[PATCH] powerpc: document the "fsl, ssi-dma-channel" compatible property

[PATCH] powerpc: document the "fsl, ssi-dma-channel" compatible property

[Timur Tabi]

The "fsl,ssi-dma-channel" compatible property is used to specify a DMA channel
on the Freescale Elo DMA controller that should be used exclusively by the
Freescale SSI audio controller.  When a property is marked as such, the Elo
DMA driver will ignore it, and so it will be available for the sound drivers.

Signed-off-by: Timur Tabi <timur@freescale.com>
---
 Documentation/powerpc/dts-bindings/fsl/dma.txt |   13 +++++++++++--
 Documentation/powerpc/dts-bindings/fsl/ssi.txt |   20 ++++++++++++++------
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/Documentation/powerpc/dts-bindings/fsl/dma.txt b/Documentation/powerpc/dts-bindings/fsl/dma.txt
index 86826df..cc45311 100644
--- a/Documentation/powerpc/dts-bindings/fsl/dma.txt
+++ b/Documentation/powerpc/dts-bindings/fsl/dma.txt
@@ -20,7 +20,7 @@ Required properties:
         - compatible        : compatible list, contains 2 entries, first is
 			 "fsl,CHIP-dma-channel", where CHIP is the processor
 			 (mpc8349, mpc8350, etc.) and the second is
-			 "fsl,elo-dma-channel"
+			 "fsl,elo-dma-channel". However, see note below.
         - reg               : <registers mapping for channel>
         - cell-index        : dma channel index starts at 0.
 
@@ -82,7 +82,7 @@ Required properties:
         - compatible        : compatible list, contains 2 entries, first is
 			 "fsl,CHIP-dma-channel", where CHIP is the processor
 			 (mpc8540, mpc8560, etc.) and the second is
-			 "fsl,eloplus-dma-channel"
+			 "fsl,eloplus-dma-channel". However, see note below.
         - cell-index        : dma channel index starts at 0.
         - reg               : <registers mapping for channel>
         - interrupts        : <interrupt mapping for DMA channel IRQ>
@@ -125,3 +125,12 @@ Example:
 			interrupts = <17 2>;
 		};
 	};
+
+Note on DMA channel compatible properties: The compatible property must say
+"fsl,elo-dma-channel" or "fsl,eloplus-dma-channel" to be used by the Elo DMA
+driver (fsldma).  Any DMA channel used by fsldma cannot be used by another
+DMA driver, such as the SSI sound drivers for the MPC8610.  Therefore, any DMA
+channel that should be used for another driver should not use
+"fsl,elo-dma-channel" or "fsl,eloplus-dma-channel".  For the SSI drivers, for
+example, the compatible property should be "fsl,ssi-dma-channel".  See ssi.txt
+for more information.
diff --git a/Documentation/powerpc/dts-bindings/fsl/ssi.txt b/Documentation/powerpc/dts-bindings/fsl/ssi.txt
index 5d98413..a2d9639 100644
--- a/Documentation/powerpc/dts-bindings/fsl/ssi.txt
+++ b/Documentation/powerpc/dts-bindings/fsl/ssi.txt
@@ -24,12 +24,12 @@ Required properties:
 		    "rj-master" - r.j., SSI is clock master
 		    "ac97-slave" - AC97 mode, SSI is clock slave
 		    "ac97-master" - AC97 mode, SSI is clock master
-- fsl,playback-dma: phandle to a DMA node for the DMA channel to use for
-		    playback of audio.  This is typically dictated by SOC
-		    design.  See the notes below.
-- fsl,capture-dma:  phandle to a DMA node for the DMA channel to use for
-		    capture (recording) of audio.  This is typically dictated
-		    by SOC design.  See the notes below.
+- fsl,playback-dma: phandle to a node for the DMA channel to use for
+                    playback of audio.  This is typically dictated by SOC
+                    design.  See the notes below.
+- fsl,capture-dma:  phandle to a node for the DMA channel to use for
+                    capture (recording) of audio.  This is typically dictated
+                    by SOC design.  See the notes below.
 
 Optional properties:
 - codec-handle	  : phandle to a 'codec' node that defines an audio
@@ -51,3 +51,11 @@ playback and DMA channel 1 for capture.  SSI2 must use DMA channel 2 for
 playback and DMA channel 3 for capture.  The developer can choose which
 DMA controller to use, but the channels themselves are hard-wired.  The
 purpose of these two properties is to represent this hardware design.
+
+The device tree nodes for the DMA channels that are referenced by
+"fsl,playback-dma" and "fsl,capture-dma" must be marked as compatible with
+"fsl,ssi-dma-channel".  The SOC-specific compatible string (e.g.
+"fsl,mpc8610-dma-channel") can remain.  If these nodes are left as
+"fsl,elo-dma-channel" or "fsl,eloplus-dma-channel", then the generic Elo DMA
+drivers (fsldma) will attempt to use them, and it will conflict with the
+sound drivers.
-- 
1.5.5

[PATCH] powerpc: reserve two DMA channels for audio in MPC8610 HPCD device tree

[Timur Tabi]

The Freescale Elo DMA driver binds to all DMA channels in the device tree that
are compatible with "fsl,eloplus-dma-channel".  This conflicts with the sound
drivers for the MPC8610 HPCD.  On this board, the SSI uses two DMA channels and
therefore those channels are not available for general purpose use.  We
change the compatible properties for these channels "fsl,ssi-dma-channel".
This works because the sound drivers don't actually check the compatible
property when it grabs channels.

Signed-off-by: Timur Tabi <timur@freescale.com>
---
 arch/powerpc/boot/dts/mpc8610_hpcd.dts |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/boot/dts/mpc8610_hpcd.dts b/arch/powerpc/boot/dts/mpc8610_hpcd.dts
index 0f3a36e..3f4c610 100644
--- a/arch/powerpc/boot/dts/mpc8610_hpcd.dts
+++ b/arch/powerpc/boot/dts/mpc8610_hpcd.dts
@@ -237,7 +237,7 @@
 
 			dma00: dma-channel@0 {
 				compatible = "fsl,mpc8610-dma-channel",
-					"fsl,eloplus-dma-channel";
+					"fsl,ssi-dma-channel";
 				cell-index = <0>;
 				reg = <0x0 0x80>;
 				interrupt-parent = <&mpic>;
@@ -245,7 +245,7 @@
 			};
 			dma01: dma-channel@1 {
 				compatible = "fsl,mpc8610-dma-channel",
-					"fsl,eloplus-dma-channel";
+					"fsl,ssi-dma-channel";
 				cell-index = <1>;
 				reg = <0x80 0x80>;
 				interrupt-parent = <&mpic>;
-- 
1.5.5

Re: [PATCH] powerpc: reserve two DMA channels for audio in MPC8610 HPCD device tree

[Kumar Gala]

On Oct 10, 2008, at 11:52 AM, Timur Tabi wrote:

> The Freescale Elo DMA driver binds to all DMA channels in the device  
> tree that
> are compatible with "fsl,eloplus-dma-channel".  This conflicts with  
> the sound
> drivers for the MPC8610 HPCD.  On this board, the SSI uses two DMA  
> channels and
> therefore those channels are not available for general purpose use.   
> We
> change the compatible properties for these channels "fsl,ssi-dma- 
> channel".
> This works because the sound drivers don't actually check the  
> compatible
> property when it grabs channels.
>
> Signed-off-by: Timur Tabi <timur@freescale.com>
> ---
> arch/powerpc/boot/dts/mpc8610_hpcd.dts |    4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)

applied

- k

Re: [PATCH] powerpc: document the "fsl, ssi-dma-channel" compatible property

[Kumar Gala]

On Oct 10, 2008, at 11:52 AM, Timur Tabi wrote:

> The "fsl,ssi-dma-channel" compatible property is used to specify a  
> DMA channel
> on the Freescale Elo DMA controller that should be used exclusively  
> by the
> Freescale SSI audio controller.  When a property is marked as such,  
> the Elo
> DMA driver will ignore it, and so it will be available for the sound  
> drivers.
>
> Signed-off-by: Timur Tabi <timur@freescale.com>
> ---
> Documentation/powerpc/dts-bindings/fsl/dma.txt |   13 +++++++++++--
> Documentation/powerpc/dts-bindings/fsl/ssi.txt |   20 +++++++++++++ 
> +------
> 2 files changed, 25 insertions(+), 8 deletions(-)

applied

- k