Messages in this thread Patch in this message | | | From | Jacob Pan <> | Subject | [PATCH 7/8] x86/mrst: add vrtc driver which serves as a wall clock device | Date | Fri, 7 May 2010 10:41:47 -0700 |
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From: Feng Tang <feng.tang@intel.com>
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.
Signed-off-by: Feng Tang <feng.tang@intel.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> --- arch/x86/include/asm/fixmap.h | 4 ++ arch/x86/include/asm/vrtc.h | 27 +++++++++++ arch/x86/kernel/Makefile | 2 +- arch/x86/kernel/mrst.c | 20 ++++++++ arch/x86/kernel/vrtc.c | 100 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 152 insertions(+), 1 deletions(-) create mode 100644 arch/x86/include/asm/vrtc.h create mode 100644 arch/x86/kernel/vrtc.c
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index d07b44f..c4ba8d9 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/vrtc.h b/arch/x86/include/asm/vrtc.h new file mode 100644 index 0000000..4e40129 --- /dev/null +++ b/arch/x86/include/asm/vrtc.h @@ -0,0 +1,27 @@ +#ifndef _MRST_VRTC_H +#define _MRST_VRTC_H + +#ifdef CONFIG_X86_MRST +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); +extern void vrtc_set_base(void __iomem *base); + +#define MRST_VRTC_PGOFFSET (0xc00) + +#else +static inline unsigned char vrtc_cmos_read(unsigned char reg) +{ + return 0xff; +} + +static inline void vrtc_cmos_write(unsigned char val, unsigned char reg) +{ + return; +} +#endif + +#define MRST_VRTC_MAP_SZ (1024) + +#endif diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index e77b220..f3fdcbe 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -104,7 +104,7 @@ obj-$(CONFIG_SCx200) += scx200.o scx200-y += scx200_32.o obj-$(CONFIG_OLPC) += olpc.o -obj-$(CONFIG_X86_MRST) += mrst.o +obj-$(CONFIG_X86_MRST) += mrst.o vrtc.o microcode-y := microcode_core.o microcode-$(CONFIG_MICROCODE_INTEL) += microcode_intel.o diff --git a/arch/x86/kernel/mrst.c b/arch/x86/kernel/mrst.c index 9e14e7f..0b3ef9f 100644 --- a/arch/x86/kernel/mrst.c +++ b/arch/x86/kernel/mrst.c @@ -24,6 +24,7 @@ #include <asm/io.h> #include <asm/i8259.h> #include <asm/apb_timer.h> +#include <asm/vrtc.h> /** * the clockevent devices on Moorestown/Medfield can be APBT or LAPIC clock, @@ -268,7 +269,24 @@ void __init mrst_time_init(void) 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_set_base(virt_base); + + x86_platform.get_wallclock = vrtc_get_time; + x86_platform.set_wallclock = vrtc_set_mmss; } /* @@ -326,6 +344,8 @@ void __init x86_mrst_early_setup(void) x86_cpuinit.setup_percpu_clockev = mrst_setup_secondary_clock; x86_platform.calibrate_tsc = mrst_calibrate_tsc; + x86_platform.wallclock_init = mrst_rtc_init; + x86_init.pci.init = pci_mrst_init; x86_init.pci.fixup_irqs = x86_init_noop; diff --git a/arch/x86/kernel/vrtc.c b/arch/x86/kernel/vrtc.c new file mode 100644 index 0000000..fa1eb63 --- /dev/null +++ b/arch/x86/kernel/vrtc.c @@ -0,0 +1,100 @@ +/* + * 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 <asm/vrtc.h> +#include <asm/time.h> +#include <asm/fixmap.h> + +static unsigned char __iomem *vrtc_virt_base; + +void vrtc_set_base(void __iomem *base) +{ + vrtc_virt_base = 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(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(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; +} -- 1.6.3.3
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