x86/platform/intel-mid: Keep SRAM powered on at boot
[deliverable/linux.git] / arch / x86 / platform / intel-mid / pwr.c
CommitLineData
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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>
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24#include <linux/interrupt.h>
25#include <linux/kernel.h>
cc3ae7b0 26#include <linux/export.h>
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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_D3cold (1 << 21)
48
49/* List of commands */
50#define CMD_SET_CFG 0x01
51
52/* Bits in PM_ICS */
53#define PM_ICS_INT_STATUS(x) ((x) & 0xff)
54#define PM_ICS_IE (1 << 8)
55#define PM_ICS_IP (1 << 9)
56#define PM_ICS_SW_INT_STS (1 << 10)
57
58/* List of interrupts */
59#define INT_INVALID 0
60#define INT_CMD_COMPLETE 1
61#define INT_CMD_ERR 2
62#define INT_WAKE_EVENT 3
63#define INT_LSS_POWER_ERR 4
64#define INT_S0iX_MSG_ERR 5
65#define INT_NO_C6 6
66#define INT_TRIGGER_ERR 7
67#define INT_INACTIVITY 8
68
69/* South Complex devices */
70#define LSS_MAX_SHARED_DEVS 4
71#define LSS_MAX_DEVS 64
72
73#define LSS_WS_BITS 1 /* wake state width */
74#define LSS_PWS_BITS 2 /* power state width */
75
76/* Supported device IDs */
ca22312d 77#define PCI_DEVICE_ID_PENWELL 0x0828
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78#define PCI_DEVICE_ID_TANGIER 0x11a1
79
80struct mid_pwr_dev {
81 struct pci_dev *pdev;
82 pci_power_t state;
83};
84
85struct mid_pwr {
86 struct device *dev;
87 void __iomem *regs;
88 int irq;
89 bool available;
90
91 struct mutex lock;
92 struct mid_pwr_dev lss[LSS_MAX_DEVS][LSS_MAX_SHARED_DEVS];
93};
94
95static struct mid_pwr *midpwr;
96
97static u32 mid_pwr_get_state(struct mid_pwr *pwr, int reg)
98{
99 return readl(pwr->regs + PM_SSS(reg));
100}
101
102static void mid_pwr_set_state(struct mid_pwr *pwr, int reg, u32 value)
103{
104 writel(value, pwr->regs + PM_SSC(reg));
105}
106
107static void mid_pwr_set_wake(struct mid_pwr *pwr, int reg, u32 value)
108{
109 writel(value, pwr->regs + PM_WKC(reg));
110}
111
112static void mid_pwr_interrupt_disable(struct mid_pwr *pwr)
113{
114 writel(~PM_ICS_IE, pwr->regs + PM_ICS);
115}
116
117static bool mid_pwr_is_busy(struct mid_pwr *pwr)
118{
119 return !!(readl(pwr->regs + PM_STS) & PM_STS_BUSY);
120}
121
122/* Wait 500ms that the latest PWRMU command finished */
123static int mid_pwr_wait(struct mid_pwr *pwr)
124{
125 unsigned int count = 500000;
126 bool busy;
127
128 do {
129 busy = mid_pwr_is_busy(pwr);
130 if (!busy)
131 return 0;
132 udelay(1);
133 } while (--count);
134
135 return -EBUSY;
136}
137
138static int mid_pwr_wait_for_cmd(struct mid_pwr *pwr, u8 cmd)
139{
140 writel(PM_CMD_CMD(cmd), pwr->regs + PM_CMD);
141 return mid_pwr_wait(pwr);
142}
143
144static int __update_power_state(struct mid_pwr *pwr, int reg, int bit, int new)
145{
146 int curstate;
147 u32 power;
148 int ret;
149
150 /* Check if the device is already in desired state */
151 power = mid_pwr_get_state(pwr, reg);
152 curstate = (power >> bit) & 3;
153 if (curstate == new)
154 return 0;
155
156 /* Update the power state */
157 mid_pwr_set_state(pwr, reg, (power & ~(3 << bit)) | (new << bit));
158
159 /* Send command to SCU */
160 ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
161 if (ret)
162 return ret;
163
164 /* Check if the device is already in desired state */
165 power = mid_pwr_get_state(pwr, reg);
166 curstate = (power >> bit) & 3;
167 if (curstate != new)
168 return -EAGAIN;
169
170 return 0;
171}
172
173static pci_power_t __find_weakest_power_state(struct mid_pwr_dev *lss,
174 struct pci_dev *pdev,
175 pci_power_t state)
176{
177 pci_power_t weakest = PCI_D3hot;
178 unsigned int j;
179
180 /* Find device in cache or first free cell */
181 for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
182 if (lss[j].pdev == pdev || !lss[j].pdev)
183 break;
184 }
185
186 /* Store the desired state in cache */
187 if (j < LSS_MAX_SHARED_DEVS) {
188 lss[j].pdev = pdev;
189 lss[j].state = state;
190 } else {
191 dev_WARN(&pdev->dev, "No room for device in PWRMU LSS cache\n");
192 weakest = state;
193 }
194
195 /* Find the power state we may use */
196 for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
197 if (lss[j].state < weakest)
198 weakest = lss[j].state;
199 }
200
201 return weakest;
202}
203
204static int __set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
205 pci_power_t state, int id, int reg, int bit)
206{
207 const char *name;
208 int ret;
209
210 state = __find_weakest_power_state(pwr->lss[id], pdev, state);
211 name = pci_power_name(state);
212
213 ret = __update_power_state(pwr, reg, bit, (__force int)state);
214 if (ret) {
215 dev_warn(&pdev->dev, "Can't set power state %s: %d\n", name, ret);
216 return ret;
217 }
218
219 dev_vdbg(&pdev->dev, "Set power state %s\n", name);
220 return 0;
221}
222
223static int mid_pwr_set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
224 pci_power_t state)
225{
226 int id, reg, bit;
227 int ret;
228
229 id = intel_mid_pwr_get_lss_id(pdev);
230 if (id < 0)
231 return id;
232
233 reg = (id * LSS_PWS_BITS) / 32;
234 bit = (id * LSS_PWS_BITS) % 32;
235
236 /* We support states between PCI_D0 and PCI_D3hot */
237 if (state < PCI_D0)
238 state = PCI_D0;
239 if (state > PCI_D3hot)
240 state = PCI_D3hot;
241
242 mutex_lock(&pwr->lock);
243 ret = __set_power_state(pwr, pdev, state, id, reg, bit);
244 mutex_unlock(&pwr->lock);
245 return ret;
246}
247
248int intel_mid_pci_set_power_state(struct pci_dev *pdev, pci_power_t state)
249{
250 struct mid_pwr *pwr = midpwr;
251 int ret = 0;
252
253 might_sleep();
254
255 if (pwr && pwr->available)
256 ret = mid_pwr_set_power_state(pwr, pdev, state);
257 dev_vdbg(&pdev->dev, "set_power_state() returns %d\n", ret);
258
259 return 0;
260}
261EXPORT_SYMBOL_GPL(intel_mid_pci_set_power_state);
262
263int intel_mid_pwr_get_lss_id(struct pci_dev *pdev)
264{
265 int vndr;
266 u8 id;
267
268 /*
269 * Mapping to PWRMU index is kept in the Logical SubSystem ID byte of
270 * Vendor capability.
271 */
272 vndr = pci_find_capability(pdev, PCI_CAP_ID_VNDR);
273 if (!vndr)
274 return -EINVAL;
275
276 /* Read the Logical SubSystem ID byte */
277 pci_read_config_byte(pdev, vndr + INTEL_MID_PWR_LSS_OFFSET, &id);
278 if (!(id & INTEL_MID_PWR_LSS_TYPE))
279 return -ENODEV;
280
281 id &= ~INTEL_MID_PWR_LSS_TYPE;
282 if (id >= LSS_MAX_DEVS)
283 return -ERANGE;
284
285 return id;
286}
287
288static irqreturn_t mid_pwr_irq_handler(int irq, void *dev_id)
289{
290 struct mid_pwr *pwr = dev_id;
291 u32 ics;
292
293 ics = readl(pwr->regs + PM_ICS);
294 if (!(ics & PM_ICS_IP))
295 return IRQ_NONE;
296
297 writel(ics | PM_ICS_IP, pwr->regs + PM_ICS);
298
299 dev_warn(pwr->dev, "Unexpected IRQ: %#x\n", PM_ICS_INT_STATUS(ics));
300 return IRQ_HANDLED;
301}
302
303struct mid_pwr_device_info {
304 int (*set_initial_state)(struct mid_pwr *pwr);
305};
306
307static int mid_pwr_probe(struct pci_dev *pdev, const struct pci_device_id *id)
308{
309 struct mid_pwr_device_info *info = (void *)id->driver_data;
310 struct device *dev = &pdev->dev;
311 struct mid_pwr *pwr;
312 int ret;
313
314 ret = pcim_enable_device(pdev);
315 if (ret < 0) {
316 dev_err(&pdev->dev, "error: could not enable device\n");
317 return ret;
318 }
319
320 ret = pcim_iomap_regions(pdev, 1 << 0, pci_name(pdev));
321 if (ret) {
322 dev_err(&pdev->dev, "I/O memory remapping failed\n");
323 return ret;
324 }
325
326 pwr = devm_kzalloc(dev, sizeof(*pwr), GFP_KERNEL);
327 if (!pwr)
328 return -ENOMEM;
329
330 pwr->dev = dev;
331 pwr->regs = pcim_iomap_table(pdev)[0];
332 pwr->irq = pdev->irq;
333
334 mutex_init(&pwr->lock);
335
336 /* Disable interrupts */
337 mid_pwr_interrupt_disable(pwr);
338
339 if (info && info->set_initial_state) {
340 ret = info->set_initial_state(pwr);
341 if (ret)
342 dev_warn(dev, "Can't set initial state: %d\n", ret);
343 }
344
345 ret = devm_request_irq(dev, pdev->irq, mid_pwr_irq_handler,
346 IRQF_NO_SUSPEND, pci_name(pdev), pwr);
347 if (ret)
348 return ret;
349
350 pwr->available = true;
351 midpwr = pwr;
352
353 pci_set_drvdata(pdev, pwr);
354 return 0;
355}
356
4c314987 357static int mid_set_initial_state(struct mid_pwr *pwr, const u32 *states)
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358{
359 unsigned int i, j;
360 int ret;
361
362 /*
363 * Enable wake events.
364 *
365 * PWRMU supports up to 32 sources for wake up the system. Ungate them
366 * all here.
367 */
368 mid_pwr_set_wake(pwr, 0, 0xffffffff);
369 mid_pwr_set_wake(pwr, 1, 0xffffffff);
370
371 /*
372 * Power off South Complex devices.
373 *
374 * There is a map (see a note below) of 64 devices with 2 bits per each
375 * on 32-bit HW registers. The following calls set all devices to one
376 * known initial state, i.e. PCI_D3hot. This is done in conjunction
377 * with PMCSR setting in arch/x86/pci/intel_mid_pci.c.
378 *
379 * NOTE: The actual device mapping is provided by a platform at run
380 * time using vendor capability of PCI configuration space.
381 */
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382 mid_pwr_set_state(pwr, 0, states[0]);
383 mid_pwr_set_state(pwr, 1, states[1]);
384 mid_pwr_set_state(pwr, 2, states[2]);
385 mid_pwr_set_state(pwr, 3, states[3]);
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386
387 /* Send command to SCU */
388 ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
389 if (ret)
390 return ret;
391
392 for (i = 0; i < LSS_MAX_DEVS; i++) {
393 for (j = 0; j < LSS_MAX_SHARED_DEVS; j++)
394 pwr->lss[i][j].state = PCI_D3hot;
395 }
396
397 return 0;
398}
399
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400static int pnw_set_initial_state(struct mid_pwr *pwr)
401{
402 /* On Penwell SRAM must stay powered on */
403 const u32 states[] = {
404 0xf00fffff, /* PM_SSC(0) */
405 0xffffffff, /* PM_SSC(1) */
406 0xffffffff, /* PM_SSC(2) */
407 0xffffffff, /* PM_SSC(3) */
408 };
409 return mid_set_initial_state(pwr, states);
410}
411
412static int tng_set_initial_state(struct mid_pwr *pwr)
413{
414 const u32 states[] = {
415 0xffffffff, /* PM_SSC(0) */
416 0xffffffff, /* PM_SSC(1) */
417 0xffffffff, /* PM_SSC(2) */
418 0xffffffff, /* PM_SSC(3) */
419 };
420 return mid_set_initial_state(pwr, states);
421}
422
423static const struct mid_pwr_device_info pnw_info = {
424 .set_initial_state = pnw_set_initial_state,
425};
426
427static const struct mid_pwr_device_info tng_info = {
428 .set_initial_state = tng_set_initial_state,
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429};
430
768235b2 431/* This table should be in sync with the one in drivers/pci/pci-mid.c */
5823d089 432static const struct pci_device_id mid_pwr_pci_ids[] = {
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433 { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PENWELL), (kernel_ulong_t)&pnw_info },
434 { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_TANGIER), (kernel_ulong_t)&tng_info },
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435 {}
436};
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437
438static struct pci_driver mid_pwr_pci_driver = {
439 .name = "intel_mid_pwr",
440 .probe = mid_pwr_probe,
441 .id_table = mid_pwr_pci_ids,
442};
443
444builtin_pci_driver(mid_pwr_pci_driver);
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