#ifndef UART_H
#define UART_H

#include <stdint.h>
#include "global.h"
#include "interrupts.h"

#define DEFAULT_UART_CLOCK_RATE 3000000

#define UART_WLEN_8_BITS (0b11 << 5)
#define UART_WLEN_7_BITS (0b10 << 5)
#define UART_WLEN_6_BITS (0b01 << 5)
#define UART_WLEN_5_BITS  0b00

#define UART_2_STOP (1 << 3)
#define UART_1_STOP  0

#define UART_ODD_PAR   (1 << 1)
#define UART_EVEN_PAR ((1 << 1) | (1 << 2))
#define UART_NO_PAR     0

// The offsets for reach register.

// GPIO Pin Pull-up/down Enable
#define GPPUD (GPIO_BASE + 0x94)

// GPIO Pin Pull-up/down Enable Clock 0
#define GPPUDCLK0 (GPIO_BASE + 0x98)

// The base address for UART.
#define PL011_UART_BASE (GPIO_BASE + 0x1000)
  
// The offsets for reach register for the UART.
#define PL011_UART_DR     (PL011_UART_BASE + 0x00)
#define PL011_UART_RSRECR (PL011_UART_BASE + 0x04)
#define PL011_UART_FR     (PL011_UART_BASE + 0x18)
#define PL011_UART_ILPR   (PL011_UART_BASE + 0x20)
#define PL011_UART_IBRD   (PL011_UART_BASE + 0x24)
#define PL011_UART_FBRD   (PL011_UART_BASE + 0x28)
#define PL011_UART_LCRH   (PL011_UART_BASE + 0x2C)
#define PL011_UART_CR     (PL011_UART_BASE + 0x30)
#define PL011_UART_IFLS   (PL011_UART_BASE + 0x34)
#define PL011_UART_IMSC   (PL011_UART_BASE + 0x38)
#define PL011_UART_RIS    (PL011_UART_BASE + 0x3C)
#define PL011_UART_MIS    (PL011_UART_BASE + 0x40)
#define PL011_UART_ICR    (PL011_UART_BASE + 0x44)
#define PL011_UART_DMACR  (PL011_UART_BASE + 0x48)
#define PL011_UART_ITCR   (PL011_UART_BASE + 0x80)
#define PL011_UART_ITIP   (PL011_UART_BASE + 0x84)
#define PL011_UART_ITOP   (PL011_UART_BASE + 0x88)
#define PL011_UART_TDR    (PL011_UART_BASE + 0x8C)

void uart_init();
void putchar(char c);
char getchar(void);
_Bool putchar_non_blocking(char c);
int getchar_non_blocking(void);

// TODO experiment to see if this gives us raw uart irq or the uart
// irq bit or'd with it's enable bit (not crucial for now, sice in our
// code this function only gets called when this irq is enabled)
static inline _Bool uart_irq_pending(void)
{
  return
    ((uint32_t) 1 << 25) & rd32(ARM_IRQ_PENDING_2);
}

static inline void uart_irq_disable(void)
{
  // Mask uart in arm peripheral interrupts
  wr32(ARM_DISABLE_IRQS_2, ((uint32_t) 1) << 25);
}

static inline void uart_irq_enable(void)
{
  // Unmask uart in arm peripheral interrupts
  wr32(ARM_ENABLE_IRQS_2, ((uint32_t) 1) << 25);
}

static inline _Bool uart_recv_irq_pending(void)
{
  return (1 << 4) & rd32(PL011_UART_MIS);
}

static inline void uart_recv_irq_disable(void)
{
  wr32(PL011_UART_IMSC, rd32(PL011_UART_IMSC) & ~(1 << 4));
}

static inline void uart_recv_irq_enable(void)
{
  wr32(PL011_UART_IMSC, rd32(PL011_UART_IMSC) | (1 << 4));
}

static inline void uart_clear_recv_irq(void)
{
  wr32(PL011_UART_ICR, (1 << 4));
}

static inline _Bool uart_send_irq_pending(void)
{
  return (1 << 5) & rd32(PL011_UART_MIS);
}

static inline void uart_send_irq_disable(void)
{
  wr32(PL011_UART_IMSC, rd32(PL011_UART_IMSC) & ~(1 << 5));
}

static inline void uart_send_irq_enable(void)
{
  wr32(PL011_UART_IMSC, rd32(PL011_UART_IMSC) | (1 << 5));
}

static inline void uart_clear_send_irq(void)
{
  wr32(PL011_UART_ICR, (1 << 5));
}

#endif // UART_H