You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
77 lines
1.6 KiB
77 lines
1.6 KiB
#include <string.h>
|
|
#include "uart.h"
|
|
#include "fdt.h"
|
|
|
|
volatile uint32_t* uart;
|
|
|
|
void uart_putchar(uint8_t ch)
|
|
{
|
|
#ifdef __riscv_atomic
|
|
int32_t r;
|
|
do {
|
|
__asm__ __volatile__ (
|
|
"amoor.w %0, %2, %1\n"
|
|
: "=r" (r), "+A" (uart[UART_REG_TXFIFO])
|
|
: "r" (ch));
|
|
} while (r < 0);
|
|
#else
|
|
volatile uint32_t *tx = uart + UART_REG_TXFIFO;
|
|
while ((int32_t)(*tx) < 0);
|
|
*tx = ch;
|
|
#endif
|
|
}
|
|
|
|
int uart_getchar()
|
|
{
|
|
int32_t ch = uart[UART_REG_RXFIFO];
|
|
if (ch < 0) return -1;
|
|
return ch;
|
|
}
|
|
|
|
struct uart_scan
|
|
{
|
|
int compat;
|
|
uint64_t reg;
|
|
};
|
|
|
|
static void uart_open(const struct fdt_scan_node *node, void *extra)
|
|
{
|
|
struct uart_scan *scan = (struct uart_scan *)extra;
|
|
memset(scan, 0, sizeof(*scan));
|
|
}
|
|
|
|
static void uart_prop(const struct fdt_scan_prop *prop, void *extra)
|
|
{
|
|
struct uart_scan *scan = (struct uart_scan *)extra;
|
|
if (!strcmp(prop->name, "compatible") && !strcmp((const char*)prop->value, "sifive,uart0")) {
|
|
scan->compat = 1;
|
|
} else if (!strcmp(prop->name, "reg")) {
|
|
fdt_get_address(prop->node->parent, prop->value, &scan->reg);
|
|
}
|
|
}
|
|
|
|
static void uart_done(const struct fdt_scan_node *node, void *extra)
|
|
{
|
|
struct uart_scan *scan = (struct uart_scan *)extra;
|
|
if (!scan->compat || !scan->reg || uart) return;
|
|
|
|
// Enable Rx/Tx channels
|
|
uart = (void*)(uintptr_t)scan->reg;
|
|
uart[UART_REG_TXCTRL] = UART_TXEN;
|
|
uart[UART_REG_RXCTRL] = UART_RXEN;
|
|
}
|
|
|
|
void query_uart(uintptr_t fdt)
|
|
{
|
|
struct fdt_cb cb;
|
|
struct uart_scan scan;
|
|
|
|
memset(&cb, 0, sizeof(cb));
|
|
cb.open = uart_open;
|
|
cb.prop = uart_prop;
|
|
cb.done = uart_done;
|
|
cb.extra = &scan;
|
|
|
|
fdt_scan(fdt, &cb);
|
|
}
|