There is no code change here, just new comments, but this keeps me from having to do another audit from scratch in the future.
Signed-off-by: Mike Frysinger vapier@gentoo.org --- cpu/blackfin/serial.c | 21 ++++++++++++++++++++- cpu/blackfin/serial.h | 2 +- 2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/cpu/blackfin/serial.c b/cpu/blackfin/serial.c index 3861955..2abda18 100644 --- a/cpu/blackfin/serial.c +++ b/cpu/blackfin/serial.c @@ -24,6 +24,19 @@ * Licensed under the GPL-2 or later. */
+/* Anomaly notes: + * 05000086 - we don't support autobaud + * 05000099 - we only use DR bit, so losing others is not a problem + * 05000100 - we don't use the UART_IIR register + * 05000215 - we poll the uart (no dma/interrupts) + * 05000225 - no workaround possible, but this shouldnt cause errors ... + * 05000230 - we tweak the baud rate calculation slightly + * 05000231 - we always use 1 stop bit + * 05000309 - we always enable the uart before we modify it in anyway + * 05000350 - we always enable the uart regardless of boot mode + * 05000363 - we don't support break signals, so don't generate one + */ + #include <common.h> #include <watchdog.h> #include <asm/blackfin.h> @@ -43,7 +56,9 @@ uint16_t cached_rbr[256]; size_t cache_count;
/* The LSR is read-to-clear on some parts, so we have to make sure status - * bits aren't inadvertently lost when doing various tests. + * bits aren't inadvertently lost when doing various tests. This also + * works around anomaly 05000099 at the same time by keeping a cumulative + * tally of all the status bits. */ static uint16_t uart_lsr_save; static uint16_t uart_lsr_read(void) @@ -59,6 +74,10 @@ static void uart_lsr_clear(void) *pUART_LSR |= -1; } #else +/* When debugging is disabled, we only care about the DR bit, so if other + * bits get set/cleared, we don't really care since we don't read them + * anyways (and thus anomaly 05000099 is irrelevant). + */ static inline uint16_t uart_lsr_read(void) { return *pUART_LSR; } static inline void uart_lsr_clear(void) { *pUART_LSR = -1; } #endif diff --git a/cpu/blackfin/serial.h b/cpu/blackfin/serial.h index ce39148..7b47878 100644 --- a/cpu/blackfin/serial.h +++ b/cpu/blackfin/serial.h @@ -146,7 +146,7 @@ static inline void serial_early_init(void) /* handle portmux crap on different Blackfins */ serial_do_portmux();
- /* Enable UART */ + /* always enable UART -- avoids anomalies 05000309 and 05000350 */ *pUART_GCTL = UCEN;
/* Set LCR to Word Lengh 8-bit word select */