serial: atmel_usart: Support enable an early debug UART

Add support to enable an early debug UART for debugging.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Andreas Bießmann <andreas@biessmann.org>
This commit is contained in:
Wenyou Yang 2016-10-17 09:49:55 +08:00 committed by Andreas Bießmann
parent 6ec739aa52
commit 998cf3c2be
2 changed files with 29 additions and 0 deletions

View File

@ -98,6 +98,13 @@ config DEBUG_UART_AR933X
driver will be available until the real driver model serial is
running.
config DEBUG_UART_ATMEL
bool "Atmel USART"
help
Select this to enable a debug UART using the atmel usart driver. You
will need to provide parameters to make this work. The driver will
be available until the real driver-model serial is running.
config DEBUG_UART_NS16550
bool "ns16550"
help

View File

@ -11,6 +11,7 @@
#include <errno.h>
#include <watchdog.h>
#include <serial.h>
#include <debug_uart.h>
#include <linux/compiler.h>
#include <asm/io.h>
@ -226,3 +227,24 @@ U_BOOT_DRIVER(serial_atmel) = {
.priv_auto_alloc_size = sizeof(struct atmel_serial_priv),
};
#endif
#ifdef CONFIG_DEBUG_UART_ATMEL
static inline void _debug_uart_init(void)
{
atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_DEBUG_UART_BASE;
atmel_serial_setbrg_internal(usart, 0, CONFIG_BAUDRATE);
}
static inline void _debug_uart_putc(int ch)
{
atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_DEBUG_UART_BASE;
while (!(readl(&usart->csr) & USART3_BIT(TXRDY)))
;
writel(ch, &usart->thr);
}
DEBUG_UART_FUNCS
#endif