linux/drivers/memory/bt1-l2-ctl.c
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   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 */
  42struct 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 */
  54enum 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 */
  65struct 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
  77static 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
 103static 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
 140static 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
 148static 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
 170static 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
 181static 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
 196static 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
 212static 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
 228static 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
 247static L2_CTL_ATTR_RW(l2_ws_latency, l2_ctl_latency, L2_WS_STALL);
 248static L2_CTL_ATTR_RW(l2_tag_latency, l2_ctl_latency, L2_TAG_STALL);
 249static L2_CTL_ATTR_RW(l2_data_latency, l2_ctl_latency, L2_DATA_STALL);
 250
 251static 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};
 257ATTRIBUTE_GROUPS(l2_ctl_sysfs);
 258
 259static 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
 266static 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
 283static 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
 307static const struct of_device_id l2_ctl_of_match[] = {
 308        { .compatible = "baikal,bt1-l2-ctl" },
 309        { }
 310};
 311MODULE_DEVICE_TABLE(of, l2_ctl_of_match);
 312
 313static 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};
 320module_platform_driver(l2_ctl_driver);
 321
 322MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
 323MODULE_DESCRIPTION("Baikal-T1 L2-cache driver");
 324MODULE_LICENSE("GPL v2");
 325