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microwatt
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Breakout the console code so it can be reused.

Browse Source 
No functional change.

Signed-off-by: Michael Neuling <mikey@neuling.org>
pull/155/head
Michael Neuling 4 years ago
parent 8bee4ae3cc
commit 96fbd61de8
4 changed files with 140 additions and 129 deletions
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4
hello_world/Makefile
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@ -15,8 +15,8 @@ LDFLAGS = -T powerpc.lds

all: hello_world.hex

hello_world.elf: hello_world.o head.o
$(LD) $(LDFLAGS) -o hello_world.elf hello_world.o head.o
hello_world.elf: hello_world.o head.o console.o
$(LD) $(LDFLAGS) -o hello_world.elf hello_world.o head.o console.o

hello_world.bin: hello_world.elf
$(OBJCOPY) -O binary hello_world.elf hello_world.bin

132
hello_world/console.c
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@ -0,0 +1,132 @@
#include <unistd.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>

/*
* Core UART functions to implement for a port
*/

static uint64_t potato_uart_base;

#define PROC_FREQ 50000000
#define UART_FREQ 115200
#define UART_BASE 0xc0002000

#define POTATO_CONSOLE_TX 0x00
#define POTATO_CONSOLE_RX 0x08
#define POTATO_CONSOLE_STATUS 0x10
#define POTATO_CONSOLE_STATUS_RX_EMPTY 0x01
#define POTATO_CONSOLE_STATUS_TX_EMPTY 0x02
#define POTATO_CONSOLE_STATUS_RX_FULL 0x04
#define POTATO_CONSOLE_STATUS_TX_FULL 0x08
#define POTATO_CONSOLE_CLOCK_DIV 0x18
#define POTATO_CONSOLE_IRQ_EN 0x20

static uint64_t potato_uart_reg_read(int offset)
{
uint64_t addr;
uint64_t val;

addr = potato_uart_base + offset;

val = *(volatile uint64_t *)addr;

return val;
}

static void potato_uart_reg_write(int offset, uint64_t val)
{
uint64_t addr;

addr = potato_uart_base + offset;

*(volatile uint64_t *)addr = val;
}

static int potato_uart_rx_empty(void)
{
uint64_t val;

val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);

if (val & POTATO_CONSOLE_STATUS_RX_EMPTY)
return 1;

return 0;
}

static int potato_uart_tx_full(void)
{
uint64_t val;

val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);

if (val & POTATO_CONSOLE_STATUS_TX_FULL)
return 1;

return 0;
}

static char potato_uart_read(void)
{
uint64_t val;

val = potato_uart_reg_read(POTATO_CONSOLE_RX);

return (char)(val & 0x000000ff);
}

static void potato_uart_write(char c)
{
uint64_t val;

val = c;

potato_uart_reg_write(POTATO_CONSOLE_TX, val);
}

static unsigned long potato_uart_divisor(unsigned long proc_freq, unsigned long uart_freq)
{
return proc_freq / (uart_freq * 16) - 1;
}

void potato_uart_init(void)
{
potato_uart_base = UART_BASE;

potato_uart_reg_write(POTATO_CONSOLE_CLOCK_DIV, potato_uart_divisor(PROC_FREQ, UART_FREQ));
}

int getchar(void)
{
while (potato_uart_rx_empty())
/* Do nothing */ ;

return potato_uart_read();
}

void putchar(unsigned char c)
{
while (potato_uart_tx_full())
/* Do Nothing */;

potato_uart_write(c);
}

void putstr(const char *str, unsigned long len)
{
for (unsigned long i = 0; i < len; i++) {
putchar(str[i]);
}
}

size_t strlen(const char *s)
{
size_t len = 0;

while (*s++)
len++;

return len;
}

5
hello_world/console.h
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@ -0,0 +1,5 @@
void potato_uart_init(void);
int getchar(void);
void putchar(unsigned char c);
void putstr(const char *str, unsigned long len);
size_t strlen(const char *s);

128
hello_world/hello_world.c
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@ -3,133 +3,7 @@
#include <stdint.h>
#include <stdbool.h>

/*
* Core UART functions to implement for a port
*/

static uint64_t potato_uart_base;

#define PROC_FREQ 50000000
#define UART_FREQ 115200
#define UART_BASE 0xc0002000

#define POTATO_CONSOLE_TX 0x00
#define POTATO_CONSOLE_RX 0x08
#define POTATO_CONSOLE_STATUS 0x10
#define POTATO_CONSOLE_STATUS_RX_EMPTY 0x01
#define POTATO_CONSOLE_STATUS_TX_EMPTY 0x02
#define POTATO_CONSOLE_STATUS_RX_FULL 0x04
#define POTATO_CONSOLE_STATUS_TX_FULL 0x08
#define POTATO_CONSOLE_CLOCK_DIV 0x18
#define POTATO_CONSOLE_IRQ_EN 0x20

static uint64_t potato_uart_reg_read(int offset)
{
uint64_t addr;
uint64_t val;

addr = potato_uart_base + offset;

val = *(volatile uint64_t *)addr;

return val;
}

static void potato_uart_reg_write(int offset, uint64_t val)
{
uint64_t addr;

addr = potato_uart_base + offset;

*(volatile uint64_t *)addr = val;
}

static int potato_uart_rx_empty(void)
{
uint64_t val;

val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);

if (val & POTATO_CONSOLE_STATUS_RX_EMPTY)
return 1;

return 0;
}

static int potato_uart_tx_full(void)
{
uint64_t val;

val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);

if (val & POTATO_CONSOLE_STATUS_TX_FULL)
return 1;

return 0;
}

static char potato_uart_read(void)
{
uint64_t val;

val = potato_uart_reg_read(POTATO_CONSOLE_RX);

return (char)(val & 0x000000ff);
}

static void potato_uart_write(char c)
{
uint64_t val;

val = c;

potato_uart_reg_write(POTATO_CONSOLE_TX, val);
}

static unsigned long potato_uart_divisor(unsigned long proc_freq, unsigned long uart_freq)
{
return proc_freq / (uart_freq * 16) - 1;
}

void potato_uart_init(void)
{
potato_uart_base = UART_BASE;

potato_uart_reg_write(POTATO_CONSOLE_CLOCK_DIV, potato_uart_divisor(PROC_FREQ, UART_FREQ));
}

int getchar(void)
{
while (potato_uart_rx_empty())
/* Do nothing */ ;

return potato_uart_read();
}

void putchar(unsigned char c)
{
while (potato_uart_tx_full())
/* Do Nothing */;

potato_uart_write(c);
}

void putstr(const char *str, unsigned long len)
{
for (unsigned long i = 0; i < len; i++) {
putchar(str[i]);
}
}

size_t strlen(const char *s)
{
size_t len = 0;

while (*s++)
len++;

return len;
}
#include "console.h"

#define HELLO_WORLD "Hello World\r\n"


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