On Sat, Sep 13, 2014 at 09:53:00PM +0800, Chen-Yu Tsai wrote: > The A23 SoC has the same dma engine as the A31 (sun6i), with a > reduced amount of endpoints and physical channels. Add the proper > config data and compatible string to support it. > > A slight difference in sun8i is an undocumented register needs > to be toggled for dma to function. > > Signed-off-by: Chen-Yu Tsai <[email protected]> > --- > Documentation/devicetree/bindings/dma/sun6i-dma.txt | 2 +- > drivers/dma/Kconfig | 4 ++-- > drivers/dma/sun6i-dma.c | 20 ++++++++++++++++++++ > 3 files changed, 23 insertions(+), 3 deletions(-) > > diff --git a/Documentation/devicetree/bindings/dma/sun6i-dma.txt > b/Documentation/devicetree/bindings/dma/sun6i-dma.txt > index 3e145c1..9cdcba24d 100644 > --- a/Documentation/devicetree/bindings/dma/sun6i-dma.txt > +++ b/Documentation/devicetree/bindings/dma/sun6i-dma.txt > @@ -4,7 +4,7 @@ This driver follows the generic DMA bindings defined in > dma.txt. > > Required properties: > > -- compatible: Must be "allwinner,sun6i-a31-dma" > +- compatible: Must be "allwinner,sun6i-a31-dma" or > "allwinner,sun8i-a23-dma" > - reg: Should contain the registers base address and length > - interrupts: Should contain a reference to the interrupt used by > this device > - clocks: Should contain a reference to the parent AHB clock > diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig > index 9b1ea0e..5361aa7 100644 > --- a/drivers/dma/Kconfig > +++ b/drivers/dma/Kconfig > @@ -395,12 +395,12 @@ config XILINX_VDMA > > config DMA_SUN6I > tristate "Allwinner A31 SoCs DMA support" > - depends on MACH_SUN6I || COMPILE_TEST > + depends on MACH_SUN6I || MACH_SUN8I || COMPILE_TEST > depends on RESET_CONTROLLER > select DMA_ENGINE > select DMA_VIRTUAL_CHANNELS > help > - Support for the DMA engine for Allwinner A31 SoCs. > + Support for the DMA engine first found in Allwinner A31 SoCs. > > config NBPFAXI_DMA > tristate "Renesas Type-AXI NBPF DMA support" > diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c > index 89ca0c4..29667dd 100644 > --- a/drivers/dma/sun6i-dma.c > +++ b/drivers/dma/sun6i-dma.c > @@ -878,8 +878,20 @@ static struct sun6i_dma_config sun6i_a31_dma_cfg = { > .nr_max_vchans = 53, > }; > > +/* > + * The A23 only has 8 physical channels, a maximum DRQ port id of 24, > + * and a total of 37 usable source and destination endpoints. > + */ > + > +static struct sun6i_dma_config sun8i_a23_dma_cfg = { > + .nr_max_channels = 8, > + .nr_max_requests = 24, > + .nr_max_vchans = 37, > +}; > + > static struct of_device_id sun6i_dma_match[] = { > { .compatible = "allwinner,sun6i-a31-dma", .data = &sun6i_a31_dma_cfg }, > + { .compatible = "allwinner,sun8i-a23-dma", .data = &sun8i_a23_dma_cfg }, > { /* sentinel */ } > }; > > @@ -1008,6 +1020,14 @@ static int sun6i_dma_probe(struct platform_device > *pdev) > goto err_dma_unregister; > } > > + /* > + * sun8i variant requires us to toggle an undocumented register, > + * as seen in Allwinner's SDK.
The BSP I have has this:
static void sunxi_dma_hw_init(struct sunxi_dmadev *dev)
{
struct sunxi_dmadev *sunxi_dev = dev;
clk_prepare_enable(sunxi_dev->ahb_clk);
#ifdef CONFIG_ARCH_SUN8IW3
writel(0x04, sunxi_dev->base + DMA_GATE);
#endif
}
/* All is ok, and open the clock */
sunxi_dma_hw_init(sunxi_dev);
So I guess we can say that it's not that undocumented :)
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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