src/soc/qualcomm/ipq806x/timer.c

   1 /* SPDX-License-Identifier: BSD-3-Clause */
   2
   3 #include <delay.h>
   4 #include <soc/iomap.h>
   5 #include <soc/ipq_timer.h>
   6 #include <timer.h>
   7
   8 /*
   9  * DGT runs at 25 MHz / 4, or 6.25 ticks per microsecond
  10  */
  11 #define DGT_MHZ_NUM     25
  12 #define DGT_MHZ_DEN     4
  13
  14 #define TIMER_TICKS(us) ((DGT_MHZ_NUM*(us) + (DGT_MHZ_DEN - 1)) / DGT_MHZ_DEN)
  15 #define TIMER_USECS(ticks) (DGT_MHZ_DEN*(ticks) / DGT_MHZ_NUM)
  16
  17 /* Clock divider values for the timer. */
  18 #define DGT_CLK_DIV_1   0
  19 #define DGT_CLK_DIV_2   1
  20 #define DGT_CLK_DIV_3   2
  21 #define DGT_CLK_DIV_4   3
  22
  23 /**
  24  * init_timer - initialize timer
  25  */
  26 void init_timer(void)
  27 {
  28         /* disable timer */
  29         writel_i(0, DGT_ENABLE);
  30
  31         /* DGT uses TCXO source which is 25MHz.
  32          * The timer should run at 1/4th the frequency of TCXO
  33          * according to clock plan.
  34          * Set clock divider to 4.
  35          */
  36         writel_i(DGT_CLK_DIV_4, DGT_CLK_CTL);
  37
  38         /* Enable timer */
  39         writel_i(0, DGT_CLEAR);
  40         writel_i(DGT_ENABLE_EN, DGT_ENABLE);
  41 }
  42
  43 /**
  44  * udelay -  generates micro second delay.
  45  * @param usec: delay duration in microseconds
  46  */
  47 void udelay(unsigned int usec)
  48 {
  49         uint32_t now;
  50         uint32_t last;
  51         uint32_t ticks;
  52         uint32_t curr_ticks = 0;
  53
  54         /* Calculate number of ticks required. */
  55         ticks = TIMER_TICKS(usec);
  56
  57         /* Obtain the current timer value. */
  58         last = readl_i(DGT_COUNT_VAL);
  59
  60         /* Loop until the right number of ticks. */
  61         while (curr_ticks < ticks) {
  62                 now = readl_i(DGT_COUNT_VAL);
  63                 curr_ticks += now - last;
  64                 last = now;
  65         }
  66 }
  67
  68 void timer_monotonic_get(struct mono_time *mt)
  69 {
  70         mono_time_set_usecs(mt, TIMER_USECS(readl_i(DGT_COUNT_VAL)));
  71 }