arch/arm/plat-orion/time.c

   1 /*
   2  * arch/arm/plat-orion/time.c
   3  *
   4  * Marvell Orion SoC timer handling.
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2.  This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  *
  10  * Timer 0 is used as free-running clocksource, while timer 1 is
  11  * used as clock_event_device.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/timer.h>
  16 #include <linux/clockchips.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/irq.h>
  19 #include <asm/sched_clock.h>
  20
  21 /*
  22  * MBus bridge block registers.
  23  */
  24 #define BRIDGE_CAUSE_OFF        0x0110
  25 #define BRIDGE_MASK_OFF         0x0114
  26 #define  BRIDGE_INT_TIMER0       0x0002
  27 #define  BRIDGE_INT_TIMER1       0x0004
  28
  29
  30 /*
  31  * Timer block registers.
  32  */
  33 #define TIMER_CTRL_OFF          0x0000
  34 #define  TIMER0_EN               0x0001
  35 #define  TIMER0_RELOAD_EN        0x0002
  36 #define  TIMER1_EN               0x0004
  37 #define  TIMER1_RELOAD_EN        0x0008
  38 #define TIMER0_RELOAD_OFF       0x0010
  39 #define TIMER0_VAL_OFF          0x0014
  40 #define TIMER1_RELOAD_OFF       0x0018
  41 #define TIMER1_VAL_OFF          0x001c
  42
  43
  44 /*
  45  * SoC-specific data.
  46  */
  47 static void __iomem *bridge_base;
  48 static u32 bridge_timer1_clr_mask;
  49 static void __iomem *timer_base;
  50
  51
  52 /*
  53  * Number of timer ticks per jiffy.
  54  */
  55 static u32 ticks_per_jiffy;
  56
  57
  58 /*
  59  * Orion's sched_clock implementation. It has a resolution of
  60  * at least 7.5ns (133MHz TCLK).
  61  */
  62
  63 static u32 notrace orion_read_sched_clock(void)
  64 {
  65         return ~readl(timer_base + TIMER0_VAL_OFF);
  66 }
  67
  68 /*
  69  * Clockevent handling.
  70  */
  71 static int
  72 orion_clkevt_next_event(unsigned long delta, struct clock_event_device *dev)
  73 {
  74         unsigned long flags;
  75         u32 u;
  76
  77         if (delta == 0)
  78                 return -ETIME;
  79
  80         local_irq_save(flags);
  81
  82         /*
  83          * Clear and enable clockevent timer interrupt.
  84          */
  85         writel(bridge_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF);
  86
  87         u = readl(bridge_base + BRIDGE_MASK_OFF);
  88         u |= BRIDGE_INT_TIMER1;
  89         writel(u, bridge_base + BRIDGE_MASK_OFF);
  90
  91         /*
  92          * Setup new clockevent timer value.
  93          */
  94         writel(delta, timer_base + TIMER1_VAL_OFF);
  95
  96         /*
  97          * Enable the timer.
  98          */
  99         u = readl(timer_base + TIMER_CTRL_OFF);
 100         u = (u & ~TIMER1_RELOAD_EN) | TIMER1_EN;
 101         writel(u, timer_base + TIMER_CTRL_OFF);
 102
 103         local_irq_restore(flags);
 104
 105         return 0;
 106 }
 107
 108 static void
 109 orion_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev)
 110 {
 111         unsigned long flags;
 112         u32 u;
 113
 114         local_irq_save(flags);
 115         if (mode == CLOCK_EVT_MODE_PERIODIC) {
 116                 /*
 117                  * Setup timer to fire at 1/HZ intervals.
 118                  */
 119                 writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD_OFF);
 120                 writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL_OFF);
 121
 122                 /*
 123                  * Enable timer interrupt.
 124                  */
 125                 u = readl(bridge_base + BRIDGE_MASK_OFF);
 126                 writel(u | BRIDGE_INT_TIMER1, bridge_base + BRIDGE_MASK_OFF);
 127
 128                 /*
 129                  * Enable timer.
 130                  */
 131                 u = readl(timer_base + TIMER_CTRL_OFF);
 132                 writel(u | TIMER1_EN | TIMER1_RELOAD_EN,
 133                        timer_base + TIMER_CTRL_OFF);
 134         } else {
 135                 /*
 136                  * Disable timer.
 137                  */
 138                 u = readl(timer_base + TIMER_CTRL_OFF);
 139                 writel(u & ~TIMER1_EN, timer_base + TIMER_CTRL_OFF);
 140
 141                 /*
 142                  * Disable timer interrupt.
 143                  */
 144                 u = readl(bridge_base + BRIDGE_MASK_OFF);
 145                 writel(u & ~BRIDGE_INT_TIMER1, bridge_base + BRIDGE_MASK_OFF);
 146
 147                 /*
 148                  * ACK pending timer interrupt.
 149                  */
 150                 writel(bridge_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF);
 151
 152         }
 153         local_irq_restore(flags);
 154 }
 155
 156 static struct clock_event_device orion_clkevt = {
 157         .name           = "orion_tick",
 158         .features       = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
 159         .shift          = 32,
 160         .rating         = 300,
 161         .set_next_event = orion_clkevt_next_event,
 162         .set_mode       = orion_clkevt_mode,
 163 };
 164
 165 static irqreturn_t orion_timer_interrupt(int irq, void *dev_id)
 166 {
 167         /*
 168          * ACK timer interrupt and call event handler.
 169          */
 170         writel(bridge_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF);
 171         orion_clkevt.event_handler(&orion_clkevt);
 172
 173         return IRQ_HANDLED;
 174 }
 175
 176 static struct irqaction orion_timer_irq = {
 177         .name           = "orion_tick",
 178         .flags          = IRQF_DISABLED | IRQF_TIMER,
 179         .handler        = orion_timer_interrupt
 180 };
 181
 182 void __init
 183 orion_time_set_base(u32 _timer_base)
 184 {
 185         timer_base = (void __iomem *)_timer_base;
 186 }
 187
 188 void __init
 189 orion_time_init(u32 _bridge_base, u32 _bridge_timer1_clr_mask,
 190                 unsigned int irq, unsigned int tclk)
 191 {
 192         u32 u;
 193
 194         /*
 195          * Set SoC-specific data.
 196          */
 197         bridge_base = (void __iomem *)_bridge_base;
 198         bridge_timer1_clr_mask = _bridge_timer1_clr_mask;
 199
 200         ticks_per_jiffy = (tclk + HZ/2) / HZ;
 201
 202         /*
 203          * Set scale and timer for sched_clock.
 204          */
 205         setup_sched_clock(orion_read_sched_clock, 32, tclk);
 206
 207         /*
 208          * Setup free-running clocksource timer (interrupts
 209          * disabled).
 210          */
 211         writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
 212         writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
 213         u = readl(bridge_base + BRIDGE_MASK_OFF);
 214         writel(u & ~BRIDGE_INT_TIMER0, bridge_base + BRIDGE_MASK_OFF);
 215         u = readl(timer_base + TIMER_CTRL_OFF);
 216         writel(u | TIMER0_EN | TIMER0_RELOAD_EN, timer_base + TIMER_CTRL_OFF);
 217         clocksource_mmio_init(timer_base + TIMER0_VAL_OFF, "orion_clocksource",
 218                 tclk, 300, 32, clocksource_mmio_readl_down);
 219
 220         /*
 221          * Setup clockevent timer (interrupt-driven).
 222          */
 223         setup_irq(irq, &orion_timer_irq);
 224         orion_clkevt.mult = div_sc(tclk, NSEC_PER_SEC, orion_clkevt.shift);
 225         orion_clkevt.max_delta_ns = clockevent_delta2ns(0xfffffffe, &orion_clkevt);
 226         orion_clkevt.min_delta_ns = clockevent_delta2ns(1, &orion_clkevt);
 227         orion_clkevt.cpumask = cpumask_of(0);
 228         clockevents_register_device(&orion_clkevt);
 229 }