kernel/arch/earm/bsp/ti/omap_rtc.c

   1 /*
   2  * This is a mini driver for the AM335X Real Time Clock. The majority of the
   3  * work is done in user space in readclock, but for power-off the clock needs
   4  * to be put into run mode at the last possible moment in arch_reset.c. This
   5  * driver just implements mapping the memory and re-starting the clock.
   6  */
   7
   8 #include <assert.h>
   9 #include <sys/types.h>
  10 #include <machine/cpu.h>
  11 #include <minix/type.h>
  12 #include <minix/board.h>
  13 #include <io.h>
  14
  15 #include "kernel/kernel.h"
  16 #include "kernel/proc.h"
  17 #include "kernel/vm.h"
  18 #include "kernel/proto.h"
  19 #include "arch_proto.h"
  20 #include "omap_rtc.h"
  21
  22 #define RTC_SS_BASE 0x44e3e000
  23 #define RTC_SS_SIZE 0x1000
  24 #define RTC_CTRL_REG 0x40
  25 #define RTC_CTRL_RTC_STOP_BIT 0
  26
  27 struct omap_rtc
  28 {
  29         vir_bytes base;
  30         vir_bytes size;
  31 };
  32
  33 static struct omap_rtc omap_rtc = {
  34         .base = RTC_SS_BASE,
  35         .size = RTC_SS_SIZE
  36 };
  37
  38 static kern_phys_map rtc_phys_map;
  39
  40 void
  41 omap3_rtc_init(void)
  42 {
  43         if (BOARD_IS_BB(machine.board_id)) {
  44                 kern_phys_map_ptr(omap_rtc.base, omap_rtc.size,
  45                     VMMF_UNCACHED | VMMF_WRITE, &rtc_phys_map,
  46                     (vir_bytes) & omap_rtc.base);
  47         }
  48 }
  49
  50 void
  51 omap3_rtc_run(void)
  52 {
  53         if (BOARD_IS_BB(machine.board_id)) {
  54                 /* Setting the stop bit starts the RTC running */
  55                 mmio_set((omap_rtc.base + RTC_CTRL_REG),
  56                     (1 << RTC_CTRL_RTC_STOP_BIT));
  57         }
  58 }