diff options
author | 2015-08-28 09:58:54 +0800 | |
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committer | 2015-09-01 12:44:00 +0800 | |
commit | e44e3482bdb4d0ebde2d8b41830ac2cdb07948fb (patch) | |
tree | 66b09f592c55df2878107a468a91d21506104d3f /qemu/roms/seabios/src/hw/rtc.c | |
parent | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (diff) |
Add qemu 2.4.0
Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
Diffstat (limited to 'qemu/roms/seabios/src/hw/rtc.c')
-rw-r--r-- | qemu/roms/seabios/src/hw/rtc.c | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/qemu/roms/seabios/src/hw/rtc.c b/qemu/roms/seabios/src/hw/rtc.c new file mode 100644 index 000000000..628d5429f --- /dev/null +++ b/qemu/roms/seabios/src/hw/rtc.c @@ -0,0 +1,93 @@ +// Support for MC146818 Real Time Clock chip. +// +// Copyright (C) 2008-2013 Kevin O'Connor <kevin@koconnor.net> +// Copyright (C) 2002 MandrakeSoft S.A. +// +// This file may be distributed under the terms of the GNU LGPLv3 license. + +#include "biosvar.h" // GET_LOW +#include "rtc.h" // rtc_read +#include "stacks.h" // yield +#include "util.h" // timer_calc +#include "x86.h" // inb + +u8 +rtc_read(u8 index) +{ + index |= NMI_DISABLE_BIT; + outb(index, PORT_CMOS_INDEX); + return inb(PORT_CMOS_DATA); +} + +void +rtc_write(u8 index, u8 val) +{ + index |= NMI_DISABLE_BIT; + outb(index, PORT_CMOS_INDEX); + outb(val, PORT_CMOS_DATA); +} + +void +rtc_mask(u8 index, u8 off, u8 on) +{ + outb(index, PORT_CMOS_INDEX); + u8 val = inb(PORT_CMOS_DATA); + outb((val & ~off) | on, PORT_CMOS_DATA); +} + +int +rtc_updating(void) +{ + // This function checks to see if the update-in-progress bit + // is set in CMOS Status Register A. If not, it returns 0. + // If it is set, it tries to wait until there is a transition + // to 0, and will return 0 if such a transition occurs. A -1 + // is returned only after timing out. The maximum period + // that this bit should be set is constrained to (1984+244) + // useconds, but we wait for longer just to be sure. + + if ((rtc_read(CMOS_STATUS_A) & RTC_A_UIP) == 0) + return 0; + u32 end = timer_calc(15); + for (;;) { + if ((rtc_read(CMOS_STATUS_A) & RTC_A_UIP) == 0) + return 0; + if (timer_check(end)) + // update-in-progress never transitioned to 0 + return -1; + yield(); + } +} + +void +rtc_setup(void) +{ + rtc_write(CMOS_STATUS_A, 0x26); // 32,768Khz src, 976.5625us updates + rtc_mask(CMOS_STATUS_B, ~RTC_B_DSE, RTC_B_24HR); + rtc_read(CMOS_STATUS_C); + rtc_read(CMOS_STATUS_D); +} + +int RTCusers VARLOW; + +void +rtc_use(void) +{ + int count = GET_LOW(RTCusers); + SET_LOW(RTCusers, count+1); + if (count) + return; + // Turn on the Periodic Interrupt timer + rtc_mask(CMOS_STATUS_B, 0, RTC_B_PIE); +} + +void +rtc_release(void) +{ + int count = GET_LOW(RTCusers); + SET_LOW(RTCusers, count-1); + if (count != 1) + return; + // Clear the Periodic Interrupt. + rtc_mask(CMOS_STATUS_B, RTC_B_PIE, 0); +} |