max80_fw/rv32/io.h

#ifndef IO_H
#define IO_H

#include <stdint.h>
#include <stdarg.h>
#include <stdbool.h>
#include "ioregs.h"
#include "picorv32.h"
#include "irq.h"

#define barrier() do { asm volatile("" : : : "memory"); } while (0)

static __always_inline void relax(void)
{
    /* Placeholder for anything that might want to be done while waiting */
}

static __always_inline void set_leds(unsigned int leds)
{
    SYS_LED = leds;
}

static __always_inline void set_led(unsigned int led, bool on)
{
    unsigned int leds = SYS_LED;
    unsigned int mask = 1 << led;

    leds &= ~mask;
    leds |= on ? mask : 0;
    SYS_LED = leds;
}

enum leds {
    LED_SDCARD,
    LED_DISKIO,
    LED_ABCBUS
};

static __always_inline no_return reset(unsigned int type)
{
    disable_irqs();
    for (;;)
	SYS_RESET = type;
}

extern const uint32_t time_zero;

static __always_inline uint32_t rdtime(void)
{
    uint32_t t;

    asm volatile("rdtime %0" : "=r" (t));
    return t;
}

static __always_inline uint64_t rdtimeq(void)
{
    uint32_t l, h1, h0;

    asm volatile("rdtimeh %0; rdtime %1; %rdtimeh %2"
		 : "=r" (h1), "=r" (l), "=r" (h0));

    return ((uint64_t)(((int32_t)l < 0) ? h1 : h0) << 32) + l;
}

static __always_inline void cdelay(uint32_t cycles)
{
    if (!__builtin_constant_p(cycles) || cycles >= 4) {
	uint32_t start = rdtime();
	while (rdtime() - start < cycles)
	    relax();
    }
}
static __always_inline void udelay(uint32_t us)
{
    cdelay(us * (CPU_HZ / 1000000));
}
static __always_inline void mdelay(uint32_t ms)
{
    cdelay(ms * (CPU_HZ / 1000));
}

static inline void i2c_set_speed(unsigned int khz)
{
    I2C_DIVISOR = ((CPU_HZ/4000)-1)/khz;
}

static __always_inline void wait_romcopy_done(void)
{
    while (~irqmask() & (1 << ROMCOPY_IRQ))
	relax();

    barrier();
}

/* Read a random 32-bit number */
static inline uint32_t rdrand(void)
{
    waitfor(RANDOM_IRQ);
    return RANDOM_DATA;
}

#endif /* IO_H */