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// See LICENSE for license details.
#include <string.h>
#include "uart_litex.h"
#include "fdt.h"
volatile unsigned int *uart_litex;
#define UART_REG_RXTX 0
#define UART_REG_TXFULL 1
#define UART_REG_RXEMPTY 2
#define UART_REG_EV_STATUS 3
#define UART_REG_EV_PENDING 4
#define UART_REG_EV_ENABLE 5
void uart_litex_putchar(uint8_t c)
{
while ((uart_litex[UART_REG_TXFULL] & 0x01)); // wait while tx-buffer full
uart_litex[UART_REG_RXTX] = c;
}
int uart_litex_getchar()
{
int c = -1;
if (!(uart_litex[UART_REG_RXEMPTY] & 0x01)) { // if rx-buffer not empty
c = uart_litex[UART_REG_RXTX];
uart_litex[UART_REG_EV_PENDING] = 0x02; // ack (UART_EV_RX)
}
return c;
}
struct uart_litex_scan
{
int compat;
uint64_t reg;
};
static void uart_litex_open(const struct fdt_scan_node *node, void *extra)
{
struct uart_litex_scan *scan = (struct uart_litex_scan *)extra;
memset(scan, 0, sizeof(*scan));
}
static void uart_litex_prop(const struct fdt_scan_prop *prop, void *extra)
{
struct uart_litex_scan *scan = (struct uart_litex_scan *)extra;
if (!strcmp(prop->name, "compatible") &&
(!strcmp((const char *)prop->value, "litex,uart0") ||
!strcmp((const char *)prop->value, "litex,liteuart"))) {
scan->compat = 1;
} else if (!strcmp(prop->name, "reg")) {
fdt_get_address(prop->node->parent, prop->value, &scan->reg);
}
}
static void uart_litex_done(const struct fdt_scan_node *node, void *extra)
{
struct uart_litex_scan *scan = (struct uart_litex_scan *)extra;
if (!scan->compat || !scan->reg || uart_litex)
return;
// Initialize LiteX UART
uart_litex = (void *)(uintptr_t)scan->reg;
}
void query_uart_litex(uintptr_t fdt)
{
struct fdt_cb cb;
struct uart_litex_scan scan;
memset(&cb, 0, sizeof(cb));
cb.open = uart_litex_open;
cb.prop = uart_litex_prop;
cb.done = uart_litex_done;
cb.extra = &scan;
fdt_scan(fdt, &cb);
}
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