Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma

drivers/acpi/acpi_platform.c. This limitation is only for the platform

devices, SPI and I2C devices are created automatically as described below.

DMA support

~~~~~~~~~~~

DMA controllers enumerated via ACPI should be registered in the system to

provide generic access to their resources. For example, a driver that would

like to be accessible to slave devices via generic API call

dma_request_slave_channel() must register itself at the end of the probe

function like this:

	err = devm_acpi_dma_controller_register(dev, xlate_func, dw);

	/* Handle the error if it's not a case of !CONFIG_ACPI */

and implement custom xlate function if needed (usually acpi_dma_simple_xlate()

is enough) which converts the FixedDMA resource provided by struct

acpi_dma_spec into the corresponding DMA channel. A piece of code for that case

could look like:

	#ifdef CONFIG_ACPI

	struct filter_args {

		/* Provide necessary information for the filter_func */

		...

	};

	static bool filter_func(struct dma_chan *chan, void *param)

	{

		/* Choose the proper channel */

		...

	}

	static struct dma_chan *xlate_func(struct acpi_dma_spec *dma_spec,

			struct acpi_dma *adma)

	{

		dma_cap_mask_t cap;

		struct filter_args args;

		/* Prepare arguments for filter_func */

		...

		return dma_request_channel(cap, filter_func, &args);

	}

	#else

	static struct dma_chan *xlate_func(struct acpi_dma_spec *dma_spec,

			struct acpi_dma *adma)

	{

		return NULL;

	}

	#endif

dma_request_slave_channel() will call xlate_func() for each registered DMA

controller. In the xlate function the proper channel must be chosen based on

information in struct acpi_dma_spec and the properties of the controller

provided by struct acpi_dma.

Clients must call dma_request_slave_channel() with the string parameter that

corresponds to a specific FixedDMA resource. By default "tx" means the first

entry of the FixedDMA resource array, "rx" means the second entry. The table

below shows a layout:

	Device (I2C0)

	{

		...

		Method (_CRS, 0, NotSerialized)

		{

			Name (DBUF, ResourceTemplate ()

			{

				FixedDMA (0x0018, 0x0004, Width32bit, _Y48)

				FixedDMA (0x0019, 0x0005, Width32bit, )

			})

		...

		}

	}

So, the FixedDMA with request line 0x0018 is "tx" and next one is "rx" in

this example.

In robust cases the client unfortunately needs to call

acpi_dma_request_slave_chan_by_index() directly and therefore choose the

specific FixedDMA resource by its index.

SPI serial bus support

~~~~~~~~~~~~~~~~~~~~~~

Slave devices behind SPI bus have SpiSerialBus resource attached to them.

* Atmel Direct Memory Access Controller (DMA)

Required properties:

- compatible: Should be "atmel,<chip>-dma"

- reg: Should contain DMA registers location and length

- interrupts: Should contain DMA interrupt

- compatible: Should be "atmel,<chip>-dma".

- reg: Should contain DMA registers location and length.

- interrupts: Should contain DMA interrupt.

- #dma-cells: Must be <2>, used to represent the number of integer cells in

the dmas property of client devices.

Examples:

Example:

dma@ffffec00 {

dma0: dma@ffffec00 {

	compatible = "atmel,at91sam9g45-dma";

	reg = <0xffffec00 0x200>;

	interrupts = <21>;

	#dma-cells = <2>;

};

DMA clients connected to the Atmel DMA controller must use the format

described in the dma.txt file, using a three-cell specifier for each channel:

a phandle plus two interger cells.

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.

Example:

i2c0@i2c@f8010000 {

	compatible = "atmel,at91sam9x5-i2c";

	reg = <0xf8010000 0x100>;

	interrupts = <9 4 6>;

	dmas = <&dma0 1 7>,

	       <&dma0 1 8>;

	dma-names = "tx", "rx";

};

				DMA Test Guide

				==============

		Andy Shevchenko <andriy.shevchenko@linux.intel.com>

This small document introduces how to test DMA drivers using dmatest module.

	Part 1 - How to build the test module

The menuconfig contains an option that could be found by following path:

	Device Drivers -> DMA Engine support -> DMA Test client

In the configuration file the option called CONFIG_DMATEST. The dmatest could

be built as module or inside kernel. Let's consider those cases.

	Part 2 - When dmatest is built as a module...

After mounting debugfs and loading the module, the /sys/kernel/debug/dmatest

folder with nodes will be created. They are the same as module parameters with

addition of the 'run' node that controls run and stop phases of the test.

Note that in this case test will not run on load automatically.

Example of usage:

	% echo dma0chan0 > /sys/kernel/debug/dmatest/channel

	% echo 2000 > /sys/kernel/debug/dmatest/timeout

	% echo 1 > /sys/kernel/debug/dmatest/iterations

	% echo 1 > /sys/kernel/debug/dmatest/run

Hint: available channel list could be extracted by running the following

command:

	% ls -1 /sys/class/dma/

After a while you will start to get messages about current status or error like

in the original code.

Note that running a new test will stop any in progress test.

The following command should return actual state of the test.

	% cat /sys/kernel/debug/dmatest/run

To wait for test done the user may perform a busy loop that checks the state.

	% while [ $(cat /sys/kernel/debug/dmatest/run) = "Y" ]

	> do

	> 	echo -n "."

	> 	sleep 1

	> done

	> echo

	Part 3 - When built-in in the kernel...

The module parameters that is supplied to the kernel command line will be used

for the first performed test. After user gets a control, the test could be

interrupted or re-run with same or different parameters. For the details see

the above section "Part 2 - When dmatest is built as a module..."

In both cases the module parameters are used as initial values for the test case.

You always could check them at run-time by running

	% grep -H . /sys/module/dmatest/parameters/*

	Part 4 - Gathering the test results

The module provides a storage for the test results in the memory. The gathered

data could be used after test is done.

The special file 'results' in the debugfs represents gathered data of the in

progress test. The messages collected are printed to the kernel log as well.

Example of output:

	% cat /sys/kernel/debug/dmatest/results

	dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)

The message format is unified across the different types of errors. A number in

the parens represents additional information, e.g. error code, error counter,

or status.

Comparison between buffers is stored to the dedicated structure.

Note that the verify result is now accessible only via file 'results' in the

debugfs.

#include <linux/init.h>

#include <linux/device.h>

#include <linux/dma-mapping.h>

#include <linux/of.h>

#include <linux/omap-dma.h>

#include "soc.h"

	if (res)

		return res;

	if (of_have_populated_dt())

		return res;

	pdev = platform_device_register_full(&omap_dma_dev_info);

	if (IS_ERR(pdev))

		return PTR_ERR(pdev);

	depends on PCI && X86

	select DMA_ENGINE

	select DCA

	select ASYNC_TX_DISABLE_PQ_VAL_DMA

	select ASYNC_TX_DISABLE_XOR_VAL_DMA

	help

	  Enable support for the Intel(R) I/OAT DMA engine present

	  in recent Intel Xeon chipsets.

	  This DMA controller transfers data from memory to peripheral fifo

	  or vice versa. It does not support memory to memory data transfer.

config SH_DMAE

	tristate "Renesas SuperH DMAC support"

	depends on (SUPERH && SH_DMA) || (ARM && ARCH_SHMOBILE)

	depends on !SH_DMA_API

	select DMA_ENGINE

	help

	  Enable support for the Renesas SuperH DMA controllers.

source "drivers/dma/sh/Kconfig"

config COH901318

	bool "ST-Ericsson COH901318 DMA support"

config DMA_VIRTUAL_CHANNELS

	tristate

config DMA_ACPI

	def_bool y

	depends on ACPI

config DMA_OF

	def_bool y

	depends on OF