diff options
Diffstat (limited to 'drivers/rtc/rtc-mrst.c')
| -rw-r--r-- | drivers/rtc/rtc-mrst.c | 542 |
1 files changed, 542 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-mrst.c b/drivers/rtc/rtc-mrst.c new file mode 100644 index 00000000000..e2436d14017 --- /dev/null +++ b/drivers/rtc/rtc-mrst.c @@ -0,0 +1,542 @@ +/* + * 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"); |