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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
89struct mid_pwr_dev {
90 struct pci_dev *pdev;
91 pci_power_t state;
92};
93
94struct 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
104static struct mid_pwr *midpwr;
105
106static u32 mid_pwr_get_state(struct mid_pwr *pwr, int reg)
107{
108 return readl(pwr->regs + PM_SSS(reg));
109}
110
111static void mid_pwr_set_state(struct mid_pwr *pwr, int reg, u32 value)
112{
113 writel(value, pwr->regs + PM_SSC(reg));
114}
115
116static void mid_pwr_set_wake(struct mid_pwr *pwr, int reg, u32 value)
117{
118 writel(value, pwr->regs + PM_WKC(reg));
119}
120
121static void mid_pwr_interrupt_disable(struct mid_pwr *pwr)
122{
123 writel(~PM_ICS_IE, pwr->regs + PM_ICS);
124}
125
126static 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 */
132static 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
147static 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
153static 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
182static 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
213static 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
232static 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
257int 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
271pci_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
290void 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
304int 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
329static 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
344struct mid_pwr_device_info {
345 int (*set_initial_state)(struct mid_pwr *pwr);
346};
347
348static 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
398static 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
441static 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
453static 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
464static const struct mid_pwr_device_info pnw_info = {
465 .set_initial_state = pnw_set_initial_state,
466};
467
468static 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 */
473static 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
479static 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
485builtin_pci_driver(mid_pwr_pci_driver);