[PATCH 1/5] dmaengine: mxs-dma: add dma support for i.MX23/28

This patch adds dma support for Freescale MXS-based SoC i.MX23/28,
including apbh-dma and apbx-dma.

* apbh-dma and apbx-dma are supported in the driver as two instances,
  and have to be filtered by dma clients via device id.  It becomes
  the convention that apbh-dma always gets registered prior to
  apbx-dma.

* apbh-dma is different between mx23 and mx28, hardware version
  register is used to handle the differences.

* Every the mxs dma channel is statically assigned to client device
  by soc design with fixed irq.  The irq number is being passed by
  alloc_chan function with mxs_dma_data, and client driver has to
  filter the correct channel by its channel id.

* mxs-dma supports pio function besides data transfer.  The driver
  uses dma_data_direction DMA_NONE to identify the pio mode, and
  steals sgl and sg_len to get pio words and numbers from clients.

* mxs dmaengine has some very specific features, like sense function
  and the special NAND support (nand_lock, nand_wait4ready).  These
  are too specific to implemented in generic dmaengine driver.

* The parameter "flags" of prep functions is currently being used to
  pass wait4end flag from clients.

* The driver refers to imx-sdma and only a single descriptor is
  statically assigned to each channel.

Signed-off-by: Shawn Guo <redacted>
---
 arch/arm/mach-mxs/include/mach/dma.h |   16 +
 drivers/dma/Kconfig                  |    8 +
 drivers/dma/Makefile                 |    1 +
 drivers/dma/mxs-dma.c                |  702 ++++++++++++++++++++++++++++++++++
 4 files changed, 727 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/mach-mxs/include/mach/dma.h
 create mode 100644 drivers/dma/mxs-dma.c

diff --git a/arch/arm/mach-mxs/include/mach/dma.h b/arch/arm/mach-mxs/include/mach/dma.h
new file mode 100644
index 0000000..429f431
--- /dev/null
+++ b/arch/arm/mach-mxs/include/mach/dma.h

@@ -0,0 +1,16 @@
+/*
+ * Copyright 2011 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __MACH_MXS_DMA_H__
+#define __MACH_MXS_DMA_H__
+
+struct mxs_dma_data {
+	int chan_irq;
+};