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 #include <asm/delay.h>
  22
  23 /*
  24  * MBus bridge block registers.
  25  */
  26 #define BRIDGE_CAUSE_OFF        0x0110
  27 #define BRIDGE_MASK_OFF         0x0114
  28 #define  BRIDGE_INT_TIMER0       0x0002
  29 #define  BRIDGE_INT_TIMER1       0x0004
  30
  31
  32 /*
  33  * Timer block registers.
  34  */
  35 #define TIMER_CTRL_OFF          0x0000
  36 #define  TIMER0_EN               0x0001
  37 #define  TIMER0_RELOAD_EN        0x0002
  38 #define  TIMER1_EN               0x0004
  39 #define  TIMER1_RELOAD_EN        0x0008
  40 #define TIMER0_RELOAD_OFF       0x0010
  41 #define TIMER0_VAL_OFF          0x0014
  42 #define TIMER1_RELOAD_OFF       0x0018
  43 #define TIMER1_VAL_OFF          0x001c
  44
  45
  46 /*
  47  * SoC-specific data.
  48  */
  49 static void __iomem *bridge_base;
  50 static u32 bridge_timer1_clr_mask;
  51 static void __iomem *timer_base;
  52
  53
  54 /*
  55  * Number of timer ticks per jiffy.
  56  */
  57 static u32 ticks_per_jiffy;
  58
  59
  60 /*
  61  * Orion's sched_clock implementation. It has a resolution of
  62  * at least 7.5ns (133MHz TCLK).
  63  */
  64
  65 static u64 notrace orion_read_sched_clock(void)
  66 {
  67         return ~readl(timer_base + TIMER0_VAL_OFF);
  68 }
  69
  70 /*
  71  * Clockevent handling.
  72  */
  73 static int
  74 orion_clkevt_next_event(unsigned long delta, struct clock_event_device *dev)
  75 {
  76         unsigned long flags;
  77         u32 u;
  78
  79         if (delta == 0)
  80                 return -ETIME;
  81
  82         local_irq_save(flags);
  83
  84         /*
  85          * Clear and enable clockevent timer interrupt.
  86          */
  87         writel(bridge_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF);
  88
  89         u = readl(bridge_base + BRIDGE_MASK_OFF);
  90         u |= BRIDGE_INT_TIMER1;
  91         writel(u, bridge_base + BRIDGE_MASK_OFF);
  92
  93         /*
  94          * Setup new clockevent timer value.
  95          */
  96         writel(delta, timer_base + TIMER1_VAL_OFF);
  97
  98         /*
  99          * Enable the timer.
 100          */
 101         u = readl(timer_base + TIMER_CTRL_OFF);
 102         u = (u & ~TIMER1_RELOAD_EN) | TIMER1_EN;
 103         writel(u, timer_base + TIMER_CTRL_OFF);
 104
 105         local_irq_restore(flags);
 106
 107         return 0;
 108 }
 109
 110 static int orion_clkevt_shutdown(struct clock_event_device *evt)
 111 {
 112         unsigned long flags;
 113         u32 u;
 114
 115         local_irq_save(flags);
 116
 117         /* Disable timer */
 118         u = readl(timer_base + TIMER_CTRL_OFF);
 119         writel(u & ~TIMER1_EN, timer_base + TIMER_CTRL_OFF);
 120
 121         /* Disable timer interrupt */
 122         u = readl(bridge_base + BRIDGE_MASK_OFF);
 123         writel(u & ~BRIDGE_INT_TIMER1, bridge_base + BRIDGE_MASK_OFF);
 124
 125         /* ACK pending timer interrupt */
 126         writel(bridge_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF);
 127
 128         local_irq_restore(flags);
 129
 130         return 0;
 131 }
 132
 133 static int orion_clkevt_set_periodic(struct clock_event_device *evt)
 134 {
 135         unsigned long flags;
 136         u32 u;
 137
 138         local_irq_save(flags);
 139
 140         /* Setup timer to fire at 1/HZ intervals */
 141         writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD_OFF);
 142         writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL_OFF);
 143
 144         /* Enable timer interrupt */
 145         u = readl(bridge_base + BRIDGE_MASK_OFF);
 146         writel(u | BRIDGE_INT_TIMER1, bridge_base + BRIDGE_MASK_OFF);
 147
 148         /* Enable timer */
 149         u = readl(timer_base + TIMER_CTRL_OFF);
 150         writel(u | TIMER1_EN | TIMER1_RELOAD_EN, timer_base + TIMER_CTRL_OFF);
 151
 152         local_irq_restore(flags);
 153
 154         return 0;
 155 }
 156
 157 static struct clock_event_device orion_clkevt = {
 158         .name                   = "orion_tick",
 159         .features               = CLOCK_EVT_FEAT_ONESHOT |
 160                                   CLOCK_EVT_FEAT_PERIODIC,
 161         .rating                 = 300,
 162         .set_next_event         = orion_clkevt_next_event,
 163         .set_state_shutdown     = orion_clkevt_shutdown,
 164         .set_state_periodic     = orion_clkevt_set_periodic,
 165         .set_state_oneshot      = orion_clkevt_shutdown,
 166         .tick_resume            = orion_clkevt_shutdown,
 167 };
 168
 169 static irqreturn_t orion_timer_interrupt(int irq, void *dev_id)
 170 {
 171         /*
 172          * ACK timer interrupt and call event handler.
 173          */
 174         writel(bridge_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF);
 175         orion_clkevt.event_handler(&orion_clkevt);
 176
 177         return IRQ_HANDLED;
 178 }
 179
 180 void __init
 181 orion_time_set_base(void __iomem *_timer_base)
 182 {
 183         timer_base = _timer_base;
 184 }
 185
 186 static unsigned long orion_delay_timer_read(void)
 187 {
 188         return ~readl(timer_base + TIMER0_VAL_OFF);
 189 }
 190
 191 static struct delay_timer orion_delay_timer = {
 192         .read_current_timer = orion_delay_timer_read,
 193 };
 194
 195 void __init
 196 orion_time_init(void __iomem *_bridge_base, u32 _bridge_timer1_clr_mask,
 197                 unsigned int irq, unsigned int tclk)
 198 {
 199         u32 u;
 200
 201         /*
 202          * Set SoC-specific data.
 203          */
 204         bridge_base = _bridge_base;
 205         bridge_timer1_clr_mask = _bridge_timer1_clr_mask;
 206
 207         ticks_per_jiffy = (tclk + HZ/2) / HZ;
 208
 209         orion_delay_timer.freq = tclk;
 210         register_current_timer_delay(&orion_delay_timer);
 211
 212         /*
 213          * Set scale and timer for sched_clock.
 214          */
 215         sched_clock_register(orion_read_sched_clock, 32, tclk);
 216
 217         /*
 218          * Setup free-running clocksource timer (interrupts
 219          * disabled).
 220          */
 221         writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
 222         writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
 223         u = readl(bridge_base + BRIDGE_MASK_OFF);
 224         writel(u & ~BRIDGE_INT_TIMER0, bridge_base + BRIDGE_MASK_OFF);
 225         u = readl(timer_base + TIMER_CTRL_OFF);
 226         writel(u | TIMER0_EN | TIMER0_RELOAD_EN, timer_base + TIMER_CTRL_OFF);
 227         clocksource_mmio_init(timer_base + TIMER0_VAL_OFF, "orion_clocksource",
 228                 tclk, 300, 32, clocksource_mmio_readl_down);
 229
 230         /*
 231          * Setup clockevent timer (interrupt-driven).
 232          */
 233         if (request_irq(irq, orion_timer_interrupt, IRQF_TIMER, "orion_tick",
 234                         NULL))
 235                 pr_err("Failed to request irq %u (orion_tick)\n", irq);
 236         orion_clkevt.cpumask = cpumask_of(0);
 237         clockevents_config_and_register(&orion_clkevt, tclk, 1, 0xfffffffe);
 238 }