1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) 2013 MundoReader S.L.
4  * Author: Heiko Stuebner <heiko@sntech.de>
5  */
6 
7 #include <linux/delay.h>
8 #include <linux/init.h>
9 #include <linux/smp.h>
10 #include <linux/io.h>
11 #include <linux/of.h>
12 #include <linux/of_address.h>
13 #include <linux/regmap.h>
14 #include <linux/mfd/syscon.h>
15 
16 #include <linux/reset.h>
17 #include <linux/cpu.h>
18 #include <asm/cacheflush.h>
19 #include <asm/cp15.h>
20 #include <asm/smp_scu.h>
21 #include <asm/smp_plat.h>
22 #include <asm/mach/map.h>
23 
24 #include "core.h"
25 
26 static void __iomem *scu_base_addr;
27 static void __iomem *sram_base_addr;
28 static int ncores;
29 
30 #define PMU_PWRDN_CON		0x08
31 #define PMU_PWRDN_ST		0x0c
32 
33 #define PMU_PWRDN_SCU		4
34 
35 static struct regmap *pmu;
36 static int has_pmu = true;
37 
pmu_power_domain_is_on(int pd)38 static int pmu_power_domain_is_on(int pd)
39 {
40 	u32 val;
41 	int ret;
42 
43 	ret = regmap_read(pmu, PMU_PWRDN_ST, &val);
44 	if (ret < 0)
45 		return ret;
46 
47 	return !(val & BIT(pd));
48 }
49 
rockchip_get_core_reset(int cpu)50 static struct reset_control *rockchip_get_core_reset(int cpu)
51 {
52 	struct device *dev = get_cpu_device(cpu);
53 	struct device_node *np;
54 
55 	/* The cpu device is only available after the initial core bringup */
56 	if (dev)
57 		np = dev->of_node;
58 	else
59 		np = of_get_cpu_node(cpu, NULL);
60 
61 	return of_reset_control_get_exclusive(np, NULL);
62 }
63 
pmu_set_power_domain(int pd,bool on)64 static int pmu_set_power_domain(int pd, bool on)
65 {
66 	u32 val = (on) ? 0 : BIT(pd);
67 	struct reset_control *rstc = rockchip_get_core_reset(pd);
68 	int ret;
69 
70 	if (IS_ERR(rstc) && read_cpuid_part() != ARM_CPU_PART_CORTEX_A9) {
71 		pr_err("%s: could not get reset control for core %d\n",
72 		       __func__, pd);
73 		return PTR_ERR(rstc);
74 	}
75 
76 	/*
77 	 * We need to soft reset the cpu when we turn off the cpu power domain,
78 	 * or else the active processors might be stalled when the individual
79 	 * processor is powered down.
80 	 */
81 	if (!IS_ERR(rstc) && !on)
82 		reset_control_assert(rstc);
83 
84 	if (has_pmu) {
85 		ret = regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), val);
86 		if (ret < 0) {
87 			pr_err("%s: could not update power domain\n",
88 			       __func__);
89 			return ret;
90 		}
91 
92 		ret = -1;
93 		while (ret != on) {
94 			ret = pmu_power_domain_is_on(pd);
95 			if (ret < 0) {
96 				pr_err("%s: could not read power domain state\n",
97 				       __func__);
98 				return ret;
99 			}
100 		}
101 	}
102 
103 	if (!IS_ERR(rstc)) {
104 		if (on)
105 			reset_control_deassert(rstc);
106 		reset_control_put(rstc);
107 	}
108 
109 	return 0;
110 }
111 
112 /*
113  * Handling of CPU cores
114  */
115 
rockchip_boot_secondary(unsigned int cpu,struct task_struct * idle)116 static int rockchip_boot_secondary(unsigned int cpu, struct task_struct *idle)
117 {
118 	int ret;
119 
120 	if (!sram_base_addr || (has_pmu && !pmu)) {
121 		pr_err("%s: sram or pmu missing for cpu boot\n", __func__);
122 		return -ENXIO;
123 	}
124 
125 	if (cpu >= ncores) {
126 		pr_err("%s: cpu %d outside maximum number of cpus %d\n",
127 		       __func__, cpu, ncores);
128 		return -ENXIO;
129 	}
130 
131 	/* start the core */
132 	ret = pmu_set_power_domain(0 + cpu, true);
133 	if (ret < 0)
134 		return ret;
135 
136 	if (read_cpuid_part() != ARM_CPU_PART_CORTEX_A9) {
137 		/*
138 		 * We communicate with the bootrom to active the cpus other
139 		 * than cpu0, after a blob of initialize code, they will
140 		 * stay at wfe state, once they are activated, they will check
141 		 * the mailbox:
142 		 * sram_base_addr + 4: 0xdeadbeaf
143 		 * sram_base_addr + 8: start address for pc
144 		 * The cpu0 need to wait the other cpus other than cpu0 entering
145 		 * the wfe state.The wait time is affected by many aspects.
146 		 * (e.g: cpu frequency, bootrom frequency, sram frequency, ...)
147 		 */
148 		mdelay(1); /* ensure the cpus other than cpu0 to startup */
149 
150 		writel(__pa_symbol(secondary_startup), sram_base_addr + 8);
151 		writel(0xDEADBEAF, sram_base_addr + 4);
152 		dsb_sev();
153 	}
154 
155 	return 0;
156 }
157 
158 /**
159  * rockchip_smp_prepare_sram - populate necessary sram block
160  * Starting cores execute the code residing at the start of the on-chip sram
161  * after power-on. Therefore make sure, this sram region is reserved and
162  * big enough. After this check, copy the trampoline code that directs the
163  * core to the real startup code in ram into the sram-region.
164  * @node: mmio-sram device node
165  */
rockchip_smp_prepare_sram(struct device_node * node)166 static int __init rockchip_smp_prepare_sram(struct device_node *node)
167 {
168 	unsigned int trampoline_sz = &rockchip_secondary_trampoline_end -
169 					    &rockchip_secondary_trampoline;
170 	struct resource res;
171 	unsigned int rsize;
172 	int ret;
173 
174 	ret = of_address_to_resource(node, 0, &res);
175 	if (ret < 0) {
176 		pr_err("%s: could not get address for node %pOF\n",
177 		       __func__, node);
178 		return ret;
179 	}
180 
181 	rsize = resource_size(&res);
182 	if (rsize < trampoline_sz) {
183 		pr_err("%s: reserved block with size 0x%x is too small for trampoline size 0x%x\n",
184 		       __func__, rsize, trampoline_sz);
185 		return -EINVAL;
186 	}
187 
188 	/* set the boot function for the sram code */
189 	rockchip_boot_fn = __pa_symbol(secondary_startup);
190 
191 	/* copy the trampoline to sram, that runs during startup of the core */
192 	memcpy_toio(sram_base_addr, &rockchip_secondary_trampoline, trampoline_sz);
193 	flush_cache_all();
194 	outer_clean_range(0, trampoline_sz);
195 
196 	dsb_sev();
197 
198 	return 0;
199 }
200 
201 static const struct regmap_config rockchip_pmu_regmap_config = {
202 	.name = "rockchip-pmu",
203 	.reg_bits = 32,
204 	.val_bits = 32,
205 	.reg_stride = 4,
206 };
207 
rockchip_smp_prepare_pmu(void)208 static int __init rockchip_smp_prepare_pmu(void)
209 {
210 	struct device_node *node;
211 	void __iomem *pmu_base;
212 
213 	/*
214 	 * This function is only called via smp_ops->smp_prepare_cpu().
215 	 * That only happens if a "/cpus" device tree node exists
216 	 * and has an "enable-method" property that selects the SMP
217 	 * operations defined herein.
218 	 */
219 	node = of_find_node_by_path("/cpus");
220 
221 	pmu = syscon_regmap_lookup_by_phandle(node, "rockchip,pmu");
222 	of_node_put(node);
223 	if (!IS_ERR(pmu))
224 		return 0;
225 
226 	pmu = syscon_regmap_lookup_by_compatible("rockchip,rk3066-pmu");
227 	if (!IS_ERR(pmu))
228 		return 0;
229 
230 	/* fallback, create our own regmap for the pmu area */
231 	pmu = NULL;
232 	node = of_find_compatible_node(NULL, NULL, "rockchip,rk3066-pmu");
233 	if (!node) {
234 		pr_err("%s: could not find pmu dt node\n", __func__);
235 		return -ENODEV;
236 	}
237 
238 	pmu_base = of_iomap(node, 0);
239 	of_node_put(node);
240 	if (!pmu_base) {
241 		pr_err("%s: could not map pmu registers\n", __func__);
242 		return -ENOMEM;
243 	}
244 
245 	pmu = regmap_init_mmio(NULL, pmu_base, &rockchip_pmu_regmap_config);
246 	if (IS_ERR(pmu)) {
247 		int ret = PTR_ERR(pmu);
248 
249 		iounmap(pmu_base);
250 		pmu = NULL;
251 		pr_err("%s: regmap init failed\n", __func__);
252 		return ret;
253 	}
254 
255 	return 0;
256 }
257 
rockchip_smp_prepare_cpus(unsigned int max_cpus)258 static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
259 {
260 	struct device_node *node;
261 	unsigned int i;
262 
263 	node = of_find_compatible_node(NULL, NULL, "rockchip,rk3066-smp-sram");
264 	if (!node) {
265 		pr_err("%s: could not find sram dt node\n", __func__);
266 		return;
267 	}
268 
269 	sram_base_addr = of_iomap(node, 0);
270 	if (!sram_base_addr) {
271 		pr_err("%s: could not map sram registers\n", __func__);
272 		of_node_put(node);
273 		return;
274 	}
275 
276 	if (has_pmu && rockchip_smp_prepare_pmu()) {
277 		of_node_put(node);
278 		return;
279 	}
280 
281 	if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9) {
282 		if (rockchip_smp_prepare_sram(node)) {
283 			of_node_put(node);
284 			return;
285 		}
286 
287 		/* enable the SCU power domain */
288 		pmu_set_power_domain(PMU_PWRDN_SCU, true);
289 
290 		of_node_put(node);
291 		node = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
292 		if (!node) {
293 			pr_err("%s: missing scu\n", __func__);
294 			return;
295 		}
296 
297 		scu_base_addr = of_iomap(node, 0);
298 		if (!scu_base_addr) {
299 			pr_err("%s: could not map scu registers\n", __func__);
300 			of_node_put(node);
301 			return;
302 		}
303 
304 		/*
305 		 * While the number of cpus is gathered from dt, also get the
306 		 * number of cores from the scu to verify this value when
307 		 * booting the cores.
308 		 */
309 		ncores = scu_get_core_count(scu_base_addr);
310 		pr_err("%s: ncores %d\n", __func__, ncores);
311 
312 		scu_enable(scu_base_addr);
313 	} else {
314 		unsigned int l2ctlr;
315 
316 		asm ("mrc p15, 1, %0, c9, c0, 2\n" : "=r" (l2ctlr));
317 		ncores = ((l2ctlr >> 24) & 0x3) + 1;
318 	}
319 	of_node_put(node);
320 
321 	/* Make sure that all cores except the first are really off */
322 	for (i = 1; i < ncores; i++)
323 		pmu_set_power_domain(0 + i, false);
324 }
325 
rk3036_smp_prepare_cpus(unsigned int max_cpus)326 static void __init rk3036_smp_prepare_cpus(unsigned int max_cpus)
327 {
328 	has_pmu = false;
329 
330 	rockchip_smp_prepare_cpus(max_cpus);
331 }
332 
333 #ifdef CONFIG_HOTPLUG_CPU
rockchip_cpu_kill(unsigned int cpu)334 static int rockchip_cpu_kill(unsigned int cpu)
335 {
336 	/*
337 	 * We need a delay here to ensure that the dying CPU can finish
338 	 * executing v7_coherency_exit() and reach the WFI/WFE state
339 	 * prior to having the power domain disabled.
340 	 */
341 	mdelay(1);
342 
343 	pmu_set_power_domain(0 + cpu, false);
344 	return 1;
345 }
346 
rockchip_cpu_die(unsigned int cpu)347 static void rockchip_cpu_die(unsigned int cpu)
348 {
349 	v7_exit_coherency_flush(louis);
350 	while (1)
351 		cpu_do_idle();
352 }
353 #endif
354 
355 static const struct smp_operations rk3036_smp_ops __initconst = {
356 	.smp_prepare_cpus	= rk3036_smp_prepare_cpus,
357 	.smp_boot_secondary	= rockchip_boot_secondary,
358 #ifdef CONFIG_HOTPLUG_CPU
359 	.cpu_kill		= rockchip_cpu_kill,
360 	.cpu_die		= rockchip_cpu_die,
361 #endif
362 };
363 
364 static const struct smp_operations rockchip_smp_ops __initconst = {
365 	.smp_prepare_cpus	= rockchip_smp_prepare_cpus,
366 	.smp_boot_secondary	= rockchip_boot_secondary,
367 #ifdef CONFIG_HOTPLUG_CPU
368 	.cpu_kill		= rockchip_cpu_kill,
369 	.cpu_die		= rockchip_cpu_die,
370 #endif
371 };
372 
373 CPU_METHOD_OF_DECLARE(rk3036_smp, "rockchip,rk3036-smp", &rk3036_smp_ops);
374 CPU_METHOD_OF_DECLARE(rk3066_smp, "rockchip,rk3066-smp", &rockchip_smp_ops);
375