/* * 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; 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");