drivers/watchdog/tnetv107x_wdt.c

   1 /*
   2  * TNETV107X: Watchdog timer implementation (for reset)
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <asm/io.h>
   9 #include <asm/arch/clock.h>
  10
  11 #define MAX_DIV         0xFFFE0001
  12
  13 struct wdt_regs {
  14         u32 kick_lock;
  15 #define KICK_LOCK_1     0x5555
  16 #define KICK_LOCK_2     0xaaaa
  17         u32 kick;
  18
  19         u32 change_lock;
  20 #define CHANGE_LOCK_1   0x6666
  21 #define CHANGE_LOCK_2   0xbbbb
  22         u32 change;
  23
  24         u32 disable_lock;
  25 #define DISABLE_LOCK_1  0x7777
  26 #define DISABLE_LOCK_2  0xcccc
  27 #define DISABLE_LOCK_3  0xdddd
  28         u32 disable;
  29
  30         u32 prescale_lock;
  31 #define PRESCALE_LOCK_1 0x5a5a
  32 #define PRESCALE_LOCK_2 0xa5a5
  33         u32 prescale;
  34 };
  35
  36 static struct wdt_regs* regs = (struct wdt_regs *)TNETV107X_WDT0_ARM_BASE;
  37
  38 #define wdt_reg_read(reg)       __raw_readl(&regs->reg)
  39 #define wdt_reg_write(reg, val) __raw_writel((val), &regs->reg)
  40
  41 static int write_prescale_reg(unsigned long prescale_value)
  42 {
  43         wdt_reg_write(prescale_lock, PRESCALE_LOCK_1);
  44         if ((wdt_reg_read(prescale_lock) & 0x3) != 0x1)
  45                 return -1;
  46
  47         wdt_reg_write(prescale_lock, PRESCALE_LOCK_2);
  48         if ((wdt_reg_read(prescale_lock) & 0x3) != 0x3)
  49                 return -1;
  50
  51         wdt_reg_write(prescale, prescale_value);
  52
  53         return 0;
  54 }
  55
  56 static int write_change_reg(unsigned long initial_timer_value)
  57 {
  58         wdt_reg_write(change_lock, CHANGE_LOCK_1);
  59         if ((wdt_reg_read(change_lock) & 0x3) != 0x1)
  60                 return -1;
  61
  62         wdt_reg_write(change_lock, CHANGE_LOCK_2);
  63         if ((wdt_reg_read(change_lock) & 0x3) != 0x3)
  64                 return -1;
  65
  66         wdt_reg_write(change, initial_timer_value);
  67
  68         return 0;
  69 }
  70
  71 static int wdt_control(unsigned long disable_value)
  72 {
  73         wdt_reg_write(disable_lock, DISABLE_LOCK_1);
  74         if ((wdt_reg_read(disable_lock) & 0x3) != 0x1)
  75                 return -1;
  76
  77         wdt_reg_write(disable_lock, DISABLE_LOCK_2);
  78         if ((wdt_reg_read(disable_lock) & 0x3) != 0x2)
  79                 return -1;
  80
  81         wdt_reg_write(disable_lock, DISABLE_LOCK_3);
  82         if ((wdt_reg_read(disable_lock) & 0x3) != 0x3)
  83                 return -1;
  84
  85         wdt_reg_write(disable, disable_value);
  86         return 0;
  87 }
  88
  89 static int wdt_set_period(unsigned long msec)
  90 {
  91         unsigned long change_value, count_value;
  92         unsigned long prescale_value = 1;
  93         unsigned long refclk_khz, maxdiv;
  94         int ret;
  95
  96         refclk_khz = clk_get_rate(TNETV107X_LPSC_WDT_ARM);
  97         maxdiv = (MAX_DIV / refclk_khz);
  98
  99         if ((!msec) || (msec > maxdiv))
 100                 return -1;
 101
 102         count_value = refclk_khz * msec;
 103         if (count_value > 0xffff) {
 104                 change_value = count_value / 0xffff + 1;
 105                 prescale_value = count_value / change_value;
 106         } else {
 107                 change_value = count_value;
 108         }
 109
 110         ret = write_prescale_reg(prescale_value - 1);
 111         if (ret)
 112                 return ret;
 113
 114         ret = write_change_reg(change_value);
 115         if (ret)
 116                 return ret;
 117
 118         return 0;
 119 }
 120
 121 unsigned long last_wdt = -1;
 122
 123 int wdt_start(unsigned long msecs)
 124 {
 125         int ret;
 126         ret = wdt_control(0);
 127         if (ret)
 128                 return ret;
 129         ret = wdt_set_period(msecs);
 130         if (ret)
 131                 return ret;
 132         ret = wdt_control(1);
 133         if (ret)
 134                 return ret;
 135         ret = wdt_kick();
 136         last_wdt = msecs;
 137         return ret;
 138 }
 139
 140 int wdt_stop(void)
 141 {
 142         last_wdt = -1;
 143         return wdt_control(0);
 144 }
 145
 146 int wdt_kick(void)
 147 {
 148         wdt_reg_write(kick_lock, KICK_LOCK_1);
 149         if ((wdt_reg_read(kick_lock) & 0x3) != 0x1)
 150                 return -1;
 151
 152         wdt_reg_write(kick_lock, KICK_LOCK_2);
 153         if ((wdt_reg_read(kick_lock) & 0x3) != 0x3)
 154                 return -1;
 155
 156         wdt_reg_write(kick, 1);
 157         return 0;
 158 }
 159
 160 void reset_cpu(ulong addr)
 161 {
 162         clk_enable(TNETV107X_LPSC_WDT_ARM);
 163         wdt_start(1);
 164         wdt_kick();
 165 }