--- /dev/null
+/*
+ * intel_mid_vrtc.c: Driver for virtual RTC device on Intel MID platform
+ *
+ * (C) Copyright 2009 Intel Corporation
+ *
+ * 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 on RTC CMOS driver.
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/sfi.h>
+#include <linux/platform_device.h>
+
+#include <asm/intel-mid.h>
+#include <asm/intel_mid_vrtc.h>
+#include <asm/time.h>
+#include <asm/fixmap.h>
+
+static unsigned char __iomem *vrtc_virt_base;
+
+unsigned char vrtc_cmos_read(unsigned char reg)
+{
+ unsigned char retval;
+
+ /* vRTC's registers range from 0x0 to 0xD */
+ if (reg > 0xd || !vrtc_virt_base)
+ return 0xff;
+
+ lock_cmos_prefix(reg);
+ retval = __raw_readb(vrtc_virt_base + (reg << 2));
+ lock_cmos_suffix(reg);
+ return retval;
+}
+EXPORT_SYMBOL_GPL(vrtc_cmos_read);
+
+void vrtc_cmos_write(unsigned char val, unsigned char reg)
+{
+ if (reg > 0xd || !vrtc_virt_base)
+ return;
+
+ lock_cmos_prefix(reg);
+ __raw_writeb(val, vrtc_virt_base + (reg << 2));
+ lock_cmos_suffix(reg);
+}
+EXPORT_SYMBOL_GPL(vrtc_cmos_write);
+
+void vrtc_get_time(struct timespec *now)
+{
+ u8 sec, min, hour, mday, mon;
+ unsigned long flags;
+ u32 year;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+
+ while ((vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP))
+ cpu_relax();
+
+ sec = vrtc_cmos_read(RTC_SECONDS);
+ min = vrtc_cmos_read(RTC_MINUTES);
+ hour = vrtc_cmos_read(RTC_HOURS);
+ mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
+ mon = vrtc_cmos_read(RTC_MONTH);
+ year = vrtc_cmos_read(RTC_YEAR);
+
+ spin_unlock_irqrestore(&rtc_lock, flags);
+
+ /* vRTC YEAR reg contains the offset to 1972 */
+ year += 1972;
+
+ pr_info("vRTC: sec: %d min: %d hour: %d day: %d "
+ "mon: %d year: %d\n", sec, min, hour, mday, mon, year);
+
+ now->tv_sec = mktime(year, mon, mday, hour, min, sec);
+ now->tv_nsec = 0;
+}
+
+int vrtc_set_mmss(const struct timespec *now)
+{
+ unsigned long flags;
+ struct rtc_time tm;
+ int year;
+ int retval = 0;
+
+ rtc_time_to_tm(now->tv_sec, &tm);
+ if (!rtc_valid_tm(&tm) && tm.tm_year >= 72) {
+ /*
+ * tm.year is the number of years since 1900, and the
+ * vrtc need the years since 1972.
+ */
+ year = tm.tm_year - 72;
+ spin_lock_irqsave(&rtc_lock, flags);
+ vrtc_cmos_write(year, RTC_YEAR);
+ vrtc_cmos_write(tm.tm_mon, RTC_MONTH);
+ vrtc_cmos_write(tm.tm_mday, RTC_DAY_OF_MONTH);
+ vrtc_cmos_write(tm.tm_hour, RTC_HOURS);
+ vrtc_cmos_write(tm.tm_min, RTC_MINUTES);
+ vrtc_cmos_write(tm.tm_sec, RTC_SECONDS);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ } else {
+ pr_err("%s: Invalid vRTC value: write of %lx to vRTC failed\n",
+ __func__, now->tv_sec);
+ retval = -EINVAL;
+ }
+ return retval;
+}
+
+void __init intel_mid_rtc_init(void)
+{
+ unsigned long vrtc_paddr;
+
+ sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc);
+
+ vrtc_paddr = sfi_mrtc_array[0].phys_addr;
+ if (!sfi_mrtc_num || !vrtc_paddr)
+ return;
+
+ vrtc_virt_base = (void __iomem *)set_fixmap_offset_nocache(FIX_LNW_VRTC,
+ vrtc_paddr);
+ x86_platform.get_wallclock = vrtc_get_time;
+ x86_platform.set_wallclock = vrtc_set_mmss;
+}
+
+/*
+ * The Moorestown platform has a memory mapped virtual RTC device that emulates
+ * the programming interface of the RTC.
+ */
+
+static struct resource vrtc_resources[] = {
+ [0] = {
+ .flags = IORESOURCE_MEM,
+ },
+ [1] = {
+ .flags = IORESOURCE_IRQ,
+ }
+};
+
+static struct platform_device vrtc_device = {
+ .name = "rtc_mrst",
+ .id = -1,
+ .resource = vrtc_resources,
+ .num_resources = ARRAY_SIZE(vrtc_resources),
+};
+
+/* Register the RTC device if appropriate */
+static int __init intel_mid_device_create(void)
+{
+ /* No Moorestown, no device */
+ if (!intel_mid_identify_cpu())
+ return -ENODEV;
+ /* No timer, no device */
+ if (!sfi_mrtc_num)
+ return -ENODEV;
+
+ /* iomem resource */
+ vrtc_resources[0].start = sfi_mrtc_array[0].phys_addr;
+ vrtc_resources[0].end = sfi_mrtc_array[0].phys_addr +
+ MRST_VRTC_MAP_SZ;
+ /* irq resource */
+ vrtc_resources[1].start = sfi_mrtc_array[0].irq;
+ vrtc_resources[1].end = sfi_mrtc_array[0].irq;
+
+ return platform_device_register(&vrtc_device);
+}
+
+module_init(intel_mid_device_create);
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