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| author | Sonic Zhang <sonic.zhang@analog.com> | 2009-06-11 13:45:07 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-11 08:51:04 -0700 |
| commit | 0efa4f2c944fabffc81918cc86d4d17dba39a021 (patch) | |
| tree | d5d2c07d6177eb04555b4a6483db9aaea1d434f1 /drivers/serial/bfin_5xx.c | |
| parent | 35ff69357949cfff5c3d8e3038b77146872e3bd3 (diff) | |
| download | lwn-0efa4f2c944fabffc81918cc86d4d17dba39a021.tar.gz lwn-0efa4f2c944fabffc81918cc86d4d17dba39a021.zip | |
Blackfin Serial Driver: annotate anomalies 05000215 and 05000099
Add some comments for how these anomalies are addressed:
05000215 - UART TX Interrupt Masked Erroneously
We always clear ETBEI within last UART TX interrupt to end
a string. It is always set when starting a new tx transfer.
05000099 - UART Line Status Register (UART_LSR) Bits Are Not Updated at
the Same Time
This anomaly affects driver only in POLL code where multi bits of
UART_LSR are checked. It doesn't affect current bfin_5xx.c driver.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/serial/bfin_5xx.c')
| -rw-r--r-- | drivers/serial/bfin_5xx.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c index 854e96dfb070..ab583ef3a305 100644 --- a/drivers/serial/bfin_5xx.c +++ b/drivers/serial/bfin_5xx.c @@ -330,6 +330,11 @@ static void bfin_serial_tx_chars(struct bfin_serial_port *uart) /* Clear TFI bit */ UART_PUT_LSR(uart, TFI); #endif + /* Anomaly notes: + * 05000215 - we always clear ETBEI within last UART TX + * interrupt to end a string. It is always set + * when start a new tx. + */ UART_CLEAR_IER(uart, ETBEI); return; } @@ -528,6 +533,11 @@ static irqreturn_t bfin_serial_dma_tx_int(int irq, void *dev_id) if (!(get_dma_curr_irqstat(uart->tx_dma_channel)&DMA_RUN)) { disable_dma(uart->tx_dma_channel); clear_dma_irqstat(uart->tx_dma_channel); + /* Anomaly notes: + * 05000215 - we always clear ETBEI within last UART TX + * interrupt to end a string. It is always set + * when start a new tx. + */ UART_CLEAR_IER(uart, ETBEI); xmit->tail = (xmit->tail + uart->tx_count) & (UART_XMIT_SIZE - 1); uart->port.icount.tx += uart->tx_count; @@ -969,6 +979,10 @@ static void bfin_serial_reset_irda(struct uart_port *port) } #ifdef CONFIG_CONSOLE_POLL +/* Anomaly notes: + * 05000099 - Because we only use THRE in poll_put and DR in poll_get, + * losing other bits of UART_LSR is not a problem here. + */ static void bfin_serial_poll_put_char(struct uart_port *port, unsigned char chr) { struct bfin_serial_port *uart = (struct bfin_serial_port *)port; |