diff options
| author | Ludovic Desroches <ludovic.desroches@atmel.com> | 2013-06-13 10:39:39 +0200 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2013-07-05 11:40:54 +0530 |
| commit | 62971b29825adb06908bad81e7679d1f7904b24d (patch) | |
| tree | 6b2c29be1793d6c60ac80a4abc8686aee10dcc47 | |
| parent | 764037c6f55c5c844d0ab6049e6e7c0dc3cb7665 (diff) | |
dmaengine: at_hdmac: add FIFO configuration parameter to DMA DT binding
For most devices the FIFO configuration is the same i.e. when half FIFO size is
available/filled, a source/destination request is serviced. But USART devices
have to do it when there is enough space/data available to perform a single
AHB access so the ASAP configuration.
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
| -rw-r--r-- | Documentation/devicetree/bindings/dma/atmel-dma.txt | 7 | ||||
| -rw-r--r-- | drivers/dma/at_hdmac.c | 25 |
2 files changed, 26 insertions, 6 deletions
diff --git a/Documentation/devicetree/bindings/dma/atmel-dma.txt b/Documentation/devicetree/bindings/dma/atmel-dma.txt index c80e8a3402f0..c280a0e6f42d 100644 --- a/Documentation/devicetree/bindings/dma/atmel-dma.txt +++ b/Documentation/devicetree/bindings/dma/atmel-dma.txt @@ -24,8 +24,11 @@ The three cells in order are: 1. A phandle pointing to the DMA controller. 2. The memory interface (16 most significant bits), the peripheral interface (16 less significant bits). -3. The peripheral identifier for the hardware handshaking interface. The -identifier can be different for tx and rx. +3. Parameters for the at91 DMA configuration register which are device +dependant: + - bit 7-0: peripheral identifier for the hardware handshaking interface. The + identifier can be different for tx and rx. + - bit 11-8: FIFO configuration. 0 for half FIFO, 1 for ALAP, 1 for ASAP. Example: diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 6db5228f4134..b7050a46bd87 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -14,6 +14,7 @@ * found on AT91SAM9263. */ +#include <dt-bindings/dma/at91.h> #include <linux/clk.h> #include <linux/dmaengine.h> #include <linux/dma-mapping.h> @@ -1320,15 +1321,31 @@ static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec, atslave = devm_kzalloc(&dmac_pdev->dev, sizeof(*atslave), GFP_KERNEL); if (!atslave) return NULL; + + atslave->cfg = ATC_DST_H2SEL_HW | ATC_SRC_H2SEL_HW; /* * We can fill both SRC_PER and DST_PER, one of these fields will be * ignored depending on DMA transfer direction. */ - per_id = dma_spec->args[1]; - atslave->cfg = ATC_FIFOCFG_HALFFIFO - | ATC_DST_H2SEL_HW | ATC_SRC_H2SEL_HW - | ATC_DST_PER_MSB(per_id) | ATC_DST_PER(per_id) + per_id = dma_spec->args[1] & AT91_DMA_CFG_PER_ID_MASK; + atslave->cfg |= ATC_DST_PER_MSB(per_id) | ATC_DST_PER(per_id) | ATC_SRC_PER_MSB(per_id) | ATC_SRC_PER(per_id); + /* + * We have to translate the value we get from the device tree since + * the half FIFO configuration value had to be 0 to keep backward + * compatibility. + */ + switch (dma_spec->args[1] & AT91_DMA_CFG_FIFOCFG_MASK) { + case AT91_DMA_CFG_FIFOCFG_ALAP: + atslave->cfg |= ATC_FIFOCFG_LARGESTBURST; + break; + case AT91_DMA_CFG_FIFOCFG_ASAP: + atslave->cfg |= ATC_FIFOCFG_ENOUGHSPACE; + break; + case AT91_DMA_CFG_FIFOCFG_HALF: + default: + atslave->cfg |= ATC_FIFOCFG_HALFFIFO; + } atslave->dma_dev = &dmac_pdev->dev; chan = dma_request_channel(mask, at_dma_filter, atslave); |