Linux 5.15-rc6
[muen/linux.git] / 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");