[PATCH v5 07/14] dmaengine: add dma_request_slave_channel_compat()
From: arnd@arndb.de (Arnd Bergmann)
Date: 2013-01-23 22:29:40
Also in:
linux-devicetree, linux-mmc, linux-omap, linux-spi, lkml
Subsystem:
dma generic offload engine subsystem, the rest · Maintainers:
Vinod Koul, Linus Torvalds
On Tuesday 15 January 2013, Matt Porter wrote:
Adds a dma_request_slave_channel_compat() wrapper which accepts both the arguments from dma_request_channel() and dma_request_slave_channel(). Based on whether the driver is instantiated via DT, the appropriate channel request call will be made. This allows for a much cleaner migration of drivers to the dmaengine DT API as platforms continue to be mixed between those that boot using DT and those that do not.
I noticed today some drivers in linux-next that rely on this patch, but the patch itself still missing from -next.
quoted hunk ↗ jump to hunk
--- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h@@ -1047,6 +1047,16 @@ void dma_run_dependencies(struct dma_async_tx_descriptor *tx); struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type); struct dma_chan *net_dma_find_channel(void); #define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y) +static inline struct dma_chan +*dma_request_slave_channel_compat(dma_cap_mask_t mask, dma_filter_fn fn, + void *fn_param, struct device *dev, + char *name) +{ + if (dev->of_node) + return dma_request_slave_channel(dev, name); + else + return dma_request_channel(mask, fn, fn_param); +}
Hmm, dma_request_channel is actually a macro that passes mask by reference, presumably because it can get modified by the filter function. Also, there may be cases where we do have an of_node but don't use the dma binding yet, or where dma_request_slave_channel doesn't actually use DT information but rather one of the other methods that Vinod was talking about adding. I think what it should look like instead is the below. Arnd
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index bfcdecb..b6ffd7d 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h@@ -993,6 +993,19 @@ static inline void dma_release_channel(struct dma_chan *chan) } #endif +static inline struct dma_chan *__dma_request_slave_channel_compat(dma_cap_mask_t *mask, + dma_filter_fn fn, void *fn_param, struct device *dev, + char *name) +{ + struct dma_chan *chan; + + chan = dma_request_slave_channel(dev, name); + if (chan) + return chan; + + return __dma_request_channel(mask, fn, fn_param); +} + /* --- DMA device --- */ int dma_async_device_register(struct dma_device *device);
@@ -1001,6 +1014,8 @@ void dma_run_dependencies(struct dma_async_tx_descriptor *tx); struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type); struct dma_chan *net_dma_find_channel(void); #define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y) +#define dma_request_slave_channel_compat(mask, x, y, dev, name) \ + __dma_request_slave_channel_compat(&(mask), x, y, dev, name) /* --- Helper iov-locking functions --- */