Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d6fe89b0630080e2bd6ece20ff7b1b5c2647ed62
Commit: d6fe89b0630080e2bd6ece20ff7b1b5c2647ed62
Parent: 27bb9e79bcfedc1888d23c3c212c189fa8534fe7
Author: Bryan Wu <[EMAIL PROTECTED]>
AuthorDate: Mon Jun 11 17:34:17 2007 +0800
Committer: Bryan Wu <[EMAIL PROTECTED]>
CommitDate: Mon Jun 11 17:34:17 2007 +0800
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 <[EMAIL PROTECTED]>
Signed-off-by: Bryan Wu <[EMAIL PROTECTED]>
---
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 a2d4884..48587c2 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;
}
-
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