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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * R-Car Gen4 SYSC Power management support
4 *
5 * Copyright (C) 2021 Renesas Electronics Corp.
6 */
7
8#include <linux/bits.h>
9#include <linux/clk/renesas.h>
10#include <linux/delay.h>
11#include <linux/err.h>
12#include <linux/io.h>
13#include <linux/iopoll.h>
14#include <linux/kernel.h>
15#include <linux/mm.h>
16#include <linux/of_address.h>
17#include <linux/pm_domain.h>
18#include <linux/slab.h>
19#include <linux/spinlock.h>
20#include <linux/types.h>
21
22#include "rcar-gen4-sysc.h"
23
24/* SYSC Common */
25#define SYSCSR 0x000 /* SYSC Status Register */
26#define SYSCPONSR(x) (0x800 + ((x) * 0x4)) /* Power-ON Status Register 0 */
27#define SYSCPOFFSR(x) (0x808 + ((x) * 0x4)) /* Power-OFF Status Register */
28#define SYSCISCR(x) (0x810 + ((x) * 0x4)) /* Interrupt Status/Clear Register */
29#define SYSCIER(x) (0x820 + ((x) * 0x4)) /* Interrupt Enable Register */
30#define SYSCIMR(x) (0x830 + ((x) * 0x4)) /* Interrupt Mask Register */
31
32/* Power Domain Registers */
33#define PDRSR(n) (0x1000 + ((n) * 0x40))
34#define PDRONCR(n) (0x1004 + ((n) * 0x40))
35#define PDROFFCR(n) (0x1008 + ((n) * 0x40))
36#define PDRESR(n) (0x100C + ((n) * 0x40))
37
38/* PWRON/PWROFF */
39#define PWRON_PWROFF BIT(0) /* Power-ON/OFF request */
40
41/* PDRESR */
42#define PDRESR_ERR BIT(0)
43
44/* PDRSR */
45#define PDRSR_OFF BIT(0) /* Power-OFF state */
46#define PDRSR_ON BIT(4) /* Power-ON state */
47#define PDRSR_OFF_STATE BIT(8) /* Processing Power-OFF sequence */
48#define PDRSR_ON_STATE BIT(12) /* Processing Power-ON sequence */
49
50#define SYSCSR_BUSY GENMASK(1, 0) /* All bit sets is not busy */
51
52#define SYSCSR_TIMEOUT 10000
53#define SYSCSR_DELAY_US 10
54
55#define PDRESR_RETRIES 1000
56#define PDRESR_DELAY_US 10
57
58#define SYSCISR_TIMEOUT 10000
59#define SYSCISR_DELAY_US 10
60
61#define RCAR_GEN4_PD_ALWAYS_ON 64
62#define NUM_DOMAINS_EACH_REG BITS_PER_TYPE(u32)
63
64static void __iomem *rcar_gen4_sysc_base;
65static DEFINE_SPINLOCK(rcar_gen4_sysc_lock); /* SMP CPUs + I/O devices */
66
67static int rcar_gen4_sysc_pwr_on_off(u8 pdr, bool on)
68{
69 unsigned int reg_offs;
70 u32 val;
71 int ret;
72
73 if (on)
74 reg_offs = PDRONCR(pdr);
75 else
76 reg_offs = PDROFFCR(pdr);
77
78 /* Wait until SYSC is ready to accept a power request */
79 ret = readl_poll_timeout_atomic(rcar_gen4_sysc_base + SYSCSR, val,
80 (val & SYSCSR_BUSY) == SYSCSR_BUSY,
81 SYSCSR_DELAY_US, SYSCSR_TIMEOUT);
82 if (ret < 0)
83 return -EAGAIN;
84
85 /* Submit power shutoff or power resume request */
86 iowrite32(PWRON_PWROFF, rcar_gen4_sysc_base + reg_offs);
87
88 return 0;
89}
90
91static int clear_irq_flags(unsigned int reg_idx, unsigned int isr_mask)
92{
93 u32 val;
94 int ret;
95
96 iowrite32(isr_mask, rcar_gen4_sysc_base + SYSCISCR(reg_idx));
97
98 ret = readl_poll_timeout_atomic(rcar_gen4_sysc_base + SYSCISCR(reg_idx),
99 val, !(val & isr_mask),
100 SYSCISR_DELAY_US, SYSCISR_TIMEOUT);
101 if (ret < 0) {
102 pr_err("\n %s : Can not clear IRQ flags in SYSCISCR", __func__);
103 return -EIO;
104 }
105
106 return 0;
107}
108
109static int rcar_gen4_sysc_power(u8 pdr, bool on)
110{
111 unsigned int isr_mask;
112 unsigned int reg_idx, bit_idx;
113 unsigned int status;
114 unsigned long flags;
115 int ret = 0;
116 u32 val;
117 int k;
118
119 spin_lock_irqsave(&rcar_gen4_sysc_lock, flags);
120
121 reg_idx = pdr / NUM_DOMAINS_EACH_REG;
122 bit_idx = pdr % NUM_DOMAINS_EACH_REG;
123
124 isr_mask = BIT(bit_idx);
125
126 /*
127 * The interrupt source needs to be enabled, but masked, to prevent the
128 * CPU from receiving it.
129 */
130 iowrite32(ioread32(rcar_gen4_sysc_base + SYSCIER(reg_idx)) | isr_mask,
131 rcar_gen4_sysc_base + SYSCIER(reg_idx));
132 iowrite32(ioread32(rcar_gen4_sysc_base + SYSCIMR(reg_idx)) | isr_mask,
133 rcar_gen4_sysc_base + SYSCIMR(reg_idx));
134
135 ret = clear_irq_flags(reg_idx, isr_mask);
136 if (ret)
137 goto out;
138
139 /* Submit power shutoff or resume request until it was accepted */
140 for (k = 0; k < PDRESR_RETRIES; k++) {
141 ret = rcar_gen4_sysc_pwr_on_off(pdr, on);
142 if (ret)
143 goto out;
144
145 status = ioread32(rcar_gen4_sysc_base + PDRESR(pdr));
146 if (!(status & PDRESR_ERR))
147 break;
148
149 udelay(PDRESR_DELAY_US);
150 }
151
152 if (k == PDRESR_RETRIES) {
153 ret = -EIO;
154 goto out;
155 }
156
157 /* Wait until the power shutoff or resume request has completed * */
158 ret = readl_poll_timeout_atomic(rcar_gen4_sysc_base + SYSCISCR(reg_idx),
159 val, (val & isr_mask),
160 SYSCISR_DELAY_US, SYSCISR_TIMEOUT);
161 if (ret < 0) {
162 ret = -EIO;
163 goto out;
164 }
165
166 /* Clear interrupt flags */
167 ret = clear_irq_flags(reg_idx, isr_mask);
168 if (ret)
169 goto out;
170
171 out:
172 spin_unlock_irqrestore(&rcar_gen4_sysc_lock, flags);
173
174 pr_debug("sysc power %s domain %d: %08x -> %d\n", on ? "on" : "off",
175 pdr, ioread32(rcar_gen4_sysc_base + SYSCISCR(reg_idx)), ret);
176 return ret;
177}
178
179static bool rcar_gen4_sysc_power_is_off(u8 pdr)
180{
181 unsigned int st;
182
183 st = ioread32(rcar_gen4_sysc_base + PDRSR(pdr));
184
185 if (st & PDRSR_OFF)
186 return true;
187
188 return false;
189}
190
191struct rcar_gen4_sysc_pd {
192 struct generic_pm_domain genpd;
193 u8 pdr;
194 unsigned int flags;
195 char name[];
196};
197
198static inline struct rcar_gen4_sysc_pd *to_rcar_gen4_pd(struct generic_pm_domain *d)
199{
200 return container_of(d, struct rcar_gen4_sysc_pd, genpd);
201}
202
203static int rcar_gen4_sysc_pd_power_off(struct generic_pm_domain *genpd)
204{
205 struct rcar_gen4_sysc_pd *pd = to_rcar_gen4_pd(genpd);
206
207 pr_debug("%s: %s\n", __func__, genpd->name);
208 return rcar_gen4_sysc_power(pd->pdr, false);
209}
210
211static int rcar_gen4_sysc_pd_power_on(struct generic_pm_domain *genpd)
212{
213 struct rcar_gen4_sysc_pd *pd = to_rcar_gen4_pd(genpd);
214
215 pr_debug("%s: %s\n", __func__, genpd->name);
216 return rcar_gen4_sysc_power(pd->pdr, true);
217}
218
219static int __init rcar_gen4_sysc_pd_setup(struct rcar_gen4_sysc_pd *pd)
220{
221 struct generic_pm_domain *genpd = &pd->genpd;
222 const char *name = pd->genpd.name;
223 int error;
224
225 if (pd->flags & PD_CPU) {
226 /*
227 * This domain contains a CPU core and therefore it should
228 * only be turned off if the CPU is not in use.
229 */
230 pr_debug("PM domain %s contains %s\n", name, "CPU");
231 genpd->flags |= GENPD_FLAG_ALWAYS_ON;
232 } else if (pd->flags & PD_SCU) {
233 /*
234 * This domain contains an SCU and cache-controller, and
235 * therefore it should only be turned off if the CPU cores are
236 * not in use.
237 */
238 pr_debug("PM domain %s contains %s\n", name, "SCU");
239 genpd->flags |= GENPD_FLAG_ALWAYS_ON;
240 } else if (pd->flags & PD_NO_CR) {
241 /*
242 * This domain cannot be turned off.
243 */
244 genpd->flags |= GENPD_FLAG_ALWAYS_ON;
245 }
246
247 if (!(pd->flags & (PD_CPU | PD_SCU))) {
248 /* Enable Clock Domain for I/O devices */
249 genpd->flags |= GENPD_FLAG_PM_CLK | GENPD_FLAG_ACTIVE_WAKEUP;
250 genpd->attach_dev = cpg_mssr_attach_dev;
251 genpd->detach_dev = cpg_mssr_detach_dev;
252 }
253
254 genpd->power_off = rcar_gen4_sysc_pd_power_off;
255 genpd->power_on = rcar_gen4_sysc_pd_power_on;
256
257 if (pd->flags & (PD_CPU | PD_NO_CR)) {
258 /* Skip CPUs (handled by SMP code) and areas without control */
259 pr_debug("%s: Not touching %s\n", __func__, genpd->name);
260 goto finalize;
261 }
262
263 if (!rcar_gen4_sysc_power_is_off(pd->pdr)) {
264 pr_debug("%s: %s is already powered\n", __func__, genpd->name);
265 goto finalize;
266 }
267
268 rcar_gen4_sysc_power(pd->pdr, true);
269
270finalize:
271 error = pm_genpd_init(genpd, &simple_qos_governor, false);
272 if (error)
273 pr_err("Failed to init PM domain %s: %d\n", name, error);
274
275 return error;
276}
277
278static const struct of_device_id rcar_gen4_sysc_matches[] __initconst = {
279#ifdef CONFIG_SYSC_R8A779A0
280 { .compatible = "renesas,r8a779a0-sysc", .data = &r8a779a0_sysc_info },
281#endif
282#ifdef CONFIG_SYSC_R8A779F0
283 { .compatible = "renesas,r8a779f0-sysc", .data = &r8a779f0_sysc_info },
284#endif
285#ifdef CONFIG_SYSC_R8A779G0
286 { .compatible = "renesas,r8a779g0-sysc", .data = &r8a779g0_sysc_info },
287#endif
288 { /* sentinel */ }
289};
290
291struct rcar_gen4_pm_domains {
292 struct genpd_onecell_data onecell_data;
293 struct generic_pm_domain *domains[RCAR_GEN4_PD_ALWAYS_ON + 1];
294};
295
296static struct genpd_onecell_data *rcar_gen4_sysc_onecell_data;
297
298static int __init rcar_gen4_sysc_pd_init(void)
299{
300 const struct rcar_gen4_sysc_info *info;
301 const struct of_device_id *match;
302 struct rcar_gen4_pm_domains *domains;
303 struct device_node *np;
304 void __iomem *base;
305 unsigned int i;
306 int error;
307
308 np = of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
309 if (!np)
310 return -ENODEV;
311
312 info = match->data;
313
314 base = of_iomap(np, 0);
315 if (!base) {
316 pr_warn("%pOF: Cannot map regs\n", np);
317 error = -ENOMEM;
318 goto out_put;
319 }
320
321 rcar_gen4_sysc_base = base;
322
323 domains = kzalloc(sizeof(*domains), GFP_KERNEL);
324 if (!domains) {
325 error = -ENOMEM;
326 goto out_put;
327 }
328
329 domains->onecell_data.domains = domains->domains;
330 domains->onecell_data.num_domains = ARRAY_SIZE(domains->domains);
331 rcar_gen4_sysc_onecell_data = &domains->onecell_data;
332
333 for (i = 0; i < info->num_areas; i++) {
334 const struct rcar_gen4_sysc_area *area = &info->areas[i];
335 struct rcar_gen4_sysc_pd *pd;
336 size_t n;
337
338 if (!area->name) {
339 /* Skip NULLified area */
340 continue;
341 }
342
343 n = strlen(area->name) + 1;
344 pd = kzalloc(sizeof(*pd) + n, GFP_KERNEL);
345 if (!pd) {
346 error = -ENOMEM;
347 goto out_put;
348 }
349
350 memcpy(pd->name, area->name, n);
351 pd->genpd.name = pd->name;
352 pd->pdr = area->pdr;
353 pd->flags = area->flags;
354
355 error = rcar_gen4_sysc_pd_setup(pd);
356 if (error)
357 goto out_put;
358
359 domains->domains[area->pdr] = &pd->genpd;
360
361 if (area->parent < 0)
362 continue;
363
364 error = pm_genpd_add_subdomain(domains->domains[area->parent],
365 &pd->genpd);
366 if (error) {
367 pr_warn("Failed to add PM subdomain %s to parent %u\n",
368 area->name, area->parent);
369 goto out_put;
370 }
371 }
372
373 error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
374
375out_put:
376 of_node_put(np);
377 return error;
378}
379early_initcall(rcar_gen4_sysc_pd_init);