minix/drivers/clock/readclock/forward.c

   1 /*
   2  * Some real time clocks are embedded within other multi-function chips.
   3  * Drivers for such chips will implement the RTCDEV protocol and the
   4  * readclock driver will simply forward on the message to the driver.
   5  * This keeps things simple for any other services that need to access
   6  * the RTC as they only have to know / care about the readclock driver.
   7  */
   8
   9 #include <minix/syslib.h>
  10 #include <minix/drvlib.h>
  11 #include <minix/sysutil.h>
  12 #include <minix/log.h>
  13 #include <minix/rs.h>
  14 #include <minix/ds.h>
  15 #include <minix/safecopies.h>
  16
  17 #include <sys/mman.h>
  18 #include <sys/types.h>
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <stdarg.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include <assert.h>
  26 #include <time.h>
  27 #include <lib.h>
  28
  29 #include "forward.h"
  30 #include "readclock.h"
  31
  32 static int fwd_msg(int type, struct tm *t, int t_access, int flags);
  33
  34 static struct log log = {
  35         .name = "readclock.fwd",
  36         .log_level = LEVEL_INFO,
  37         .log_func = default_log
  38 };
  39
  40 /*
  41  * Label of the driver that messages should be forwarded to.
  42  */
  43 static char *target_label;
  44
  45 int
  46 fwd_set_label(char *label)
  47 {
  48         target_label = label;
  49         return OK;
  50 }
  51
  52 int
  53 fwd_init(void)
  54 {
  55         if (target_label == NULL) {
  56                 return EINVAL;
  57         }
  58         return OK;
  59 }
  60
  61 static int
  62 fwd_msg(int type, struct tm *t, int t_access, int flags)
  63 {
  64         int r;
  65         message m;
  66         endpoint_t ep;
  67         cp_grant_id_t gid;
  68
  69         r = ds_retrieve_label_endpt(target_label, &ep);
  70         if (r != 0) {
  71                 return -1;
  72         }
  73
  74         if (type == RTCDEV_PWR_OFF) {
  75                 /* RTCDEV_PWR_OFF messages don't contain any data/flags. */
  76                 return _syscall(ep, RTCDEV_PWR_OFF, &m);
  77         }
  78
  79         gid = cpf_grant_direct(ep, (vir_bytes) t, sizeof(struct tm), t_access);
  80         if (!GRANT_VALID(gid)) {
  81                 log_warn(&log, "Could not create grant.\n");
  82                 return -1;
  83         }
  84
  85         m.m_lc_readclock_rtcdev.grant = gid;
  86         m.m_lc_readclock_rtcdev.flags = flags;
  87
  88         r = _syscall(ep, type, &m);
  89         cpf_revoke(gid);
  90         if (r != RTCDEV_REPLY || m.m_readclock_lc_rtcdev.status != 0) {
  91                 log_warn(&log, "Call to '%s' failed.\n", target_label);
  92                 return -1;
  93         }
  94
  95         return OK;
  96 }
  97
  98 int
  99 fwd_get_time(struct tm *t, int flags)
 100 {
 101         return fwd_msg(RTCDEV_GET_TIME_G, t, CPF_WRITE, flags);
 102 }
 103
 104 int
 105 fwd_set_time(struct tm *t, int flags)
 106 {
 107         return fwd_msg(RTCDEV_SET_TIME_G, t, CPF_READ, flags);
 108 }
 109
 110 int
 111 fwd_pwr_off(void)
 112 {
 113         return fwd_msg(RTCDEV_PWR_OFF, NULL, 0, RTCDEV_NOFLAGS);
 114 }
 115
 116 void
 117 fwd_exit(void)
 118 {
 119         target_label = NULL;
 120 }