diff options
| -rw-r--r-- | drivers/spi/spi_bfin5xx.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c index b797ece0b10c..88dee87fc420 100644 --- a/drivers/spi/spi_bfin5xx.c +++ b/drivers/spi/spi_bfin5xx.c @@ -761,11 +761,10 @@ static void pump_transfers(unsigned long data) if (!full_duplex && drv_data->cur_chip->enable_dma && drv_data->len > 6) { - unsigned long dma_start_addr; + unsigned long dma_start_addr, flags; disable_dma(drv_data->dma_channel); clear_dma_irqstat(drv_data->dma_channel); - bfin_spi_disable(drv_data); /* config dma channel */ dev_dbg(&drv_data->pdev->dev, "doing dma transfer\n"); @@ -796,8 +795,7 @@ static void pump_transfers(unsigned long data) enable_dma(drv_data->dma_channel); /* start SPI transfer */ - write_CTRL(drv_data, - (cr | BIT_CTL_TIMOD_DMA_TX | BIT_CTL_ENABLE)); + write_CTRL(drv_data, cr | BIT_CTL_TIMOD_DMA_TX); /* just return here, there can only be one transfer * in this mode @@ -842,14 +840,22 @@ static void pump_transfers(unsigned long data) } else BUG(); - /* start dma */ - dma_enable_irq(drv_data->dma_channel); - set_dma_config(drv_data->dma_channel, dma_config); + /* oh man, here there be monsters ... and i dont mean the + * fluffy cute ones from pixar, i mean the kind that'll eat + * your data, kick your dog, and love it all. do *not* try + * and change these lines unless you (1) heavily test DMA + * with SPI flashes on a loaded system (e.g. ping floods), + * (2) know just how broken the DMA engine interaction with + * the SPI peripheral is, and (3) have someone else to blame + * when you screw it all up anyways. + */ set_dma_start_addr(drv_data->dma_channel, dma_start_addr); + set_dma_config(drv_data->dma_channel, dma_config); + local_irq_save(flags); enable_dma(drv_data->dma_channel); - - /* start SPI transfer */ - write_CTRL(drv_data, (cr | BIT_CTL_ENABLE)); + write_CTRL(drv_data, cr); + dma_enable_irq(drv_data->dma_channel); + local_irq_restore(flags); } else { /* IO mode write then read */ |