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");