[linux-2.6-block.git] / drivers / rtc / rtc-mrst.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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)
 *
 * 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;

	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())
		msleep(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 0;
}

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 > 172)
		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;

	spin_lock_irq(&rtc_lock);
	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	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 = devm_request_mem_region(dev, 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.dev = dev;
	dev_set_drvdata(dev, &mrst_rtc);

	mrst_rtc.rtc = devm_rtc_allocate_device(dev);
	if (IS_ERR(mrst_rtc.rtc))
		return PTR_ERR(mrst_rtc.rtc);

	mrst_rtc.rtc->ops = &mrst_rtc_ops;

	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 = devm_request_irq(dev, 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 cleanup0;
		}
	}

	retval = rtc_register_device(mrst_rtc.rtc);
	if (retval)
		goto cleanup0;

	dev_dbg(dev, "initialised\n");
	return 0;

cleanup0:
	mrst_rtc.dev = NULL;
	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);

	rtc_mrst_do_shutdown();

	mrst->rtc = 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
b886d83c	1	// SPDX-License-Identifier: GPL-2.0-only
0146f261 FT	2	/*
	3	* rtc-mrst.c: Driver for Moorestown virtual RTC
	4	*
	5	* (C) Copyright 2009 Intel Corporation
	6	* Author: Jacob Pan (jacob.jun.pan@intel.com)
	7	* Feng Tang (feng.tang@intel.com)
	8	*
0146f261 FT	9	* Note:
	10	* VRTC is emulated by system controller firmware, the real HW
	11	* RTC is located in the PMIC device. SCU FW shadows PMIC RTC
	12	* in a memory mapped IO space that is visible to the host IA
	13	* processor.
	14	*
	15	* This driver is based upon drivers/rtc/rtc-cmos.c
	16	*/
	17
	18	/*
	19	* Note:
	20	* * vRTC only supports binary mode and 24H mode
	21	* * vRTC only support PIE and AIE, no UIE, and its PIE only happens
	22	* at 23:59:59pm everyday, no support for adjustable frequency
	23	* * Alarm function is also limited to hr/min/sec.
	24	*/
	25
	26	#include <linux/mod_devicetable.h>
	27	#include <linux/platform_device.h>
	28	#include <linux/interrupt.h>
	29	#include <linux/spinlock.h>
	30	#include <linux/kernel.h>
463a8630	31	#include <linux/mc146818rtc.h>
0146f261 FT	32	#include <linux/module.h>
	33	#include <linux/init.h>
	34	#include <linux/sfi.h>
	35
0146f261	36	#include <asm/intel_scu_ipc.h>
05454c26 KS	37	#include <asm/intel-mid.h>
05454c26 KS	38	#include <asm/intel_mid_vrtc.h>
0146f261 FT	39
	40	struct mrst_rtc {
	41	struct rtc_device *rtc;
	42	struct device *dev;
	43	int irq;
0146f261 FT	44
	45	u8 enabled_wake;
	46	u8 suspend_ctrl;
	47	};
	48
	49	static const char driver_name[] = "rtc_mrst";
	50
	51	#define RTC_IRQMASK (RTC_PF \| RTC_AF)
	52
	53	static inline int is_intr(u8 rtc_intr)
	54	{
	55	if (!(rtc_intr & RTC_IRQF))
	56	return 0;
	57	return rtc_intr & RTC_IRQMASK;
	58	}
	59
168202c7 FT	60	static inline unsigned char vrtc_is_updating(void)
	61	{
	62	unsigned char uip;
	63	unsigned long flags;
	64
	65	spin_lock_irqsave(&rtc_lock, flags);
	66	uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP);
	67	spin_unlock_irqrestore(&rtc_lock, flags);
	68	return uip;
	69	}
	70
0146f261 FT	71	/*
	72	* rtc_time's year contains the increment over 1900, but vRTC's YEAR
	73	* register can't be programmed to value larger than 0x64, so vRTC
57e6319d	74	* driver chose to use 1972 (1970 is UNIX time start point) as the base,
d3e1884b FT	75	* and does the translation at read/write time.
d3e1884b FT	76	*
57e6319d	77	* Why not just use 1970 as the offset? it's because using 1972 will
d3e1884b	78	* make it consistent in leap year setting for both vrtc and low-level
57e6319d FT	79	* physical rtc devices. Then why not use 1960 as the offset? If we use
	80	* 1960, for a device's first use, its YEAR register is 0 and the system
	81	* year will be parsed as 1960 which is not a valid UNIX time and will
	82	* cause many applications to fail mysteriously.
0146f261 FT	83	*/
	84	static int mrst_read_time(struct device dev, struct rtc_time time)
	85	{
	86	unsigned long flags;
	87
168202c7	88	if (vrtc_is_updating())
c6b5eb8d	89	msleep(20);
0146f261 FT	90
	91	spin_lock_irqsave(&rtc_lock, flags);
	92	time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
	93	time->tm_min = vrtc_cmos_read(RTC_MINUTES);
	94	time->tm_hour = vrtc_cmos_read(RTC_HOURS);
	95	time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
	96	time->tm_mon = vrtc_cmos_read(RTC_MONTH);
	97	time->tm_year = vrtc_cmos_read(RTC_YEAR);
	98	spin_unlock_irqrestore(&rtc_lock, flags);
	99
57e6319d FT	100	/* Adjust for the 1972/1900 */
57e6319d FT	101	time->tm_year += 72;
0146f261	102	time->tm_mon--;
22652ba7	103	return 0;
0146f261 FT	104	}
	105
	106	static int mrst_set_time(struct device dev, struct rtc_time time)
	107	{
	108	int ret;
	109	unsigned long flags;
	110	unsigned char mon, day, hrs, min, sec;
	111	unsigned int yrs;
	112
	113	yrs = time->tm_year;
	114	mon = time->tm_mon + 1; /* tm_mon starts at zero */
	115	day = time->tm_mday;
	116	hrs = time->tm_hour;
	117	min = time->tm_min;
	118	sec = time->tm_sec;
	119
f441f98f	120	if (yrs < 72 \|\| yrs > 172)
0146f261	121	return -EINVAL;
57e6319d	122	yrs -= 72;
0146f261 FT	123
	124	spin_lock_irqsave(&rtc_lock, flags);
	125
	126	vrtc_cmos_write(yrs, RTC_YEAR);
	127	vrtc_cmos_write(mon, RTC_MONTH);
	128	vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
	129	vrtc_cmos_write(hrs, RTC_HOURS);
	130	vrtc_cmos_write(min, RTC_MINUTES);
	131	vrtc_cmos_write(sec, RTC_SECONDS);
	132
	133	spin_unlock_irqrestore(&rtc_lock, flags);
	134
	135	ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
	136	return ret;
	137	}
	138
	139	static int mrst_read_alarm(struct device dev, struct rtc_wkalrm t)
	140	{
	141	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	142	unsigned char rtc_control;
	143
	144	if (mrst->irq <= 0)
	145	return -EIO;
	146
0146f261 FT	147	/* vRTC only supports binary mode */
	148	spin_lock_irq(&rtc_lock);
	149	t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
	150	t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
	151	t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
	152
	153	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	154	spin_unlock_irq(&rtc_lock);
	155
	156	t->enabled = !!(rtc_control & RTC_AIE);
	157	t->pending = 0;
	158
	159	return 0;
	160	}
	161
	162	static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
	163	{
	164	unsigned char rtc_intr;
	165
	166	/*
	167	* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
	168	* allegedly some older rtcs need that to handle irqs properly
	169	*/
	170	rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
	171	rtc_intr &= (rtc_control & RTC_IRQMASK) \| RTC_IRQF;
	172	if (is_intr(rtc_intr))
	173	rtc_update_irq(mrst->rtc, 1, rtc_intr);
	174	}
	175
	176	static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
	177	{
	178	unsigned char rtc_control;
	179
	180	/*
	181	* Flush any pending IRQ status, notably for update irqs,
	182	* before we enable new IRQs
	183	*/
	184	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	185	mrst_checkintr(mrst, rtc_control);
	186
	187	rtc_control \|= mask;
	188	vrtc_cmos_write(rtc_control, RTC_CONTROL);
	189
	190	mrst_checkintr(mrst, rtc_control);
	191	}
	192
	193	static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
	194	{
	195	unsigned char rtc_control;
	196
	197	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	198	rtc_control &= ~mask;
	199	vrtc_cmos_write(rtc_control, RTC_CONTROL);
	200	mrst_checkintr(mrst, rtc_control);
	201	}
	202
	203	static int mrst_set_alarm(struct device dev, struct rtc_wkalrm t)
	204	{
	205	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	206	unsigned char hrs, min, sec;
	207	int ret = 0;
	208
	209	if (!mrst->irq)
	210	return -EIO;
211
212	hrs = t->time.tm_hour;
213	min = t->time.tm_min;
214	sec = t->time.tm_sec;
215
216	spin_lock_irq(&rtc_lock);
217	/* Next rtc irq must not be from previous alarm setting */
218	mrst_irq_disable(mrst, RTC_AIE);
219
220	/* Update alarm */
221	vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
222	vrtc_cmos_write(min, RTC_MINUTES_ALARM);
223	vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
224
225	spin_unlock_irq(&rtc_lock);
226
227	ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
228	if (ret)
229	return ret;
230
231	spin_lock_irq(&rtc_lock);
232	if (t->enabled)
233	mrst_irq_enable(mrst, RTC_AIE);
234
235	spin_unlock_irq(&rtc_lock);
236
237	return 0;
238	}
239
0146f261	240	/* Currently, the vRTC doesn't support UIE ON/OFF */
16380c15	241	static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
0146f261 FT	242	{
	243	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	244	unsigned long flags;
	245
0146f261	246	spin_lock_irqsave(&rtc_lock, flags);
16380c15	247	if (enabled)
0146f261	248	mrst_irq_enable(mrst, RTC_AIE);
16380c15 JS	249	else
16380c15 JS	250	mrst_irq_disable(mrst, RTC_AIE);
0146f261 FT	251	spin_unlock_irqrestore(&rtc_lock, flags);
	252	return 0;
	253	}
	254
0146f261	255
6fca3fc5	256	#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
0146f261 FT	257
	258	static int mrst_procfs(struct device dev, struct seq_file seq)
	259	{
de96bc39	260	unsigned char rtc_control;
0146f261 FT	261
	262	spin_lock_irq(&rtc_lock);
	263	rtc_control = vrtc_cmos_read(RTC_CONTROL);
0146f261 FT	264	spin_unlock_irq(&rtc_lock);
0146f261 FT	265
4395eb1f JP	266	seq_printf(seq,
	267	"periodic_IRQ\t: %s\n"
	268	"alarm\t\t: %s\n"
	269	"BCD\t\t: no\n"
	270	"periodic_freq\t: daily (not adjustable)\n",
	271	(rtc_control & RTC_PIE) ? "on" : "off",
	272	(rtc_control & RTC_AIE) ? "on" : "off");
	273
	274	return 0;
0146f261 FT	275	}
	276
	277	#else
	278	#define mrst_procfs NULL
	279	#endif
	280
	281	static const struct rtc_class_ops mrst_rtc_ops = {
0146f261 FT	282	.read_time = mrst_read_time,
	283	.set_time = mrst_set_time,
	284	.read_alarm = mrst_read_alarm,
	285	.set_alarm = mrst_set_alarm,
	286	.proc = mrst_procfs,
16380c15	287	.alarm_irq_enable = mrst_rtc_alarm_irq_enable,
0146f261 FT	288	};
	289
	290	static struct mrst_rtc mrst_rtc;
	291
	292	/*
	293	* When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
	294	* Reg B, so no need for this driver to clear it
	295	*/
	296	static irqreturn_t mrst_rtc_irq(int irq, void *p)
	297	{
	298	u8 irqstat;
	299
	300	spin_lock(&rtc_lock);
	301	/* This read will clear all IRQ flags inside Reg C */
	302	irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
	303	spin_unlock(&rtc_lock);
	304
	305	irqstat &= RTC_IRQMASK \| RTC_IRQF;
	306	if (is_intr(irqstat)) {
	307	rtc_update_irq(p, 1, irqstat);
	308	return IRQ_HANDLED;
	309	}
	310	return IRQ_NONE;
	311	}
	312
5a167f45 GKH	313	static int vrtc_mrst_do_probe(struct device dev, struct resource iomem,
5a167f45 GKH	314	int rtc_irq)
0146f261 FT	315	{
	316	int retval = 0;
	317	unsigned char rtc_control;
	318
	319	/* There can be only one ... */
	320	if (mrst_rtc.dev)
	321	return -EBUSY;
	322
	323	if (!iomem)
	324	return -ENODEV;
	325
32b41f93 AB	326	iomem = devm_request_mem_region(dev, iomem->start, resource_size(iomem),
32b41f93 AB	327	driver_name);
0146f261 FT	328	if (!iomem) {
	329	dev_dbg(dev, "i/o mem already in use.\n");
	330	return -EBUSY;
	331	}
	332
	333	mrst_rtc.irq = rtc_irq;
de97a21a FT	334	mrst_rtc.dev = dev;
de97a21a FT	335	dev_set_drvdata(dev, &mrst_rtc);
0146f261	336
32b41f93 AB	337	mrst_rtc.rtc = devm_rtc_allocate_device(dev);
	338	if (IS_ERR(mrst_rtc.rtc))
	339	return PTR_ERR(mrst_rtc.rtc);
	340
	341	mrst_rtc.rtc->ops = &mrst_rtc_ops;
0146f261	342
0146f261 FT	343	rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
	344
	345	spin_lock_irq(&rtc_lock);
	346	mrst_irq_disable(&mrst_rtc, RTC_PIE \| RTC_AIE);
	347	rtc_control = vrtc_cmos_read(RTC_CONTROL);
	348	spin_unlock_irq(&rtc_lock);
	349
	350	if (!(rtc_control & RTC_24H) \|\| (rtc_control & (RTC_DM_BINARY)))
	351	dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
	352
	353	if (rtc_irq) {
32b41f93 AB	354	retval = devm_request_irq(dev, rtc_irq, mrst_rtc_irq,
	355	0, dev_name(&mrst_rtc.rtc->dev),
	356	mrst_rtc.rtc);
0146f261 FT	357	if (retval < 0) {
	358	dev_dbg(dev, "IRQ %d is already in use, err %d\n",
	359	rtc_irq, retval);
32b41f93	360	goto cleanup0;
0146f261 FT	361	}
0146f261 FT	362	}
32b41f93 AB	363
32b41f93 AB	364	retval = rtc_register_device(mrst_rtc.rtc);
ca95ef7c	365	if (retval)
32b41f93	366	goto cleanup0;
32b41f93	367
0146f261 FT	368	dev_dbg(dev, "initialised\n");
	369	return 0;
	370
0146f261	371	cleanup0:
de97a21a	372	mrst_rtc.dev = NULL;
0146f261 FT	373	dev_err(dev, "rtc-mrst: unable to initialise\n");
	374	return retval;
	375	}
	376
	377	static void rtc_mrst_do_shutdown(void)
	378	{
	379	spin_lock_irq(&rtc_lock);
	380	mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
	381	spin_unlock_irq(&rtc_lock);
	382	}
	383
5a167f45	384	static void rtc_mrst_do_remove(struct device *dev)
0146f261 FT	385	{
0146f261 FT	386	struct mrst_rtc *mrst = dev_get_drvdata(dev);
0146f261 FT	387
	388	rtc_mrst_do_shutdown();
	389
0146f261	390	mrst->rtc = NULL;
0146f261	391	mrst->dev = NULL;
0146f261 FT	392	}
0146f261 FT	393
ddd2a30d LPC	394	#ifdef CONFIG_PM_SLEEP
ddd2a30d LPC	395	static int mrst_suspend(struct device *dev)
0146f261 FT	396	{
	397	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	398	unsigned char tmp;
	399
	400	/* Only the alarm might be a wakeup event source */
	401	spin_lock_irq(&rtc_lock);
	402	mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
	403	if (tmp & (RTC_PIE \| RTC_AIE)) {
	404	unsigned char mask;
	405
	406	if (device_may_wakeup(dev))
	407	mask = RTC_IRQMASK & ~RTC_AIE;
	408	else
	409	mask = RTC_IRQMASK;
	410	tmp &= ~mask;
	411	vrtc_cmos_write(tmp, RTC_CONTROL);
	412
	413	mrst_checkintr(mrst, tmp);
	414	}
	415	spin_unlock_irq(&rtc_lock);
	416
	417	if (tmp & RTC_AIE) {
	418	mrst->enabled_wake = 1;
	419	enable_irq_wake(mrst->irq);
	420	}
	421
	422	dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
	423	(tmp & RTC_AIE) ? ", alarm may wake" : "",
	424	tmp);
	425
	426	return 0;
	427	}
	428
	429	/*
	430	* We want RTC alarms to wake us from the deep power saving state
	431	*/
	432	static inline int mrst_poweroff(struct device *dev)
	433	{
ddd2a30d	434	return mrst_suspend(dev);
0146f261 FT	435	}
	436
	437	static int mrst_resume(struct device *dev)
	438	{
	439	struct mrst_rtc *mrst = dev_get_drvdata(dev);
	440	unsigned char tmp = mrst->suspend_ctrl;
	441
	442	/* Re-enable any irqs previously active */
	443	if (tmp & RTC_IRQMASK) {
	444	unsigned char mask;
	445
	446	if (mrst->enabled_wake) {
	447	disable_irq_wake(mrst->irq);
	448	mrst->enabled_wake = 0;
	449	}
	450
	451	spin_lock_irq(&rtc_lock);
	452	do {
	453	vrtc_cmos_write(tmp, RTC_CONTROL);
	454
	455	mask = vrtc_cmos_read(RTC_INTR_FLAGS);
	456	mask &= (tmp & RTC_IRQMASK) \| RTC_IRQF;
	457	if (!is_intr(mask))
	458	break;
	459
	460	rtc_update_irq(mrst->rtc, 1, mask);
	461	tmp &= ~RTC_AIE;
	462	} while (mask & RTC_AIE);
	463	spin_unlock_irq(&rtc_lock);
	464	}
	465
	466	dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
	467
	468	return 0;
	469	}
	470
ddd2a30d LPC	471	static SIMPLE_DEV_PM_OPS(mrst_pm_ops, mrst_suspend, mrst_resume);
	472	#define MRST_PM_OPS (&mrst_pm_ops)
	473
0146f261	474	#else
ddd2a30d	475	#define MRST_PM_OPS NULL
0146f261 FT	476
	477	static inline int mrst_poweroff(struct device *dev)
	478	{
	479	return -ENOSYS;
	480	}
	481
	482	#endif
	483
5a167f45	484	static int vrtc_mrst_platform_probe(struct platform_device *pdev)
0146f261 FT	485	{
	486	return vrtc_mrst_do_probe(&pdev->dev,
	487	platform_get_resource(pdev, IORESOURCE_MEM, 0),
	488	platform_get_irq(pdev, 0));
	489	}
	490
5a167f45	491	static int vrtc_mrst_platform_remove(struct platform_device *pdev)
0146f261 FT	492	{
	493	rtc_mrst_do_remove(&pdev->dev);
	494	return 0;
	495	}
	496
	497	static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
	498	{
	499	if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
	500	return;
	501
	502	rtc_mrst_do_shutdown();
	503	}
	504
	505	MODULE_ALIAS("platform:vrtc_mrst");
	506
	507	static struct platform_driver vrtc_mrst_platform_driver = {
	508	.probe = vrtc_mrst_platform_probe,
5a167f45	509	.remove = vrtc_mrst_platform_remove,
0146f261 FT	510	.shutdown = vrtc_mrst_platform_shutdown,
0146f261 FT	511	.driver = {
ddd2a30d LPC	512	.name = driver_name,
ddd2a30d LPC	513	.pm = MRST_PM_OPS,
0146f261 FT	514	}
	515	};
	516
0c4eae66	517	module_platform_driver(vrtc_mrst_platform_driver);
0146f261 FT	518
	519	MODULE_AUTHOR("Jacob Pan; Feng Tang");
	520	MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
	521	MODULE_LICENSE("GPL");