Re: [PATCH v3 2/3] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

[Alexander Popov]

On 28.09.2015 16:26, Timur Tabi wrote:
> Alexander Popov wrote:
>> I've just followed devicetree/bindings/dma/dma.txt...
>> This "rx-tx" doesn't mean much but it could show that LocalPlus Bus FIFO
>> uses a single DMA read-write channel. Should I really drop it?
> 
> Hmmm, I'm not sure.  Is there anything else (besides your driver) that
> parses this device tree node?

No, mpc512x_lpbfifo.c is the only piece of code which is going to use this
device tree node.

> dma.txt says this:
> 
> "The specific strings that can be used are defined in the binding of the
> DMA client device."
> 
> So this looks like it's driver-specific,

Yes.
MPC512x LocalPlus Bus FIFO uses the channel #26 of the DMA controller
both for reading and writing, and other DMA clients use other specific
DMA channels. This channel assignment is fixed in hardware and described
in the Reference Manual.

> but it is a required property.
> I guess you should keep it, but I think you should get a second opinion.

Ok, thanks.

Best regards,
Alexander
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Re: [PATCH v3 2/3] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

[Alexander Popov]

On 25.09.2015 03:18, Timur Tabi wrote:
> Alexander Popov wrote:
>> +- dma-names: should be "rx-tx";
> 
> Why bother, if it can only be one value?

I've just followed devicetree/bindings/dma/dma.txt...
This "rx-tx" doesn't mean much but it could show that LocalPlus Bus FIFO
uses a single DMA read-write channel. Should I really drop it?

Best regards,
Alexander
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Re: [PATCH v3 2/3] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

[Timur Tabi]

Alexander Popov wrote:

I've just followed devicetree/bindings/dma/dma.txt...
This "rx-tx" doesn't mean much but it could show that LocalPlus Bus FIFO
uses a single DMA read-write channel. Should I really drop it?


Hmmm, I'm not sure.  Is there anything else (besides your driver) that 
parses this device tree node?


dma.txt says this:

	"The specific strings that can be used are defined in the binding of 
the DMA client device."


So this looks like it's driver-specific, but it is a required property.
I guess you should keep it, but I think you should get a second opinion.
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[PATCH v3 2/3] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

[Alexander Popov]

Add a device tree binding for Freescale MPC512x LocalPlus Bus FIFO and
introduce the document describing that binding.

Signed-off-by: Alexander Popov 
---
 .../bindings/powerpc/fsl/mpc512x_lpbfifo.txt| 21 +
 arch/powerpc/boot/dts/mpc5121.dtsi  | 11 +--
 arch/powerpc/boot/dts/mpc5125twr.dts| 11 ++-
 3 files changed, 40 insertions(+), 3 deletions(-)
 create mode 100644 
Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt

diff --git a/Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt 
b/Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt
new file mode 100644
index 000..b3b392f
--- /dev/null
+++ b/Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt
@@ -0,0 +1,21 @@
+Freescale MPC512x LocalPlus Bus FIFO (called SCLPC in the Reference Manual)
+
+Required properties:
+- compatible: should be "fsl,mpc512x-lpbfifo";
+- reg: should contain the offset and length of SCLPC register set;
+- interrupts: should contain the interrupt specifier for SCLPC; syntax of an
+interrupt client node is described in interrupt-controller/interrupts.txt;
+- dmas: should contain the DMA specifier for SCLPC as described at
+dma/dma.txt and dma/mpc512x-dma.txt;
+- dma-names: should be "rx-tx";
+
+Example:
+
+   sclpc@10100 {
+   compatible = "fsl,mpc512x-lpbfifo";
+   reg = <0x10100 0x50>;
+   interrupts = <7 0x8>;
+   dmas = < 26>;
+   dma-names = "rx-tx";
+   };
+
diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 7f9d14f..a015e45 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -77,7 +77,6 @@
#address-cells = <2>;
#size-cells = <1>;
reg = <0x8020 0x40>;
-   interrupts = <7 0x8>;
ranges = <0x0 0x0 0xfc00 0x0400>;
};
 
@@ -329,7 +328,15 @@
/* LocalPlus controller */
lpc@1 {
compatible = "fsl,mpc5121-lpc";
-   reg = <0x1 0x200>;
+   reg = <0x1 0x100>;
+   };
+
+   sclpc@10100 {
+   compatible = "fsl,mpc512x-lpbfifo";
+   reg = <0x10100 0x50>;
+   interrupts = <7 0x8>;
+   dmas = < 26>;
+   dma-names = "rx-tx";
};
 
pata@10200 {
diff --git a/arch/powerpc/boot/dts/mpc5125twr.dts 
b/arch/powerpc/boot/dts/mpc5125twr.dts
index e4f2974..898eb58 100644
--- a/arch/powerpc/boot/dts/mpc5125twr.dts
+++ b/arch/powerpc/boot/dts/mpc5125twr.dts
@@ -246,6 +246,14 @@
status = "disabled";
};
 
+   sclpc@10100 {
+   compatible = "fsl,mpc512x-lpbfifo";
+   reg = <0x10100 0x50>;
+   interrupts = <7 0x8>;
+   dmas = < 26>;
+   dma-names = "rx-tx";
+   };
+
// 5125 PSCs are not 52xx or 5121 PSC compatible
// PSC1 uart0 aka ttyPSC0
serial@11100 {
@@ -279,10 +287,11 @@
clock-names = "ipg";
};
 
-   dma@14000 {
+   dma0: dma@14000 {
compatible = "fsl,mpc5121-dma"; // BSP name: 
"mpc512x-dma2"
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 };
-- 
1.9.1

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Re: [PATCH v3 2/3] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

[Timur Tabi]

Alexander Popov wrote:

+- dma-names: should be "rx-tx";


Why bother, if it can only be one value?
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