[mirror_ubuntu-bionic-kernel.git] / 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/mc146818rtc.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sfi.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;

	/* 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 IS_ENABLED(CONFIG_RTC_INTF_PROC)

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);

	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");

	return 0;
}

#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_SLEEP
static int mrst_suspend(struct device *dev)
{
	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);
}

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;
}

static SIMPLE_DEV_PM_OPS(mrst_pm_ops, mrst_suspend, mrst_resume);
#define MRST_PM_OPS (&mrst_pm_ops)

#else
#define MRST_PM_OPS 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	= driver_name,
		.pm	= MRST_PM_OPS,
	}
};

module_platform_driver(vrtc_mrst_platform_driver);

MODULE_AUTHOR("Jacob Pan; Feng Tang");
MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
MODULE_LICENSE("GPL");
Commit	Line	Data
0146f261 FT	1	/*
	2	* rtc-mrst.c: Driver for Moorestown virtual RTC
	3	*
	4	* (C) Copyright 2009 Intel Corporation
	5	* Author: Jacob Pan (jacob.jun.pan@intel.com)
	6	* Feng Tang (feng.tang@intel.com)
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; version 2
	11	* of the License.
	12	*
	13	* Note:
	14	* VRTC is emulated by system controller firmware, the real HW
	15	* RTC is located in the PMIC device. SCU FW shadows PMIC RTC
	16	* in a memory mapped IO space that is visible to the host IA
	17	* processor.
	18	*
	19	* This driver is based upon drivers/rtc/rtc-cmos.c
	20	*/
	21
	22	/*
	23	* Note:
	24	* * vRTC only supports binary mode and 24H mode
	25	* * vRTC only support PIE and AIE, no UIE, and its PIE only happens
	26	* at 23:59:59pm everyday, no support for adjustable frequency
	27	* * Alarm function is also limited to hr/min/sec.
	28	*/
	29
	30	#include <linux/mod_devicetable.h>
	31	#include <linux/platform_device.h>
	32	#include <linux/interrupt.h>
	33	#include <linux/spinlock.h>
	34	#include <linux/kernel.h>
463a8630	35	#include <linux/mc146818rtc.h>
0146f261 FT	36	#include <linux/module.h>
	37	#include <linux/init.h>
	38	#include <linux/sfi.h>
	39
0146f261	40	#include <asm/intel_scu_ipc.h>
05454c26 KS	41	#include <asm/intel-mid.h>
05454c26 KS	42	#include <asm/intel_mid_vrtc.h>
0146f261 FT	43
	44	struct mrst_rtc {
	45	struct rtc_device *rtc;
	46	struct device *dev;
	47	int irq;
	48	struct resource *iomem;
	49
	50	u8 enabled_wake;
	51	u8 suspend_ctrl;
	52	};
	53
	54	static const char driver_name[] = "rtc_mrst";
	55
	56	#define RTC_IRQMASK (RTC_PF \| RTC_AF)
	57
	58	static inline int is_intr(u8 rtc_intr)
	59	{
	60	if (!(rtc_intr & RTC_IRQF))
	61	return 0;
	62	return rtc_intr & RTC_IRQMASK;
	63	}
	64
168202c7 FT	65	static inline unsigned char vrtc_is_updating(void)
	66	{
	67	unsigned char uip;
	68	unsigned long flags;
	69
	70	spin_lock_irqsave(&rtc_lock, flags);
	71	uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP);
	72	spin_unlock_irqrestore(&rtc_lock, flags);
	73	return uip;
	74	}
	75
0146f261 FT	76	/*
	77	* rtc_time's year contains the increment over 1900, but vRTC's YEAR
	78	* register can't be programmed to value larger than 0x64, so vRTC
57e6319d	79	* driver chose to use 1972 (1970 is UNIX time start point) as the base,
d3e1884b FT	80	* and does the translation at read/write time.
d3e1884b FT	81	*
57e6319d	82	* Why not just use 1970 as the offset? it's because using 1972 will
d3e1884b	83	* make it consistent in leap year setting for both vrtc and low-level
57e6319d FT	84	* physical rtc devices. Then why not use 1960 as the offset? If we use
	85	* 1960, for a device's first use, its YEAR register is 0 and the system
	86	* year will be parsed as 1960 which is not a valid UNIX time and will
	87	* cause many applications to fail mysteriously.
0146f261 FT	88	*/
	89	static int mrst_read_time(struct device dev, struct rtc_time time)
	90	{
	91	unsigned long flags;
	92
168202c7	93	if (vrtc_is_updating())
0146f261 FT	94	mdelay(20);
	95
	96	spin_lock_irqsave(&rtc_lock, flags);
	97	time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
	98	time->tm_min = vrtc_cmos_read(RTC_MINUTES);
	99	time->tm_hour = vrtc_cmos_read(RTC_HOURS);
	100	time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
	101	time->tm_mon = vrtc_cmos_read(RTC_MONTH);
	102	time->tm_year = vrtc_cmos_read(RTC_YEAR);
	103	spin_unlock_irqrestore(&rtc_lock, flags);
	104
57e6319d FT	105	/* Adjust for the 1972/1900 */
57e6319d FT	106	time->tm_year += 72;
0146f261	107	time->tm_mon--;
57e6319d	108	return rtc_valid_tm(time);
0146f261 FT	109	}
	110
	111	static int mrst_set_time(struct device dev, struct rtc_time time)
	112	{
	113	int ret;
	114	unsigned long flags;
	115	unsigned char mon, day, hrs, min, sec;
	116	unsigned int yrs;
	117
	118	yrs = time->tm_year;
	119	mon = time->tm_mon + 1; /* tm_mon starts at zero */
	120	day = time->tm_mday;
	121	hrs = time->tm_hour;
	122	min = time->tm_min;
	123	sec = time->tm_sec;
	124
57e6319d	125	if (yrs < 72 \|\| yrs > 138)
0146f261	126	return -EINVAL;
57e6319d	127	yrs -= 72;
0146f261 FT	128
	129	spin_lock_irqsave(&rtc_lock, flags);
	130
	131	vrtc_cmos_write(yrs, RTC_YEAR);
	132	vrtc_cmos_write(mon, RTC_MONTH);
	133	vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
	134	vrtc_cmos_write(hrs, RTC_HOURS);
	135	vrtc_cmos_write(min, RTC_MINUTES);
	136	vrtc_cmos_write(sec, RTC_SECONDS);
	137
	138	spin_unlock_irqrestore(&rtc_lock, flags);
	139
	140	ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
	141	return ret;
	142	}
	143
	144	static int mrst_read_alarm(struct device dev, struct rtc_wkalrm t)
	145	{
	146	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	147	unsigned char rtc_control;
	148
	149	if (mrst->irq <= 0)
	150	return -EIO;
	151
0146f261 FT	152	/* vRTC only supports binary mode */
	153	spin_lock_irq(&rtc_lock);
	154	t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
	155	t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
	156	t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
	157
	158	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	159	spin_unlock_irq(&rtc_lock);
	160
	161	t->enabled = !!(rtc_control & RTC_AIE);
	162	t->pending = 0;
	163
	164	return 0;
	165	}
	166
	167	static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
	168	{
	169	unsigned char rtc_intr;
	170
	171	/*
	172	* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
	173	* allegedly some older rtcs need that to handle irqs properly
	174	*/
	175	rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
	176	rtc_intr &= (rtc_control & RTC_IRQMASK) \| RTC_IRQF;
	177	if (is_intr(rtc_intr))
	178	rtc_update_irq(mrst->rtc, 1, rtc_intr);
	179	}
	180
	181	static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
	182	{
	183	unsigned char rtc_control;
	184
	185	/*
	186	* Flush any pending IRQ status, notably for update irqs,
	187	* before we enable new IRQs
	188	*/
	189	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	190	mrst_checkintr(mrst, rtc_control);
	191
	192	rtc_control \|= mask;
	193	vrtc_cmos_write(rtc_control, RTC_CONTROL);
	194
	195	mrst_checkintr(mrst, rtc_control);
	196	}
	197
	198	static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
	199	{
	200	unsigned char rtc_control;
	201
	202	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	203	rtc_control &= ~mask;
	204	vrtc_cmos_write(rtc_control, RTC_CONTROL);
	205	mrst_checkintr(mrst, rtc_control);
	206	}
	207
	208	static int mrst_set_alarm(struct device dev, struct rtc_wkalrm t)
	209	{
	210	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	211	unsigned char hrs, min, sec;
	212	int ret = 0;
	213
	214	if (!mrst->irq)
	215	return -EIO;
216
217	hrs = t->time.tm_hour;
218	min = t->time.tm_min;
219	sec = t->time.tm_sec;
220
221	spin_lock_irq(&rtc_lock);
222	/* Next rtc irq must not be from previous alarm setting */
223	mrst_irq_disable(mrst, RTC_AIE);
224
225	/* Update alarm */
226	vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
227	vrtc_cmos_write(min, RTC_MINUTES_ALARM);
228	vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
229
230	spin_unlock_irq(&rtc_lock);
231
232	ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
233	if (ret)
234	return ret;
235
236	spin_lock_irq(&rtc_lock);
237	if (t->enabled)
238	mrst_irq_enable(mrst, RTC_AIE);
239
240	spin_unlock_irq(&rtc_lock);
241
242	return 0;
243	}
244
0146f261	245	/* Currently, the vRTC doesn't support UIE ON/OFF */
16380c15	246	static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
0146f261 FT	247	{
	248	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	249	unsigned long flags;
	250
0146f261	251	spin_lock_irqsave(&rtc_lock, flags);
16380c15	252	if (enabled)
0146f261	253	mrst_irq_enable(mrst, RTC_AIE);
16380c15 JS	254	else
16380c15 JS	255	mrst_irq_disable(mrst, RTC_AIE);
0146f261 FT	256	spin_unlock_irqrestore(&rtc_lock, flags);
	257	return 0;
	258	}
	259
0146f261	260
6fca3fc5	261	#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
0146f261 FT	262
	263	static int mrst_procfs(struct device dev, struct seq_file seq)
	264	{
	265	unsigned char rtc_control, valid;
	266
	267	spin_lock_irq(&rtc_lock);
	268	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	269	valid = vrtc_cmos_read(RTC_VALID);
	270	spin_unlock_irq(&rtc_lock);
	271
4395eb1f JP	272	seq_printf(seq,
	273	"periodic_IRQ\t: %s\n"
	274	"alarm\t\t: %s\n"
	275	"BCD\t\t: no\n"
	276	"periodic_freq\t: daily (not adjustable)\n",
	277	(rtc_control & RTC_PIE) ? "on" : "off",
	278	(rtc_control & RTC_AIE) ? "on" : "off");
	279
	280	return 0;
0146f261 FT	281	}
	282
	283	#else
	284	#define mrst_procfs NULL
	285	#endif
	286
	287	static const struct rtc_class_ops mrst_rtc_ops = {
0146f261 FT	288	.read_time = mrst_read_time,
	289	.set_time = mrst_set_time,
	290	.read_alarm = mrst_read_alarm,
	291	.set_alarm = mrst_set_alarm,
	292	.proc = mrst_procfs,
16380c15	293	.alarm_irq_enable = mrst_rtc_alarm_irq_enable,
0146f261 FT	294	};
	295
	296	static struct mrst_rtc mrst_rtc;
	297
	298	/*
	299	* When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
	300	* Reg B, so no need for this driver to clear it
	301	*/
	302	static irqreturn_t mrst_rtc_irq(int irq, void *p)
	303	{
	304	u8 irqstat;
	305
	306	spin_lock(&rtc_lock);
	307	/* This read will clear all IRQ flags inside Reg C */
	308	irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
	309	spin_unlock(&rtc_lock);
	310
	311	irqstat &= RTC_IRQMASK \| RTC_IRQF;
	312	if (is_intr(irqstat)) {
	313	rtc_update_irq(p, 1, irqstat);
	314	return IRQ_HANDLED;
	315	}
	316	return IRQ_NONE;
	317	}
	318
5a167f45 GKH	319	static int vrtc_mrst_do_probe(struct device dev, struct resource iomem,
5a167f45 GKH	320	int rtc_irq)
0146f261 FT	321	{
	322	int retval = 0;
	323	unsigned char rtc_control;
	324
	325	/* There can be only one ... */
	326	if (mrst_rtc.dev)
	327	return -EBUSY;
	328
	329	if (!iomem)
	330	return -ENODEV;
	331
28f65c11 JP	332	iomem = request_mem_region(iomem->start, resource_size(iomem),
28f65c11 JP	333	driver_name);
0146f261 FT	334	if (!iomem) {
	335	dev_dbg(dev, "i/o mem already in use.\n");
	336	return -EBUSY;
	337	}
	338
	339	mrst_rtc.irq = rtc_irq;
	340	mrst_rtc.iomem = iomem;
de97a21a FT	341	mrst_rtc.dev = dev;
de97a21a FT	342	dev_set_drvdata(dev, &mrst_rtc);
0146f261 FT	343
	344	mrst_rtc.rtc = rtc_device_register(driver_name, dev,
	345	&mrst_rtc_ops, THIS_MODULE);
	346	if (IS_ERR(mrst_rtc.rtc)) {
	347	retval = PTR_ERR(mrst_rtc.rtc);
	348	goto cleanup0;
	349	}
	350
0146f261 FT	351	rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
	352
	353	spin_lock_irq(&rtc_lock);
	354	mrst_irq_disable(&mrst_rtc, RTC_PIE \| RTC_AIE);
	355	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	356	spin_unlock_irq(&rtc_lock);
	357
	358	if (!(rtc_control & RTC_24H) \|\| (rtc_control & (RTC_DM_BINARY)))
	359	dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
	360
	361	if (rtc_irq) {
	362	retval = request_irq(rtc_irq, mrst_rtc_irq,
2f6e5f94	363	0, dev_name(&mrst_rtc.rtc->dev),
0146f261 FT	364	mrst_rtc.rtc);
	365	if (retval < 0) {
	366	dev_dbg(dev, "IRQ %d is already in use, err %d\n",
	367	rtc_irq, retval);
	368	goto cleanup1;
	369	}
	370	}
	371	dev_dbg(dev, "initialised\n");
	372	return 0;
	373
	374	cleanup1:
0146f261 FT	375	rtc_device_unregister(mrst_rtc.rtc);
0146f261 FT	376	cleanup0:
de97a21a	377	mrst_rtc.dev = NULL;
c258f9a0	378	release_mem_region(iomem->start, resource_size(iomem));
0146f261 FT	379	dev_err(dev, "rtc-mrst: unable to initialise\n");
	380	return retval;
	381	}
	382
	383	static void rtc_mrst_do_shutdown(void)
	384	{
	385	spin_lock_irq(&rtc_lock);
	386	mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
	387	spin_unlock_irq(&rtc_lock);
	388	}
	389
5a167f45	390	static void rtc_mrst_do_remove(struct device *dev)
0146f261 FT	391	{
	392	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	393	struct resource *iomem;
	394
	395	rtc_mrst_do_shutdown();
	396
	397	if (mrst->irq)
	398	free_irq(mrst->irq, mrst->rtc);
	399
	400	rtc_device_unregister(mrst->rtc);
	401	mrst->rtc = NULL;
	402
	403	iomem = mrst->iomem;
c258f9a0	404	release_mem_region(iomem->start, resource_size(iomem));
0146f261 FT	405	mrst->iomem = NULL;
	406
	407	mrst->dev = NULL;
0146f261 FT	408	}
0146f261 FT	409
ddd2a30d LPC	410	#ifdef CONFIG_PM_SLEEP
ddd2a30d LPC	411	static int mrst_suspend(struct device *dev)
0146f261 FT	412	{
	413	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	414	unsigned char tmp;
	415
	416	/* Only the alarm might be a wakeup event source */
	417	spin_lock_irq(&rtc_lock);
	418	mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
	419	if (tmp & (RTC_PIE \| RTC_AIE)) {
	420	unsigned char mask;
	421
	422	if (device_may_wakeup(dev))
	423	mask = RTC_IRQMASK & ~RTC_AIE;
	424	else
	425	mask = RTC_IRQMASK;
	426	tmp &= ~mask;
	427	vrtc_cmos_write(tmp, RTC_CONTROL);
	428
	429	mrst_checkintr(mrst, tmp);
	430	}
	431	spin_unlock_irq(&rtc_lock);
	432
	433	if (tmp & RTC_AIE) {
	434	mrst->enabled_wake = 1;
	435	enable_irq_wake(mrst->irq);
	436	}
	437
	438	dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
	439	(tmp & RTC_AIE) ? ", alarm may wake" : "",
	440	tmp);
	441
	442	return 0;
	443	}
	444
	445	/*
	446	* We want RTC alarms to wake us from the deep power saving state
	447	*/
	448	static inline int mrst_poweroff(struct device *dev)
	449	{
ddd2a30d	450	return mrst_suspend(dev);
0146f261 FT	451	}
	452
	453	static int mrst_resume(struct device *dev)
	454	{
	455	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	456	unsigned char tmp = mrst->suspend_ctrl;
	457
	458	/* Re-enable any irqs previously active */
	459	if (tmp & RTC_IRQMASK) {
	460	unsigned char mask;
	461
	462	if (mrst->enabled_wake) {
	463	disable_irq_wake(mrst->irq);
	464	mrst->enabled_wake = 0;
	465	}
	466
	467	spin_lock_irq(&rtc_lock);
	468	do {
	469	vrtc_cmos_write(tmp, RTC_CONTROL);
	470
	471	mask = vrtc_cmos_read(RTC_INTR_FLAGS);
	472	mask &= (tmp & RTC_IRQMASK) \| RTC_IRQF;
	473	if (!is_intr(mask))
	474	break;
	475
	476	rtc_update_irq(mrst->rtc, 1, mask);
	477	tmp &= ~RTC_AIE;
	478	} while (mask & RTC_AIE);
	479	spin_unlock_irq(&rtc_lock);
	480	}
	481
	482	dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
	483
	484	return 0;
	485	}
	486
ddd2a30d LPC	487	static SIMPLE_DEV_PM_OPS(mrst_pm_ops, mrst_suspend, mrst_resume);
	488	#define MRST_PM_OPS (&mrst_pm_ops)
	489
0146f261	490	#else
ddd2a30d	491	#define MRST_PM_OPS NULL
0146f261 FT	492
	493	static inline int mrst_poweroff(struct device *dev)
	494	{
	495	return -ENOSYS;
	496	}
	497
	498	#endif
	499
5a167f45	500	static int vrtc_mrst_platform_probe(struct platform_device *pdev)
0146f261 FT	501	{
	502	return vrtc_mrst_do_probe(&pdev->dev,
	503	platform_get_resource(pdev, IORESOURCE_MEM, 0),
	504	platform_get_irq(pdev, 0));
	505	}
	506
5a167f45	507	static int vrtc_mrst_platform_remove(struct platform_device *pdev)
0146f261 FT	508	{
	509	rtc_mrst_do_remove(&pdev->dev);
	510	return 0;
	511	}
	512
	513	static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
	514	{
	515	if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
	516	return;
	517
	518	rtc_mrst_do_shutdown();
	519	}
	520
	521	MODULE_ALIAS("platform:vrtc_mrst");
	522
	523	static struct platform_driver vrtc_mrst_platform_driver = {
	524	.probe = vrtc_mrst_platform_probe,
5a167f45	525	.remove = vrtc_mrst_platform_remove,
0146f261 FT	526	.shutdown = vrtc_mrst_platform_shutdown,
0146f261 FT	527	.driver = {
ddd2a30d LPC	528	.name = driver_name,
ddd2a30d LPC	529	.pm = MRST_PM_OPS,
0146f261 FT	530	}
	531	};
	532
0c4eae66	533	module_platform_driver(vrtc_mrst_platform_driver);
0146f261 FT	534
	535	MODULE_AUTHOR("Jacob Pan; Feng Tang");
	536	MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
	537	MODULE_LICENSE("GPL");