kernel/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 <linux/sched_clock.h>
  20 #include <plat/time.h>
  21
  22 /*
  23  * MBus bridge block registers.
  24  */
  25 #define BRIDGE_CAUSE_OFF        0x0110
  26 #define BRIDGE_MASK_OFF         0x0114
  27 #define  BRIDGE_INT_TIMER0       0x0002
  28 #define  BRIDGE_INT_TIMER1       0x0004
  29
  30
  31 /*
  32  * Timer block registers.
  33  */
  34 #define TIMER_CTRL_OFF          0x0000
  35 #define  TIMER0_EN               0x0001
  36 #define  TIMER0_RELOAD_EN        0x0002
  37 #define  TIMER1_EN               0x0004
  38 #define  TIMER1_RELOAD_EN        0x0008
  39 #define TIMER0_RELOAD_OFF       0x0010
  40 #define TIMER0_VAL_OFF          0x0014
  41 #define TIMER1_RELOAD_OFF       0x0018
  42 #define TIMER1_VAL_OFF          0x001c
  43
  44
  45 /*
  46  * SoC-specific data.
  47  */
  48 static void __iomem *bridge_base;
  49 static u32 bridge_timer1_clr_mask;
  50 static void __iomem *timer_base;
  51
  52
  53 /*
  54  * Number of timer ticks per jiffy.
  55  */
  56 static u32 ticks_per_jiffy;
  57
  58
  59 /*
  60  * Orion's sched_clock implementation. It has a resolution of
  61  * at least 7.5ns (133MHz TCLK).
  62  */
  63
  64 static u64 notrace orion_read_sched_clock(void)
  65 {
  66         return ~readl(timer_base + TIMER0_VAL_OFF);
  67 }
  68
  69 /*
  70  * Clockevent handling.
  71  */
  72 static int
  73 orion_clkevt_next_event(unsigned long delta, struct clock_event_device *dev)
  74 {
  75         unsigned long flags;
  76         u32 u;
  77
  78         if (delta == 0)
  79                 return -ETIME;
  80
  81         local_irq_save(flags);
  82
  83         /*
  84          * Clear and enable clockevent timer interrupt.
  85          */
  86         writel(bridge_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF);
  87
  88         u = readl(bridge_base + BRIDGE_MASK_OFF);
  89         u |= BRIDGE_INT_TIMER1;
  90         writel(u, bridge_base + BRIDGE_MASK_OFF);
  91
  92         /*
  93          * Setup new clockevent timer value.
  94          */
  95         writel(delta, timer_base + TIMER1_VAL_OFF);
  96
  97         /*
  98          * Enable the timer.
  99          */
 100         u = readl(timer_base + TIMER_CTRL_OFF);
 101         u = (u & ~TIMER1_RELOAD_EN) | TIMER1_EN;
 102         writel(u, timer_base + TIMER_CTRL_OFF);
 103
 104         local_irq_restore(flags);
 105
 106         return 0;
 107 }
 108
 109 static void
 110 orion_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev)
 111 {
 112         unsigned long flags;
 113         u32 u;
 114
 115         local_irq_save(flags);
 116         if (mode == CLOCK_EVT_MODE_PERIODIC) {
 117                 /*
 118                  * Setup timer to fire at 1/HZ intervals.
 119                  */
 120                 writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD_OFF);
 121                 writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL_OFF);
 122
 123                 /*
 124                  * Enable timer interrupt.
 125                  */
 126                 u = readl(bridge_base + BRIDGE_MASK_OFF);
 127                 writel(u | BRIDGE_INT_TIMER1, bridge_base + BRIDGE_MASK_OFF);
 128
 129                 /*
 130                  * Enable timer.
 131                  */
 132                 u = readl(timer_base + TIMER_CTRL_OFF);
 133                 writel(u | TIMER1_EN | TIMER1_RELOAD_EN,
 134                        timer_base + TIMER_CTRL_OFF);
 135         } else {
 136                 /*
 137                  * Disable timer.
 138                  */
 139                 u = readl(timer_base + TIMER_CTRL_OFF);
 140                 writel(u & ~TIMER1_EN, timer_base + TIMER_CTRL_OFF);
 141
 142                 /*
 143                  * Disable timer interrupt.
 144                  */
 145                 u = readl(bridge_base + BRIDGE_MASK_OFF);
 146                 writel(u & ~BRIDGE_INT_TIMER1, bridge_base + BRIDGE_MASK_OFF);
 147
 148                 /*
 149                  * ACK pending timer interrupt.
 150                  */
 151                 writel(bridge_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF);
 152
 153         }
 154         local_irq_restore(flags);
 155 }
 156
 157 static struct clock_event_device orion_clkevt = {
 158         .name           = "orion_tick",
 159         .features       = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
 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_TIMER,
 179         .handler        = orion_timer_interrupt
 180 };
 181
 182 void __init
 183 orion_time_set_base(void __iomem *_timer_base)
 184 {
 185         timer_base = _timer_base;
 186 }
 187
 188 void __init
 189 orion_time_init(void __iomem *_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 = _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         sched_clock_register(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.cpumask = cpumask_of(0);
 225         clockevents_config_and_register(&orion_clkevt, tclk, 1, 0xfffffffe);
 226 }