_ctl_init_sysfs(struct l2_ctl *l2)
 265 {
 266         int ret;
 267
 268         ret = device_add_groups(l2->dev, l2_ctl_sysfs_groups);
 269         if (ret) {
 270                 dev_err(l2->dev, "Failed to create L2 CTL sysfs nodes\n");
 271                 return ret;
 272         }
 273
 274         ret = devm_add_action_or_reset(l2->dev, l2_ctl_remove_sysfs, l2);
 275         if (ret)
 276                 dev_err(l2->dev, "Can't add L2 CTL sysfs remove action\n");
 277
 278         return ret;
 279 }
 280
 281 static int l2_ctl_probe(struct platform_device *pdev)
 282 {
 283         struct l2_ctl *l2;
 284         int ret;
 285
 286         l2 = l2_ctl_create_data(pdev);
 287         if (IS_ERR(l2))
 288                 return PTR_ERR(l2);
 289
 290         ret = l2_ctl_find_sys_regs(l2);
 291         if (ret)
 292                 return ret;
 293
 294         ret = l2_ctl_of_parse(l2);
 295         if (ret)
 296                 return ret;
 297
 298         ret = l2_ctl_init_sysfs(l2);
 299         if (ret)
 300                 return ret;
 301
 302         return 0;
 303 }
 304
 305 static const struct of_device_id l2_ctl_of_match[] = {
 306         { .compatible = "baikal,bt1-l2-ctl" },
 307         { }
 308 };
 309 MODULE_DEVICE_TABLE(of, l2_ctl_of_match);
 310
 311 static struct platform_driver l2_ctl_driver = {
 312         .probe = l2_ctl_probe,
 313         .driver = {
 314                 .name = "bt1-l2-ctl",
 315                 .of_match_table = l2_ctl_of_match
 316         }
 317 };
 318 module_platform_driver(l2_ctl_driver);
 319
 320 MODULE_AUTHOR("Serge Semin <[email protected]>");
 321 MODULE_DESCRIPTION("Baikal-T1 L2-cache driver");
 322 MODULE_LICENSE("GPL v2");