[U-Boot] [PATCH v3 1/2] serial: atmel_usart: Fix early debug not work in SPL

[Wenyou Yang]

Add the uart init function to be used on both probe and the early
debug uart init. For the latter, the input clock should be from
CONFIG_DEBUG_UART_CLOCK.

Signed-off-by: Wenyou Yang <wenyou.yang at atmel.com>
Reviewed-by: Simon Glass <sjg at chromium.org>
---

Changes in v3: None
Changes in v2: None

 drivers/serial/atmel_usart.c | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/serial/atmel_usart.c b/drivers/serial/atmel_usart.c
index 7674f97e8d..8b1e0d55a4 100644
--- a/drivers/serial/atmel_usart.c
+++ b/drivers/serial/atmel_usart.c
@@ -25,6 +25,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+#ifndef CONFIG_DM_SERIAL
 static void atmel_serial_setbrg_internal(atmel_usart3_t *usart, int id,
 					 int baudrate)
 {
@@ -66,7 +67,6 @@ static void atmel_serial_activate(atmel_usart3_t *usart)
 	__udelay(100);
 }
 
-#ifndef CONFIG_DM_SERIAL
 static void atmel_serial_setbrg(void)
 {
 	atmel_serial_setbrg_internal((atmel_usart3_t *)CONFIG_USART_BASE,
@@ -138,12 +138,37 @@ struct atmel_serial_priv {
 	atmel_usart3_t *usart;
 };
 
+static void _atmel_serial_set_brg(atmel_usart3_t *usart,
+				  ulong usart_clk_rate, int baudrate)
+{
+	unsigned long divisor;
+
+	divisor = (usart_clk_rate / 16 + baudrate / 2) / baudrate;
+	writel(USART3_BF(CD, divisor), &usart->brgr);
+}
+
+void _atmel_serial_init(atmel_usart3_t *usart,
+			ulong usart_clk_rate, int baudrate)
+{
+	writel(USART3_BIT(RXDIS) | USART3_BIT(TXDIS), &usart->cr);
+
+	writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL) |
+		USART3_BF(USCLKS, USART3_USCLKS_MCK) |
+		USART3_BF(CHRL, USART3_CHRL_8) |
+		USART3_BF(PAR, USART3_PAR_NONE) |
+		USART3_BF(NBSTOP, USART3_NBSTOP_1)), &usart->mr);
+
+	_atmel_serial_set_brg(usart, usart_clk_rate, baudrate);
+
+	writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr);
+	writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr);
+}
+
 int atmel_serial_setbrg(struct udevice *dev, int baudrate)
 {
 	struct atmel_serial_priv *priv = dev_get_priv(dev);
 
-	atmel_serial_setbrg_internal(priv->usart, 0 /* ignored */, baudrate);
-	atmel_serial_activate(priv->usart);
+	_atmel_serial_set_brg(priv->usart, get_usart_clk_rate(0), baudrate);
 
 	return 0;
 }
@@ -202,7 +227,8 @@ static int atmel_serial_probe(struct udevice *dev)
 	plat->base_addr = (uint32_t)addr_base;
 #endif
 	priv->usart = (atmel_usart3_t *)plat->base_addr;
-	atmel_serial_init_internal(priv->usart);
+
+	_atmel_serial_init(priv->usart, get_usart_clk_rate(0), gd->baudrate);
 
 	return 0;
 }
@@ -233,7 +259,7 @@ 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);
+	_atmel_serial_init(usart, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
 }
 
 static inline void _debug_uart_putc(int ch)
-- 
2.11.0