1/*
  2 * Match running platform with pre-defined OPP values for CPUFreq
  3 *
  4 * Author: Ajit Pal Singh <ajitpal.singh@st.com>
  5 *         Lee Jones <lee.jones@linaro.org>
  6 *
  7 * Copyright (C) 2015 STMicroelectronics (R&D) Limited
  8 *
  9 * This program is free software; you can redistribute it and/or modify
 10 * it under the terms of the version 2 of the GNU General Public License as
 11 * published by the Free Software Foundation
 12 */
 13
 14#include <linux/cpu.h>
 15#include <linux/io.h>
 16#include <linux/mfd/syscon.h>
 17#include <linux/module.h>
 18#include <linux/of.h>
 19#include <linux/of_platform.h>
 20#include <linux/pm_opp.h>
 21#include <linux/regmap.h>
 22
 23#define VERSION_ELEMENTS	3
 24#define MAX_PCODE_NAME_LEN	7
 25
 26#define VERSION_SHIFT		28
 27#define HW_INFO_INDEX		1
 28#define MAJOR_ID_INDEX		1
 29#define MINOR_ID_INDEX		2
 30
 31/*
 32 * Only match on "suitable for ALL versions" entries
 33 *
 34 * This will be used with the BIT() macro.  It sets the
 35 * top bit of a 32bit value and is equal to 0x80000000.
 36 */
 37#define DEFAULT_VERSION		31
 38
 39enum {
 40	PCODE = 0,
 41	SUBSTRATE,
 42	DVFS_MAX_REGFIELDS,
 43};
 44
 45/**
 46 * ST CPUFreq Driver Data
 47 *
 48 * @cpu_node		CPU's OF node
 49 * @syscfg_eng		Engineering Syscon register map
 50 * @regmap		Syscon register map
 51 */
 52static struct sti_cpufreq_ddata {
 53	struct device *cpu;
 54	struct regmap *syscfg_eng;
 55	struct regmap *syscfg;
 56} ddata;
 57
 58static int sti_cpufreq_fetch_major(void) {
 59	struct device_node *np = ddata.cpu->of_node;
 60	struct device *dev = ddata.cpu;
 61	unsigned int major_offset;
 62	unsigned int socid;
 63	int ret;
 64
 65	ret = of_property_read_u32_index(np, "st,syscfg",
 66					 MAJOR_ID_INDEX, &major_offset);
 67	if (ret) {
 68		dev_err(dev, "No major number offset provided in %s [%d]\n",
 69			np->full_name, ret);
 70		return ret;
 71	}
 72
 73	ret = regmap_read(ddata.syscfg, major_offset, &socid);
 74	if (ret) {
 75		dev_err(dev, "Failed to read major number from syscon [%d]\n",
 76			ret);
 77		return ret;
 78	}
 79
 80	return ((socid >> VERSION_SHIFT) & 0xf) + 1;
 81}
 82
 83static int sti_cpufreq_fetch_minor(void)
 84{
 85	struct device *dev = ddata.cpu;
 86	struct device_node *np = dev->of_node;
 87	unsigned int minor_offset;
 88	unsigned int minid;
 89	int ret;
 90
 91	ret = of_property_read_u32_index(np, "st,syscfg-eng",
 92					 MINOR_ID_INDEX, &minor_offset);
 93	if (ret) {
 94		dev_err(dev,
 95			"No minor number offset provided %s [%d]\n",
 96			np->full_name, ret);
 97		return ret;
 98	}
 99
100	ret = regmap_read(ddata.syscfg_eng, minor_offset, &minid);
101	if (ret) {
102		dev_err(dev,
103			"Failed to read the minor number from syscon [%d]\n",
104			ret);
105		return ret;
106	}
107
108	return minid & 0xf;
109}
110
111static int sti_cpufreq_fetch_regmap_field(const struct reg_field *reg_fields,
112					  int hw_info_offset, int field)
113{
114	struct regmap_field *regmap_field;
115	struct reg_field reg_field = reg_fields[field];
116	struct device *dev = ddata.cpu;
117	unsigned int value;
118	int ret;
119
120	reg_field.reg = hw_info_offset;
121	regmap_field = devm_regmap_field_alloc(dev,
122					       ddata.syscfg_eng,
123					       reg_field);
124	if (IS_ERR(regmap_field)) {
125		dev_err(dev, "Failed to allocate reg field\n");
126		return PTR_ERR(regmap_field);
127	}
128
129	ret = regmap_field_read(regmap_field, &value);
130	if (ret) {
131		dev_err(dev, "Failed to read %s code\n",
132			field ? "SUBSTRATE" : "PCODE");
133		return ret;
134	}
135
136	return value;
137}
138
139static const struct reg_field sti_stih407_dvfs_regfields[DVFS_MAX_REGFIELDS] = {
140	[PCODE]		= REG_FIELD(0, 16, 19),
141	[SUBSTRATE]	= REG_FIELD(0, 0, 2),
142};
143
144static const struct reg_field *sti_cpufreq_match(void)
145{
146	if (of_machine_is_compatible("st,stih407") ||
147	    of_machine_is_compatible("st,stih410"))
148		return sti_stih407_dvfs_regfields;
149
150	return NULL;
151}
152
153static int sti_cpufreq_set_opp_info(void)
154{
155	struct device *dev = ddata.cpu;
156	struct device_node *np = dev->of_node;
157	const struct reg_field *reg_fields;
158	unsigned int hw_info_offset;
159	unsigned int version[VERSION_ELEMENTS];
160	int pcode, substrate, major, minor;
161	int ret;
162	char name[MAX_PCODE_NAME_LEN];
163
164	reg_fields = sti_cpufreq_match();
165	if (!reg_fields) {
166		dev_err(dev, "This SoC doesn't support voltage scaling\n");
167		return -ENODEV;
168	}
169
170	ret = of_property_read_u32_index(np, "st,syscfg-eng",
171					 HW_INFO_INDEX, &hw_info_offset);
172	if (ret) {
173		dev_warn(dev, "Failed to read HW info offset from DT\n");
174		substrate = DEFAULT_VERSION;
175		pcode = 0;
176		goto use_defaults;
177	}
178
179	pcode = sti_cpufreq_fetch_regmap_field(reg_fields,
180					       hw_info_offset,
181					       PCODE);
182	if (pcode < 0) {
183		dev_warn(dev, "Failed to obtain process code\n");
184		/* Use default pcode */
185		pcode = 0;
186	}
187
188	substrate = sti_cpufreq_fetch_regmap_field(reg_fields,
189						   hw_info_offset,
190						   SUBSTRATE);
191	if (substrate) {
192		dev_warn(dev, "Failed to obtain substrate code\n");
193		/* Use default substrate */
194		substrate = DEFAULT_VERSION;
195	}
196
197use_defaults:
198	major = sti_cpufreq_fetch_major();
199	if (major < 0) {
200		dev_err(dev, "Failed to obtain major version\n");
201		/* Use default major number */
202		major = DEFAULT_VERSION;
203	}
204
205	minor = sti_cpufreq_fetch_minor();
206	if (minor < 0) {
207		dev_err(dev, "Failed to obtain minor version\n");
208		/* Use default minor number */
209		minor = DEFAULT_VERSION;
210	}
211
212	snprintf(name, MAX_PCODE_NAME_LEN, "pcode%d", pcode);
213
214	ret = dev_pm_opp_set_prop_name(dev, name);
215	if (ret) {
216		dev_err(dev, "Failed to set prop name\n");
217		return ret;
218	}
219
220	version[0] = BIT(major);
221	version[1] = BIT(minor);
222	version[2] = BIT(substrate);
223
224	ret = dev_pm_opp_set_supported_hw(dev, version, VERSION_ELEMENTS);
225	if (ret) {
226		dev_err(dev, "Failed to set supported hardware\n");
227		return ret;
228	}
229
230	dev_dbg(dev, "pcode: %d major: %d minor: %d substrate: %d\n",
231		pcode, major, minor, substrate);
232	dev_dbg(dev, "version[0]: %x version[1]: %x version[2]: %x\n",
233		version[0], version[1], version[2]);
234
235	return 0;
236}
237
238static int sti_cpufreq_fetch_syscon_regsiters(void)
239{
240	struct device *dev = ddata.cpu;
241	struct device_node *np = dev->of_node;
242
243	ddata.syscfg = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
244	if (IS_ERR(ddata.syscfg)) {
245		dev_err(dev,  "\"st,syscfg\" not supplied\n");
246		return PTR_ERR(ddata.syscfg);
247	}
248
249	ddata.syscfg_eng = syscon_regmap_lookup_by_phandle(np, "st,syscfg-eng");
250	if (IS_ERR(ddata.syscfg_eng)) {
251		dev_err(dev, "\"st,syscfg-eng\" not supplied\n");
252		return PTR_ERR(ddata.syscfg_eng);
253	}
254
255	return 0;
256}
257
258static int sti_cpufreq_init(void)
259{
260	int ret;
261
262	if ((!of_machine_is_compatible("st,stih407")) &&
263		(!of_machine_is_compatible("st,stih410")))
264		return -ENODEV;
265
266	ddata.cpu = get_cpu_device(0);
267	if (!ddata.cpu) {
268		dev_err(ddata.cpu, "Failed to get device for CPU0\n");
269		goto skip_voltage_scaling;
270	}
271
272	if (!of_get_property(ddata.cpu->of_node, "operating-points-v2", NULL)) {
273		dev_err(ddata.cpu, "OPP-v2 not supported\n");
274		goto skip_voltage_scaling;
275	}
276
277	ret = sti_cpufreq_fetch_syscon_regsiters();
278	if (ret)
279		goto skip_voltage_scaling;
280
281	ret = sti_cpufreq_set_opp_info();
282	if (!ret)
283		goto register_cpufreq_dt;
284
285skip_voltage_scaling:
286	dev_err(ddata.cpu, "Not doing voltage scaling\n");
287
288register_cpufreq_dt:
289	platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
290
291	return 0;
292}
293module_init(sti_cpufreq_init);
294
295MODULE_DESCRIPTION("STMicroelectronics CPUFreq/OPP driver");
296MODULE_AUTHOR("Ajitpal Singh <ajitpal.singh@st.com>");
297MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
298MODULE_LICENSE("GPL v2");