diff options
| author | Sonic Zhang <sonic.zhang@analog.com> | 2009-06-11 16:42:57 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-11 19:51:04 +0400 |
| commit | 35ff69357949cfff5c3d8e3038b77146872e3bd3 (patch) | |
| tree | c0503527f7c27d8e042ba81157955fa24303049a /drivers/serial | |
| parent | f9d36da9cdc2504cd9bb6034cfaba0673ce2d6df (diff) | |
| download | linux-35ff69357949cfff5c3d8e3038b77146872e3bd3.tar.xz | |
Blackfin Serial Driver: handle irregular DMA register status in auto start mode
This bug is caused by irregular behavior of DMA register CURR_X_COUNT
and CURR_Y_COUNT when an auto restart uart rx DMA run to last byte in
DMA buffer, trigger the interrupt and stay at this possiton. The status
of current x and y is 0:7 instead of 512:8 or 0:8. The driver doesn't
take care of this case when calculating the position.
URL: http://blackfin.uclinux.org/gf/tracker/5063
Reported-by: Tomasz Motylewski <t.motylewski@bfad.de>
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')
| -rw-r--r-- | drivers/serial/bfin_5xx.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c index 676efdad3712..854e96dfb070 100644 --- a/drivers/serial/bfin_5xx.c +++ b/drivers/serial/bfin_5xx.c @@ -490,7 +490,7 @@ void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart) uart->rx_dma_nrows = get_dma_curr_ycount(uart->rx_dma_channel); x_pos = get_dma_curr_xcount(uart->rx_dma_channel); uart->rx_dma_nrows = DMA_RX_YCOUNT - uart->rx_dma_nrows; - if (uart->rx_dma_nrows == DMA_RX_YCOUNT) + if (uart->rx_dma_nrows == DMA_RX_YCOUNT || x_pos == 0) uart->rx_dma_nrows = 0; x_pos = DMA_RX_XCOUNT - x_pos; if (x_pos == DMA_RX_XCOUNT) @@ -546,15 +546,16 @@ static irqreturn_t bfin_serial_dma_rx_int(int irq, void *dev_id) { struct bfin_serial_port *uart = dev_id; unsigned short irqstat; - int pos; + int x_pos, pos; spin_lock(&uart->port.lock); irqstat = get_dma_curr_irqstat(uart->rx_dma_channel); clear_dma_irqstat(uart->rx_dma_channel); uart->rx_dma_nrows = get_dma_curr_ycount(uart->rx_dma_channel); + x_pos = get_dma_curr_xcount(uart->rx_dma_channel); uart->rx_dma_nrows = DMA_RX_YCOUNT - uart->rx_dma_nrows; - if (uart->rx_dma_nrows == DMA_RX_YCOUNT) + if (uart->rx_dma_nrows == DMA_RX_YCOUNT || x_pos == 0) uart->rx_dma_nrows = 0; pos = uart->rx_dma_nrows * DMA_RX_XCOUNT; |