diff options
| author | Bryan Wu <bryan.wu@analog.com> | 2007-06-11 13:34:17 +0400 |
|---|---|---|
| committer | Bryan Wu <bryan.wu@analog.com> | 2007-06-11 13:34:17 +0400 |
| commit | d6fe89b0630080e2bd6ece20ff7b1b5c2647ed62 (patch) | |
| tree | ebccbeacb2e2fa2c5ee5319e60465cdcb7194999 | |
| parent | 27bb9e79bcfedc1888d23c3c212c189fa8534fe7 (diff) | |
| download | linux-d6fe89b0630080e2bd6ece20ff7b1b5c2647ed62.tar.xz | |
Blackfin SPI driver: fix bug SPI DMA incomplete transmission
SPI writes intermittently drop bytes at end of DMA transfer
http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=3205
http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=2892
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
| -rw-r--r-- | drivers/spi/spi_bfin5xx.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c index a2d4884752ef..48587c27050d 100644 --- a/drivers/spi/spi_bfin5xx.c +++ b/drivers/spi/spi_bfin5xx.c @@ -582,14 +582,19 @@ static irqreturn_t dma_irq_handler(int irq, void *dev_id) dev_dbg(&drv_data->pdev->dev, "in dma_irq_handler\n"); clear_dma_irqstat(CH_SPI); + /* Wait for DMA to complete */ + while (get_dma_curr_irqstat(CH_SPI) & DMA_RUN) + continue; + /* - * wait for the last transaction shifted out. yes, these two - * while loops are supposed to be the same (see the HRM). + * wait for the last transaction shifted out. HRM states: + * at this point there may still be data in the SPI DMA FIFO waiting + * to be transmitted ... software needs to poll TXS in the SPI_STAT + * register until it goes low for 2 successive reads */ if (drv_data->tx != NULL) { - while (bfin_read_SPI_STAT() & TXS) - continue; - while (bfin_read_SPI_STAT() & TXS) + while ((bfin_read_SPI_STAT() & TXS) || + (bfin_read_SPI_STAT() & TXS)) continue; } |