x86: mrst: Add vrtc driver which serves as a wall clock device

Moorestown platform doesn't have a m146818 RTC device like traditional
x86 PC, but a firmware emulated virtual RTC device(vrtc), which provides
some basic RTC functions like get/set time. vrtc serves as the only
wall clock device on Moorestown platform.

[ tglx: Changed the exports to _GPL ]

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
LKML-Reference: <20101110172837.3311.40483.stgit@localhost.localdomain>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

6 files changed, 143 insertions, 7 deletions

diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 4d293dced62f..139591a933f6 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -117,6 +117,10 @@ enum fixed_addresses {
         FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
         FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
         __end_of_permanent_fixed_addresses,
+
+#ifdef  CONFIG_X86_MRST
+        FIX_LNW_VRTC,
+#endif
         /*
          * 256 temporary boot-time mappings, used by early_ioremap(),
          * before ioremap() is functional.
diff --git a/arch/x86/include/asm/mrst-vrtc.h b/arch/x86/include/asm/mrst-vrtc.h
new file mode 100644
index 000000000000..73668abdbedf
--- /dev/null
+++ b/arch/x86/include/asm/mrst-vrtc.h
@@ -0,0 +1,9 @@
+#ifndef _MRST_VRTC_H
+#define _MRST_VRTC_H
+
+extern unsigned char vrtc_cmos_read(unsigned char reg);
+extern void vrtc_cmos_write(unsigned char val, unsigned char reg);
+extern unsigned long vrtc_get_time(void);
+extern int vrtc_set_mmss(unsigned long nowtime);
+
+#endif
diff --git a/arch/x86/include/asm/mrst.h b/arch/x86/include/asm/mrst.h
index 283debd29fc0..719f00b28ff5 100644
--- a/arch/x86/include/asm/mrst.h
+++ b/arch/x86/include/asm/mrst.h
@@ -14,7 +14,9 @@
 #include <linux/sfi.h>
 
 extern int pci_mrst_init(void);
-int __init sfi_parse_mrtc(struct sfi_table_header *table);
+extern int __init sfi_parse_mrtc(struct sfi_table_header *table);
+extern int sfi_mrtc_num;
+extern struct sfi_rtc_table_entry sfi_mrtc_array[];
 
 /*
  * Medfield is the follow-up of Moorestown, it combines two chip solution into
@@ -54,4 +56,10 @@ extern void hsu_early_console_init(void);
 extern void intel_scu_devices_create(void);
 extern void intel_scu_devices_destroy(void);
 
+/* VRTC timer */
+#define MRST_VRTC_MAP_SZ        (1024)
+/*#define MRST_VRTC_PGOFFSET    (0xc00) */
+
+extern void mrst_rtc_init(void);
+
 #endif /* _ASM_X86_MRST_H */
diff --git a/arch/x86/platform/mrst/Makefile b/arch/x86/platform/mrst/Makefile
index efbbc552fa95..4d3e256780be 100644
--- a/arch/x86/platform/mrst/Makefile
+++ b/arch/x86/platform/mrst/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_X86_MRST)          += mrst.o
+obj-$(CONFIG_X86_MRST)          += vrtc.o
diff --git a/arch/x86/platform/mrst/mrst.c b/arch/x86/platform/mrst/mrst.c
index c727d97f7f31..42a0351f302c 100644
--- a/arch/x86/platform/mrst/mrst.c
+++ b/arch/x86/platform/mrst/mrst.c
@@ -37,7 +37,6 @@
 #include <asm/apb_timer.h>
 #include <asm/reboot.h>
 
-
 /*
  * the clockevent devices on Moorestown/Medfield can be APBT or LAPIC clock,
  * cmdline option x86_mrst_timer can be used to override the configuration
@@ -242,11 +241,6 @@ void __init mrst_time_init(void)
         apbt_time_init();
 }
 
-void __init mrst_rtc_init(void)
-{
-        sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc);
-}
-
 void __cpuinit mrst_arch_setup(void)
 {
         if (boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model == 0x27)
diff --git a/arch/x86/platform/mrst/vrtc.c b/arch/x86/platform/mrst/vrtc.c
new file mode 100644
index 000000000000..4944bd521d2c
--- /dev/null
+++ b/arch/x86/platform/mrst/vrtc.c
@@ -0,0 +1,120 @@
+/*
+ * 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/init.h>
+#include <linux/sfi.h>
+
+#include <asm/mrst.h>
+#include <asm/mrst-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);
+
+unsigned long vrtc_get_time(void)
+{
+        u8 sec, min, hour, mday, mon;
+        u32 year;
+
+        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);
+
+        /* vRTC YEAR reg contains the offset to 1960 */
+        year += 1960;
+
+        printk(KERN_INFO "vRTC: sec: %d min: %d hour: %d day: %d "
+                "mon: %d year: %d\n", sec, min, hour, mday, mon, year);
+
+        return mktime(year, mon, mday, hour, min, sec);
+}
+
+/* Only care about the minutes and seconds */
+int vrtc_set_mmss(unsigned long nowtime)
+{
+        int real_sec, real_min;
+        int vrtc_min;
+
+        vrtc_min = vrtc_cmos_read(RTC_MINUTES);
+
+        real_sec = nowtime % 60;
+        real_min = nowtime / 60;
+        if (((abs(real_min - vrtc_min) + 15)/30) & 1)
+                real_min += 30;
+        real_min %= 60;
+
+        vrtc_cmos_write(real_sec, RTC_SECONDS);
+        vrtc_cmos_write(real_min, RTC_MINUTES);
+        return 0;
+}
+
+void __init mrst_rtc_init(void)
+{
+        unsigned long rtc_paddr;
+        void __iomem *virt_base;
+
+        sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc);
+        if (!sfi_mrtc_num)
+                return;
+
+        rtc_paddr = sfi_mrtc_array[0].phys_addr;
+
+        /* vRTC's register address may not be page aligned */
+        set_fixmap_nocache(FIX_LNW_VRTC, rtc_paddr);
+
+        virt_base = (void __iomem *)__fix_to_virt(FIX_LNW_VRTC);
+        virt_base += rtc_paddr & ~PAGE_MASK;
+        vrtc_virt_base = virt_base;
+
+        x86_platform.get_wallclock = vrtc_get_time;
+        x86_platform.set_wallclock = vrtc_set_mmss;
+}