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 mxs-dma
  instances.

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

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

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 1c28816152fa..76f6472ba315 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -227,6 +227,14 @@ config IMX_DMA
           Support the i.MX DMA engine. This engine is integrated into
           Freescale i.MX1/21/27 chips.
 
+config MXS_DMA
+        bool "MXS DMA support"
+        depends on SOC_IMX23 || SOC_IMX28
+        select DMA_ENGINE
+        help
+          Support the MXS DMA engine. This engine including APBH-DMA
+          and APBX-DMA is integrated into Freescale i.MX23/28 chips.
+
 config DMA_ENGINE
         bool