6d7eff8023
AM335X SoCs support power-off via a power management chip (PMIC). An alarm in the real time clock is used to trigger the PMIC to cut the power. To ensure the alarm goes off when the system is in a safe state, the RTC is frozen when the alarm is set. At the last moment, the kernel unfreezes the RTC to let the alarm go off. This patch adds a mini driver for unfreezing the RTC as well as code to handle RBT_POWEROFF on Minix/arm. Change-Id: I7d48e75791e3a81bdd2f7704997193a269409fe8
56 lines
1.2 KiB
C
56 lines
1.2 KiB
C
/*
|
|
* This is a mini driver for the AM335X Real Time Clock. The majority of the
|
|
* work is done in user space in readclock, but for power-off the clock needs
|
|
* to be put into run mode at the last possible moment in arch_reset.c. This
|
|
* driver just implements mapping the memory and re-starting the clock.
|
|
*/
|
|
|
|
#include <assert.h>
|
|
#include <sys/types.h>
|
|
#include <machine/cpu.h>
|
|
#include <minix/type.h>
|
|
#include <io.h>
|
|
|
|
#include "kernel/kernel.h"
|
|
#include "kernel/proc.h"
|
|
#include "kernel/vm.h"
|
|
#include "kernel/proto.h"
|
|
#include "arch_proto.h"
|
|
#include "omap_rtc.h"
|
|
|
|
#define RTC_SS_BASE 0x44e3e000
|
|
#define RTC_SS_SIZE 0x1000
|
|
#define RTC_CTRL_REG 0x40
|
|
#define RTC_CTRL_RTC_STOP_BIT 0
|
|
|
|
struct omap_rtc
|
|
{
|
|
vir_bytes base;
|
|
vir_bytes size;
|
|
};
|
|
|
|
static struct omap_rtc omap_rtc = {
|
|
.base = RTC_SS_BASE,
|
|
.size = RTC_SS_SIZE
|
|
};
|
|
|
|
static kern_phys_map rtc_phys_map;
|
|
|
|
void
|
|
omap3_rtc_init(void)
|
|
{
|
|
#ifdef AM335X
|
|
kern_phys_map_ptr(omap_rtc.base, omap_rtc.size, &rtc_phys_map,
|
|
&omap_rtc.base);
|
|
#endif /* AM335X */
|
|
}
|
|
|
|
void
|
|
omap3_rtc_run(void)
|
|
{
|
|
#ifdef AM335X
|
|
/* Setting the stop bit starts the RTC running */
|
|
mmio_set((omap_rtc.base + RTC_CTRL_REG), (1 << RTC_CTRL_RTC_STOP_BIT));
|
|
#endif /* AM335X */
|
|
}
|