[PATCH v1 1/2] serial: amba-pl011: reset controller on pl011_setbaudrate()

[Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>]

Reset UART controller on baudrate update. Otherwise, at least on some
systems (for example RPi2), new baudrate setting will not be updated
and system will continue to use previous settings.

Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
 drivers/serial/amba-pl011.c | 41 ++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/drivers/serial/amba-pl011.c b/drivers/serial/amba-pl011.c
index 3baadd54e7..345c58e274 100644
--- a/drivers/serial/amba-pl011.c
+++ b/drivers/serial/amba-pl011.c
@@ -54,6 +54,23 @@ to_amba_uart_port(struct console_device *uart)
 	return container_of(uart, struct amba_uart_port, uart);
 }
 
+static void pl011_rlcr(struct amba_uart_port *uart, u32 lcr)
+{
+	struct vendor_data	*vendor = uart->vendor;
+
+	writew(lcr, uart->base + vendor->lcrh_rx);
+	if (vendor->lcrh_tx != vendor->lcrh_rx) {
+		int i;
+		/*
+		 * Wait 10 PCLKs before writing LCRH_TX register,
+		 * to get this delay write read only register 10 times
+		 */
+		for (i = 0; i < 10; ++i)
+			writew(0xff, uart->base + UART011_MIS);
+		writew(lcr, uart->base +  vendor->lcrh_tx);
+	}
+}
+
 static int pl011_setbaudrate(struct console_device *cdev, int baudrate)
 {
 	struct amba_uart_port *uart = to_amba_uart_port(cdev);
@@ -61,6 +78,7 @@ static int pl011_setbaudrate(struct console_device *cdev, int baudrate)
 	unsigned int divider;
 	unsigned int remainder;
 	unsigned int fraction;
+	uint32_t cr;
 
 	/*
 	 ** Set baud rate
@@ -74,9 +92,15 @@ static int pl011_setbaudrate(struct console_device *cdev, int baudrate)
 	temp = (8 * remainder) / baudrate;
 	fraction = (temp >> 1) + (temp & 1);
 
+	cr = readl(uart->base + UART011_CR);
+	writel(0x0, uart->base + UART011_CR);
+
 	writel(divider, uart->base + UART011_IBRD);
 	writel(fraction, uart->base + UART011_FBRD);
 
+	pl011_rlcr(uart, UART01x_LCRH_WLEN_8 | UART01x_LCRH_FEN);
+	writel(cr, uart->base + UART011_CR);
+
 	return 0;
 }
 
@@ -118,23 +142,6 @@ static int pl011_tstc(struct console_device *cdev)
 	return !(readl(uart->base + UART01x_FR) & UART01x_FR_RXFE);
 }
 
-static void pl011_rlcr(struct amba_uart_port *uart, u32 lcr)
-{
-	struct vendor_data	*vendor = uart->vendor;
-
-	writew(lcr, uart->base + vendor->lcrh_rx);
-	if (vendor->lcrh_tx != vendor->lcrh_rx) {
-		int i;
-		/*
-		 * Wait 10 PCLKs before writing LCRH_TX register,
-		 * to get this delay write read only register 10 times
-		 */
-		for (i = 0; i < 10; ++i)
-			writew(0xff, uart->base + UART011_MIS);
-		writew(lcr, uart->base +  vendor->lcrh_tx);
-	}
-}
-
 static int pl011_init_port(struct console_device *cdev)
 {
 	struct amba_uart_port *uart = to_amba_uart_port(cdev);
-- 
2.30.2


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