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authorMaxime Ripard <maxime.ripard@free-electrons.com>2014-11-17 14:42:55 +0100
committerVinod Koul <vinod.koul@intel.com>2014-12-22 12:34:22 +0530
commit1faab1f2e3be3a10197840648d03a31fd0a29e93 (patch)
tree49e303cadf1197f00161c9371abe3326790f24bf /Documentation/dmaengine
parent2c44ad914c56f4e53ef43285b5e4fe3459109769 (diff)
downloadlinux-aarch64-1faab1f2e3be3a10197840648d03a31fd0a29e93.tar.gz
Documentation: dmaengine: Update the documentation
Now that we have splitted device_control and removed device_slave_caps in favor of a few dma_device variables, update the documentation accordingly. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'Documentation/dmaengine')
-rw-r--r--Documentation/dmaengine/provider.txt93
1 files changed, 51 insertions, 42 deletions
diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt
index 766658ccf235..2c391cfe37eb 100644
--- a/Documentation/dmaengine/provider.txt
+++ b/Documentation/dmaengine/provider.txt
@@ -113,6 +113,31 @@ need to initialize a few fields in there:
* channels: should be initialized as a list using the
INIT_LIST_HEAD macro for example
+ * src_addr_widths:
+ - should contain a bitmask of the supported source transfer width
+
+ * dst_addr_widths:
+ - should contain a bitmask of the supported destination transfer
+ width
+
+ * directions:
+ - should contain a bitmask of the supported slave directions
+ (i.e. excluding mem2mem transfers)
+
+ * residue_granularity:
+ - Granularity of the transfer residue reported to dma_set_residue.
+ - This can be either:
+ + Descriptor
+ -> Your device doesn't support any kind of residue
+ reporting. The framework will only know that a particular
+ transaction descriptor is done.
+ + Segment
+ -> Your device is able to report which chunks have been
+ transferred
+ + Burst
+ -> Your device is able to report which burst have been
+ transferred
+
* dev: should hold the pointer to the struct device associated
to your current driver instance.
@@ -274,48 +299,32 @@ supported.
account the current period.
- This function can be called in an interrupt context.
- * device_control
- - Used by client drivers to control and configure the channel it
- has a handle on.
- - Called with a command and an argument
- + The command is one of the values listed by the enum
- dma_ctrl_cmd. The valid commands are:
- + DMA_PAUSE
- + Pauses a transfer on the channel
- + This command should operate synchronously on the channel,
- pausing right away the work of the given channel
- + DMA_RESUME
- + Restarts a transfer on the channel
- + This command should operate synchronously on the channel,
- resuming right away the work of the given channel
- + DMA_TERMINATE_ALL
- + Aborts all the pending and ongoing transfers on the
- channel
- + This command should operate synchronously on the channel,
- terminating right away all the channels
- + DMA_SLAVE_CONFIG
- + Reconfigures the channel with passed configuration
- + This command should NOT perform synchronously, or on any
- currently queued transfers, but only on subsequent ones
- + In this case, the function will receive a
- dma_slave_config structure pointer as an argument, that
- will detail which configuration to use.
- + Even though that structure contains a direction field,
- this field is deprecated in favor of the direction
- argument given to the prep_* functions
- + FSLDMA_EXTERNAL_START
- + TODO: Why does that even exist?
- + The argument is an opaque unsigned long. This actually is a
- pointer to a struct dma_slave_config that should be used only
- in the DMA_SLAVE_CONFIG.
-
- * device_slave_caps
- - Called through the framework by client drivers in order to have
- an idea of what are the properties of the channel allocated to
- them.
- - Such properties are the buswidth, available directions, etc.
- - Required for every generic layer doing DMA transfers, such as
- ASoC.
+ * device_config
+ - Reconfigures the channel with the configuration given as
+ argument
+ - This command should NOT perform synchronously, or on any
+ currently queued transfers, but only on subsequent ones
+ - In this case, the function will receive a dma_slave_config
+ structure pointer as an argument, that will detail which
+ configuration to use.
+ - Even though that structure contains a direction field, this
+ field is deprecated in favor of the direction argument given to
+ the prep_* functions
+
+ * device_pause
+ - Pauses a transfer on the channel
+ - This command should operate synchronously on the channel,
+ pausing right away the work of the given channel
+
+ * device_resume
+ - Resumes a transfer on the channel
+ - This command should operate synchronously on the channel,
+ pausing right away the work of the given channel
+
+ * device_terminate_all
+ - Aborts all the pending and ongoing transfers on the channel
+ - This command should operate synchronously on the channel,
+ terminating right away all the channels
Misc notes (stuff that should be documented, but don't really know
where to put them)