[PATCH 0/5] Support for QCA BAM DMA command descriptor

From: Abhishek Sahu
Date: Thu Dec 15 2016 - 04:56:31 EST

These patches mainly adds the support for QCA BAM command
descriptor and per SG flags which are required for implementing
BAM DMA support for some QCA peripherals like QPIC NAND/LCD.

The BAM command descriptors perform all register reads and writes
while data descriptors do data transfer. The QPIC NAND forms the
chain of command and data descriptors for full page read/write and
submit it to BAM DMA.

Following are the limitation of existing DMA mapping function which
forces us to go for separate DMA custom mapping function and SG.

1. BAM descriptor has multiple flags which cannot be mapped with
generic DMA engine flags.
2. For each page code word i.e 512 bytes, approx 10-15 register
read/writes are required. The NAND driver combines all these into
SGL and submit it to BAM. Each register read/writes require
different flags and the current generic SG does not have field to
set dma flags for each SG. We cannot add flag parameter in generic
SG since it is being used by different subsystems across linux

So these patches add custom mapping function, QCA specific SG which
has dma flag for each SG and its DMA mapping functions. With these,
peripheral driver can set per SG flag and submit it to custom DMA
mapping function.

Abhishek Sahu (5):
dmaengine: qca: bam_dma: Add header file for bam driver
dmaengine: Add support for custom data mapping
dmaengine: qca: bam_dma: Add support for bam sgl
dmaengine: qca: bam_dma: implement custom data mapping
dmaengine: qca: bam_dma: implement command descriptor

drivers/dma/qcom/bam_dma.c | 98 +++++++++++++++++++++--
include/linux/dma/qcom_bam_dma.h | 162 +++++++++++++++++++++++++++++++++++++++
include/linux/dmaengine.h | 5 ++
3 files changed, 258 insertions(+), 7 deletions(-)
create mode 100644 include/linux/dma/qcom_bam_dma.h

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