[PATCH] [POWERPC] Add docs for Freescale DMA & DMA channel device tree nodes
timur at freescale.com
Wed Jan 23 08:30:03 EST 2008
Kumar Gala wrote:
> Signed-off-by: Zhang Wei <wei.zhang at freescale.com>
> Signed-off-by: Ebony Zhu <ebony.zhu at freescale.com>
> Signed-off-by: Kumar Gala <galak at kernel.crashing.org>
> Guys please review and make sure I got all your previous comments fixed
> up. I've added cell-index. and the examples should represent real HW.
> Documentation/powerpc/booting-without-of.txt | 128 ++++++++++++++++++++++++++
> 1 files changed, 128 insertions(+), 0 deletions(-)
> diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
> index da98154..3584c33 100644
> --- a/Documentation/powerpc/booting-without-of.txt
> +++ b/Documentation/powerpc/booting-without-of.txt
> @@ -2615,6 +2615,134 @@ platforms are moved over to use the flattened-device-tree model.
> - clock-frequency : The frequency of the input clock, which typically
> comes from an on-board dedicated oscillator.
> + * Freescale 83xx DMA Controller
> + Freescale PowerPC 83xx have on chip general purpose DMA controllers.
> + Required properties:
> + - compatible : compatible list, contains 2 entries, first is
> + "fsl,CHIP-dma", where CHIP is the processor
> + (mpc8349, mpc8360, etc.) and the second is
> + "fsl,elo-dma"
> + - reg : <registers mapping for DMA general status reg>
> + - ranges : Should be defined as specified in 1) to describe the
> + DMA controller channels.
What does "Should be defined as specified in 1)" mean?
> + - cell-index : controller index. 0 for controller @ 0x8100
This should be more generic. I believe for each of our SoCs, we designation one
DMA controller to be "DMA Controller 1", and that one should have a cell-index
> + - interrupts : <interrupt mapping for DMA IRQ>
> + - interrupt-parent : optional, if needed for interrupt mapping
On 83xx, all DMA channels share the same interrupt? Couldn't we just specify
the same IRQ in each channel's node, so that they look the same across 83xx,
85xx, and 86xx? My sound driver doesn't use Extended Mode, but it does check
for "fsl,8610-dma-channel". I'm thinking that maybe I should change to to look
for "elo" or "eloplus", but it would be nice if we could make the DMA node for
an 86xx SoC compatible with a driver that expects "fsl,elo-dma-channel".
Linux kernel developer at Freescale
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