xref: /openbmc/linux/drivers/memory/bt1-l2-ctl.c (revision d2456ddb)
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 
l2_ctl_get_latency(struct l2_ctl * l2,enum l2_ctl_stall id,u32 * val)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 
l2_ctl_set_latency(struct l2_ctl * l2,enum l2_ctl_stall id,u32 val)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 
l2_ctl_clear_data(void * data)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 
l2_ctl_create_data(struct platform_device * pdev)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 
l2_ctl_find_sys_regs(struct l2_ctl * l2)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 
l2_ctl_of_parse_property(struct l2_ctl * l2,enum l2_ctl_stall id,const char * propname)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 
l2_ctl_of_parse(struct l2_ctl * l2)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 
l2_ctl_latency_show(struct device * dev,struct device_attribute * attr,char * buf)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 
l2_ctl_latency_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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 
l2_ctl_remove_sysfs(void * data)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 
l2_ctl_init_sysfs(struct l2_ctl * l2)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 
l2_ctl_probe(struct platform_device * pdev)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