1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * CPU idle driver for Tegra CPUs
4  *
5  * Copyright (c) 2010-2013, NVIDIA Corporation.
6  * Copyright (c) 2011 Google, Inc.
7  * Author: Colin Cross <ccross@android.com>
8  *         Gary King <gking@nvidia.com>
9  *
10  * Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com>
11  *
12  * Tegra20/124 driver unification by Dmitry Osipenko <digetx@gmail.com>
13  */
14 
15 #define pr_fmt(fmt)	"tegra-cpuidle: " fmt
16 
17 #include <linux/atomic.h>
18 #include <linux/cpuidle.h>
19 #include <linux/cpumask.h>
20 #include <linux/cpu_pm.h>
21 #include <linux/delay.h>
22 #include <linux/errno.h>
23 #include <linux/platform_device.h>
24 #include <linux/types.h>
25 
26 #include <linux/clk/tegra.h>
27 #include <linux/firmware/trusted_foundations.h>
28 
29 #include <soc/tegra/cpuidle.h>
30 #include <soc/tegra/flowctrl.h>
31 #include <soc/tegra/fuse.h>
32 #include <soc/tegra/irq.h>
33 #include <soc/tegra/pm.h>
34 #include <soc/tegra/pmc.h>
35 
36 #include <asm/cpuidle.h>
37 #include <asm/firmware.h>
38 #include <asm/smp_plat.h>
39 #include <asm/suspend.h>
40 
41 enum tegra_state {
42 	TEGRA_C1,
43 	TEGRA_C7,
44 	TEGRA_CC6,
45 	TEGRA_STATE_COUNT,
46 };
47 
48 static atomic_t tegra_idle_barrier;
49 static atomic_t tegra_abort_flag;
50 
51 static void tegra_cpuidle_report_cpus_state(void)
52 {
53 	unsigned long cpu, lcpu, csr;
54 
55 	for_each_cpu(lcpu, cpu_possible_mask) {
56 		cpu = cpu_logical_map(lcpu);
57 		csr = flowctrl_read_cpu_csr(cpu);
58 
59 		pr_err("cpu%lu: online=%d flowctrl_csr=0x%08lx\n",
60 		       cpu, cpu_online(lcpu), csr);
61 	}
62 }
63 
64 static int tegra_cpuidle_wait_for_secondary_cpus_parking(void)
65 {
66 	unsigned int retries = 3;
67 
68 	while (retries--) {
69 		unsigned int delay_us = 10;
70 		unsigned int timeout_us = 500 * 1000 / delay_us;
71 
72 		/*
73 		 * The primary CPU0 core shall wait for the secondaries
74 		 * shutdown in order to power-off CPU's cluster safely.
75 		 * The timeout value depends on the current CPU frequency,
76 		 * it takes about 40-150us in average and over 1000us in
77 		 * a worst case scenario.
78 		 */
79 		do {
80 			if (tegra_cpu_rail_off_ready())
81 				return 0;
82 
83 			udelay(delay_us);
84 
85 		} while (timeout_us--);
86 
87 		pr_err("secondary CPU taking too long to park\n");
88 
89 		tegra_cpuidle_report_cpus_state();
90 	}
91 
92 	pr_err("timed out waiting secondaries to park\n");
93 
94 	return -ETIMEDOUT;
95 }
96 
97 static void tegra_cpuidle_unpark_secondary_cpus(void)
98 {
99 	unsigned int cpu, lcpu;
100 
101 	for_each_cpu(lcpu, cpu_online_mask) {
102 		cpu = cpu_logical_map(lcpu);
103 
104 		if (cpu > 0) {
105 			tegra_enable_cpu_clock(cpu);
106 			tegra_cpu_out_of_reset(cpu);
107 			flowctrl_write_cpu_halt(cpu, 0);
108 		}
109 	}
110 }
111 
112 static int tegra_cpuidle_cc6_enter(unsigned int cpu)
113 {
114 	int ret;
115 
116 	if (cpu > 0) {
117 		ret = cpu_suspend(cpu, tegra_pm_park_secondary_cpu);
118 	} else {
119 		ret = tegra_cpuidle_wait_for_secondary_cpus_parking();
120 		if (!ret)
121 			ret = tegra_pm_enter_lp2();
122 
123 		tegra_cpuidle_unpark_secondary_cpus();
124 	}
125 
126 	return ret;
127 }
128 
129 static int tegra_cpuidle_c7_enter(void)
130 {
131 	int err;
132 
133 	err = call_firmware_op(prepare_idle, TF_PM_MODE_LP2_NOFLUSH_L2);
134 	if (err && err != -ENOSYS)
135 		return err;
136 
137 	return cpu_suspend(0, tegra30_pm_secondary_cpu_suspend);
138 }
139 
140 static int tegra_cpuidle_coupled_barrier(struct cpuidle_device *dev)
141 {
142 	if (tegra_pending_sgi()) {
143 		/*
144 		 * CPU got local interrupt that will be lost after GIC's
145 		 * shutdown because GIC driver doesn't save/restore the
146 		 * pending SGI state across CPU cluster PM.  Abort and retry
147 		 * next time.
148 		 */
149 		atomic_set(&tegra_abort_flag, 1);
150 	}
151 
152 	cpuidle_coupled_parallel_barrier(dev, &tegra_idle_barrier);
153 
154 	if (atomic_read(&tegra_abort_flag)) {
155 		cpuidle_coupled_parallel_barrier(dev, &tegra_idle_barrier);
156 		atomic_set(&tegra_abort_flag, 0);
157 		return -EINTR;
158 	}
159 
160 	return 0;
161 }
162 
163 static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
164 				     int index, unsigned int cpu)
165 {
166 	int err;
167 
168 	/*
169 	 * CC6 state is the "CPU cluster power-off" state.  In order to
170 	 * enter this state, at first the secondary CPU cores need to be
171 	 * parked into offline mode, then the last CPU should clean out
172 	 * remaining dirty cache lines into DRAM and trigger Flow Controller
173 	 * logic that turns off the cluster's power domain (which includes
174 	 * CPU cores, GIC and L2 cache).
175 	 */
176 	if (index == TEGRA_CC6) {
177 		err = tegra_cpuidle_coupled_barrier(dev);
178 		if (err)
179 			return err;
180 	}
181 
182 	local_fiq_disable();
183 	RCU_NONIDLE(tegra_pm_set_cpu_in_lp2());
184 	cpu_pm_enter();
185 
186 	switch (index) {
187 	case TEGRA_C7:
188 		err = tegra_cpuidle_c7_enter();
189 		break;
190 
191 	case TEGRA_CC6:
192 		err = tegra_cpuidle_cc6_enter(cpu);
193 		break;
194 
195 	default:
196 		err = -EINVAL;
197 		break;
198 	}
199 
200 	cpu_pm_exit();
201 	RCU_NONIDLE(tegra_pm_clear_cpu_in_lp2());
202 	local_fiq_enable();
203 
204 	return err ?: index;
205 }
206 
207 static int tegra_cpuidle_adjust_state_index(int index, unsigned int cpu)
208 {
209 	/*
210 	 * On Tegra30 CPU0 can't be power-gated separately from secondary
211 	 * cores because it gates the whole CPU cluster.
212 	 */
213 	if (cpu > 0 || index != TEGRA_C7 || tegra_get_chip_id() != TEGRA30)
214 		return index;
215 
216 	/* put CPU0 into C1 if C7 is requested and secondaries are online */
217 	if (!IS_ENABLED(CONFIG_PM_SLEEP) || num_online_cpus() > 1)
218 		index = TEGRA_C1;
219 	else
220 		index = TEGRA_CC6;
221 
222 	return index;
223 }
224 
225 static int tegra_cpuidle_enter(struct cpuidle_device *dev,
226 			       struct cpuidle_driver *drv,
227 			       int index)
228 {
229 	unsigned int cpu = cpu_logical_map(dev->cpu);
230 	int ret;
231 
232 	index = tegra_cpuidle_adjust_state_index(index, cpu);
233 	if (dev->states_usage[index].disable)
234 		return -1;
235 
236 	if (index == TEGRA_C1)
237 		ret = arm_cpuidle_simple_enter(dev, drv, index);
238 	else
239 		ret = tegra_cpuidle_state_enter(dev, index, cpu);
240 
241 	if (ret < 0) {
242 		if (ret != -EINTR || index != TEGRA_CC6)
243 			pr_err_once("failed to enter state %d err: %d\n",
244 				    index, ret);
245 		index = -1;
246 	} else {
247 		index = ret;
248 	}
249 
250 	return index;
251 }
252 
253 static int tegra114_enter_s2idle(struct cpuidle_device *dev,
254 				 struct cpuidle_driver *drv,
255 				 int index)
256 {
257 	tegra_cpuidle_enter(dev, drv, index);
258 
259 	return 0;
260 }
261 
262 /*
263  * The previous versions of Tegra CPUIDLE driver used a different "legacy"
264  * terminology for naming of the idling states, while this driver uses the
265  * new terminology.
266  *
267  * Mapping of the old terms into the new ones:
268  *
269  * Old | New
270  * ---------
271  * LP3 | C1	(CPU core clock gating)
272  * LP2 | C7	(CPU core power gating)
273  * LP2 | CC6	(CPU cluster power gating)
274  *
275  * Note that that the older CPUIDLE driver versions didn't explicitly
276  * differentiate the LP2 states because these states either used the same
277  * code path or because CC6 wasn't supported.
278  */
279 static struct cpuidle_driver tegra_idle_driver = {
280 	.name = "tegra_idle",
281 	.states = {
282 		[TEGRA_C1] = ARM_CPUIDLE_WFI_STATE_PWR(600),
283 		[TEGRA_C7] = {
284 			.enter			= tegra_cpuidle_enter,
285 			.exit_latency		= 2000,
286 			.target_residency	= 2200,
287 			.power_usage		= 100,
288 			.flags			= CPUIDLE_FLAG_TIMER_STOP,
289 			.name			= "C7",
290 			.desc			= "CPU core powered off",
291 		},
292 		[TEGRA_CC6] = {
293 			.enter			= tegra_cpuidle_enter,
294 			.exit_latency		= 5000,
295 			.target_residency	= 10000,
296 			.power_usage		= 0,
297 			.flags			= CPUIDLE_FLAG_TIMER_STOP |
298 						  CPUIDLE_FLAG_COUPLED,
299 			.name			= "CC6",
300 			.desc			= "CPU cluster powered off",
301 		},
302 	},
303 	.state_count = TEGRA_STATE_COUNT,
304 	.safe_state_index = TEGRA_C1,
305 };
306 
307 static inline void tegra_cpuidle_disable_state(enum tegra_state state)
308 {
309 	cpuidle_driver_state_disabled(&tegra_idle_driver, state, true);
310 }
311 
312 /*
313  * Tegra20 HW appears to have a bug such that PCIe device interrupts, whether
314  * they are legacy IRQs or MSI, are lost when CC6 is enabled.  To work around
315  * this, simply disable CC6 if the PCI driver and DT node are both enabled.
316  */
317 void tegra_cpuidle_pcie_irqs_in_use(void)
318 {
319 	struct cpuidle_state *state_cc6 = &tegra_idle_driver.states[TEGRA_CC6];
320 
321 	if ((state_cc6->flags & CPUIDLE_FLAG_UNUSABLE) ||
322 	    tegra_get_chip_id() != TEGRA20)
323 		return;
324 
325 	pr_info("disabling CC6 state, since PCIe IRQs are in use\n");
326 	tegra_cpuidle_disable_state(TEGRA_CC6);
327 }
328 
329 static void tegra_cpuidle_setup_tegra114_c7_state(void)
330 {
331 	struct cpuidle_state *s = &tegra_idle_driver.states[TEGRA_C7];
332 
333 	s->enter_s2idle = tegra114_enter_s2idle;
334 	s->target_residency = 1000;
335 	s->exit_latency = 500;
336 }
337 
338 static int tegra_cpuidle_probe(struct platform_device *pdev)
339 {
340 	if (tegra_pmc_get_suspend_mode() == TEGRA_SUSPEND_NOT_READY)
341 		return -EPROBE_DEFER;
342 
343 	/* LP2 could be disabled in device-tree */
344 	if (tegra_pmc_get_suspend_mode() < TEGRA_SUSPEND_LP2)
345 		tegra_cpuidle_disable_state(TEGRA_CC6);
346 
347 	/*
348 	 * Required suspend-resume functionality, which is provided by the
349 	 * Tegra-arch core and PMC driver, is unavailable if PM-sleep option
350 	 * is disabled.
351 	 */
352 	if (!IS_ENABLED(CONFIG_PM_SLEEP)) {
353 		tegra_cpuidle_disable_state(TEGRA_C7);
354 		tegra_cpuidle_disable_state(TEGRA_CC6);
355 	}
356 
357 	/*
358 	 * Generic WFI state (also known as C1 or LP3) and the coupled CPU
359 	 * cluster power-off (CC6 or LP2) states are common for all Tegra SoCs.
360 	 */
361 	switch (tegra_get_chip_id()) {
362 	case TEGRA20:
363 		/* Tegra20 isn't capable to power-off individual CPU cores */
364 		tegra_cpuidle_disable_state(TEGRA_C7);
365 		break;
366 
367 	case TEGRA30:
368 		break;
369 
370 	case TEGRA114:
371 	case TEGRA124:
372 		tegra_cpuidle_setup_tegra114_c7_state();
373 
374 		/* coupled CC6 (LP2) state isn't implemented yet */
375 		tegra_cpuidle_disable_state(TEGRA_CC6);
376 		break;
377 
378 	default:
379 		return -EINVAL;
380 	}
381 
382 	return cpuidle_register(&tegra_idle_driver, cpu_possible_mask);
383 }
384 
385 static struct platform_driver tegra_cpuidle_driver = {
386 	.probe = tegra_cpuidle_probe,
387 	.driver = {
388 		.name = "tegra-cpuidle",
389 	},
390 };
391 builtin_platform_driver(tegra_cpuidle_driver);
392