1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * DDR Self-Refresh Power Down (SRPD) support for Broadcom STB SoCs |
4 | * |
5 | */ |
6 | |
7 | #include <linux/init.h> |
8 | #include <linux/io.h> |
9 | #include <linux/kernel.h> |
10 | #include <linux/module.h> |
11 | #include <linux/of.h> |
12 | #include <linux/platform_device.h> |
13 | #include <linux/property.h> |
14 | |
15 | #define REG_MEMC_CNTRLR_CONFIG 0x00 |
16 | #define CNTRLR_CONFIG_LPDDR4_SHIFT 5 |
17 | #define CNTRLR_CONFIG_MASK 0xf |
18 | #define REG_MEMC_SRPD_CFG_21 0x20 |
19 | #define REG_MEMC_SRPD_CFG_20 0x34 |
20 | #define REG_MEMC_SRPD_CFG_1x 0x3c |
21 | #define INACT_COUNT_SHIFT 0 |
22 | #define INACT_COUNT_MASK 0xffff |
23 | #define SRPD_EN_SHIFT 16 |
24 | |
25 | struct brcmstb_memc_data { |
26 | u32 srpd_offset; |
27 | }; |
28 | |
29 | struct brcmstb_memc { |
30 | struct device *dev; |
31 | void __iomem *ddr_ctrl; |
32 | unsigned int timeout_cycles; |
33 | u32 frequency; |
34 | u32 srpd_offset; |
35 | }; |
36 | |
37 | static int brcmstb_memc_uses_lpddr4(struct brcmstb_memc *memc) |
38 | { |
39 | void __iomem *config = memc->ddr_ctrl + REG_MEMC_CNTRLR_CONFIG; |
40 | u32 reg; |
41 | |
42 | reg = readl_relaxed(config) & CNTRLR_CONFIG_MASK; |
43 | |
44 | return reg == CNTRLR_CONFIG_LPDDR4_SHIFT; |
45 | } |
46 | |
47 | static int brcmstb_memc_srpd_config(struct brcmstb_memc *memc, |
48 | unsigned int cycles) |
49 | { |
50 | void __iomem *cfg = memc->ddr_ctrl + memc->srpd_offset; |
51 | u32 val; |
52 | |
53 | /* Max timeout supported in HW */ |
54 | if (cycles > INACT_COUNT_MASK) |
55 | return -EINVAL; |
56 | |
57 | memc->timeout_cycles = cycles; |
58 | |
59 | val = (cycles << INACT_COUNT_SHIFT) & INACT_COUNT_MASK; |
60 | if (cycles) |
61 | val |= BIT(SRPD_EN_SHIFT); |
62 | |
63 | writel_relaxed(val, cfg); |
64 | /* Ensure the write is committed to the controller */ |
65 | (void)readl_relaxed(cfg); |
66 | |
67 | return 0; |
68 | } |
69 | |
70 | static ssize_t frequency_show(struct device *dev, |
71 | struct device_attribute *attr, char *buf) |
72 | { |
73 | struct brcmstb_memc *memc = dev_get_drvdata(dev); |
74 | |
75 | return sprintf(buf, fmt: "%d\n" , memc->frequency); |
76 | } |
77 | |
78 | static ssize_t srpd_show(struct device *dev, |
79 | struct device_attribute *attr, char *buf) |
80 | { |
81 | struct brcmstb_memc *memc = dev_get_drvdata(dev); |
82 | |
83 | return sprintf(buf, fmt: "%d\n" , memc->timeout_cycles); |
84 | } |
85 | |
86 | static ssize_t srpd_store(struct device *dev, struct device_attribute *attr, |
87 | const char *buf, size_t count) |
88 | { |
89 | struct brcmstb_memc *memc = dev_get_drvdata(dev); |
90 | unsigned int val; |
91 | int ret; |
92 | |
93 | /* |
94 | * Cannot change the inactivity timeout on LPDDR4 chips because the |
95 | * dynamic tuning process will also get affected by the inactivity |
96 | * timeout, thus making it non functional. |
97 | */ |
98 | if (brcmstb_memc_uses_lpddr4(memc)) |
99 | return -EOPNOTSUPP; |
100 | |
101 | ret = kstrtouint(s: buf, base: 10, res: &val); |
102 | if (ret < 0) |
103 | return ret; |
104 | |
105 | ret = brcmstb_memc_srpd_config(memc, cycles: val); |
106 | if (ret) |
107 | return ret; |
108 | |
109 | return count; |
110 | } |
111 | |
112 | static DEVICE_ATTR_RO(frequency); |
113 | static DEVICE_ATTR_RW(srpd); |
114 | |
115 | static struct attribute *dev_attrs[] = { |
116 | &dev_attr_frequency.attr, |
117 | &dev_attr_srpd.attr, |
118 | NULL, |
119 | }; |
120 | |
121 | static struct attribute_group dev_attr_group = { |
122 | .attrs = dev_attrs, |
123 | }; |
124 | |
125 | static int brcmstb_memc_probe(struct platform_device *pdev) |
126 | { |
127 | const struct brcmstb_memc_data *memc_data; |
128 | struct device *dev = &pdev->dev; |
129 | struct brcmstb_memc *memc; |
130 | int ret; |
131 | |
132 | memc = devm_kzalloc(dev, size: sizeof(*memc), GFP_KERNEL); |
133 | if (!memc) |
134 | return -ENOMEM; |
135 | |
136 | dev_set_drvdata(dev, data: memc); |
137 | |
138 | memc_data = device_get_match_data(dev); |
139 | memc->srpd_offset = memc_data->srpd_offset; |
140 | |
141 | memc->ddr_ctrl = devm_platform_ioremap_resource(pdev, index: 0); |
142 | if (IS_ERR(ptr: memc->ddr_ctrl)) |
143 | return PTR_ERR(ptr: memc->ddr_ctrl); |
144 | |
145 | of_property_read_u32(np: pdev->dev.of_node, propname: "clock-frequency" , |
146 | out_value: &memc->frequency); |
147 | |
148 | ret = sysfs_create_group(kobj: &dev->kobj, grp: &dev_attr_group); |
149 | if (ret) |
150 | return ret; |
151 | |
152 | return 0; |
153 | } |
154 | |
155 | static int brcmstb_memc_remove(struct platform_device *pdev) |
156 | { |
157 | struct device *dev = &pdev->dev; |
158 | |
159 | sysfs_remove_group(kobj: &dev->kobj, grp: &dev_attr_group); |
160 | |
161 | return 0; |
162 | } |
163 | |
164 | enum brcmstb_memc_hwtype { |
165 | BRCMSTB_MEMC_V21, |
166 | BRCMSTB_MEMC_V20, |
167 | BRCMSTB_MEMC_V1X, |
168 | }; |
169 | |
170 | static const struct brcmstb_memc_data brcmstb_memc_versions[] = { |
171 | { .srpd_offset = REG_MEMC_SRPD_CFG_21 }, |
172 | { .srpd_offset = REG_MEMC_SRPD_CFG_20 }, |
173 | { .srpd_offset = REG_MEMC_SRPD_CFG_1x }, |
174 | }; |
175 | |
176 | static const struct of_device_id brcmstb_memc_of_match[] = { |
177 | { |
178 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.1.x" , |
179 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V1X] |
180 | }, |
181 | { |
182 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.0" , |
183 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V20] |
184 | }, |
185 | { |
186 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.1" , |
187 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
188 | }, |
189 | { |
190 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.2" , |
191 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
192 | }, |
193 | { |
194 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.3" , |
195 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
196 | }, |
197 | { |
198 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.5" , |
199 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
200 | }, |
201 | { |
202 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.6" , |
203 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
204 | }, |
205 | { |
206 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.7" , |
207 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
208 | }, |
209 | { |
210 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.8" , |
211 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
212 | }, |
213 | { |
214 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.3.0" , |
215 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
216 | }, |
217 | { |
218 | .compatible = "brcm,brcmstb-memc-ddr-rev-b.3.1" , |
219 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
220 | }, |
221 | { |
222 | .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.0" , |
223 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
224 | }, |
225 | { |
226 | .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.1" , |
227 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
228 | }, |
229 | { |
230 | .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.2" , |
231 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
232 | }, |
233 | { |
234 | .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.3" , |
235 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
236 | }, |
237 | { |
238 | .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.4" , |
239 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21] |
240 | }, |
241 | /* default to the original offset */ |
242 | { |
243 | .compatible = "brcm,brcmstb-memc-ddr" , |
244 | .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V1X] |
245 | }, |
246 | {} |
247 | }; |
248 | |
249 | static int brcmstb_memc_suspend(struct device *dev) |
250 | { |
251 | struct brcmstb_memc *memc = dev_get_drvdata(dev); |
252 | void __iomem *cfg = memc->ddr_ctrl + memc->srpd_offset; |
253 | u32 val; |
254 | |
255 | if (memc->timeout_cycles == 0) |
256 | return 0; |
257 | |
258 | /* |
259 | * Disable SRPD prior to suspending the system since that can |
260 | * cause issues with other memory clients managed by the ARM |
261 | * trusted firmware to access memory. |
262 | */ |
263 | val = readl_relaxed(cfg); |
264 | val &= ~BIT(SRPD_EN_SHIFT); |
265 | writel_relaxed(val, cfg); |
266 | /* Ensure the write is committed to the controller */ |
267 | (void)readl_relaxed(cfg); |
268 | |
269 | return 0; |
270 | } |
271 | |
272 | static int brcmstb_memc_resume(struct device *dev) |
273 | { |
274 | struct brcmstb_memc *memc = dev_get_drvdata(dev); |
275 | |
276 | if (memc->timeout_cycles == 0) |
277 | return 0; |
278 | |
279 | return brcmstb_memc_srpd_config(memc, cycles: memc->timeout_cycles); |
280 | } |
281 | |
282 | static DEFINE_SIMPLE_DEV_PM_OPS(brcmstb_memc_pm_ops, brcmstb_memc_suspend, |
283 | brcmstb_memc_resume); |
284 | |
285 | static struct platform_driver brcmstb_memc_driver = { |
286 | .probe = brcmstb_memc_probe, |
287 | .remove = brcmstb_memc_remove, |
288 | .driver = { |
289 | .name = "brcmstb_memc" , |
290 | .of_match_table = brcmstb_memc_of_match, |
291 | .pm = pm_ptr(&brcmstb_memc_pm_ops), |
292 | }, |
293 | }; |
294 | module_platform_driver(brcmstb_memc_driver); |
295 | |
296 | MODULE_LICENSE("GPL" ); |
297 | MODULE_AUTHOR("Broadcom" ); |
298 | MODULE_DESCRIPTION("DDR SRPD driver for Broadcom STB chips" ); |
299 | |