| Message ID | 1360813208-9498-5-git-send-email-padma.v@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Feb 14, 2013 at 09:10:08AM +0530, Padmavathi Venna wrote: > This patch adds #dma-cells property to PL330 DMA controller > nodes for supporting generic dma dt bindings on samsung > exynos5250 platform. Can you comment on the following thread? https://lists.ozlabs.org/pipermail/devicetree-discuss/2013-February/028188.html Describing DMA controllers is part of a wider problem of how to describe bus masters in DT. The key problem is that nobody knows what subset of the bus hierarchy is accessed by a DMA controller (or something else) in its master role. Currently I think that the PCI-oriented standard bindings in the ePAPR specification are not adequate to describe arbitrary SoC platforms, but maybe I'm missing something or being too pessimistic... The "what does a master see" problem is mostly independent of your DMA bindings, except that coherency is not specific to DMA controllers, and ideally we would describe that in a common way for all masters. (Also, in general most devices don't power up coherent -- configuration both in the peripheral and in the bus fabric may be needed before coherency is established). Cheers ---Dave > > Signed-off-by: Padmavathi Venna <padma.v@samsung.com> > Acked-by: Arnd Bergmann <arnd@arndb.de> > --- > .../devicetree/bindings/dma/arm-pl330.txt | 21 +++++++++++++++---- > arch/arm/boot/dts/exynos5250.dtsi | 12 +++++++++++ > 2 files changed, 28 insertions(+), 5 deletions(-) > > diff --git a/Documentation/devicetree/bindings/dma/arm-pl330.txt b/Documentation/devicetree/bindings/dma/arm-pl330.txt > index 36e27d5..2675658 100644 > --- a/Documentation/devicetree/bindings/dma/arm-pl330.txt > +++ b/Documentation/devicetree/bindings/dma/arm-pl330.txt > @@ -10,7 +10,11 @@ Required properties: > - interrupts: interrupt number to the cpu. > > Optional properties: > -- dma-coherent : Present if dma operations are coherent > + - dma-coherent : Present if dma operations are coherent > + - #dma-cells: must be <1>. used to represent the number of integer > + cells in the dmas property of client device. > + - dma-channels: contains the total number of DMA channels supported by the DMAC > + - dma-requests: contains the total number of DMA requests supported by the DMAC > > Example: > > @@ -18,16 +22,23 @@ Example: > compatible = "arm,pl330", "arm,primecell"; > reg = <0x12680000 0x1000>; > interrupts = <99>; > + #dma-cells = <1>; > + #dma-channels = <8>; > + #dma-requests = <32>; > }; > > Client drivers (device nodes requiring dma transfers from dev-to-mem or > -mem-to-dev) should specify the DMA channel numbers using a two-value pair > +mem-to-dev) should specify the DMA channel numbers and dma channel names > as shown below. > > [property name] = <[phandle of the dma controller] [dma request id]>; > + [property name] = <[dma channel name]> > > where 'dma request id' is the dma request number which is connected > - to the client controller. The 'property name' is recommended to be > - of the form <name>-dma-channel. > + to the client controller. The 'property name' 'dmas' and 'dma-names' > + as required by the generic dma device tree binding helpers. The dma > + names correspond 1:1 with the dma request ids in the dmas property. > > - Example: tx-dma-channel = <&pdma0 12>; > + Example: dmas = <&pdma0 12 > + &pdma1 11>; > + dma-names = "tx", "rx"; > diff --git a/arch/arm/boot/dts/exynos5250.dtsi b/arch/arm/boot/dts/exynos5250.dtsi > index 2e3b6ef..c774aae 100644 > --- a/arch/arm/boot/dts/exynos5250.dtsi > +++ b/arch/arm/boot/dts/exynos5250.dtsi > @@ -280,24 +280,36 @@ > compatible = "arm,pl330", "arm,primecell"; > reg = <0x121A0000 0x1000>; > interrupts = <0 34 0>; > + #dma-cells = <1>; > + #dma-channels = <8>; > + #dma-requests = <32>; > }; > > pdma1: pdma@121B0000 { > compatible = "arm,pl330", "arm,primecell"; > reg = <0x121B0000 0x1000>; > interrupts = <0 35 0>; > + #dma-cells = <1>; > + #dma-channels = <8>; > + #dma-requests = <32>; > }; > > mdma0: mdma@10800000 { > compatible = "arm,pl330", "arm,primecell"; > reg = <0x10800000 0x1000>; > interrupts = <0 33 0>; > + #dma-cells = <1>; > + #dma-channels = <8>; > + #dma-requests = <1>; > }; > > mdma1: mdma@11C10000 { > compatible = "arm,pl330", "arm,primecell"; > reg = <0x11C10000 0x1000>; > interrupts = <0 124 0>; > + #dma-cells = <1>; > + #dma-channels = <8>; > + #dma-requests = <1>; > }; > }; > > -- > 1.7.4.4 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/Documentation/devicetree/bindings/dma/arm-pl330.txt b/Documentation/devicetree/bindings/dma/arm-pl330.txt index 36e27d5..2675658 100644 --- a/Documentation/devicetree/bindings/dma/arm-pl330.txt +++ b/Documentation/devicetree/bindings/dma/arm-pl330.txt @@ -10,7 +10,11 @@ Required properties: - interrupts: interrupt number to the cpu. Optional properties: -- dma-coherent : Present if dma operations are coherent + - dma-coherent : Present if dma operations are coherent + - #dma-cells: must be <1>. used to represent the number of integer + cells in the dmas property of client device. + - dma-channels: contains the total number of DMA channels supported by the DMAC + - dma-requests: contains the total number of DMA requests supported by the DMAC Example: @@ -18,16 +22,23 @@ Example: compatible = "arm,pl330", "arm,primecell"; reg = <0x12680000 0x1000>; interrupts = <99>; + #dma-cells = <1>; + #dma-channels = <8>; + #dma-requests = <32>; }; Client drivers (device nodes requiring dma transfers from dev-to-mem or -mem-to-dev) should specify the DMA channel numbers using a two-value pair +mem-to-dev) should specify the DMA channel numbers and dma channel names as shown below. [property name] = <[phandle of the dma controller] [dma request id]>; + [property name] = <[dma channel name]> where 'dma request id' is the dma request number which is connected - to the client controller. The 'property name' is recommended to be - of the form <name>-dma-channel. + to the client controller. The 'property name' 'dmas' and 'dma-names' + as required by the generic dma device tree binding helpers. The dma + names correspond 1:1 with the dma request ids in the dmas property. - Example: tx-dma-channel = <&pdma0 12>; + Example: dmas = <&pdma0 12 + &pdma1 11>; + dma-names = "tx", "rx"; diff --git a/arch/arm/boot/dts/exynos5250.dtsi b/arch/arm/boot/dts/exynos5250.dtsi index 2e3b6ef..c774aae 100644 --- a/arch/arm/boot/dts/exynos5250.dtsi +++ b/arch/arm/boot/dts/exynos5250.dtsi @@ -280,24 +280,36 @@ compatible = "arm,pl330", "arm,primecell"; reg = <0x121A0000 0x1000>; interrupts = <0 34 0>; + #dma-cells = <1>; + #dma-channels = <8>; + #dma-requests = <32>; }; pdma1: pdma@121B0000 { compatible = "arm,pl330", "arm,primecell"; reg = <0x121B0000 0x1000>; interrupts = <0 35 0>; + #dma-cells = <1>; + #dma-channels = <8>; + #dma-requests = <32>; }; mdma0: mdma@10800000 { compatible = "arm,pl330", "arm,primecell"; reg = <0x10800000 0x1000>; interrupts = <0 33 0>; + #dma-cells = <1>; + #dma-channels = <8>; + #dma-requests = <1>; }; mdma1: mdma@11C10000 { compatible = "arm,pl330", "arm,primecell"; reg = <0x11C10000 0x1000>; interrupts = <0 124 0>; + #dma-cells = <1>; + #dma-channels = <8>; + #dma-requests = <1>; }; };