xref: /openbmc/linux/arch/x86/platform/intel-mid/pwr.c (revision b8265621) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Intel MID Power Management Unit (PWRMU) device driver
4  *
5  * Copyright (C) 2016, Intel Corporation
6  *
7  * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
8  *
9  * Intel MID Power Management Unit device driver handles the South Complex PCI
10  * devices such as GPDMA, SPI, I2C, PWM, and so on. By default PCI core
11  * modifies bits in PMCSR register in the PCI configuration space. This is not
12  * enough on some SoCs like Intel Tangier. In such case PCI core sets a new
13  * power state of the device in question through a PM hook registered in struct
14  * pci_platform_pm_ops (see drivers/pci/pci-mid.c).
15  */
16 
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 
19 #include <linux/delay.h>
20 #include <linux/errno.h>
21 #include <linux/interrupt.h>
22 #include <linux/kernel.h>
23 #include <linux/export.h>
24 #include <linux/mutex.h>
25 #include <linux/pci.h>
26 
27 #include <asm/intel-mid.h>
28 
29 /* Registers */
30 #define PM_STS			0x00
31 #define PM_CMD			0x04
32 #define PM_ICS			0x08
33 #define PM_WKC(x)		(0x10 + (x) * 4)
34 #define PM_WKS(x)		(0x18 + (x) * 4)
35 #define PM_SSC(x)		(0x20 + (x) * 4)
36 #define PM_SSS(x)		(0x30 + (x) * 4)
37 
38 /* Bits in PM_STS */
39 #define PM_STS_BUSY		(1 << 8)
40 
41 /* Bits in PM_CMD */
42 #define PM_CMD_CMD(x)		((x) << 0)
43 #define PM_CMD_IOC		(1 << 8)
44 #define PM_CMD_CM_NOP		(0 << 9)
45 #define PM_CMD_CM_IMMEDIATE	(1 << 9)
46 #define PM_CMD_CM_DELAY		(2 << 9)
47 #define PM_CMD_CM_TRIGGER	(3 << 9)
48 
49 /* System states */
50 #define PM_CMD_SYS_STATE_S5	(5 << 16)
51 
52 /* Trigger variants */
53 #define PM_CMD_CFG_TRIGGER_NC	(3 << 19)
54 
55 /* Message to wait for TRIGGER_NC case */
56 #define TRIGGER_NC_MSG_2	(2 << 22)
57 
58 /* List of commands */
59 #define CMD_SET_CFG		0x01
60 
61 /* Bits in PM_ICS */
62 #define PM_ICS_INT_STATUS(x)	((x) & 0xff)
63 #define PM_ICS_IE		(1 << 8)
64 #define PM_ICS_IP		(1 << 9)
65 #define PM_ICS_SW_INT_STS	(1 << 10)
66 
67 /* List of interrupts */
68 #define INT_INVALID		0
69 #define INT_CMD_COMPLETE	1
70 #define INT_CMD_ERR		2
71 #define INT_WAKE_EVENT		3
72 #define INT_LSS_POWER_ERR	4
73 #define INT_S0iX_MSG_ERR	5
74 #define INT_NO_C6		6
75 #define INT_TRIGGER_ERR		7
76 #define INT_INACTIVITY		8
77 
78 /* South Complex devices */
79 #define LSS_MAX_SHARED_DEVS	4
80 #define LSS_MAX_DEVS		64
81 
82 #define LSS_WS_BITS		1	/* wake state width */
83 #define LSS_PWS_BITS		2	/* power state width */
84 
85 /* Supported device IDs */
86 #define PCI_DEVICE_ID_PENWELL	0x0828
87 #define PCI_DEVICE_ID_TANGIER	0x11a1
88 
89 struct mid_pwr_dev {
90 	struct pci_dev *pdev;
91 	pci_power_t state;
92 };
93 
94 struct mid_pwr {
95 	struct device *dev;
96 	void __iomem *regs;
97 	int irq;
98 	bool available;
99 
100 	struct mutex lock;
101 	struct mid_pwr_dev lss[LSS_MAX_DEVS][LSS_MAX_SHARED_DEVS];
102 };
103 
104 static struct mid_pwr *midpwr;
105 
106 static u32 mid_pwr_get_state(struct mid_pwr *pwr, int reg)
107 {
108 	return readl(pwr->regs + PM_SSS(reg));
109 }
110 
111 static void mid_pwr_set_state(struct mid_pwr *pwr, int reg, u32 value)
112 {
113 	writel(value, pwr->regs + PM_SSC(reg));
114 }
115 
116 static void mid_pwr_set_wake(struct mid_pwr *pwr, int reg, u32 value)
117 {
118 	writel(value, pwr->regs + PM_WKC(reg));
119 }
120 
121 static void mid_pwr_interrupt_disable(struct mid_pwr *pwr)
122 {
123 	writel(~PM_ICS_IE, pwr->regs + PM_ICS);
124 }
125 
126 static bool mid_pwr_is_busy(struct mid_pwr *pwr)
127 {
128 	return !!(readl(pwr->regs + PM_STS) & PM_STS_BUSY);
129 }
130 
131 /* Wait 500ms that the latest PWRMU command finished */
132 static int mid_pwr_wait(struct mid_pwr *pwr)
133 {
134 	unsigned int count = 500000;
135 	bool busy;
136 
137 	do {
138 		busy = mid_pwr_is_busy(pwr);
139 		if (!busy)
140 			return 0;
141 		udelay(1);
142 	} while (--count);
143 
144 	return -EBUSY;
145 }
146 
147 static int mid_pwr_wait_for_cmd(struct mid_pwr *pwr, u8 cmd)
148 {
149 	writel(PM_CMD_CMD(cmd) | PM_CMD_CM_IMMEDIATE, pwr->regs + PM_CMD);
150 	return mid_pwr_wait(pwr);
151 }
152 
153 static int __update_power_state(struct mid_pwr *pwr, int reg, int bit, int new)
154 {
155 	int curstate;
156 	u32 power;
157 	int ret;
158 
159 	/* Check if the device is already in desired state */
160 	power = mid_pwr_get_state(pwr, reg);
161 	curstate = (power >> bit) & 3;
162 	if (curstate == new)
163 		return 0;
164 
165 	/* Update the power state */
166 	mid_pwr_set_state(pwr, reg, (power & ~(3 << bit)) | (new << bit));
167 
168 	/* Send command to SCU */
169 	ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
170 	if (ret)
171 		return ret;
172 
173 	/* Check if the device is already in desired state */
174 	power = mid_pwr_get_state(pwr, reg);
175 	curstate = (power >> bit) & 3;
176 	if (curstate != new)
177 		return -EAGAIN;
178 
179 	return 0;
180 }
181 
182 static pci_power_t __find_weakest_power_state(struct mid_pwr_dev *lss,
183 					      struct pci_dev *pdev,
184 					      pci_power_t state)
185 {
186 	pci_power_t weakest = PCI_D3hot;
187 	unsigned int j;
188 
189 	/* Find device in cache or first free cell */
190 	for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
191 		if (lss[j].pdev == pdev || !lss[j].pdev)
192 			break;
193 	}
194 
195 	/* Store the desired state in cache */
196 	if (j < LSS_MAX_SHARED_DEVS) {
197 		lss[j].pdev = pdev;
198 		lss[j].state = state;
199 	} else {
200 		dev_WARN(&pdev->dev, "No room for device in PWRMU LSS cache\n");
201 		weakest = state;
202 	}
203 
204 	/* Find the power state we may use */
205 	for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
206 		if (lss[j].state < weakest)
207 			weakest = lss[j].state;
208 	}
209 
210 	return weakest;
211 }
212 
213 static int __set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
214 			     pci_power_t state, int id, int reg, int bit)
215 {
216 	const char *name;
217 	int ret;
218 
219 	state = __find_weakest_power_state(pwr->lss[id], pdev, state);
220 	name = pci_power_name(state);
221 
222 	ret = __update_power_state(pwr, reg, bit, (__force int)state);
223 	if (ret) {
224 		dev_warn(&pdev->dev, "Can't set power state %s: %d\n", name, ret);
225 		return ret;
226 	}
227 
228 	dev_vdbg(&pdev->dev, "Set power state %s\n", name);
229 	return 0;
230 }
231 
232 static int mid_pwr_set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
233 				   pci_power_t state)
234 {
235 	int id, reg, bit;
236 	int ret;
237 
238 	id = intel_mid_pwr_get_lss_id(pdev);
239 	if (id < 0)
240 		return id;
241 
242 	reg = (id * LSS_PWS_BITS) / 32;
243 	bit = (id * LSS_PWS_BITS) % 32;
244 
245 	/* We support states between PCI_D0 and PCI_D3hot */
246 	if (state < PCI_D0)
247 		state = PCI_D0;
248 	if (state > PCI_D3hot)
249 		state = PCI_D3hot;
250 
251 	mutex_lock(&pwr->lock);
252 	ret = __set_power_state(pwr, pdev, state, id, reg, bit);
253 	mutex_unlock(&pwr->lock);
254 	return ret;
255 }
256 
257 int intel_mid_pci_set_power_state(struct pci_dev *pdev, pci_power_t state)
258 {
259 	struct mid_pwr *pwr = midpwr;
260 	int ret = 0;
261 
262 	might_sleep();
263 
264 	if (pwr && pwr->available)
265 		ret = mid_pwr_set_power_state(pwr, pdev, state);
266 	dev_vdbg(&pdev->dev, "set_power_state() returns %d\n", ret);
267 
268 	return 0;
269 }
270 
271 pci_power_t intel_mid_pci_get_power_state(struct pci_dev *pdev)
272 {
273 	struct mid_pwr *pwr = midpwr;
274 	int id, reg, bit;
275 	u32 power;
276 
277 	if (!pwr || !pwr->available)
278 		return PCI_UNKNOWN;
279 
280 	id = intel_mid_pwr_get_lss_id(pdev);
281 	if (id < 0)
282 		return PCI_UNKNOWN;
283 
284 	reg = (id * LSS_PWS_BITS) / 32;
285 	bit = (id * LSS_PWS_BITS) % 32;
286 	power = mid_pwr_get_state(pwr, reg);
287 	return (__force pci_power_t)((power >> bit) & 3);
288 }
289 
290 void intel_mid_pwr_power_off(void)
291 {
292 	struct mid_pwr *pwr = midpwr;
293 	u32 cmd = PM_CMD_SYS_STATE_S5 |
294 		  PM_CMD_CMD(CMD_SET_CFG) |
295 		  PM_CMD_CM_TRIGGER |
296 		  PM_CMD_CFG_TRIGGER_NC |
297 		  TRIGGER_NC_MSG_2;
298 
299 	/* Send command to SCU */
300 	writel(cmd, pwr->regs + PM_CMD);
301 	mid_pwr_wait(pwr);
302 }
303 
304 int intel_mid_pwr_get_lss_id(struct pci_dev *pdev)
305 {
306 	int vndr;
307 	u8 id;
308 
309 	/*
310 	 * Mapping to PWRMU index is kept in the Logical SubSystem ID byte of
311 	 * Vendor capability.
312 	 */
313 	vndr = pci_find_capability(pdev, PCI_CAP_ID_VNDR);
314 	if (!vndr)
315 		return -EINVAL;
316 
317 	/* Read the Logical SubSystem ID byte */
318 	pci_read_config_byte(pdev, vndr + INTEL_MID_PWR_LSS_OFFSET, &id);
319 	if (!(id & INTEL_MID_PWR_LSS_TYPE))
320 		return -ENODEV;
321 
322 	id &= ~INTEL_MID_PWR_LSS_TYPE;
323 	if (id >= LSS_MAX_DEVS)
324 		return -ERANGE;
325 
326 	return id;
327 }
328 
329 static irqreturn_t mid_pwr_irq_handler(int irq, void *dev_id)
330 {
331 	struct mid_pwr *pwr = dev_id;
332 	u32 ics;
333 
334 	ics = readl(pwr->regs + PM_ICS);
335 	if (!(ics & PM_ICS_IP))
336 		return IRQ_NONE;
337 
338 	writel(ics | PM_ICS_IP, pwr->regs + PM_ICS);
339 
340 	dev_warn(pwr->dev, "Unexpected IRQ: %#x\n", PM_ICS_INT_STATUS(ics));
341 	return IRQ_HANDLED;
342 }
343 
344 struct mid_pwr_device_info {
345 	int (*set_initial_state)(struct mid_pwr *pwr);
346 };
347 
348 static int mid_pwr_probe(struct pci_dev *pdev, const struct pci_device_id *id)
349 {
350 	struct mid_pwr_device_info *info = (void *)id->driver_data;
351 	struct device *dev = &pdev->dev;
352 	struct mid_pwr *pwr;
353 	int ret;
354 
355 	ret = pcim_enable_device(pdev);
356 	if (ret < 0) {
357 		dev_err(&pdev->dev, "error: could not enable device\n");
358 		return ret;
359 	}
360 
361 	ret = pcim_iomap_regions(pdev, 1 << 0, pci_name(pdev));
362 	if (ret) {
363 		dev_err(&pdev->dev, "I/O memory remapping failed\n");
364 		return ret;
365 	}
366 
367 	pwr = devm_kzalloc(dev, sizeof(*pwr), GFP_KERNEL);
368 	if (!pwr)
369 		return -ENOMEM;
370 
371 	pwr->dev = dev;
372 	pwr->regs = pcim_iomap_table(pdev)[0];
373 	pwr->irq = pdev->irq;
374 
375 	mutex_init(&pwr->lock);
376 
377 	/* Disable interrupts */
378 	mid_pwr_interrupt_disable(pwr);
379 
380 	if (info && info->set_initial_state) {
381 		ret = info->set_initial_state(pwr);
382 		if (ret)
383 			dev_warn(dev, "Can't set initial state: %d\n", ret);
384 	}
385 
386 	ret = devm_request_irq(dev, pdev->irq, mid_pwr_irq_handler,
387 			       IRQF_NO_SUSPEND, pci_name(pdev), pwr);
388 	if (ret)
389 		return ret;
390 
391 	pwr->available = true;
392 	midpwr = pwr;
393 
394 	pci_set_drvdata(pdev, pwr);
395 	return 0;
396 }
397 
398 static int mid_set_initial_state(struct mid_pwr *pwr, const u32 *states)
399 {
400 	unsigned int i, j;
401 	int ret;
402 
403 	/*
404 	 * Enable wake events.
405 	 *
406 	 * PWRMU supports up to 32 sources for wake up the system. Ungate them
407 	 * all here.
408 	 */
409 	mid_pwr_set_wake(pwr, 0, 0xffffffff);
410 	mid_pwr_set_wake(pwr, 1, 0xffffffff);
411 
412 	/*
413 	 * Power off South Complex devices.
414 	 *
415 	 * There is a map (see a note below) of 64 devices with 2 bits per each
416 	 * on 32-bit HW registers. The following calls set all devices to one
417 	 * known initial state, i.e. PCI_D3hot. This is done in conjunction
418 	 * with PMCSR setting in arch/x86/pci/intel_mid_pci.c.
419 	 *
420 	 * NOTE: The actual device mapping is provided by a platform at run
421 	 * time using vendor capability of PCI configuration space.
422 	 */
423 	mid_pwr_set_state(pwr, 0, states[0]);
424 	mid_pwr_set_state(pwr, 1, states[1]);
425 	mid_pwr_set_state(pwr, 2, states[2]);
426 	mid_pwr_set_state(pwr, 3, states[3]);
427 
428 	/* Send command to SCU */
429 	ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
430 	if (ret)
431 		return ret;
432 
433 	for (i = 0; i < LSS_MAX_DEVS; i++) {
434 		for (j = 0; j < LSS_MAX_SHARED_DEVS; j++)
435 			pwr->lss[i][j].state = PCI_D3hot;
436 	}
437 
438 	return 0;
439 }
440 
441 static int pnw_set_initial_state(struct mid_pwr *pwr)
442 {
443 	/* On Penwell SRAM must stay powered on */
444 	static const u32 states[] = {
445 		0xf00fffff,		/* PM_SSC(0) */
446 		0xffffffff,		/* PM_SSC(1) */
447 		0xffffffff,		/* PM_SSC(2) */
448 		0xffffffff,		/* PM_SSC(3) */
449 	};
450 	return mid_set_initial_state(pwr, states);
451 }
452 
453 static int tng_set_initial_state(struct mid_pwr *pwr)
454 {
455 	static const u32 states[] = {
456 		0xffffffff,		/* PM_SSC(0) */
457 		0xffffffff,		/* PM_SSC(1) */
458 		0xffffffff,		/* PM_SSC(2) */
459 		0xffffffff,		/* PM_SSC(3) */
460 	};
461 	return mid_set_initial_state(pwr, states);
462 }
463 
464 static const struct mid_pwr_device_info pnw_info = {
465 	.set_initial_state = pnw_set_initial_state,
466 };
467 
468 static const struct mid_pwr_device_info tng_info = {
469 	.set_initial_state = tng_set_initial_state,
470 };
471 
472 /* This table should be in sync with the one in drivers/pci/pci-mid.c */
473 static const struct pci_device_id mid_pwr_pci_ids[] = {
474 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PENWELL), (kernel_ulong_t)&pnw_info },
475 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_TANGIER), (kernel_ulong_t)&tng_info },
476 	{}
477 };
478 
479 static struct pci_driver mid_pwr_pci_driver = {
480 	.name		= "intel_mid_pwr",
481 	.probe		= mid_pwr_probe,
482 	.id_table	= mid_pwr_pci_ids,
483 };
484 
485 builtin_pci_driver(mid_pwr_pci_driver);
486