rpi4-osdev/part10-multicore/io.c
2021-02-21 20:58:04 +00:00

199 lines
5.9 KiB
C

#include "io.h"
// GPIO
enum {
GPFSEL0 = PERIPHERAL_BASE + 0x200000,
GPSET0 = PERIPHERAL_BASE + 0x20001C,
GPCLR0 = PERIPHERAL_BASE + 0x200028,
GPPUPPDN0 = PERIPHERAL_BASE + 0x2000E4
};
enum {
GPIO_MAX_PIN = 53,
GPIO_FUNCTION_OUT = 1,
GPIO_FUNCTION_ALT5 = 2,
GPIO_FUNCTION_ALT3 = 7,
GPIO_FUNCTION_ALT0 = 4
};
enum {
Pull_None = 0,
Pull_Down = 1, // Are down and up the right way around?
Pull_Up = 2
};
void mmio_write(long reg, unsigned int val) { *(volatile unsigned int *)reg = val; }
unsigned int mmio_read(long reg) { return *(volatile unsigned int *)reg; }
unsigned int gpio_call(unsigned int pin_number, unsigned int value, unsigned int base, unsigned int field_size, unsigned int field_max) {
unsigned int field_mask = (1 << field_size) - 1;
if (pin_number > field_max) return 0;
if (value > field_mask) return 0;
unsigned int num_fields = 32 / field_size;
unsigned int reg = base + ((pin_number / num_fields) * 4);
unsigned int shift = (pin_number % num_fields) * field_size;
unsigned int curval = mmio_read(reg);
curval &= ~(field_mask << shift);
curval |= value << shift;
mmio_write(reg, curval);
return 1;
}
unsigned int gpio_set (unsigned int pin_number, unsigned int value) { return gpio_call(pin_number, value, GPSET0, 1, GPIO_MAX_PIN); }
unsigned int gpio_clear (unsigned int pin_number, unsigned int value) { return gpio_call(pin_number, value, GPCLR0, 1, GPIO_MAX_PIN); }
unsigned int gpio_pull (unsigned int pin_number, unsigned int value) { return gpio_call(pin_number, value, GPPUPPDN0, 2, GPIO_MAX_PIN); }
unsigned int gpio_function(unsigned int pin_number, unsigned int value) { return gpio_call(pin_number, value, GPFSEL0, 3, GPIO_MAX_PIN); }
void gpio_useAsAlt0(unsigned int pin_number) {
gpio_pull(pin_number, Pull_None);
gpio_function(pin_number, GPIO_FUNCTION_ALT0);
}
void gpio_useAsAlt3(unsigned int pin_number) {
gpio_pull(pin_number, Pull_None);
gpio_function(pin_number, GPIO_FUNCTION_ALT3);
}
void gpio_useAsAlt5(unsigned int pin_number) {
gpio_pull(pin_number, Pull_None);
gpio_function(pin_number, GPIO_FUNCTION_ALT5);
}
void gpio_initOutputPinWithPullNone(unsigned int pin_number) {
gpio_pull(pin_number, Pull_None);
gpio_function(pin_number, GPIO_FUNCTION_OUT);
}
void gpio_setPinOutputBool(unsigned int pin_number, unsigned int onOrOff) {
if (onOrOff) {
gpio_set(pin_number, 1);
} else {
gpio_clear(pin_number, 1);
}
}
// UART
enum {
AUX_BASE = PERIPHERAL_BASE + 0x215000,
AUX_IRQ = AUX_BASE,
AUX_ENABLES = AUX_BASE + 4,
AUX_MU_IO_REG = AUX_BASE + 64,
AUX_MU_IER_REG = AUX_BASE + 68,
AUX_MU_IIR_REG = AUX_BASE + 72,
AUX_MU_LCR_REG = AUX_BASE + 76,
AUX_MU_MCR_REG = AUX_BASE + 80,
AUX_MU_LSR_REG = AUX_BASE + 84,
AUX_MU_MSR_REG = AUX_BASE + 88,
AUX_MU_SCRATCH = AUX_BASE + 92,
AUX_MU_CNTL_REG = AUX_BASE + 96,
AUX_MU_STAT_REG = AUX_BASE + 100,
AUX_MU_BAUD_REG = AUX_BASE + 104,
AUX_UART_CLOCK = 500000000,
UART_MAX_QUEUE = 16 * 1024
};
#define AUX_MU_BAUD(baud) ((AUX_UART_CLOCK/(baud*8))-1)
unsigned char uart_output_queue[UART_MAX_QUEUE];
unsigned int uart_output_queue_write = 0;
unsigned int uart_output_queue_read = 0;
void uart_init() {
mmio_write(AUX_ENABLES, 1); //enable UART1
mmio_write(AUX_MU_IER_REG, 0);
mmio_write(AUX_MU_CNTL_REG, 0);
mmio_write(AUX_MU_LCR_REG, 3); //8 bits
mmio_write(AUX_MU_MCR_REG, 0);
mmio_write(AUX_MU_IER_REG, 0);
mmio_write(AUX_MU_IIR_REG, 0xC6); //disable interrupts
mmio_write(AUX_MU_BAUD_REG, AUX_MU_BAUD(115200));
gpio_useAsAlt5(14);
gpio_useAsAlt5(15);
mmio_write(AUX_MU_CNTL_REG, 3); //enable RX/TX
}
unsigned int uart_isOutputQueueEmpty() {
return uart_output_queue_read == uart_output_queue_write;
}
unsigned int uart_isReadByteReady() { return mmio_read(AUX_MU_LSR_REG) & 0x01; }
unsigned int uart_isWriteByteReady() { return mmio_read(AUX_MU_LSR_REG) & 0x20; }
unsigned char uart_readByte() {
while (!uart_isReadByteReady());
return (unsigned char)mmio_read(AUX_MU_IO_REG);
}
void uart_writeByteBlockingActual(unsigned char ch) {
while (!uart_isWriteByteReady());
mmio_write(AUX_MU_IO_REG, (unsigned int)ch);
}
void uart_loadOutputFifo() {
while (!uart_isOutputQueueEmpty() && uart_isWriteByteReady()) {
uart_writeByteBlockingActual(uart_output_queue[uart_output_queue_read]);
uart_output_queue_read = (uart_output_queue_read + 1) & (UART_MAX_QUEUE - 1); // Don't overrun
}
}
void uart_writeByteBlocking(unsigned char ch) {
unsigned int next = (uart_output_queue_write + 1) & (UART_MAX_QUEUE - 1); // Don't overrun
while (next == uart_output_queue_read) uart_loadOutputFifo();
uart_output_queue[uart_output_queue_write] = ch;
uart_output_queue_write = next;
}
void uart_writeText(char *buffer) {
while (*buffer) {
if (*buffer == '\n') uart_writeByteBlockingActual('\r');
uart_writeByteBlockingActual(*buffer++);
}
}
void uart_drainOutputQueue() {
while (!uart_isOutputQueueEmpty()) uart_loadOutputFifo();
}
void uart_update() {
uart_loadOutputFifo();
if (uart_isReadByteReady()) {
unsigned char ch = uart_readByte();
if (ch == '\r') uart_writeText("\n"); else uart_writeByteBlocking(ch);
}
}
void uart_hex(unsigned int d) {
unsigned int n;
int c;
for(c=28;c>=0;c-=4) {
// get highest tetrad
n=(d>>c)&0xF;
// 0-9 => '0'-'9', 10-15 => 'A'-'F'
n+=n>9?0x37:0x30;
uart_writeByteBlockingActual(n);
}
}
void uart_byte(unsigned char b) {
unsigned int n;
int c;
for(c=4;c>=0;c-=4) {
// get highest tetrad
n=(b>>c)&0xF;
// 0-9 => '0'-'9', 10-15 => 'A'-'F'
n+=n>9?0x37:0x30;
uart_writeByteBlockingActual(n);
}
uart_writeByteBlockingActual(' ');
}