rtc: Add drivers/rtc/rtc-mrst.c

Provide the standard kernel rtc driver interface on top of the vrtc layer
added in the previous patch.

Signed-off-by: Feng Tang <feng.tang@intel.com>
LKML-Reference: <20101110172911.3311.20593.stgit@localhost.localdomain>
[Fixed swapped arguments on IPC]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
[Cleaned up and the device creation moved to arch/x86/platform]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 591 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2883428d5ac8..4941cade319f 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -463,6 +463,18 @@ config RTC_DRV_CMOS
           This driver can also be built as a module. If so, the module
           will be called rtc-cmos.
 
+config RTC_DRV_VRTC
+        tristate "Virtual RTC for Moorestown platforms"
+        depends on X86_MRST
+        default y if X86_MRST
+
+        help
+        Say "yes" here to get direct support for the real time clock
+        found on Moorestown platforms. The VRTC is a emulated RTC that
+        derives its clock source from a real RTC in the PMIC. The MC146818
+        style programming interface is mostly conserved, but any
+        updates are done via IPC calls to the system controller FW.
+
 config RTC_DRV_DS1216
         tristate "Dallas DS1216"
         depends on SNI_RM
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 4c2832df4697..2afdaf3ff986 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_RTC_DRV_CMOS)	+= rtc-cmos.o
 obj-$(CONFIG_RTC_DRV_COH901331) += rtc-coh901331.o
 obj-$(CONFIG_RTC_DRV_DAVINCI)   += rtc-davinci.o
 obj-$(CONFIG_RTC_DRV_DM355EVM)  += rtc-dm355evm.o
+obj-$(CONFIG_RTC_DRV_VRTC)      += rtc-mrst.o
 obj-$(CONFIG_RTC_DRV_DS1216)    += rtc-ds1216.o
 obj-$(CONFIG_RTC_DRV_DS1286)    += rtc-ds1286.o
 obj-$(CONFIG_RTC_DRV_DS1302)    += rtc-ds1302.o
diff --git a/drivers/rtc/rtc-mrst.c b/drivers/rtc/rtc-mrst.c
new file mode 100644
index 000000000000..67b6be2b874d
--- /dev/null
+++ b/drivers/rtc/rtc-mrst.c
@@ -0,0 +1,578 @@
+/*
+ * 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/mrst.h>
+#include <asm/mrst-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;
+}
+
+/*
+ * 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 1960 (1970 is UNIX time start point) as the base,
+ * and does the translation at read/write time
+ */
+static int mrst_read_time(struct device *dev, struct rtc_time *time)
+{
+        unsigned long flags;
+
+        if (rtc_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 1960/1900 */
+        time->tm_year += 60;
+        time->tm_mon--;
+        return RTC_24H;
+}
+
+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 < 70 || yrs > 138)
+                return -EINVAL;
+        yrs -= 60;
+
+        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;
+}
+
+static int mrst_irq_set_state(struct device *dev, int enabled)
+{
+        struct mrst_rtc *mrst = dev_get_drvdata(dev);
+        unsigned long   flags;
+
+        if (!mrst->irq)
+                return -ENXIO;
+
+        spin_lock_irqsave(&rtc_lock, flags);
+
+        if (enabled)
+                mrst_irq_enable(mrst, RTC_PIE);
+        else
+                mrst_irq_disable(mrst, RTC_PIE);
+
+        spin_unlock_irqrestore(&rtc_lock, flags);
+        return 0;
+}
+
+#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
+
+/* Currently, the vRTC doesn't support UIE ON/OFF */
+static int
+mrst_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+        struct mrst_rtc *mrst = dev_get_drvdata(dev);
+        unsigned long   flags;
+
+        switch (cmd) {
+        case RTC_AIE_OFF:
+        case RTC_AIE_ON:
+                if (!mrst->irq)
+                        return -EINVAL;
+                break;
+        default:
+                /* PIE ON/OFF is handled by mrst_irq_set_state() */
+                return -ENOIOCTLCMD;
+        }
+
+        spin_lock_irqsave(&rtc_lock, flags);
+        switch (cmd) {
+        case RTC_AIE_OFF:       /* alarm off */
+                mrst_irq_disable(mrst, RTC_AIE);
+                break;
+        case RTC_AIE_ON:        /* alarm on */
+                mrst_irq_enable(mrst, RTC_AIE);
+                break;
+        }
+        spin_unlock_irqrestore(&rtc_lock, flags);
+        return 0;
+}
+
+#else
+#define mrst_rtc_ioctl  NULL
+#endif
+
+#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 = {
+        .ioctl          = mrst_rtc_ioctl,
+        .read_time      = mrst_read_time,
+        .set_time       = mrst_set_time,
+        .read_alarm     = mrst_read_alarm,
+        .set_alarm      = mrst_set_alarm,
+        .proc           = mrst_procfs,
+        .irq_set_state  = mrst_irq_set_state,
+};
+
+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 __init
+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,
+                        iomem->end + 1 - iomem->start,
+                        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.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;
+        }
+
+        mrst_rtc.dev = dev;
+        dev_set_drvdata(dev, &mrst_rtc);
+        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,
+                                IRQF_DISABLED, 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:
+        mrst_rtc.dev = NULL;
+        rtc_device_unregister(mrst_rtc.rtc);
+cleanup0:
+        release_region(iomem->start, iomem->end + 1 - iomem->start);
+        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 __exit 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_region(iomem->start, iomem->end + 1 - iomem->start);
+        mrst->iomem = NULL;
+
+        mrst->dev = NULL;
+        dev_set_drvdata(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 __init 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 __exit 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         = __exit_p(vrtc_mrst_platform_remove),
+        .shutdown       = vrtc_mrst_platform_shutdown,
+        .driver = {
+                .name           = (char *) driver_name,
+                .suspend        = mrst_suspend,
+                .resume         = mrst_resume,
+        }
+};
+
+static int __init vrtc_mrst_init(void)
+{
+        return platform_driver_register(&vrtc_mrst_platform_driver);
+}
+
+static void __exit vrtc_mrst_exit(void)
+{
+        platform_driver_unregister(&vrtc_mrst_platform_driver);
+}
+
+module_init(vrtc_mrst_init);
+module_exit(vrtc_mrst_exit);
+
+MODULE_AUTHOR("Jacob Pan; Feng Tang");
+MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
+MODULE_LICENSE("GPL");