2 * Intel MID Power Management Unit (PWRMU) device driver
4 * Copyright (C) 2016, Intel Corporation
6 * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
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.
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).
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 #include <linux/delay.h>
23 #include <linux/errno.h>
24 #include <linux/init.h>
25 #include <linux/interrupt.h>
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/mutex.h>
29 #include <linux/pci.h>
31 #include <asm/intel-mid.h>
37 #define PM_WKC(x) (0x10 + (x) * 4)
38 #define PM_WKS(x) (0x18 + (x) * 4)
39 #define PM_SSC(x) (0x20 + (x) * 4)
40 #define PM_SSS(x) (0x30 + (x) * 4)
43 #define PM_STS_BUSY (1 << 8)
46 #define PM_CMD_CMD(x) ((x) << 0)
47 #define PM_CMD_IOC (1 << 8)
48 #define PM_CMD_D3cold (1 << 21)
50 /* List of commands */
51 #define CMD_SET_CFG 0x01
54 #define PM_ICS_INT_STATUS(x) ((x) & 0xff)
55 #define PM_ICS_IE (1 << 8)
56 #define PM_ICS_IP (1 << 9)
57 #define PM_ICS_SW_INT_STS (1 << 10)
59 /* List of interrupts */
61 #define INT_CMD_COMPLETE 1
63 #define INT_WAKE_EVENT 3
64 #define INT_LSS_POWER_ERR 4
65 #define INT_S0iX_MSG_ERR 5
67 #define INT_TRIGGER_ERR 7
68 #define INT_INACTIVITY 8
70 /* South Complex devices */
71 #define LSS_MAX_SHARED_DEVS 4
72 #define LSS_MAX_DEVS 64
74 #define LSS_WS_BITS 1 /* wake state width */
75 #define LSS_PWS_BITS 2 /* power state width */
77 /* Supported device IDs */
78 #define PCI_DEVICE_ID_PENWELL 0x0828
79 #define PCI_DEVICE_ID_TANGIER 0x11a1
93 struct mid_pwr_dev lss[LSS_MAX_DEVS][LSS_MAX_SHARED_DEVS];
96 static struct mid_pwr *midpwr;
98 static u32 mid_pwr_get_state(struct mid_pwr *pwr, int reg)
100 return readl(pwr->regs + PM_SSS(reg));
103 static void mid_pwr_set_state(struct mid_pwr *pwr, int reg, u32 value)
105 writel(value, pwr->regs + PM_SSC(reg));
108 static void mid_pwr_set_wake(struct mid_pwr *pwr, int reg, u32 value)
110 writel(value, pwr->regs + PM_WKC(reg));
113 static void mid_pwr_interrupt_disable(struct mid_pwr *pwr)
115 writel(~PM_ICS_IE, pwr->regs + PM_ICS);
118 static bool mid_pwr_is_busy(struct mid_pwr *pwr)
120 return !!(readl(pwr->regs + PM_STS) & PM_STS_BUSY);
123 /* Wait 500ms that the latest PWRMU command finished */
124 static int mid_pwr_wait(struct mid_pwr *pwr)
126 unsigned int count = 500000;
130 busy = mid_pwr_is_busy(pwr);
139 static int mid_pwr_wait_for_cmd(struct mid_pwr *pwr, u8 cmd)
141 writel(PM_CMD_CMD(cmd), pwr->regs + PM_CMD);
142 return mid_pwr_wait(pwr);
145 static int __update_power_state(struct mid_pwr *pwr, int reg, int bit, int new)
151 /* Check if the device is already in desired state */
152 power = mid_pwr_get_state(pwr, reg);
153 curstate = (power >> bit) & 3;
157 /* Update the power state */
158 mid_pwr_set_state(pwr, reg, (power & ~(3 << bit)) | (new << bit));
160 /* Send command to SCU */
161 ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
165 /* Check if the device is already in desired state */
166 power = mid_pwr_get_state(pwr, reg);
167 curstate = (power >> bit) & 3;
174 static pci_power_t __find_weakest_power_state(struct mid_pwr_dev *lss,
175 struct pci_dev *pdev,
178 pci_power_t weakest = PCI_D3hot;
181 /* Find device in cache or first free cell */
182 for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
183 if (lss[j].pdev == pdev || !lss[j].pdev)
187 /* Store the desired state in cache */
188 if (j < LSS_MAX_SHARED_DEVS) {
190 lss[j].state = state;
192 dev_WARN(&pdev->dev, "No room for device in PWRMU LSS cache\n");
196 /* Find the power state we may use */
197 for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
198 if (lss[j].state < weakest)
199 weakest = lss[j].state;
205 static int __set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
206 pci_power_t state, int id, int reg, int bit)
211 state = __find_weakest_power_state(pwr->lss[id], pdev, state);
212 name = pci_power_name(state);
214 ret = __update_power_state(pwr, reg, bit, (__force int)state);
216 dev_warn(&pdev->dev, "Can't set power state %s: %d\n", name, ret);
220 dev_vdbg(&pdev->dev, "Set power state %s\n", name);
224 static int mid_pwr_set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
230 id = intel_mid_pwr_get_lss_id(pdev);
234 reg = (id * LSS_PWS_BITS) / 32;
235 bit = (id * LSS_PWS_BITS) % 32;
237 /* We support states between PCI_D0 and PCI_D3hot */
240 if (state > PCI_D3hot)
243 mutex_lock(&pwr->lock);
244 ret = __set_power_state(pwr, pdev, state, id, reg, bit);
245 mutex_unlock(&pwr->lock);
249 int intel_mid_pci_set_power_state(struct pci_dev *pdev, pci_power_t state)
251 struct mid_pwr *pwr = midpwr;
256 if (pwr && pwr->available)
257 ret = mid_pwr_set_power_state(pwr, pdev, state);
258 dev_vdbg(&pdev->dev, "set_power_state() returns %d\n", ret);
262 EXPORT_SYMBOL_GPL(intel_mid_pci_set_power_state);
264 int intel_mid_pwr_get_lss_id(struct pci_dev *pdev)
270 * Mapping to PWRMU index is kept in the Logical SubSystem ID byte of
273 vndr = pci_find_capability(pdev, PCI_CAP_ID_VNDR);
277 /* Read the Logical SubSystem ID byte */
278 pci_read_config_byte(pdev, vndr + INTEL_MID_PWR_LSS_OFFSET, &id);
279 if (!(id & INTEL_MID_PWR_LSS_TYPE))
282 id &= ~INTEL_MID_PWR_LSS_TYPE;
283 if (id >= LSS_MAX_DEVS)
289 static irqreturn_t mid_pwr_irq_handler(int irq, void *dev_id)
291 struct mid_pwr *pwr = dev_id;
294 ics = readl(pwr->regs + PM_ICS);
295 if (!(ics & PM_ICS_IP))
298 writel(ics | PM_ICS_IP, pwr->regs + PM_ICS);
300 dev_warn(pwr->dev, "Unexpected IRQ: %#x\n", PM_ICS_INT_STATUS(ics));
304 struct mid_pwr_device_info {
305 int (*set_initial_state)(struct mid_pwr *pwr);
308 static int mid_pwr_probe(struct pci_dev *pdev, const struct pci_device_id *id)
310 struct mid_pwr_device_info *info = (void *)id->driver_data;
311 struct device *dev = &pdev->dev;
315 ret = pcim_enable_device(pdev);
317 dev_err(&pdev->dev, "error: could not enable device\n");
321 ret = pcim_iomap_regions(pdev, 1 << 0, pci_name(pdev));
323 dev_err(&pdev->dev, "I/O memory remapping failed\n");
327 pwr = devm_kzalloc(dev, sizeof(*pwr), GFP_KERNEL);
332 pwr->regs = pcim_iomap_table(pdev)[0];
333 pwr->irq = pdev->irq;
335 mutex_init(&pwr->lock);
337 /* Disable interrupts */
338 mid_pwr_interrupt_disable(pwr);
340 if (info && info->set_initial_state) {
341 ret = info->set_initial_state(pwr);
343 dev_warn(dev, "Can't set initial state: %d\n", ret);
346 ret = devm_request_irq(dev, pdev->irq, mid_pwr_irq_handler,
347 IRQF_NO_SUSPEND, pci_name(pdev), pwr);
351 pwr->available = true;
354 pci_set_drvdata(pdev, pwr);
358 static int mid_set_initial_state(struct mid_pwr *pwr)
364 * Enable wake events.
366 * PWRMU supports up to 32 sources for wake up the system. Ungate them
369 mid_pwr_set_wake(pwr, 0, 0xffffffff);
370 mid_pwr_set_wake(pwr, 1, 0xffffffff);
373 * Power off South Complex devices.
375 * There is a map (see a note below) of 64 devices with 2 bits per each
376 * on 32-bit HW registers. The following calls set all devices to one
377 * known initial state, i.e. PCI_D3hot. This is done in conjunction
378 * with PMCSR setting in arch/x86/pci/intel_mid_pci.c.
380 * NOTE: The actual device mapping is provided by a platform at run
381 * time using vendor capability of PCI configuration space.
383 mid_pwr_set_state(pwr, 0, 0xffffffff);
384 mid_pwr_set_state(pwr, 1, 0xffffffff);
385 mid_pwr_set_state(pwr, 2, 0xffffffff);
386 mid_pwr_set_state(pwr, 3, 0xffffffff);
388 /* Send command to SCU */
389 ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
393 for (i = 0; i < LSS_MAX_DEVS; i++) {
394 for (j = 0; j < LSS_MAX_SHARED_DEVS; j++)
395 pwr->lss[i][j].state = PCI_D3hot;
401 static const struct mid_pwr_device_info mid_info = {
402 .set_initial_state = mid_set_initial_state,
405 static const struct pci_device_id mid_pwr_pci_ids[] = {
406 { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PENWELL), (kernel_ulong_t)&mid_info },
407 { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_TANGIER), (kernel_ulong_t)&mid_info },
410 MODULE_DEVICE_TABLE(pci, mid_pwr_pci_ids);
412 static struct pci_driver mid_pwr_pci_driver = {
413 .name = "intel_mid_pwr",
414 .probe = mid_pwr_probe,
415 .id_table = mid_pwr_pci_ids,
418 builtin_pci_driver(mid_pwr_pci_driver);