a40df4b6f7
Move and rename function to enable_pclock() - in keeping with other ARM ports. Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
64 lines
1.4 KiB
C
64 lines
1.4 KiB
C
// lpc176x timer interrupt scheduling
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//
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// Copyright (C) 2018 Kevin O'Connor <kevin@koconnor.net>
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//
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// This file may be distributed under the terms of the GNU GPLv3 license.
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#include "LPC17xx.h" // LPC_TIM0
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#include "board/irq.h" // irq_disable
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#include "board/misc.h" // timer_read_time
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#include "board/timer_irq.h" // timer_dispatch_many
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#include "internal.h" // enable_pclock
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#include "sched.h" // DECL_INIT
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// Set the next irq time
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static void
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timer_set(uint32_t value)
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{
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LPC_TIM0->MR0 = value;
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LPC_TIM0->IR = 0x01;
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}
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// Return the current time (in absolute clock ticks).
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uint32_t
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timer_read_time(void)
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{
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return LPC_TIM0->TC;
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}
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// Activate timer dispatch as soon as possible
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void
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timer_kick(void)
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{
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timer_set(timer_read_time() + 50);
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}
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void
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timer_init(void)
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{
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// Disable timer
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LPC_TIM0->TCR = 0x02;
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// Setup clock and prescaler (divide sys clock by 4)
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enable_pclock(PCLK_TIMER0);
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LPC_TIM0->PR = 3;
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// Enable interrupts
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NVIC_SetPriority(TIMER0_IRQn, 2);
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NVIC_EnableIRQ(TIMER0_IRQn);
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LPC_TIM0->MCR = 0x01;
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// Clear counter value
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LPC_TIM0->TC = 0;
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timer_kick();
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// Start timer
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LPC_TIM0->TCR = 0x01;
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}
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DECL_INIT(timer_init);
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void __visible __aligned(16) // aligning helps stabilize perf benchmarks
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TIMER0_IRQHandler(void)
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{
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irq_disable();
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uint32_t next = timer_dispatch_many();
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timer_set(next);
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irq_enable();
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}
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