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 #include <asm/snapgear.h>
  22
  23 static int use_ds1302;
  24
  25 /****************************************************************************/
  26 /*
  27  *      we need to implement a DS1302 driver here that can operate in
  28  *      conjunction with the builtin rtc driver which is already quite friendly
  29  */
  30 /*****************************************************************************/
  31
  32 #define RTC_CMD_READ    0x81            /* Read command */
  33 #define RTC_CMD_WRITE   0x80            /* Write command */
  34
  35 #define RTC_ADDR_YEAR   0x06            /* Address of year register */
  36 #define RTC_ADDR_DAY    0x05            /* Address of day of week register */
  37 #define RTC_ADDR_MON    0x04            /* Address of month register */
  38 #define RTC_ADDR_DATE   0x03            /* Address of day of month register */
  39 #define RTC_ADDR_HOUR   0x02            /* Address of hour register */
  40 #define RTC_ADDR_MIN    0x01            /* Address of minute register */
  41 #define RTC_ADDR_SEC    0x00            /* Address of second register */
  42
  43 #define RTC_RESET       0x1000
  44 #define RTC_IODATA      0x0800
  45 #define RTC_SCLK        0x0400
  46
  47 #define set_dirp(x)
  48 #define get_dirp(x) 0
  49 #define set_dp(x)       SECUREEDGE_WRITE_IOPORT(x, 0x1c00)
  50 #define get_dp(x)       SECUREEDGE_READ_IOPORT()
  51
  52 static void ds1302_sendbits(unsigned int val)
  53 {
  54         int     i;
  55
  56         for (i = 8; (i); i--, val >>= 1) {
  57                 set_dp((get_dp() & ~RTC_IODATA) | ((val & 0x1) ? RTC_IODATA : 0));
  58                 set_dp(get_dp() | RTC_SCLK);    // clock high
  59                 set_dp(get_dp() & ~RTC_SCLK);   // clock low
  60         }
  61 }
  62
  63 static unsigned int ds1302_recvbits(void)
  64 {
  65         unsigned int    val;
  66         int             i;
  67
  68         for (i = 0, val = 0; (i < 8); i++) {
  69                 val |= (((get_dp() & RTC_IODATA) ? 1 : 0) << i);
  70                 set_dp(get_dp() | RTC_SCLK);    // clock high
  71                 set_dp(get_dp() & ~RTC_SCLK);   // clock low
  72         }
  73         return(val);
  74 }
  75
  76 static unsigned int ds1302_readbyte(unsigned int addr)
  77 {
  78         unsigned int    val;
  79         unsigned long   flags;
  80
  81         local_irq_save(flags);
  82         set_dirp(get_dirp() | RTC_RESET | RTC_IODATA | RTC_SCLK);
  83         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
  84
  85         set_dp(get_dp() | RTC_RESET);
  86         ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ);
  87         set_dirp(get_dirp() & ~RTC_IODATA);
  88         val = ds1302_recvbits();
  89         set_dp(get_dp() & ~RTC_RESET);
  90         local_irq_restore(flags);
  91
  92         return(val);
  93 }
  94
  95 static void ds1302_writebyte(unsigned int addr, unsigned int val)
  96 {
  97         unsigned long   flags;
  98
  99         local_irq_save(flags);
 100         set_dirp(get_dirp() | RTC_RESET | RTC_IODATA | RTC_SCLK);
 101         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
 102         set_dp(get_dp() | RTC_RESET);
 103         ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE);
 104         ds1302_sendbits(val);
 105         set_dp(get_dp() & ~RTC_RESET);
 106         local_irq_restore(flags);
 107 }
 108
 109 static void ds1302_reset(void)
 110 {
 111         unsigned long   flags;
 112         /* Hardware dependant reset/init */
 113         local_irq_save(flags);
 114         set_dirp(get_dirp() | RTC_RESET | RTC_IODATA | RTC_SCLK);
 115         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
 116         local_irq_restore(flags);
 117 }
 118
 119 /*****************************************************************************/
 120
 121 static inline int bcd2int(int val)
 122 {
 123         return((((val & 0xf0) >> 4) * 10) + (val & 0xf));
 124 }
 125
 126 static inline int int2bcd(int val)
 127 {
 128         return(((val / 10) << 4) + (val % 10));
 129 }
 130
 131 /*****************************************************************************/
 132 /*
 133  *      Write and Read some RAM in the DS1302,  if it works assume it's there
 134  *      Otherwise use the SH4 internal RTC
 135  */
 136
 137 void snapgear_rtc_gettimeofday(struct timespec *);
 138 int snapgear_rtc_settimeofday(const time_t);
 139
 140 void __init secureedge5410_rtc_init(void)
 141 {
 142         unsigned char *test = "snapgear";
 143         int i;
 144
 145         ds1302_reset();
 146
 147         use_ds1302 = 1;
 148
 149         for (i = 0; test[i]; i++)
 150                 ds1302_writebyte(32 + i, test[i]);
 151
 152         for (i = 0; test[i]; i++)
 153                 if (ds1302_readbyte(32 + i) != test[i]) {
 154                         use_ds1302 = 0;
 155                         break;
 156                 }
 157
 158         if (use_ds1302) {
 159                 rtc_sh_get_time = snapgear_rtc_gettimeofday;
 160                 rtc_sh_set_time = snapgear_rtc_settimeofday;
 161         }
 162
 163         printk("SnapGear RTC: using %s rtc.\n", use_ds1302 ? "ds1302" : "internal");
 164 }
 165
 166 /****************************************************************************/
 167 /*
 168  *      our generic interface that chooses the correct code to use
 169  */
 170
 171 void snapgear_rtc_gettimeofday(struct timespec *ts)
 172 {
 173         unsigned int sec, min, hr, day, mon, yr;
 174
 175         if (!use_ds1302)
 176                 return;
 177
 178         sec = bcd2int(ds1302_readbyte(RTC_ADDR_SEC));
 179         min = bcd2int(ds1302_readbyte(RTC_ADDR_MIN));
 180         hr  = bcd2int(ds1302_readbyte(RTC_ADDR_HOUR));
 181         day = bcd2int(ds1302_readbyte(RTC_ADDR_DATE));
 182         mon = bcd2int(ds1302_readbyte(RTC_ADDR_MON));
 183         yr  = bcd2int(ds1302_readbyte(RTC_ADDR_YEAR));
 184
 185 bad_time:
 186         if (yr > 99 || mon < 1 || mon > 12 || day > 31 || day < 1 ||
 187             hr > 23 || min > 59 || sec > 59) {
 188                 printk(KERN_ERR
 189                        "SnapGear RTC: invalid value, resetting to 1 Jan 2000\n");
 190                 ds1302_writebyte(RTC_ADDR_MIN,  min = 0);
 191                 ds1302_writebyte(RTC_ADDR_HOUR, hr  = 0);
 192                 ds1302_writebyte(RTC_ADDR_DAY,        7);
 193                 ds1302_writebyte(RTC_ADDR_DATE, day = 1);
 194                 ds1302_writebyte(RTC_ADDR_MON,  mon = 1);
 195                 ds1302_writebyte(RTC_ADDR_YEAR, yr  = 0);
 196                 ds1302_writebyte(RTC_ADDR_SEC,  sec = 0);
 197         }
 198
 199         ts->tv_sec = mktime(2000 + yr, mon, day, hr, min, sec);
 200         if (ts->tv_sec < 0) {
 201 #if 0
 202                 printk("BAD TIME %d %d %d %d %d %d\n", yr, mon, day, hr, min, sec);
 203 #endif
 204                 yr = 100;
 205                 goto bad_time;
 206         }
 207         ts->tv_nsec = 0;
 208 }
 209
 210 int snapgear_rtc_settimeofday(const time_t secs)
 211 {
 212         int retval = 0;
 213         int real_seconds, real_minutes, cmos_minutes;
 214         unsigned long nowtime;
 215
 216         if (!use_ds1302)
 217                 return 0;
 218
 219 /*
 220  *      This is called direct from the kernel timer handling code.
 221  *      It is supposed to synchronize the kernel clock to the RTC.
 222  */
 223
 224         nowtime = secs;
 225
 226         /* STOP RTC */
 227         ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80);
 228
 229         cmos_minutes = bcd2int(ds1302_readbyte(RTC_ADDR_MIN));
 230
 231         /*
 232          * since we're only adjusting minutes and seconds,
 233          * don't interfere with hour overflow. This avoids
 234          * messing with unknown time zones but requires your
 235          * RTC not to be off by more than 15 minutes
 236          */
 237         real_seconds = nowtime % 60;
 238         real_minutes = nowtime / 60;
 239         if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
 240                 real_minutes += 30;     /* correct for half hour time zone */
 241         real_minutes %= 60;
 242
 243         if (abs(real_minutes - cmos_minutes) < 30) {
 244                 ds1302_writebyte(RTC_ADDR_MIN, int2bcd(real_minutes));
 245                 ds1302_writebyte(RTC_ADDR_SEC, int2bcd(real_seconds));
 246         } else {
 247                 printk(KERN_WARNING
 248                        "SnapGear RTC: can't update from %d to %d\n",
 249                        cmos_minutes, real_minutes);
 250                 retval = -1;
 251         }
 252
 253         /* START RTC */
 254         ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80);
 255         return(0);
 256 }
 257
 258 unsigned char secureedge5410_cmos_read(int addr)
 259 {
 260         unsigned char val = 0;
 261
 262         if (!use_ds1302)
 263                 return(__CMOS_READ(addr, w));
 264
 265         switch(addr) {
 266         case RTC_SECONDS:       val = ds1302_readbyte(RTC_ADDR_SEC);  break;
 267         case RTC_SECONDS_ALARM:                                       break;
 268         case RTC_MINUTES:       val = ds1302_readbyte(RTC_ADDR_MIN);  break;
 269         case RTC_MINUTES_ALARM:                                       break;
 270         case RTC_HOURS:         val = ds1302_readbyte(RTC_ADDR_HOUR); break;
 271         case RTC_HOURS_ALARM:                                         break;
 272         case RTC_DAY_OF_WEEK:   val = ds1302_readbyte(RTC_ADDR_DAY);  break;
 273         case RTC_DAY_OF_MONTH:  val = ds1302_readbyte(RTC_ADDR_DATE); break;
 274         case RTC_MONTH:         val = ds1302_readbyte(RTC_ADDR_MON);  break;
 275         case RTC_YEAR:          val = ds1302_readbyte(RTC_ADDR_YEAR); break;
 276         case RTC_REG_A:         /* RTC_FREQ_SELECT */                 break;
 277         case RTC_REG_B:         /* RTC_CONTROL */                     break;
 278         case RTC_REG_C:         /* RTC_INTR_FLAGS */                  break;
 279         case RTC_REG_D:         val = RTC_VRT /* RTC_VALID */;        break;
 280         default:                                                      break;
 281         }
 282
 283         return(val);
 284 }
 285
 286 void secureedge5410_cmos_write(unsigned char val, int addr)
 287 {
 288         if (!use_ds1302) {
 289                 __CMOS_WRITE(val, addr, w);
 290                 return;
 291         }
 292
 293         switch(addr) {
 294         case RTC_SECONDS:       ds1302_writebyte(RTC_ADDR_SEC, val);  break;
 295         case RTC_SECONDS_ALARM:                                       break;
 296         case RTC_MINUTES:       ds1302_writebyte(RTC_ADDR_MIN, val);  break;
 297         case RTC_MINUTES_ALARM:                                       break;
 298         case RTC_HOURS:         ds1302_writebyte(RTC_ADDR_HOUR, val); break;
 299         case RTC_HOURS_ALARM:                                         break;
 300         case RTC_DAY_OF_WEEK:   ds1302_writebyte(RTC_ADDR_DAY, val);  break;
 301         case RTC_DAY_OF_MONTH:  ds1302_writebyte(RTC_ADDR_DATE, val); break;
 302         case RTC_MONTH:         ds1302_writebyte(RTC_ADDR_MON, val);  break;
 303         case RTC_YEAR:          ds1302_writebyte(RTC_ADDR_YEAR, val); break;
 304         case RTC_REG_A:         /* RTC_FREQ_SELECT */                 break;
 305         case RTC_REG_B:         /* RTC_CONTROL */                     break;
 306         case RTC_REG_C:         /* RTC_INTR_FLAGS */                  break;
 307         case RTC_REG_D:         /* RTC_VALID */                       break;
 308         default:                                                      break;
 309         }
 310 }