- 根目录:
- drivers
- rtc
- rtc-mrst.c
/*
* rtc-mrst.c: Driver for Moorestown virtual RTC
*
* (C) Copyright 2009 Intel Corporation
* Author: Jacob Pan (jacob.jun.pan@intel.com)
* Feng Tang (feng.tang@intel.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License.
*
* Note:
* VRTC is emulated by system controller firmware, the real HW
* RTC is located in the PMIC device. SCU FW shadows PMIC RTC
* in a memory mapped IO space that is visible to the host IA
* processor.
*
* This driver is based upon drivers/rtc/rtc-cmos.c
*/
/*
* Note:
* * vRTC only supports binary mode and 24H mode
* * vRTC only support PIE and AIE, no UIE, and its PIE only happens
* at 23:59:59pm everyday, no support for adjustable frequency
* * Alarm function is also limited to hr/min/sec.
*/
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sfi.h>
#include <asm-generic/rtc.h>
#include <asm/intel_scu_ipc.h>
#include <asm/intel-mid.h>
#include <asm/intel_mid_vrtc.h>
struct mrst_rtc {
struct rtc_device *rtc;
struct device *dev;
int irq;
struct resource *iomem;
u8 enabled_wake;
u8 suspend_ctrl;
};
static const char driver_name[] = "rtc_mrst";
#define RTC_IRQMASK (RTC_PF | RTC_AF)
static inline int is_intr(u8 rtc_intr)
{
if (!(rtc_intr & RTC_IRQF))
return 0;
return rtc_intr & RTC_IRQMASK;
}
static inline unsigned char vrtc_is_updating(void)
{
unsigned char uip;
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP);
spin_unlock_irqrestore(&rtc_lock, flags);
return uip;
}
/*
* rtc_time's year contains the increment over 1900, but vRTC's YEAR
* register can't be programmed to value larger than 0x64, so vRTC
* driver chose to use 1972 (1970 is UNIX time start point) as the base,
* and does the translation at read/write time.
*
* Why not just use 1970 as the offset? it's because using 1972 will
* make it consistent in leap year setting for both vrtc and low-level
* physical rtc devices. Then why not use 1960 as the offset? If we use
* 1960, for a device's first use, its YEAR register is 0 and the system
* year will be parsed as 1960 which is not a valid UNIX time and will
* cause many applications to fail mysteriously.
*/
static int mrst_read_time(struct device *dev, struct rtc_time *time)
{
unsigned long flags;
if (vrtc_is_updating())
mdelay(20);
spin_lock_irqsave(&rtc_lock, flags);
time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
time->tm_min = vrtc_cmos_read(RTC_MINUTES);
time->tm_hour = vrtc_cmos_read(RTC_HOURS);
time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
time->tm_mon = vrtc_cmos_read(RTC_MONTH);
time->tm_year = vrtc_cmos_read(RTC_YEAR);
spin_unlock_irqrestore(&rtc_lock, flags);
/* Adjust for the 1972/1900 */
time->tm_year += 72;
time->tm_mon--;
return rtc_valid_tm(time);
}
static int mrst_set_time(struct device *dev, struct rtc_time *time)
{
int ret;
unsigned long flags;
unsigned char mon, day, hrs, min, sec;
unsigned int yrs;
yrs = time->tm_year;
mon = time->tm_mon + 1; /* tm_mon starts at zero */
day = time->tm_mday;
hrs = time->tm_hour;
min = time->tm_min;
sec = time->tm_sec;
if (yrs < 72 || yrs > 138)
return -EINVAL;
yrs -= 72;
spin_lock_irqsave(&rtc_lock, flags);
vrtc_cmos_write(yrs, RTC_YEAR);
vrtc_cmos_write(mon, RTC_MONTH);
vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
vrtc_cmos_write(hrs, RTC_HOURS);
vrtc_cmos_write(min, RTC_MINUTES);
vrtc_cmos_write(sec, RTC_SECONDS);
spin_unlock_irqrestore(&rtc_lock, flags);
ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
return ret;
}
static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct mrst_rtc *mrst = dev_get_drvdata(dev);
unsigned char rtc_control;
if (mrst->irq <= 0)
return -EIO;
/* Basic alarms only support hour, minute, and seconds fields.
* Some also support day and month, for alarms up to a year in
* the future.
*/
t->time.tm_mday = -1;
t->time.tm_mon = -1;
t->time.tm_year = -1;
/* vRTC only supports binary mode */
spin_lock_irq(&rtc_lock);
t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
rtc_control = vrtc_cmos_read(RTC_CONTROL);
spin_unlock_irq(&rtc_lock);
t->enabled = !!(rtc_control & RTC_AIE);
t->pending = 0;
return 0;
}
static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
{
unsigned char rtc_intr;
/*
* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
* allegedly some older rtcs need that to handle irqs properly
*/
rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
if (is_intr(rtc_intr))
rtc_update_irq(mrst->rtc, 1, rtc_intr);
}
static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
{
unsigned char rtc_control;
/*
* Flush any pending IRQ status, notably for update irqs,
* before we enable new IRQs
*/
rtc_control = vrtc_cmos_read(RTC_CONTROL);
mrst_checkintr(mrst, rtc_control);
rtc_control |= mask;
vrtc_cmos_write(rtc_control, RTC_CONTROL);
mrst_checkintr(mrst, rtc_control);
}
static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
{
unsigned char rtc_control;
rtc_control = vrtc_cmos_read(RTC_CONTROL);
rtc_control &= ~mask;
vrtc_cmos_write(rtc_control, RTC_CONTROL);
mrst_checkintr(mrst, rtc_control);
}
static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct mrst_rtc *mrst = dev_get_drvdata(dev);
unsigned char hrs, min, sec;
int ret = 0;
if (!mrst->irq)
return -EIO;
hrs = t->time.tm_hour;
min = t->time.tm_min;
sec = t->time.tm_sec;
spin_lock_irq(&rtc_lock);
/* Next rtc irq must not be from previous alarm setting */
mrst_irq_disable(mrst, RTC_AIE);
/* Update alarm */
vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
vrtc_cmos_write(min, RTC_MINUTES_ALARM);
vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
spin_unlock_irq(&rtc_lock);
ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
if (ret)
return ret;
spin_lock_irq(&rtc_lock);
if (t->enabled)
mrst_irq_enable(mrst, RTC_AIE);
spin_unlock_irq(&rtc_lock);
return 0;
}
/* Currently, the vRTC doesn't support UIE ON/OFF */
static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct mrst_rtc *mrst = dev_get_drvdata(dev);
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
if (enabled)
mrst_irq_enable(mrst, RTC_AIE);
else
mrst_irq_disable(mrst, RTC_AIE);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
static int mrst_procfs(struct device *dev, struct seq_file *seq)
{
unsigned char rtc_control, valid;
spin_lock_irq(&rtc_lock);
rtc_control = vrtc_cmos_read(RTC_CONTROL);
valid = vrtc_cmos_read(RTC_VALID);
spin_unlock_irq(&rtc_lock);
return seq_printf(seq,
"periodic_IRQ\t: %s\n"
"alarm\t\t: %s\n"
"BCD\t\t: no\n"
"periodic_freq\t: daily (not adjustable)\n",
(rtc_control & RTC_PIE) ? "on" : "off",
(rtc_control & RTC_AIE) ? "on" : "off");
}
#else
#define mrst_procfs NULL
#endif
static const struct rtc_class_ops mrst_rtc_ops = {
.read_time = mrst_read_time,
.set_time = mrst_set_time,
.read_alarm = mrst_read_alarm,
.set_alarm = mrst_set_alarm,
.proc = mrst_procfs,
.alarm_irq_enable = mrst_rtc_alarm_irq_enable,
};
static struct mrst_rtc mrst_rtc;
/*
* When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
* Reg B, so no need for this driver to clear it
*/
static irqreturn_t mrst_rtc_irq(int irq, void *p)
{
u8 irqstat;
spin_lock(&rtc_lock);
/* This read will clear all IRQ flags inside Reg C */
irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
spin_unlock(&rtc_lock);
irqstat &= RTC_IRQMASK | RTC_IRQF;
if (is_intr(irqstat)) {
rtc_update_irq(p, 1, irqstat);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static int vrtc_mrst_do_probe(struct device *dev, struct resource *iomem,
int rtc_irq)
{
int retval = 0;
unsigned char rtc_control;
/* There can be only one ... */
if (mrst_rtc.dev)
return -EBUSY;
if (!iomem)
return -ENODEV;
iomem = request_mem_region(iomem->start, resource_size(iomem),
driver_name);
if (!iomem) {
dev_dbg(dev, "i/o mem already in use.\n");
return -EBUSY;
}
mrst_rtc.irq = rtc_irq;
mrst_rtc.iomem = iomem;
mrst_rtc.dev = dev;
dev_set_drvdata(dev, &mrst_rtc);
mrst_rtc.rtc = rtc_device_register(driver_name, dev,
&mrst_rtc_ops, THIS_MODULE);
if (IS_ERR(mrst_rtc.rtc)) {
retval = PTR_ERR(mrst_rtc.rtc);
goto cleanup0;
}
rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
spin_lock_irq(&rtc_lock);
mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
rtc_control = vrtc_cmos_read(RTC_CONTROL);
spin_unlock_irq(&rtc_lock);
if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
if (rtc_irq) {
retval = request_irq(rtc_irq, mrst_rtc_irq,
0, dev_name(&mrst_rtc.rtc->dev),
mrst_rtc.rtc);
if (retval < 0) {
dev_dbg(dev, "IRQ %d is already in use, err %d\n",
rtc_irq, retval);
goto cleanup1;
}
}
dev_dbg(dev, "initialised\n");
return 0;
cleanup1:
rtc_device_unregister(mrst_rtc.rtc);
cleanup0:
mrst_rtc.dev = NULL;
release_mem_region(iomem->start, resource_size(iomem));
dev_err(dev, "rtc-mrst: unable to initialise\n");
return retval;
}
static void rtc_mrst_do_shutdown(void)
{
spin_lock_irq(&rtc_lock);
mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
spin_unlock_irq(&rtc_lock);
}
static void rtc_mrst_do_remove(struct device *dev)
{
struct mrst_rtc *mrst = dev_get_drvdata(dev);
struct resource *iomem;
rtc_mrst_do_shutdown();
if (mrst->irq)
free_irq(mrst->irq, mrst->rtc);
rtc_device_unregister(mrst->rtc);
mrst->rtc = NULL;
iomem = mrst->iomem;
release_mem_region(iomem->start, resource_size(iomem));
mrst->iomem = NULL;
mrst->dev = NULL;
}
#ifdef CONFIG_PM
static int mrst_suspend(struct device *dev, pm_message_t mesg)
{
struct mrst_rtc *mrst = dev_get_drvdata(dev);
unsigned char tmp;
/* Only the alarm might be a wakeup event source */
spin_lock_irq(&rtc_lock);
mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
if (tmp & (RTC_PIE | RTC_AIE)) {
unsigned char mask;
if (device_may_wakeup(dev))
mask = RTC_IRQMASK & ~RTC_AIE;
else
mask = RTC_IRQMASK;
tmp &= ~mask;
vrtc_cmos_write(tmp, RTC_CONTROL);
mrst_checkintr(mrst, tmp);
}
spin_unlock_irq(&rtc_lock);
if (tmp & RTC_AIE) {
mrst->enabled_wake = 1;
enable_irq_wake(mrst->irq);
}
dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
(tmp & RTC_AIE) ? ", alarm may wake" : "",
tmp);
return 0;
}
/*
* We want RTC alarms to wake us from the deep power saving state
*/
static inline int mrst_poweroff(struct device *dev)
{
return mrst_suspend(dev, PMSG_HIBERNATE);
}
static int mrst_resume(struct device *dev)
{
struct mrst_rtc *mrst = dev_get_drvdata(dev);
unsigned char tmp = mrst->suspend_ctrl;
/* Re-enable any irqs previously active */
if (tmp & RTC_IRQMASK) {
unsigned char mask;
if (mrst->enabled_wake) {
disable_irq_wake(mrst->irq);
mrst->enabled_wake = 0;
}
spin_lock_irq(&rtc_lock);
do {
vrtc_cmos_write(tmp, RTC_CONTROL);
mask = vrtc_cmos_read(RTC_INTR_FLAGS);
mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
if (!is_intr(mask))
break;
rtc_update_irq(mrst->rtc, 1, mask);
tmp &= ~RTC_AIE;
} while (mask & RTC_AIE);
spin_unlock_irq(&rtc_lock);
}
dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
return 0;
}
#else
#define mrst_suspend NULL
#define mrst_resume NULL
static inline int mrst_poweroff(struct device *dev)
{
return -ENOSYS;
}
#endif
static int vrtc_mrst_platform_probe(struct platform_device *pdev)
{
return vrtc_mrst_do_probe(&pdev->dev,
platform_get_resource(pdev, IORESOURCE_MEM, 0),
platform_get_irq(pdev, 0));
}
static int vrtc_mrst_platform_remove(struct platform_device *pdev)
{
rtc_mrst_do_remove(&pdev->dev);
return 0;
}
static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
{
if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
return;
rtc_mrst_do_shutdown();
}
MODULE_ALIAS("platform:vrtc_mrst");
static struct platform_driver vrtc_mrst_platform_driver = {
.probe = vrtc_mrst_platform_probe,
.remove = vrtc_mrst_platform_remove,
.shutdown = vrtc_mrst_platform_shutdown,
.driver = {
.name = (char *) driver_name,
.suspend = mrst_suspend,
.resume = mrst_resume,
}
};
module_platform_driver(vrtc_mrst_platform_driver);
MODULE_AUTHOR("Jacob Pan; Feng Tang");
MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
MODULE_LICENSE("GPL");