serial_mxc: disable new features of autobaud detection

PATCH New Eric Nelson 2 participants 3 messages May 14, 2014 – May 28, 2014

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Eric Nelson

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2014-05-14 23:58 UTC #0 lore raw

PATCH 1/1 serial_mxc: disable new features of autobaud detection

Bit 7 of UCR3 is described in the i.MX3x/i.MX5x/i.MX6x reference manuals as follows:

Autobaud Detection Not Improved-. Disables new features of autobaud detection (See Baud Rate Automatic Detection Protocol, for more details).

0 Autobaud detection new features selected 1 Keep old autobaud detection mechanism

On at least i.MX6DQ, i.MX6DLS and i.MX53, the "new features" occasionally cause the receiver to get out of sync and continuously produce received characters of '\xff'.

This patch disables the "new feature" on all boards, since there's no support for auto-baud in U-Boot on any of them.

More details are available in this post on i.MX Community:

	https://community.freescale.com/message/403254

Signed-off-by Eric Nelson <[email protected]>

Tested-by Fabio Estevam <[email protected]>

---
 drivers/serial/serial_mxc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

drivers/serial/serial_mxc.c +2 -2

index 56bee55..313d560 100644
@@ -77,7 +77,7 @@
 #define  UCR3_DSR        (1<<10) /* Data set ready */
 #define  UCR3_DCD        (1<<9)  /* Data carrier detect */
 #define  UCR3_RI         (1<<8)  /* Ring indicator */
-#define  UCR3_TIMEOUTEN  (1<<7)  /* Timeout interrupt enable */
+#define  UCR3_ADNIMP     (1<<7)  /* Autobaud Detection Not Improved */
 #define  UCR3_RXDSEN	 (1<<6)  /* Receive status interrupt enable */
 #define  UCR3_AIRINTEN   (1<<5)  /* Async IR wake interrupt enable */
 #define  UCR3_AWAKEN	 (1<<4)  /* Async wake interrupt enable */

@@ -186,7 +186,7 @@ static int mxc_serial_init(void)
 
 	while (!(__REG(UART_PHYS + UCR2) & UCR2_SRST));
 
-	__REG(UART_PHYS + UCR3) = 0x0704;
+	__REG(UART_PHYS + UCR3) = 0x0704 | UCR3_ADNIMP;
 	__REG(UART_PHYS + UCR4) = 0x8000;
 	__REG(UART_PHYS + UESC) = 0x002b;
 	__REG(UART_PHYS + UTIM) = 0x0;

Signature · 1 line

1.9.1

Stefano Babic

2014-05-15 09:21 UTC #1 lore raw

PATCH 1/1 serial_mxc: disable new features of autobaud detection

Hi Eric,

Quoted 41 lines · Eric Nelson

Bit 7 of UCR3 is described in the i.MX3x/i.MX5x/i.MX6x reference manuals as follows:
Autobaud Detection Not Improved-. Disables new features of autobaud detection (See Baud Rate Automatic Detection Protocol, for more details).
0 Autobaud detection new features selected 1 Keep old autobaud detection mechanism
On at least i.MX6DQ, i.MX6DLS and i.MX53, the "new features" occasionally cause the receiver to get out of sync and continuously produce received characters of '\xff'.
This patch disables the "new feature" on all boards, since there's no support for auto-baud in U-Boot on any of them.
More details are available in this post on i.MX Community:
	https://community.freescale.com/message/403254
Signed-off-by Eric Nelson <[email protected]>
Tested-by Fabio Estevam <[email protected]>
---
 drivers/serial/serial_mxc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/serial/serial_mxc.c +1 -1
index 56bee55..313d560 100644
@@ -77,7 +77,7 @@
 #define  UCR3_DSR        (1<<10) /* Data set ready */
 #define  UCR3_DCD        (1<<9)  /* Data carrier detect */
 #define  UCR3_RI         (1<<8)  /* Ring indicator */
-#define  UCR3_TIMEOUTEN  (1<<7)  /* Timeout interrupt enable */
+#define  UCR3_ADNIMP     (1<<7)  /* Autobaud Detection Not Improved */
 #define  UCR3_RXDSEN	 (1<<6)  /* Receive status interrupt enable */
 #define  UCR3_AIRINTEN   (1<<5)  /* Async IR wake interrupt enable */
 #define  UCR3_AWAKEN	 (1<<4)  /* Async wake interrupt enable */

drivers/serial/serial_mxc.c static int mxc_serial_init(void) · line 192

Quoted 8 lines

drivers/serial/serial_mxc.c +1 -1

@@ -186,7 +186,7 @@ static int mxc_serial_init(void)
 
 	while (!(__REG(UART_PHYS + UCR2) & UCR2_SRST));
 
-	__REG(UART_PHYS + UCR3) = 0x0704;
+	__REG(UART_PHYS + UCR3) = 0x0704 | UCR3_ADNIMP;
 	__REG(UART_PHYS + UCR4) = 0x8000;
 	__REG(UART_PHYS + UESC) = 0x002b;
 	__REG(UART_PHYS + UTIM) = 0x0;

Thanks to have found a solved this issue !

Acked-by Stefano Babic <[email protected]>

Best regards,
Stefano Babic

Signature · 5 lines

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================

Stefano Babic

2014-05-28 15:39 UTC #2 lore raw

PATCH 1/1 serial_mxc: disable new features of autobaud detection

In reply to Eric Nelson

Quoted 17 lines · Eric Nelson

Bit 7 of UCR3 is described in the i.MX3x/i.MX5x/i.MX6x reference manuals as follows:
Autobaud Detection Not Improved-. Disables new features of autobaud detection (See Baud Rate Automatic Detection Protocol, for more details).
0 Autobaud detection new features selected 1 Keep old autobaud detection mechanism
On at least i.MX6DQ, i.MX6DLS and i.MX53, the "new features" occasionally cause the receiver to get out of sync and continuously produce received characters of '\xff'.
This patch disables the "new feature" on all boards, since there's no support for auto-baud in U-Boot on any of them.

Quoted 6 lines

More details are available in this post on i.MX Community:
	https://community.freescale.com/message/403254
Signed-off-by Eric Nelson <[email protected]>
Tested-by Fabio Estevam <[email protected]>
---

Applied to u-boot-imx, thanks !

Best regards,
Stefano Babic

Signature · 5 lines

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================