diff mbox series

[U-Boot,3/5] serial: zynq: Initialize uart only before relocation

Message ID 477d0b7119f9a73848c713e86a60696c84380d89.1528968775.git.michal.simek@xilinx.com
State Accepted
Commit a673025535ae6b559be9badb9fd4c2c9e692b880
Delegated to: Michal Simek
Headers show
Series serial: zynq: Fix serial driver | expand

Commit Message

Michal Simek June 14, 2018, 9:32 a.m. UTC 
This issue was found when OF_LIVE was enabled that there are scrambled
chars on the console like this:
Chip ID:	zu3eg
Watchdog: Started��j�   sdhci@ff160000: 0, sdhci@ff170000: 1
In:    serial@ff010000

I found a solution for this problem exactly the same as I found later in
serial_msm fixed by:
"serial: serial_msm: initialize uart only before relocation"
(sha1: 7e5ad796bcd65772a87da236ae21cd536ae3a4d2)

What it is happening is that output TX fifo still contains chars to be
sent and _uart_zynq_serial_init() resets TX fifo even in the middle of
transfer.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

 drivers/serial/serial_zynq.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Simon Glass June 14, 2018, 12:58 p.m. UTC | #1 
On 14 June 2018 at 03:32, Michal Simek <michal.simek@xilinx.com> wrote:
> This issue was found when OF_LIVE was enabled that there are scrambled
> chars on the console like this:
> Chip ID:        zu3eg
> Watchdog: Started��j�   sdhci@ff160000: 0, sdhci@ff170000: 1
> In:    serial@ff010000
>
> I found a solution for this problem exactly the same as I found later in
> serial_msm fixed by:
> "serial: serial_msm: initialize uart only before relocation"
> (sha1: 7e5ad796bcd65772a87da236ae21cd536ae3a4d2)
>
> What it is happening is that output TX fifo still contains chars to be
> sent and _uart_zynq_serial_init() resets TX fifo even in the middle of
> transfer.
>
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> ---
>
>  drivers/serial/serial_zynq.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>

Reviewed-by: Simon Glass <sjg@chromium.org>
diff mbox series

Patch

diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c
index 4ae24939ab23..cc14bfa39cff 100644
--- a/drivers/serial/serial_zynq.c
+++ b/drivers/serial/serial_zynq.c
@@ -15,6 +15,8 @@ 
 #include <linux/compiler.h>
 #include <serial.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 #define ZYNQ_UART_SR_TXACTIVE	BIT(11) /* TX active */
 #define ZYNQ_UART_SR_TXFULL	BIT(4) /* TX FIFO full */
 #define ZYNQ_UART_SR_RXEMPTY	BIT(1) /* RX FIFO empty */
@@ -137,6 +139,10 @@  static int zynq_serial_probe(struct udevice *dev)
 {
 	struct zynq_uart_priv *priv = dev_get_priv(dev);
 
+	/* No need to reinitialize the UART after relocation */
+	if (gd->flags & GD_FLG_RELOC)
+		return 0;
+
 	_uart_zynq_serial_init(priv->regs);
 
 	return 0;