xref: /openbmc/linux/arch/x86/platform/intel-mid/pwr.c (revision 8e8e69d6) 
1 /*
2  * Intel MID Power Management Unit (PWRMU) device driver
3  *
4  * Copyright (C) 2016, Intel Corporation
5  *
6  * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms and conditions of the GNU General Public License,
10  * version 2, as published by the Free Software Foundation.
11  *
12  * Intel MID Power Management Unit device driver handles the South Complex PCI
13  * devices such as GPDMA, SPI, I2C, PWM, and so on. By default PCI core
14  * modifies bits in PMCSR register in the PCI configuration space. This is not
15  * enough on some SoCs like Intel Tangier. In such case PCI core sets a new
16  * power state of the device in question through a PM hook registered in struct
17  * pci_platform_pm_ops (see drivers/pci/pci-mid.c).
18  */
19 
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 
22 #include <linux/delay.h>
23 #include <linux/errno.h>
24 #include <linux/interrupt.h>
25 #include <linux/kernel.h>
26 #include <linux/export.h>
27 #include <linux/mutex.h>
28 #include <linux/pci.h>
29 
30 #include <asm/intel-mid.h>
31 
32 /* Registers */
33 #define PM_STS			0x00
34 #define PM_CMD			0x04
35 #define PM_ICS			0x08
36 #define PM_WKC(x)		(0x10 + (x) * 4)
37 #define PM_WKS(x)		(0x18 + (x) * 4)
38 #define PM_SSC(x)		(0x20 + (x) * 4)
39 #define PM_SSS(x)		(0x30 + (x) * 4)
40 
41 /* Bits in PM_STS */
42 #define PM_STS_BUSY		(1 << 8)
43 
44 /* Bits in PM_CMD */
45 #define PM_CMD_CMD(x)		((x) << 0)
46 #define PM_CMD_IOC		(1 << 8)
47 #define PM_CMD_CM_NOP		(0 << 9)
48 #define PM_CMD_CM_IMMEDIATE	(1 << 9)
49 #define PM_CMD_CM_DELAY		(2 << 9)
50 #define PM_CMD_CM_TRIGGER	(3 << 9)
51 
52 /* System states */
53 #define PM_CMD_SYS_STATE_S5	(5 << 16)
54 
55 /* Trigger variants */
56 #define PM_CMD_CFG_TRIGGER_NC	(3 << 19)
57 
58 /* Message to wait for TRIGGER_NC case */
59 #define TRIGGER_NC_MSG_2	(2 << 22)
60 
61 /* List of commands */
62 #define CMD_SET_CFG		0x01
63 
64 /* Bits in PM_ICS */
65 #define PM_ICS_INT_STATUS(x)	((x) & 0xff)
66 #define PM_ICS_IE		(1 << 8)
67 #define PM_ICS_IP		(1 << 9)
68 #define PM_ICS_SW_INT_STS	(1 << 10)
69 
70 /* List of interrupts */
71 #define INT_INVALID		0
72 #define INT_CMD_COMPLETE	1
73 #define INT_CMD_ERR		2
74 #define INT_WAKE_EVENT		3
75 #define INT_LSS_POWER_ERR	4
76 #define INT_S0iX_MSG_ERR	5
77 #define INT_NO_C6		6
78 #define INT_TRIGGER_ERR		7
79 #define INT_INACTIVITY		8
80 
81 /* South Complex devices */
82 #define LSS_MAX_SHARED_DEVS	4
83 #define LSS_MAX_DEVS		64
84 
85 #define LSS_WS_BITS		1	/* wake state width */
86 #define LSS_PWS_BITS		2	/* power state width */
87 
88 /* Supported device IDs */
89 #define PCI_DEVICE_ID_PENWELL	0x0828
90 #define PCI_DEVICE_ID_TANGIER	0x11a1
91 
92 struct mid_pwr_dev {
93 	struct pci_dev *pdev;
94 	pci_power_t state;
95 };
96 
97 struct mid_pwr {
98 	struct device *dev;
99 	void __iomem *regs;
100 	int irq;
101 	bool available;
102 
103 	struct mutex lock;
104 	struct mid_pwr_dev lss[LSS_MAX_DEVS][LSS_MAX_SHARED_DEVS];
105 };
106 
107 static struct mid_pwr *midpwr;
108 
109 static u32 mid_pwr_get_state(struct mid_pwr *pwr, int reg)
110 {
111 	return readl(pwr->regs + PM_SSS(reg));
112 }
113 
114 static void mid_pwr_set_state(struct mid_pwr *pwr, int reg, u32 value)
115 {
116 	writel(value, pwr->regs + PM_SSC(reg));
117 }
118 
119 static void mid_pwr_set_wake(struct mid_pwr *pwr, int reg, u32 value)
120 {
121 	writel(value, pwr->regs + PM_WKC(reg));
122 }
123 
124 static void mid_pwr_interrupt_disable(struct mid_pwr *pwr)
125 {
126 	writel(~PM_ICS_IE, pwr->regs + PM_ICS);
127 }
128 
129 static bool mid_pwr_is_busy(struct mid_pwr *pwr)
130 {
131 	return !!(readl(pwr->regs + PM_STS) & PM_STS_BUSY);
132 }
133 
134 /* Wait 500ms that the latest PWRMU command finished */
135 static int mid_pwr_wait(struct mid_pwr *pwr)
136 {
137 	unsigned int count = 500000;
138 	bool busy;
139 
140 	do {
141 		busy = mid_pwr_is_busy(pwr);
142 		if (!busy)
143 			return 0;
144 		udelay(1);
145 	} while (--count);
146 
147 	return -EBUSY;
148 }
149 
150 static int mid_pwr_wait_for_cmd(struct mid_pwr *pwr, u8 cmd)
151 {
152 	writel(PM_CMD_CMD(cmd) | PM_CMD_CM_IMMEDIATE, pwr->regs + PM_CMD);
153 	return mid_pwr_wait(pwr);
154 }
155 
156 static int __update_power_state(struct mid_pwr *pwr, int reg, int bit, int new)
157 {
158 	int curstate;
159 	u32 power;
160 	int ret;
161 
162 	/* Check if the device is already in desired state */
163 	power = mid_pwr_get_state(pwr, reg);
164 	curstate = (power >> bit) & 3;
165 	if (curstate == new)
166 		return 0;
167 
168 	/* Update the power state */
169 	mid_pwr_set_state(pwr, reg, (power & ~(3 << bit)) | (new << bit));
170 
171 	/* Send command to SCU */
172 	ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
173 	if (ret)
174 		return ret;
175 
176 	/* Check if the device is already in desired state */
177 	power = mid_pwr_get_state(pwr, reg);
178 	curstate = (power >> bit) & 3;
179 	if (curstate != new)
180 		return -EAGAIN;
181 
182 	return 0;
183 }
184 
185 static pci_power_t __find_weakest_power_state(struct mid_pwr_dev *lss,
186 					      struct pci_dev *pdev,
187 					      pci_power_t state)
188 {
189 	pci_power_t weakest = PCI_D3hot;
190 	unsigned int j;
191 
192 	/* Find device in cache or first free cell */
193 	for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
194 		if (lss[j].pdev == pdev || !lss[j].pdev)
195 			break;
196 	}
197 
198 	/* Store the desired state in cache */
199 	if (j < LSS_MAX_SHARED_DEVS) {
200 		lss[j].pdev = pdev;
201 		lss[j].state = state;
202 	} else {
203 		dev_WARN(&pdev->dev, "No room for device in PWRMU LSS cache\n");
204 		weakest = state;
205 	}
206 
207 	/* Find the power state we may use */
208 	for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
209 		if (lss[j].state < weakest)
210 			weakest = lss[j].state;
211 	}
212 
213 	return weakest;
214 }
215 
216 static int __set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
217 			     pci_power_t state, int id, int reg, int bit)
218 {
219 	const char *name;
220 	int ret;
221 
222 	state = __find_weakest_power_state(pwr->lss[id], pdev, state);
223 	name = pci_power_name(state);
224 
225 	ret = __update_power_state(pwr, reg, bit, (__force int)state);
226 	if (ret) {
227 		dev_warn(&pdev->dev, "Can't set power state %s: %d\n", name, ret);
228 		return ret;
229 	}
230 
231 	dev_vdbg(&pdev->dev, "Set power state %s\n", name);
232 	return 0;
233 }
234 
235 static int mid_pwr_set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
236 				   pci_power_t state)
237 {
238 	int id, reg, bit;
239 	int ret;
240 
241 	id = intel_mid_pwr_get_lss_id(pdev);
242 	if (id < 0)
243 		return id;
244 
245 	reg = (id * LSS_PWS_BITS) / 32;
246 	bit = (id * LSS_PWS_BITS) % 32;
247 
248 	/* We support states between PCI_D0 and PCI_D3hot */
249 	if (state < PCI_D0)
250 		state = PCI_D0;
251 	if (state > PCI_D3hot)
252 		state = PCI_D3hot;
253 
254 	mutex_lock(&pwr->lock);
255 	ret = __set_power_state(pwr, pdev, state, id, reg, bit);
256 	mutex_unlock(&pwr->lock);
257 	return ret;
258 }
259 
260 int intel_mid_pci_set_power_state(struct pci_dev *pdev, pci_power_t state)
261 {
262 	struct mid_pwr *pwr = midpwr;
263 	int ret = 0;
264 
265 	might_sleep();
266 
267 	if (pwr && pwr->available)
268 		ret = mid_pwr_set_power_state(pwr, pdev, state);
269 	dev_vdbg(&pdev->dev, "set_power_state() returns %d\n", ret);
270 
271 	return 0;
272 }
273 
274 pci_power_t intel_mid_pci_get_power_state(struct pci_dev *pdev)
275 {
276 	struct mid_pwr *pwr = midpwr;
277 	int id, reg, bit;
278 	u32 power;
279 
280 	if (!pwr || !pwr->available)
281 		return PCI_UNKNOWN;
282 
283 	id = intel_mid_pwr_get_lss_id(pdev);
284 	if (id < 0)
285 		return PCI_UNKNOWN;
286 
287 	reg = (id * LSS_PWS_BITS) / 32;
288 	bit = (id * LSS_PWS_BITS) % 32;
289 	power = mid_pwr_get_state(pwr, reg);
290 	return (__force pci_power_t)((power >> bit) & 3);
291 }
292 
293 void intel_mid_pwr_power_off(void)
294 {
295 	struct mid_pwr *pwr = midpwr;
296 	u32 cmd = PM_CMD_SYS_STATE_S5 |
297 		  PM_CMD_CMD(CMD_SET_CFG) |
298 		  PM_CMD_CM_TRIGGER |
299 		  PM_CMD_CFG_TRIGGER_NC |
300 		  TRIGGER_NC_MSG_2;
301 
302 	/* Send command to SCU */
303 	writel(cmd, pwr->regs + PM_CMD);
304 	mid_pwr_wait(pwr);
305 }
306 
307 int intel_mid_pwr_get_lss_id(struct pci_dev *pdev)
308 {
309 	int vndr;
310 	u8 id;
311 
312 	/*
313 	 * Mapping to PWRMU index is kept in the Logical SubSystem ID byte of
314 	 * Vendor capability.
315 	 */
316 	vndr = pci_find_capability(pdev, PCI_CAP_ID_VNDR);
317 	if (!vndr)
318 		return -EINVAL;
319 
320 	/* Read the Logical SubSystem ID byte */
321 	pci_read_config_byte(pdev, vndr + INTEL_MID_PWR_LSS_OFFSET, &id);
322 	if (!(id & INTEL_MID_PWR_LSS_TYPE))
323 		return -ENODEV;
324 
325 	id &= ~INTEL_MID_PWR_LSS_TYPE;
326 	if (id >= LSS_MAX_DEVS)
327 		return -ERANGE;
328 
329 	return id;
330 }
331 
332 static irqreturn_t mid_pwr_irq_handler(int irq, void *dev_id)
333 {
334 	struct mid_pwr *pwr = dev_id;
335 	u32 ics;
336 
337 	ics = readl(pwr->regs + PM_ICS);
338 	if (!(ics & PM_ICS_IP))
339 		return IRQ_NONE;
340 
341 	writel(ics | PM_ICS_IP, pwr->regs + PM_ICS);
342 
343 	dev_warn(pwr->dev, "Unexpected IRQ: %#x\n", PM_ICS_INT_STATUS(ics));
344 	return IRQ_HANDLED;
345 }
346 
347 struct mid_pwr_device_info {
348 	int (*set_initial_state)(struct mid_pwr *pwr);
349 };
350 
351 static int mid_pwr_probe(struct pci_dev *pdev, const struct pci_device_id *id)
352 {
353 	struct mid_pwr_device_info *info = (void *)id->driver_data;
354 	struct device *dev = &pdev->dev;
355 	struct mid_pwr *pwr;
356 	int ret;
357 
358 	ret = pcim_enable_device(pdev);
359 	if (ret < 0) {
360 		dev_err(&pdev->dev, "error: could not enable device\n");
361 		return ret;
362 	}
363 
364 	ret = pcim_iomap_regions(pdev, 1 << 0, pci_name(pdev));
365 	if (ret) {
366 		dev_err(&pdev->dev, "I/O memory remapping failed\n");
367 		return ret;
368 	}
369 
370 	pwr = devm_kzalloc(dev, sizeof(*pwr), GFP_KERNEL);
371 	if (!pwr)
372 		return -ENOMEM;
373 
374 	pwr->dev = dev;
375 	pwr->regs = pcim_iomap_table(pdev)[0];
376 	pwr->irq = pdev->irq;
377 
378 	mutex_init(&pwr->lock);
379 
380 	/* Disable interrupts */
381 	mid_pwr_interrupt_disable(pwr);
382 
383 	if (info && info->set_initial_state) {
384 		ret = info->set_initial_state(pwr);
385 		if (ret)
386 			dev_warn(dev, "Can't set initial state: %d\n", ret);
387 	}
388 
389 	ret = devm_request_irq(dev, pdev->irq, mid_pwr_irq_handler,
390 			       IRQF_NO_SUSPEND, pci_name(pdev), pwr);
391 	if (ret)
392 		return ret;
393 
394 	pwr->available = true;
395 	midpwr = pwr;
396 
397 	pci_set_drvdata(pdev, pwr);
398 	return 0;
399 }
400 
401 static int mid_set_initial_state(struct mid_pwr *pwr, const u32 *states)
402 {
403 	unsigned int i, j;
404 	int ret;
405 
406 	/*
407 	 * Enable wake events.
408 	 *
409 	 * PWRMU supports up to 32 sources for wake up the system. Ungate them
410 	 * all here.
411 	 */
412 	mid_pwr_set_wake(pwr, 0, 0xffffffff);
413 	mid_pwr_set_wake(pwr, 1, 0xffffffff);
414 
415 	/*
416 	 * Power off South Complex devices.
417 	 *
418 	 * There is a map (see a note below) of 64 devices with 2 bits per each
419 	 * on 32-bit HW registers. The following calls set all devices to one
420 	 * known initial state, i.e. PCI_D3hot. This is done in conjunction
421 	 * with PMCSR setting in arch/x86/pci/intel_mid_pci.c.
422 	 *
423 	 * NOTE: The actual device mapping is provided by a platform at run
424 	 * time using vendor capability of PCI configuration space.
425 	 */
426 	mid_pwr_set_state(pwr, 0, states[0]);
427 	mid_pwr_set_state(pwr, 1, states[1]);
428 	mid_pwr_set_state(pwr, 2, states[2]);
429 	mid_pwr_set_state(pwr, 3, states[3]);
430 
431 	/* Send command to SCU */
432 	ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
433 	if (ret)
434 		return ret;
435 
436 	for (i = 0; i < LSS_MAX_DEVS; i++) {
437 		for (j = 0; j < LSS_MAX_SHARED_DEVS; j++)
438 			pwr->lss[i][j].state = PCI_D3hot;
439 	}
440 
441 	return 0;
442 }
443 
444 static int pnw_set_initial_state(struct mid_pwr *pwr)
445 {
446 	/* On Penwell SRAM must stay powered on */
447 	static const u32 states[] = {
448 		0xf00fffff,		/* PM_SSC(0) */
449 		0xffffffff,		/* PM_SSC(1) */
450 		0xffffffff,		/* PM_SSC(2) */
451 		0xffffffff,		/* PM_SSC(3) */
452 	};
453 	return mid_set_initial_state(pwr, states);
454 }
455 
456 static int tng_set_initial_state(struct mid_pwr *pwr)
457 {
458 	static const u32 states[] = {
459 		0xffffffff,		/* PM_SSC(0) */
460 		0xffffffff,		/* PM_SSC(1) */
461 		0xffffffff,		/* PM_SSC(2) */
462 		0xffffffff,		/* PM_SSC(3) */
463 	};
464 	return mid_set_initial_state(pwr, states);
465 }
466 
467 static const struct mid_pwr_device_info pnw_info = {
468 	.set_initial_state = pnw_set_initial_state,
469 };
470 
471 static const struct mid_pwr_device_info tng_info = {
472 	.set_initial_state = tng_set_initial_state,
473 };
474 
475 /* This table should be in sync with the one in drivers/pci/pci-mid.c */
476 static const struct pci_device_id mid_pwr_pci_ids[] = {
477 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PENWELL), (kernel_ulong_t)&pnw_info },
478 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_TANGIER), (kernel_ulong_t)&tng_info },
479 	{}
480 };
481 
482 static struct pci_driver mid_pwr_pci_driver = {
483 	.name		= "intel_mid_pwr",
484 	.probe		= mid_pwr_probe,
485 	.id_table	= mid_pwr_pci_ids,
486 };
487 
488 builtin_pci_driver(mid_pwr_pci_driver);
489