Commit Graph

5 Commits

Author SHA1 Message Date
Andy Shevchenko 39d1447811 acpi-dma: align documentation with kernel-doc format
It mostly fixes the "RETURN" sections in the resulting manual page.

There is no functional change.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-01-26 17:33:57 +05:30
Andy Shevchenko b4d6d33676 acpi-dma: remove ugly conversion
In case of big endian CPU we have to convert either all fields in the structure
or leave this job to ACPICA. The second choice seems the best.

So, let's remove the ugly conversion that is not fully comprehensive anyway.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-08-25 16:43:45 +05:30
Andy Shevchenko 4aed508fc5 acpi-dma: fix sparse warning
This patch fixes sparse warning:
	drivers/dma/acpi-dma.c:76:21: sparse: cast to restricted __le32

Since everything in all ACPI tables is little-endian, by definition, the used
types in practice are uXX. Thus, we have to enforce __leXX if we want to
convert them to CPU order.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-08-05 09:32:25 +05:30
Andy Shevchenko ee8209fd02 dma: acpi-dma: parse CSRT to extract additional resources
Since we have CSRT only to get additional DMA controller resources, let's get
rid of drivers/acpi/csrt.c and move its logic inside ACPI DMA helpers code.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-05-14 10:23:57 +05:30
Andy Shevchenko 1b2e98bc1e dma: acpi-dma: introduce ACPI DMA helpers
There is a new generic API to get a DMA channel for a slave device (commit
9a6cecc8 "dmaengine: add helper function to request a slave DMA channel"). In
similar fashion to the DT case (commit aa3da644 "of: Add generic device tree
DMA helpers") we introduce helpers to the DMAC drivers which are enumerated by
ACPI.

The proposed extension provides the following API calls:
	acpi_dma_controller_register(), devm_acpi_dma_controller_register()
	acpi_dma_controller_free(), devm_acpi_dma_controller_free()
	acpi_dma_simple_xlate()
	acpi_dma_request_slave_chan_by_index()
	acpi_dma_request_slave_chan_by_name()

The first two should be used, for example, at probe() and remove() of the
corresponding DMAC driver. At the register stage the DMAC driver supplies a
custom xlate() function to translate a struct dma_spec into struct dma_chan.

Accordingly to the ACPI Fixed DMA resource specification the only two pieces of
information the slave device has are the channel id and the request line (slave
id). Those two are represented by struct dma_spec. The
acpi_dma_request_slave_chan_by_index() provides access to the specifix FixedDMA
resource by its index. Whereas dma_request_slave_channel() takes a string
parameter to identify the DMA resources required by the slave device. To make a
slave device driver work with both DeviceTree and ACPI enumeration a simple
convention is established: "tx" corresponds to the index 0 and "rx" to the
index 1. In case of robust configuration the slave device driver unfortunately
needs to call acpi_dma_request_slave_chan_by_index() directly.

Additionally the patch provides "managed" version of the register/free pair
i.e. devm_acpi_dma_controller_register() and devm_acpi_dma_controller_free().
Usually, the driver uses only devm_acpi_dma_controller_register().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2013-04-15 22:04:10 +05:30