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Blackfin SPI Driver: ensure cache coherency before doing DMA

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Flush or invalidate caches before doing DMA transfer, if needed.

[Mike Frysinger <[email protected]>: add comment to address the
issue "Full duplex only works for non-DMA transfers".]
Signed-off-by: Vitja Makarov <[email protected]>
Signed-off-by: Mike Frysinger <[email protected]>
Signed-off-by: Bryan Wu <[email protected]>
Cc: David Brownell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Vitja Makarov 2009-04-06 19:00:31 -07:00 • committed by Linus Torvalds
commit 8cf5858c51
1 changed files with 20 additions and 3 deletions
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23
drivers/spi/spi_bfin5xx.c
View file

@ -26,6 +26,10 @@
#include <asm/portmux.h>
#include <asm/bfin5xx_spi.h>
/* reserved_mem_dcache_on and cache friends */
#include <asm/cplbinit.h>
#include <asm/cacheflush.h>
#define DRV_NAME "bfin-spi"
#define DRV_AUTHOR "Bryan Wu, Luke Yang"
#define DRV_DESC "Blackfin BF5xx on-chip SPI Controller Driver"
@ -738,9 +742,10 @@ static void pump_transfers(unsigned long data)
width, transfer->len);
/*
* Try to map dma buffer and do a dma transfer if
* successful use different way to r/w according to
* drv_data->cur_chip->enable_dma
* Try to map dma buffer and do a dma transfer. If successful use,
* different way to r/w according to the enable_dma settings and if
* we are not doing a full duplex transfer (since the hardware does
* not support full duplex DMA transfers).
*/
if (!full_duplex && drv_data->cur_chip->enable_dma
&& drv_data->len > 6) {
@ -795,6 +800,12 @@ static void pump_transfers(unsigned long data)
/* set transfer mode, and enable SPI */
dev_dbg(&drv_data->pdev->dev, "doing DMA in.\n");
/* invalidate caches, if needed */
if (bfin_addr_dcachable((unsigned long) drv_data->rx))
invalidate_dcache_range((unsigned long) drv_data->rx,
(unsigned long) (drv_data->rx +
drv_data->len));
/* clear tx reg soformer data is not shifted out */
write_TDBR(drv_data, 0xFFFF);
@ -815,6 +826,12 @@ static void pump_transfers(unsigned long data)
} else if (drv_data->tx != NULL) {
dev_dbg(&drv_data->pdev->dev, "doing DMA out.\n");
/* flush caches, if needed */
if (bfin_addr_dcachable((unsigned long) drv_data->tx))
flush_dcache_range((unsigned long) drv_data->tx,
(unsigned long) (drv_data->tx +
drv_data->len));
/* start dma */
dma_enable_irq(drv_data->dma_channel);
dma_config = (RESTART | dma_width | DI_EN);