diff options
author | Stefan Agner <stefan.agner@toradex.com> | 2014-08-19 17:46:26 +0200 |
---|---|---|
committer | Stefan Agner <stefan.agner@toradex.com> | 2014-08-19 17:46:26 +0200 |
commit | 9afd458f90646e1544d21c6678ca4d379fe39833 (patch) | |
tree | 2a0d7362368c34774cae0d99adc2b28c5dfb2a0a | |
parent | 36b44c6fc7ddde29aec7f39ebcb5cc959d24b469 (diff) |
arm: vf610: lpuart: correct status register handling
The status register 1 (S1) is not writeable, hence we should not
write it. In order to clear the RDRF flag we only need to read
the data register.
Also, when stressing U-Boot a lot with serial input, an overflow can
occur which asserts the S1_OR flag (while not asserting the S1_RDRF
flag). To clear this flag we again just need to read the data
register, hence add this flag to the abort conditions for the while
loop.
Insert a compiler barrier to make sure reading the data register
gets executed after reading the status register.
-rw-r--r-- | drivers/serial/serial_lpuart.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/drivers/serial/serial_lpuart.c b/drivers/serial/serial_lpuart.c index da5f9a21f46..96173ca4409 100644 --- a/drivers/serial/serial_lpuart.c +++ b/drivers/serial/serial_lpuart.c @@ -14,6 +14,7 @@ #define US1_TDRE (1 << 7) #define US1_RDRF (1 << 5) +#define US1_OR (1 << 3) #define UC2_TE (1 << 3) #define UC2_RE (1 << 2) @@ -38,14 +39,10 @@ static void lpuart_serial_setbrg(void) static int lpuart_serial_getc(void) { - u8 status; - - while (!(__raw_readb(&base->us1) & US1_RDRF)) + while (!(__raw_readb(&base->us1) & (US1_RDRF | US1_OR))) WATCHDOG_RESET(); - status = __raw_readb(&base->us1); - status |= US1_RDRF; - __raw_writeb(status, &base->us1); + barrier(); return __raw_readb(&base->ud); } |