drivers/memory/bt1-l2-ctl.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
0004  *
0005  * Authors:
0006  *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
0007  *
0008  * Baikal-T1 CM2 L2-cache Control Block driver.
0009  */
0010
0011 #include <linux/kernel.h>
0012 #include <linux/module.h>
0013 #include <linux/bitfield.h>
0014 #include <linux/types.h>
0015 #include <linux/device.h>
0016 #include <linux/platform_device.h>
0017 #include <linux/regmap.h>
0018 #include <linux/mfd/syscon.h>
0019 #include <linux/sysfs.h>
0020 #include <linux/of.h>
0021
0022 #define L2_CTL_REG          0x028
0023 #define L2_CTL_DATA_STALL_FLD       0
0024 #define L2_CTL_DATA_STALL_MASK      GENMASK(1, L2_CTL_DATA_STALL_FLD)
0025 #define L2_CTL_TAG_STALL_FLD        2
0026 #define L2_CTL_TAG_STALL_MASK       GENMASK(3, L2_CTL_TAG_STALL_FLD)
0027 #define L2_CTL_WS_STALL_FLD     4
0028 #define L2_CTL_WS_STALL_MASK        GENMASK(5, L2_CTL_WS_STALL_FLD)
0029 #define L2_CTL_SET_CLKRATIO     BIT(13)
0030 #define L2_CTL_CLKRATIO_LOCK        BIT(31)
0031
0032 #define L2_CTL_STALL_MIN        0
0033 #define L2_CTL_STALL_MAX        3
0034 #define L2_CTL_STALL_SET_DELAY_US   1
0035 #define L2_CTL_STALL_SET_TOUT_US    1000
0036
0037 /*
0038  * struct l2_ctl - Baikal-T1 L2 Control block private data.
0039  * @dev: Pointer to the device structure.
0040  * @sys_regs: Baikal-T1 System Controller registers map.
0041  */
0042 struct l2_ctl {
0043     struct device *dev;
0044
0045     struct regmap *sys_regs;
0046 };
0047
0048 /*
0049  * enum l2_ctl_stall - Baikal-T1 L2-cache-RAM stall identifier.
0050  * @L2_WSSTALL: Way-select latency.
0051  * @L2_TAGSTALL: Tag latency.
0052  * @L2_DATASTALL: Data latency.
0053  */
0054 enum l2_ctl_stall {
0055     L2_WS_STALL,
0056     L2_TAG_STALL,
0057     L2_DATA_STALL
0058 };
0059
0060 /*
0061  * struct l2_ctl_device_attribute - Baikal-T1 L2-cache device attribute.
0062  * @dev_attr: Actual sysfs device attribute.
0063  * @id: L2-cache stall field identifier.
0064  */
0065 struct l2_ctl_device_attribute {
0066     struct device_attribute dev_attr;
0067     enum l2_ctl_stall id;
0068 };
0069
0070 #define to_l2_ctl_dev_attr(_dev_attr) \
0071     container_of(_dev_attr, struct l2_ctl_device_attribute, dev_attr)
0072
0073 #define L2_CTL_ATTR_RW(_name, _prefix, _id) \
0074     struct l2_ctl_device_attribute l2_ctl_attr_##_name = \
0075         { __ATTR(_name, 0644, _prefix##_show, _prefix##_store), _id }
0076
0077 static int l2_ctl_get_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 *val)
0078 {
0079     u32 data = 0;
0080     int ret;
0081
0082     ret = regmap_read(l2->sys_regs, L2_CTL_REG, &data);
0083     if (ret)
0084         return ret;
0085
0086     switch (id) {
0087     case L2_WS_STALL:
0088         *val = FIELD_GET(L2_CTL_WS_STALL_MASK, data);
0089         break;
0090     case L2_TAG_STALL:
0091         *val = FIELD_GET(L2_CTL_TAG_STALL_MASK, data);
0092         break;
0093     case L2_DATA_STALL:
0094         *val = FIELD_GET(L2_CTL_DATA_STALL_MASK, data);
0095         break;
0096     default:
0097         return -EINVAL;
0098     }
0099
0100     return 0;
0101 }
0102
0103 static int l2_ctl_set_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 val)
0104 {
0105     u32 mask = 0, data = 0;
0106     int ret;
0107
0108     val = clamp_val(val, L2_CTL_STALL_MIN, L2_CTL_STALL_MAX);
0109
0110     switch (id) {
0111     case L2_WS_STALL:
0112         data = FIELD_PREP(L2_CTL_WS_STALL_MASK, val);
0113         mask = L2_CTL_WS_STALL_MASK;
0114         break;
0115     case L2_TAG_STALL:
0116         data = FIELD_PREP(L2_CTL_TAG_STALL_MASK, val);
0117         mask = L2_CTL_TAG_STALL_MASK;
0118         break;
0119     case L2_DATA_STALL:
0120         data = FIELD_PREP(L2_CTL_DATA_STALL_MASK, val);
0121         mask = L2_CTL_DATA_STALL_MASK;
0122         break;
0123     default:
0124         return -EINVAL;
0125     }
0126
0127     data |= L2_CTL_SET_CLKRATIO;
0128     mask |= L2_CTL_SET_CLKRATIO;
0129
0130     ret = regmap_update_bits(l2->sys_regs, L2_CTL_REG, mask, data);
0131     if (ret)
0132         return ret;
0133
0134     return regmap_read_poll_timeout(l2->sys_regs, L2_CTL_REG, data,
0135                     data & L2_CTL_CLKRATIO_LOCK,
0136                     L2_CTL_STALL_SET_DELAY_US,
0137                     L2_CTL_STALL_SET_TOUT_US);
0138 }
0139
0140 static void l2_ctl_clear_data(void *data)
0141 {
0142     struct l2_ctl *l2 = data;
0143     struct platform_device *pdev = to_platform_device(l2->dev);
0144
0145     platform_set_drvdata(pdev, NULL);
0146 }
0147
0148 static struct l2_ctl *l2_ctl_create_data(struct platform_device *pdev)
0149 {
0150     struct device *dev = &pdev->dev;
0151     struct l2_ctl *l2;
0152     int ret;
0153
0154     l2 = devm_kzalloc(dev, sizeof(*l2), GFP_KERNEL);
0155     if (!l2)
0156         return ERR_PTR(-ENOMEM);
0157
0158     ret = devm_add_action(dev, l2_ctl_clear_data, l2);
0159     if (ret) {
0160         dev_err(dev, "Can't add L2 CTL data clear action\n");
0161         return ERR_PTR(ret);
0162     }
0163
0164     l2->dev = dev;
0165     platform_set_drvdata(pdev, l2);
0166
0167     return l2;
0168 }
0169
0170 static int l2_ctl_find_sys_regs(struct l2_ctl *l2)
0171 {
0172     l2->sys_regs = syscon_node_to_regmap(l2->dev->of_node->parent);
0173     if (IS_ERR(l2->sys_regs)) {
0174         dev_err(l2->dev, "Couldn't get L2 CTL register map\n");
0175         return PTR_ERR(l2->sys_regs);
0176     }
0177
0178     return 0;
0179 }
0180
0181 static int l2_ctl_of_parse_property(struct l2_ctl *l2, enum l2_ctl_stall id,
0182                     const char *propname)
0183 {
0184     int ret = 0;
0185     u32 data;
0186
0187     if (!of_property_read_u32(l2->dev->of_node, propname, &data)) {
0188         ret = l2_ctl_set_latency(l2, id, data);
0189         if (ret)
0190             dev_err(l2->dev, "Invalid value of '%s'\n", propname);
0191     }
0192
0193     return ret;
0194 }
0195
0196 static int l2_ctl_of_parse(struct l2_ctl *l2)
0197 {
0198     int ret;
0199
0200     ret = l2_ctl_of_parse_property(l2, L2_WS_STALL, "baikal,l2-ws-latency");
0201     if (ret)
0202         return ret;
0203
0204     ret = l2_ctl_of_parse_property(l2, L2_TAG_STALL, "baikal,l2-tag-latency");
0205     if (ret)
0206         return ret;
0207
0208     return l2_ctl_of_parse_property(l2, L2_DATA_STALL,
0209                     "baikal,l2-data-latency");
0210 }
0211
0212 static ssize_t l2_ctl_latency_show(struct device *dev,
0213                    struct device_attribute *attr,
0214                    char *buf)
0215 {
0216     struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
0217     struct l2_ctl *l2 = dev_get_drvdata(dev);
0218     u32 data;
0219     int ret;
0220
0221     ret = l2_ctl_get_latency(l2, devattr->id, &data);
0222     if (ret)
0223         return ret;
0224
0225     return scnprintf(buf, PAGE_SIZE, "%u\n", data);
0226 }
0227
0228 static ssize_t l2_ctl_latency_store(struct device *dev,
0229                     struct device_attribute *attr,
0230                     const char *buf, size_t count)
0231 {
0232     struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
0233     struct l2_ctl *l2 = dev_get_drvdata(dev);
0234     u32 data;
0235     int ret;
0236
0237     if (kstrtouint(buf, 0, &data) < 0)
0238         return -EINVAL;
0239
0240     ret = l2_ctl_set_latency(l2, devattr->id, data);
0241     if (ret)
0242         return ret;
0243
0244     return count;
0245 }
0246
0247 static L2_CTL_ATTR_RW(l2_ws_latency, l2_ctl_latency, L2_WS_STALL);
0248 static L2_CTL_ATTR_RW(l2_tag_latency, l2_ctl_latency, L2_TAG_STALL);
0249 static L2_CTL_ATTR_RW(l2_data_latency, l2_ctl_latency, L2_DATA_STALL);
0250
0251 static struct attribute *l2_ctl_sysfs_attrs[] = {
0252     &l2_ctl_attr_l2_ws_latency.dev_attr.attr,
0253     &l2_ctl_attr_l2_tag_latency.dev_attr.attr,
0254     &l2_ctl_attr_l2_data_latency.dev_attr.attr,
0255     NULL
0256 };
0257 ATTRIBUTE_GROUPS(l2_ctl_sysfs);
0258
0259 static void l2_ctl_remove_sysfs(void *data)
0260 {
0261     struct l2_ctl *l2 = data;
0262
0263     device_remove_groups(l2->dev, l2_ctl_sysfs_groups);
0264 }
0265
0266 static int l2_ctl_init_sysfs(struct l2_ctl *l2)
0267 {
0268     int ret;
0269
0270     ret = device_add_groups(l2->dev, l2_ctl_sysfs_groups);
0271     if (ret) {
0272         dev_err(l2->dev, "Failed to create L2 CTL sysfs nodes\n");
0273         return ret;
0274     }
0275
0276     ret = devm_add_action_or_reset(l2->dev, l2_ctl_remove_sysfs, l2);
0277     if (ret)
0278         dev_err(l2->dev, "Can't add L2 CTL sysfs remove action\n");
0279
0280     return ret;
0281 }
0282
0283 static int l2_ctl_probe(struct platform_device *pdev)
0284 {
0285     struct l2_ctl *l2;
0286     int ret;
0287
0288     l2 = l2_ctl_create_data(pdev);
0289     if (IS_ERR(l2))
0290         return PTR_ERR(l2);
0291
0292     ret = l2_ctl_find_sys_regs(l2);
0293     if (ret)
0294         return ret;
0295
0296     ret = l2_ctl_of_parse(l2);
0297     if (ret)
0298         return ret;
0299
0300     ret = l2_ctl_init_sysfs(l2);
0301     if (ret)
0302         return ret;
0303
0304     return 0;
0305 }
0306
0307 static const struct of_device_id l2_ctl_of_match[] = {
0308     { .compatible = "baikal,bt1-l2-ctl" },
0309     { }
0310 };
0311 MODULE_DEVICE_TABLE(of, l2_ctl_of_match);
0312
0313 static struct platform_driver l2_ctl_driver = {
0314     .probe = l2_ctl_probe,
0315     .driver = {
0316         .name = "bt1-l2-ctl",
0317         .of_match_table = l2_ctl_of_match
0318     }
0319 };
0320 module_platform_driver(l2_ctl_driver);
0321
0322 MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
0323 MODULE_DESCRIPTION("Baikal-T1 L2-cache driver");
0324 MODULE_LICENSE("GPL v2");