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|
// 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
|