1 files changed, 485 insertions, 0 deletions
diff --git a/arch/x86/platform/intel-mid/pwr.c b/arch/x86/platform/intel-mid/pwr.c
new file mode 100644
index 000000000..27288d8d3
--- /dev/null
+++ b/arch/x86/platform/intel-mid/pwr.c
@@ -0,0 +1,485 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel MID Power Management Unit (PWRMU) device driver
+ *
+ * Copyright (C) 2016, Intel Corporation
+ *
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *
+ * Intel MID Power Management Unit device driver handles the South Complex PCI
+ * devices such as GPDMA, SPI, I2C, PWM, and so on. By default PCI core
+ * modifies bits in PMCSR register in the PCI configuration space. This is not
+ * enough on some SoCs like Intel Tangier. In such case PCI core sets a new
+ * power state of the device in question through a PM hook registered in struct
+ * pci_platform_pm_ops (see drivers/pci/pci-mid.c).
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+
+#include <asm/intel-mid.h>
+
+/* Registers */
+#define PM_STS			0x00
+#define PM_CMD			0x04
+#define PM_ICS			0x08
+#define PM_WKC(x)		(0x10 + (x) * 4)
+#define PM_WKS(x)		(0x18 + (x) * 4)
+#define PM_SSC(x)		(0x20 + (x) * 4)
+#define PM_SSS(x)		(0x30 + (x) * 4)
+
+/* Bits in PM_STS */
+#define PM_STS_BUSY		(1 << 8)
+
+/* Bits in PM_CMD */
+#define PM_CMD_CMD(x)		((x) << 0)
+#define PM_CMD_IOC		(1 << 8)
+#define PM_CMD_CM_NOP		(0 << 9)
+#define PM_CMD_CM_IMMEDIATE	(1 << 9)
+#define PM_CMD_CM_DELAY		(2 << 9)
+#define PM_CMD_CM_TRIGGER	(3 << 9)
+
+/* System states */
+#define PM_CMD_SYS_STATE_S5	(5 << 16)
+
+/* Trigger variants */
+#define PM_CMD_CFG_TRIGGER_NC	(3 << 19)
+
+/* Message to wait for TRIGGER_NC case */
+#define TRIGGER_NC_MSG_2	(2 << 22)
+
+/* List of commands */
+#define CMD_SET_CFG		0x01
+
+/* Bits in PM_ICS */
+#define PM_ICS_INT_STATUS(x)	((x) & 0xff)
+#define PM_ICS_IE		(1 << 8)
+#define PM_ICS_IP		(1 << 9)
+#define PM_ICS_SW_INT_STS	(1 << 10)
+
+/* List of interrupts */
+#define INT_INVALID		0
+#define INT_CMD_COMPLETE	1
+#define INT_CMD_ERR		2
+#define INT_WAKE_EVENT		3
+#define INT_LSS_POWER_ERR	4
+#define INT_S0iX_MSG_ERR	5
+#define INT_NO_C6		6
+#define INT_TRIGGER_ERR		7
+#define INT_INACTIVITY		8
+
+/* South Complex devices */
+#define LSS_MAX_SHARED_DEVS	4
+#define LSS_MAX_DEVS		64
+
+#define LSS_WS_BITS		1	/* wake state width */
+#define LSS_PWS_BITS		2	/* power state width */
+
+/* Supported device IDs */
+#define PCI_DEVICE_ID_PENWELL	0x0828
+#define PCI_DEVICE_ID_TANGIER	0x11a1
+
+struct mid_pwr_dev {
+	struct pci_dev *pdev;
+	pci_power_t state;
+};
+
+struct mid_pwr {
+	struct device *dev;
+	void __iomem *regs;
+	int irq;
+	bool available;
+
+	struct mutex lock;
+	struct mid_pwr_dev lss[LSS_MAX_DEVS][LSS_MAX_SHARED_DEVS];
+};
+
+static struct mid_pwr *midpwr;
+
+static u32 mid_pwr_get_state(struct mid_pwr *pwr, int reg)
+{
+	return readl(pwr->regs + PM_SSS(reg));
+}
+
+static void mid_pwr_set_state(struct mid_pwr *pwr, int reg, u32 value)
+{
+	writel(value, pwr->regs + PM_SSC(reg));
+}
+
+static void mid_pwr_set_wake(struct mid_pwr *pwr, int reg, u32 value)
+{
+	writel(value, pwr->regs + PM_WKC(reg));
+}
+
+static void mid_pwr_interrupt_disable(struct mid_pwr *pwr)
+{
+	writel(~PM_ICS_IE, pwr->regs + PM_ICS);
+}
+
+static bool mid_pwr_is_busy(struct mid_pwr *pwr)
+{
+	return !!(readl(pwr->regs + PM_STS) & PM_STS_BUSY);
+}
+
+/* Wait 500ms that the latest PWRMU command finished */
+static int mid_pwr_wait(struct mid_pwr *pwr)
+{
+	unsigned int count = 500000;
+	bool busy;
+
+	do {
+		busy = mid_pwr_is_busy(pwr);
+		if (!busy)
+			return 0;
+		udelay(1);
+	} while (--count);
+
+	return -EBUSY;
+}
+
+static int mid_pwr_wait_for_cmd(struct mid_pwr *pwr, u8 cmd)
+{
+	writel(PM_CMD_CMD(cmd) | PM_CMD_CM_IMMEDIATE, pwr->regs + PM_CMD);
+	return mid_pwr_wait(pwr);
+}
+
+static int __update_power_state(struct mid_pwr *pwr, int reg, int bit, int new)
+{
+	int curstate;
+	u32 power;
+	int ret;
+
+	/* Check if the device is already in desired state */
+	power = mid_pwr_get_state(pwr, reg);
+	curstate = (power >> bit) & 3;
+	if (curstate == new)
+		return 0;
+
+	/* Update the power state */
+	mid_pwr_set_state(pwr, reg, (power & ~(3 << bit)) | (new << bit));
+
+	/* Send command to SCU */
+	ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
+	if (ret)
+		return ret;
+
+	/* Check if the device is already in desired state */
+	power = mid_pwr_get_state(pwr, reg);
+	curstate = (power >> bit) & 3;
+	if (curstate != new)
+		return -EAGAIN;
+
+	return 0;
+}
+
+static pci_power_t __find_weakest_power_state(struct mid_pwr_dev *lss,
+					      struct pci_dev *pdev,
+					      pci_power_t state)
+{
+	pci_power_t weakest = PCI_D3hot;
+	unsigned int j;
+
+	/* Find device in cache or first free cell */
+	for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
+		if (lss[j].pdev == pdev || !lss[j].pdev)
+			break;
+	}
+
+	/* Store the desired state in cache */
+	if (j < LSS_MAX_SHARED_DEVS) {
+		lss[j].pdev = pdev;
+		lss[j].state = state;
+	} else {
+		dev_WARN(&pdev->dev, "No room for device in PWRMU LSS cache\n");
+		weakest = state;
+	}
+
+	/* Find the power state we may use */
+	for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
+		if (lss[j].state < weakest)
+			weakest = lss[j].state;
+	}
+
+	return weakest;
+}
+
+static int __set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
+			     pci_power_t state, int id, int reg, int bit)
+{
+	const char *name;
+	int ret;
+
+	state = __find_weakest_power_state(pwr->lss[id], pdev, state);
+	name = pci_power_name(state);
+
+	ret = __update_power_state(pwr, reg, bit, (__force int)state);
+	if (ret) {
+		dev_warn(&pdev->dev, "Can't set power state %s: %d\n", name, ret);
+		return ret;
+	}
+
+	dev_vdbg(&pdev->dev, "Set power state %s\n", name);
+	return 0;
+}
+
+static int mid_pwr_set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
+				   pci_power_t state)
+{
+	int id, reg, bit;
+	int ret;
+
+	id = intel_mid_pwr_get_lss_id(pdev);
+	if (id < 0)
+		return id;
+
+	reg = (id * LSS_PWS_BITS) / 32;
+	bit = (id * LSS_PWS_BITS) % 32;
+
+	/* We support states between PCI_D0 and PCI_D3hot */
+	if (state < PCI_D0)
+		state = PCI_D0;
+	if (state > PCI_D3hot)
+		state = PCI_D3hot;
+
+	mutex_lock(&pwr->lock);
+	ret = __set_power_state(pwr, pdev, state, id, reg, bit);
+	mutex_unlock(&pwr->lock);
+	return ret;
+}
+
+int intel_mid_pci_set_power_state(struct pci_dev *pdev, pci_power_t state)
+{
+	struct mid_pwr *pwr = midpwr;
+	int ret = 0;
+
+	might_sleep();
+
+	if (pwr && pwr->available)
+		ret = mid_pwr_set_power_state(pwr, pdev, state);
+	dev_vdbg(&pdev->dev, "set_power_state() returns %d\n", ret);
+
+	return 0;
+}
+
+pci_power_t intel_mid_pci_get_power_state(struct pci_dev *pdev)
+{
+	struct mid_pwr *pwr = midpwr;
+	int id, reg, bit;
+	u32 power;
+
+	if (!pwr || !pwr->available)
+		return PCI_UNKNOWN;
+
+	id = intel_mid_pwr_get_lss_id(pdev);
+	if (id < 0)
+		return PCI_UNKNOWN;
+
+	reg = (id * LSS_PWS_BITS) / 32;
+	bit = (id * LSS_PWS_BITS) % 32;
+	power = mid_pwr_get_state(pwr, reg);
+	return (__force pci_power_t)((power >> bit) & 3);
+}
+
+void intel_mid_pwr_power_off(void)
+{
+	struct mid_pwr *pwr = midpwr;
+	u32 cmd = PM_CMD_SYS_STATE_S5 |
+		  PM_CMD_CMD(CMD_SET_CFG) |
+		  PM_CMD_CM_TRIGGER |
+		  PM_CMD_CFG_TRIGGER_NC |
+		  TRIGGER_NC_MSG_2;
+
+	/* Send command to SCU */
+	writel(cmd, pwr->regs + PM_CMD);
+	mid_pwr_wait(pwr);
+}
+
+int intel_mid_pwr_get_lss_id(struct pci_dev *pdev)
+{
+	int vndr;
+	u8 id;
+
+	/*
+	 * Mapping to PWRMU index is kept in the Logical SubSystem ID byte of
+	 * Vendor capability.
+	 */
+	vndr = pci_find_capability(pdev, PCI_CAP_ID_VNDR);
+	if (!vndr)
+		return -EINVAL;
+
+	/* Read the Logical SubSystem ID byte */
+	pci_read_config_byte(pdev, vndr + INTEL_MID_PWR_LSS_OFFSET, &id);
+	if (!(id & INTEL_MID_PWR_LSS_TYPE))
+		return -ENODEV;
+
+	id &= ~INTEL_MID_PWR_LSS_TYPE;
+	if (id >= LSS_MAX_DEVS)
+		return -ERANGE;
+
+	return id;
+}
+
+static irqreturn_t mid_pwr_irq_handler(int irq, void *dev_id)
+{
+	struct mid_pwr *pwr = dev_id;
+	u32 ics;
+
+	ics = readl(pwr->regs + PM_ICS);
+	if (!(ics & PM_ICS_IP))
+		return IRQ_NONE;
+
+	writel(ics | PM_ICS_IP, pwr->regs + PM_ICS);
+
+	dev_warn(pwr->dev, "Unexpected IRQ: %#x\n", PM_ICS_INT_STATUS(ics));
+	return IRQ_HANDLED;
+}
+
+struct mid_pwr_device_info {
+	int (*set_initial_state)(struct mid_pwr *pwr);
+};
+
+static int mid_pwr_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct mid_pwr_device_info *info = (void *)id->driver_data;
+	struct device *dev = &pdev->dev;
+	struct mid_pwr *pwr;
+	int ret;
+
+	ret = pcim_enable_device(pdev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "error: could not enable device\n");
+		return ret;
+	}
+
+	ret = pcim_iomap_regions(pdev, 1 << 0, pci_name(pdev));
+	if (ret) {
+		dev_err(&pdev->dev, "I/O memory remapping failed\n");
+		return ret;
+	}
+
+	pwr = devm_kzalloc(dev, sizeof(*pwr), GFP_KERNEL);
+	if (!pwr)
+		return -ENOMEM;
+
+	pwr->dev = dev;
+	pwr->regs = pcim_iomap_table(pdev)[0];
+	pwr->irq = pdev->irq;
+
+	mutex_init(&pwr->lock);
+
+	/* Disable interrupts */
+	mid_pwr_interrupt_disable(pwr);
+
+	if (info && info->set_initial_state) {
+		ret = info->set_initial_state(pwr);
+		if (ret)
+			dev_warn(dev, "Can't set initial state: %d\n", ret);
+	}
+
+	ret = devm_request_irq(dev, pdev->irq, mid_pwr_irq_handler,
+			       IRQF_NO_SUSPEND, pci_name(pdev), pwr);
+	if (ret)
+		return ret;
+
+	pwr->available = true;
+	midpwr = pwr;
+
+	pci_set_drvdata(pdev, pwr);
+	return 0;
+}
+
+static int mid_set_initial_state(struct mid_pwr *pwr, const u32 *states)
+{
+	unsigned int i, j;
+	int ret;
+
+	/*
+	 * Enable wake events.
+	 *
+	 * PWRMU supports up to 32 sources for wake up the system. Ungate them
+	 * all here.
+	 */
+	mid_pwr_set_wake(pwr, 0, 0xffffffff);
+	mid_pwr_set_wake(pwr, 1, 0xffffffff);
+
+	/*
+	 * Power off South Complex devices.
+	 *
+	 * There is a map (see a note below) of 64 devices with 2 bits per each
+	 * on 32-bit HW registers. The following calls set all devices to one
+	 * known initial state, i.e. PCI_D3hot. This is done in conjunction
+	 * with PMCSR setting in arch/x86/pci/intel_mid_pci.c.
+	 *
+	 * NOTE: The actual device mapping is provided by a platform at run
+	 * time using vendor capability of PCI configuration space.
+	 */
+	mid_pwr_set_state(pwr, 0, states[0]);
+	mid_pwr_set_state(pwr, 1, states[1]);
+	mid_pwr_set_state(pwr, 2, states[2]);
+	mid_pwr_set_state(pwr, 3, states[3]);
+
+	/* Send command to SCU */
+	ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < LSS_MAX_DEVS; i++) {
+		for (j = 0; j < LSS_MAX_SHARED_DEVS; j++)
+			pwr->lss[i][j].state = PCI_D3hot;
+	}
+
+	return 0;
+}
+
+static int pnw_set_initial_state(struct mid_pwr *pwr)
+{
+	/* On Penwell SRAM must stay powered on */
+	static const u32 states[] = {
+		0xf00fffff,		/* PM_SSC(0) */
+		0xffffffff,		/* PM_SSC(1) */
+		0xffffffff,		/* PM_SSC(2) */
+		0xffffffff,		/* PM_SSC(3) */
+	};
+	return mid_set_initial_state(pwr, states);
+}
+
+static int tng_set_initial_state(struct mid_pwr *pwr)
+{
+	static const u32 states[] = {
+		0xffffffff,		/* PM_SSC(0) */
+		0xffffffff,		/* PM_SSC(1) */
+		0xffffffff,		/* PM_SSC(2) */
+		0xffffffff,		/* PM_SSC(3) */
+	};
+	return mid_set_initial_state(pwr, states);
+}
+
+static const struct mid_pwr_device_info pnw_info = {
+	.set_initial_state = pnw_set_initial_state,
+};
+
+static const struct mid_pwr_device_info tng_info = {
+	.set_initial_state = tng_set_initial_state,
+};
+
+/* This table should be in sync with the one in drivers/pci/pci-mid.c */
+static const struct pci_device_id mid_pwr_pci_ids[] = {
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PENWELL), (kernel_ulong_t)&pnw_info },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_TANGIER), (kernel_ulong_t)&tng_info },
+	{}
+};
+
+static struct pci_driver mid_pwr_pci_driver = {
+	.name		= "intel_mid_pwr",
+	.probe		= mid_pwr_probe,
+	.id_table	= mid_pwr_pci_ids,
+};
+
+builtin_pci_driver(mid_pwr_pci_driver);