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-rw-r--r--cpu/blackfin/serial.c21
-rw-r--r--cpu/blackfin/serial.h2
2 files changed, 21 insertions, 2 deletions
diff --git a/cpu/blackfin/serial.c b/cpu/blackfin/serial.c
index 38619555666..2abda186ecb 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 ce39148f83f..7b47878df3d 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 */