[U-Boot] [PATCH 0/5] Add DMA driver for DMA330 controller

[Chee, Tien Fong]

On Thu, 2018-05-31 at 11:58 +0200, Marek Vasut wrote:
> On 05/31/2018 11:50 AM, See, Chin Liang wrote:
> > 
> > On Thu, 2018-05-31 at 11:24 +0200, Marek Vasut wrote:
> > > 
> > > On 05/31/2018 10:08 AM, tien.fong.chee at intel.com wrote:
> > > > 
> > > > 
> > > > From: Tien Fong Chee <tien.fong.chee at intel.com>
> > > > 
> > > > This patchset contains dm driver for DMA330 controller.
> > > > 
> > > > This series is working on top of u-boot-socfpga.git -
> > > >  http://git.denx.de/u-boot.git .
> > > > 
> > > > Tien Fong Chee (5):
> > > >   drivers: dma: Enable DMA-330 driver support
> > > >   drivers: dma: Add function to zeroes a range of destination
> > > > such
> > > > as
> > > >     memory
> > > >   drivers: dma: Factor out dma_get_device from DMA class
> > > > function
> > > >   include: dma: Update the function description for dma_memcpy
> > > >   arm: dts: socfpga: stratix10: update pdma
> > > > 
> > > >  arch/arm/dts/socfpga_stratix10.dtsi |   20 +
> > > >  drivers/dma/Kconfig                 |    9 +-
> > > >  drivers/dma/Makefile                |    1 +
> > > >  drivers/dma/dma-uclass.c            |   23 +-
> > > >  drivers/dma/dma330.c                | 1514
> > > > +++++++++++++++++++++++++++++++++++
> > > >  drivers/mtd/spi/spi_flash.c         |    9 +-
> > > >  include/dma.h                       |   19 +-
> > > >  include/dma330.h                    |  136 ++++
> > > >  8 files changed, 1719 insertions(+), 12 deletions(-)
> > > >  create mode 100644 drivers/dma/dma330.c
> > > >  create mode 100644 include/dma330.h
> > > > 
> > > I presume this is to zero-out the ECC RAM ? Just enable caches
> > > and
> > > use
> > > memset, it is much faster than this DMA witchcraft, at least on
> > > the
> > > A10.
> > Yes and no :) 
> > 
> > The patch enable DMA-330 support and also zero-out ECC RAM. 
> Right, that's what I said ?
> 
This driver also enable source to destination transferring through DMA.
> > 
> > While for the speed, DMA still faster as it has larger burst size.
> It takes ~0.9s to erase 2 GiB of RAM on the A10. How fast is the DMA?
> 
That is pretty fast. Using DMA dm on Stratix 10 also need around 3-4s
for 2GiB DRAM.

Would you mind to share us the codes for enabling the both cache and
MMU in SPL. I would like to replicate your changes at Stratix 10 for
the performance measurement.
> > 
> > We
> > can also parallel the zero out task with other tasks such as flash
> > controller init.
> The flash controller also needs some zeroing out ?
> 
I believe what Chin Liang saying is CPU is free to do other HW
initialization while DMA is zeroing the DRAM.

However, current driver is blocking, which means CPU has to wait the
DMA finish transferring.

I can pull the DMA transfer status check function out as a new class
function so user can check the DMA status at anytime.