release/src-rt-6.x/linux/linux-2.6/arch/sh/boards/snapgear/rtc.c

   1 /****************************************************************************/
   2 /*
   3  * linux/arch/sh/boards/snapgear/rtc.c -- Secureedge5410 RTC code
   4  *
   5  *  Copyright (C) 2002  David McCullough <davidm@snapgear.com>
   6  *  Copyright (C) 2003  Paul Mundt <lethal@linux-sh.org>
   7  *
   8  * The SecureEdge5410 can have one of 2 real time clocks, the SH
   9  * built in version or the preferred external DS1302.  Here we work out
  10  * each to see what we have and then run with it.
  11  */
  12 /****************************************************************************/
  13
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/sched.h>
  17 #include <linux/time.h>
  18 #include <linux/rtc.h>
  19 #include <linux/mc146818rtc.h>
  20 #include <asm/io.h>
  21
  22 static int use_ds1302;
  23
  24 /****************************************************************************/
  25 /*
  26  *      we need to implement a DS1302 driver here that can operate in
  27  *      conjunction with the builtin rtc driver which is already quite friendly
  28  */
  29 /*****************************************************************************/
  30
  31 #define RTC_CMD_READ    0x81            /* Read command */
  32 #define RTC_CMD_WRITE   0x80            /* Write command */
  33
  34 #define RTC_ADDR_YEAR   0x06            /* Address of year register */
  35 #define RTC_ADDR_DAY    0x05            /* Address of day of week register */
  36 #define RTC_ADDR_MON    0x04            /* Address of month register */
  37 #define RTC_ADDR_DATE   0x03            /* Address of day of month register */
  38 #define RTC_ADDR_HOUR   0x02            /* Address of hour register */
  39 #define RTC_ADDR_MIN    0x01            /* Address of minute register */
  40 #define RTC_ADDR_SEC    0x00            /* Address of second register */
  41
  42 #define RTC_RESET       0x1000
  43 #define RTC_IODATA      0x0800
  44 #define RTC_SCLK        0x0400
  45
  46 #define set_dirp(x)
  47 #define get_dirp(x) 0
  48 #define set_dp(x)       SECUREEDGE_WRITE_IOPORT(x, 0x1c00)
  49 #define get_dp(x)       SECUREEDGE_READ_IOPORT()
  50
  51 static void ds1302_sendbits(unsigned int val)
  52 {
  53         int     i;
  54
  55         for (i = 8; (i); i--, val >>= 1) {
  56                 set_dp((get_dp() & ~RTC_IODATA) | ((val & 0x1) ? RTC_IODATA : 0));
  57                 set_dp(get_dp() | RTC_SCLK);    // clock high
  58                 set_dp(get_dp() & ~RTC_SCLK);   // clock low
  59         }
  60 }
  61
  62 static unsigned int ds1302_recvbits(void)
  63 {
  64         unsigned int    val;
  65         int             i;
  66
  67         for (i = 0, val = 0; (i < 8); i++) {
  68                 val |= (((get_dp() & RTC_IODATA) ? 1 : 0) << i);
  69                 set_dp(get_dp() | RTC_SCLK);    // clock high
  70                 set_dp(get_dp() & ~RTC_SCLK);   // clock low
  71         }
  72         return(val);
  73 }
  74
  75 static unsigned int ds1302_readbyte(unsigned int addr)
  76 {
  77         unsigned int    val;
  78         unsigned long   flags;
  79
  80         local_irq_save(flags);
  81         set_dirp(get_dirp() | RTC_RESET | RTC_IODATA | RTC_SCLK);
  82         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
  83
  84         set_dp(get_dp() | RTC_RESET);
  85         ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ);
  86         set_dirp(get_dirp() & ~RTC_IODATA);
  87         val = ds1302_recvbits();
  88         set_dp(get_dp() & ~RTC_RESET);
  89         local_irq_restore(flags);
  90
  91         return(val);
  92 }
  93
  94 static void ds1302_writebyte(unsigned int addr, unsigned int val)
  95 {
  96         unsigned long   flags;
  97
  98         local_irq_save(flags);
  99         set_dirp(get_dirp() | RTC_RESET | RTC_IODATA | RTC_SCLK);
 100         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
 101         set_dp(get_dp() | RTC_RESET);
 102         ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE);
 103         ds1302_sendbits(val);
 104         set_dp(get_dp() & ~RTC_RESET);
 105         local_irq_restore(flags);
 106 }
 107
 108 static void ds1302_reset(void)
 109 {
 110         unsigned long   flags;
 111         /* Hardware dependent reset/init */
 112         local_irq_save(flags);
 113         set_dirp(get_dirp() | RTC_RESET | RTC_IODATA | RTC_SCLK);
 114         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
 115         local_irq_restore(flags);
 116 }
 117
 118 /*****************************************************************************/
 119
 120 static inline int bcd2int(int val)
 121 {
 122         return((((val & 0xf0) >> 4) * 10) + (val & 0xf));
 123 }
 124
 125 static inline int int2bcd(int val)
 126 {
 127         return(((val / 10) << 4) + (val % 10));
 128 }
 129
 130 /*****************************************************************************/
 131 /*
 132  *      Write and Read some RAM in the DS1302,  if it works assume it's there
 133  *      Otherwise use the SH4 internal RTC
 134  */
 135
 136 void snapgear_rtc_gettimeofday(struct timespec *);
 137 int snapgear_rtc_settimeofday(const time_t);
 138
 139 void __init secureedge5410_rtc_init(void)
 140 {
 141         unsigned char *test = "snapgear";
 142         int i;
 143
 144         ds1302_reset();
 145
 146         use_ds1302 = 1;
 147
 148         for (i = 0; test[i]; i++)
 149                 ds1302_writebyte(32 + i, test[i]);
 150
 151         for (i = 0; test[i]; i++)
 152                 if (ds1302_readbyte(32 + i) != test[i]) {
 153                         use_ds1302 = 0;
 154                         break;
 155                 }
 156
 157         if (use_ds1302) {
 158                 rtc_sh_get_time = snapgear_rtc_gettimeofday;
 159                 rtc_sh_set_time = snapgear_rtc_settimeofday;
 160         }
 161
 162         printk("SnapGear RTC: using %s rtc.\n", use_ds1302 ? "ds1302" : "internal");
 163 }
 164
 165 /****************************************************************************/
 166 /*
 167  *      our generic interface that chooses the correct code to use
 168  */
 169
 170 void snapgear_rtc_gettimeofday(struct timespec *ts)
 171 {
 172         unsigned int sec, min, hr, day, mon, yr;
 173
 174         if (!use_ds1302)
 175                 return;
 176
 177         sec = bcd2int(ds1302_readbyte(RTC_ADDR_SEC));
 178         min = bcd2int(ds1302_readbyte(RTC_ADDR_MIN));
 179         hr  = bcd2int(ds1302_readbyte(RTC_ADDR_HOUR));
 180         day = bcd2int(ds1302_readbyte(RTC_ADDR_DATE));
 181         mon = bcd2int(ds1302_readbyte(RTC_ADDR_MON));
 182         yr  = bcd2int(ds1302_readbyte(RTC_ADDR_YEAR));
 183
 184 bad_time:
 185         if (yr > 99 || mon < 1 || mon > 12 || day > 31 || day < 1 ||
 186             hr > 23 || min > 59 || sec > 59) {
 187                 printk(KERN_ERR
 188                        "SnapGear RTC: invalid value, resetting to 1 Jan 2000\n");
 189                 ds1302_writebyte(RTC_ADDR_MIN,  min = 0);
 190                 ds1302_writebyte(RTC_ADDR_HOUR, hr  = 0);
 191                 ds1302_writebyte(RTC_ADDR_DAY,        7);
 192                 ds1302_writebyte(RTC_ADDR_DATE, day = 1);
 193                 ds1302_writebyte(RTC_ADDR_MON,  mon = 1);
 194                 ds1302_writebyte(RTC_ADDR_YEAR, yr  = 0);
 195                 ds1302_writebyte(RTC_ADDR_SEC,  sec = 0);
 196         }
 197
 198         ts->tv_sec = mktime(2000 + yr, mon, day, hr, min, sec);
 199         if (ts->tv_sec < 0) {
 200 #if 0
 201                 printk("BAD TIME %d %d %d %d %d %d\n", yr, mon, day, hr, min, sec);
 202 #endif
 203                 yr = 100;
 204                 goto bad_time;
 205         }
 206         ts->tv_nsec = 0;
 207 }
 208
 209 int snapgear_rtc_settimeofday(const time_t secs)
 210 {
 211         int retval = 0;
 212         int real_seconds, real_minutes, cmos_minutes;
 213         unsigned long nowtime;
 214
 215         if (!use_ds1302)
 216                 return 0;
 217
 218 /*
 219  *      This is called direct from the kernel timer handling code.
 220  *      It is supposed to synchronize the kernel clock to the RTC.
 221  */
 222
 223         nowtime = secs;
 224
 225         /* STOP RTC */
 226         ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80);
 227
 228         cmos_minutes = bcd2int(ds1302_readbyte(RTC_ADDR_MIN));
 229
 230         /*
 231          * since we're only adjusting minutes and seconds,
 232          * don't interfere with hour overflow. This avoids
 233          * messing with unknown time zones but requires your
 234          * RTC not to be off by more than 15 minutes
 235          */
 236         real_seconds = nowtime % 60;
 237         real_minutes = nowtime / 60;
 238         if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
 239                 real_minutes += 30;     /* correct for half hour time zone */
 240         real_minutes %= 60;
 241
 242         if (abs(real_minutes - cmos_minutes) < 30) {
 243                 ds1302_writebyte(RTC_ADDR_MIN, int2bcd(real_minutes));
 244                 ds1302_writebyte(RTC_ADDR_SEC, int2bcd(real_seconds));
 245         } else {
 246                 printk(KERN_WARNING
 247                        "SnapGear RTC: can't update from %d to %d\n",
 248                        cmos_minutes, real_minutes);
 249                 retval = -1;
 250         }
 251
 252         /* START RTC */
 253         ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80);
 254         return(0);
 255 }
 256
 257 unsigned char secureedge5410_cmos_read(int addr)
 258 {
 259         unsigned char val = 0;
 260
 261         if (!use_ds1302)
 262                 return(__CMOS_READ(addr, w));
 263
 264         switch(addr) {
 265         case RTC_SECONDS:       val = ds1302_readbyte(RTC_ADDR_SEC);  break;
 266         case RTC_SECONDS_ALARM:                                       break;
 267         case RTC_MINUTES:       val = ds1302_readbyte(RTC_ADDR_MIN);  break;
 268         case RTC_MINUTES_ALARM:                                       break;
 269         case RTC_HOURS:         val = ds1302_readbyte(RTC_ADDR_HOUR); break;
 270         case RTC_HOURS_ALARM:                                         break;
 271         case RTC_DAY_OF_WEEK:   val = ds1302_readbyte(RTC_ADDR_DAY);  break;
 272         case RTC_DAY_OF_MONTH:  val = ds1302_readbyte(RTC_ADDR_DATE); break;
 273         case RTC_MONTH:         val = ds1302_readbyte(RTC_ADDR_MON);  break;
 274         case RTC_YEAR:          val = ds1302_readbyte(RTC_ADDR_YEAR); break;
 275         case RTC_REG_A:         /* RTC_FREQ_SELECT */                 break;
 276         case RTC_REG_B:         /* RTC_CONTROL */                     break;
 277         case RTC_REG_C:         /* RTC_INTR_FLAGS */                  break;
 278         case RTC_REG_D:         val = RTC_VRT /* RTC_VALID */;        break;
 279         default:                                                      break;
 280         }
 281
 282         return(val);
 283 }
 284
 285 void secureedge5410_cmos_write(unsigned char val, int addr)
 286 {
 287         if (!use_ds1302) {
 288                 __CMOS_WRITE(val, addr, w);
 289                 return;
 290         }
 291
 292         switch(addr) {
 293         case RTC_SECONDS:       ds1302_writebyte(RTC_ADDR_SEC, val);  break;
 294         case RTC_SECONDS_ALARM:                                       break;
 295         case RTC_MINUTES:       ds1302_writebyte(RTC_ADDR_MIN, val);  break;
 296         case RTC_MINUTES_ALARM:                                       break;
 297         case RTC_HOURS:         ds1302_writebyte(RTC_ADDR_HOUR, val); break;
 298         case RTC_HOURS_ALARM:                                         break;
 299         case RTC_DAY_OF_WEEK:   ds1302_writebyte(RTC_ADDR_DAY, val);  break;
 300         case RTC_DAY_OF_MONTH:  ds1302_writebyte(RTC_ADDR_DATE, val); break;
 301         case RTC_MONTH:         ds1302_writebyte(RTC_ADDR_MON, val);  break;
 302         case RTC_YEAR:          ds1302_writebyte(RTC_ADDR_YEAR, val); break;
 303         case RTC_REG_A:         /* RTC_FREQ_SELECT */                 break;
 304         case RTC_REG_B:         /* RTC_CONTROL */                     break;
 305         case RTC_REG_C:         /* RTC_INTR_FLAGS */                  break;
 306         case RTC_REG_D:         /* RTC_VALID */                       break;
 307         default:                                                      break;
 308         }
 309 }