This patch allows testing of patch 2/2 in the series by forcing bytes read from the i.MX serial port to be printable.

Without this, it's very hard to tell that a series of in-bound '\xff' characters are being produced, because they'll be silently ignored.

Note that this is only submitted for testing.

Signed-off-by: Eric Nelson eric.nelson@boundarydevices.com --- drivers/serial/serial_mxc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/serial/serial_mxc.c b/drivers/serial/serial_mxc.c index 56bee55..ef308dc 100644 --- a/drivers/serial/serial_mxc.c +++ b/drivers/serial/serial_mxc.c @@ -145,9 +145,13 @@ static void mxc_serial_setbrg(void)

static int mxc_serial_getc(void) { + unsigned char rx; while (__REG(UART_PHYS + UTS) & UTS_RXEMPTY) WATCHDOG_RESET(); - return (__REG(UART_PHYS + URXD) & URXD_RX_DATA); /* mask out status from upper word */ + rx = (__REG(UART_PHYS + URXD) & URXD_RX_DATA); /* mask out status from upper word */ + if (0x80 <= rx) + rx = '?'; + return rx; }

static void mxc_serial_putc(const char c)

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 eric.nelson@boundarydevices.com --- drivers/serial/serial_mxc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/serial/serial_mxc.c b/drivers/serial/serial_mxc.c index ef308dc..0e24828 100644 --- a/drivers/serial/serial_mxc.c +++ b/drivers/serial/serial_mxc.c @@ -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 */ @@ -190,7 +190,7 @@ 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;