The current davinci SPI driver, in DMA mode, is limited to 65535 words for a single transfer. Modify the driver by configuring a 3 dimensional EDMA transfer to support up to 65535x65535 words.
Signed-off-by: Michael Williamson <[email protected]> --- This patch is an attempt to address the issue raised here: http://comments.gmane.org/gmane.linux.davinci/20581 Tested with: dd if=/dev/mtd7 of=/tmp/test.1K bs=1024 count=1024 dd if=/dev/mtd7 of=/tmp/test.64K bs=65536 count=16 dd if=/dev/mtd7 of=/tmp/test.128K bs=131072 count=8 md5sum /tmp/test* drivers/spi/davinci_spi.c | 33 +++++++++++++++++++++++++-------- 1 files changed, 25 insertions(+), 8 deletions(-) diff --git a/drivers/spi/davinci_spi.c b/drivers/spi/davinci_spi.c index 037ba82..411cc32 100644 --- a/drivers/spi/davinci_spi.c +++ b/drivers/spi/davinci_spi.c @@ -571,6 +571,7 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t) unsigned long tx_reg, rx_reg; struct edmacc_param param; void *rx_buf; + int b, c; dma = &dspi->dma; @@ -599,14 +600,30 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t) } } + /* + * If number of words is greater than 65535, then we need + * to configure a 3 dimension transfer. Use the BCNTRLD + * feature to allow for transfers that aren't even multiples + * of 65535 (or any other possible b size) by first transferring + * the remainder amount then grabbing the next N blocks of + * 65535 words. + */ + + c = dspi->wcount/(SZ_64K-1); /* N 65535 count Blocks */ + b = dspi->wcount-c*(SZ_64K-1); /* Remainder */ + if (b) + c++; + else + b = SZ_64K-1; + param.opt = TCINTEN | EDMA_TCC(dma->tx_channel); param.src = t->tx_buf ? t->tx_dma : tx_reg; - param.a_b_cnt = dspi->wcount << 16 | data_type; + param.a_b_cnt = b << 16 | data_type; param.dst = tx_reg; param.src_dst_bidx = t->tx_buf ? data_type : 0; - param.link_bcntrld = 0xffff; - param.src_dst_cidx = 0; - param.ccnt = 1; + param.link_bcntrld = 0xffffffff; + param.src_dst_cidx = t->tx_buf ? data_type : 0; + param.ccnt = c; edma_write_slot(dma->tx_channel, ¶m); edma_link(dma->tx_channel, dma->dummy_param_slot); @@ -643,12 +660,12 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t) param.opt = TCINTEN | EDMA_TCC(dma->rx_channel); param.src = rx_reg; - param.a_b_cnt = dspi->rcount << 16 | data_type; + param.a_b_cnt = b << 16 | data_type; param.dst = t->rx_dma; param.src_dst_bidx = (t->rx_buf ? data_type : 0) << 16; - param.link_bcntrld = 0xffff; - param.src_dst_cidx = 0; - param.ccnt = 1; + param.link_bcntrld = 0xffffffff; + param.src_dst_cidx = (t->rx_buf ? data_type : 0) << 16; + param.ccnt = c; edma_write_slot(dma->rx_channel, ¶m); if (pdata->cshold_bug) -- 1.7.0.4 _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
