Le lun. 9 juil. 2018 à 19:03, Vinod <vkoul@xxxxxxxxxx> a écrit :
On 03-07-18, 14:32, Paul Cercueil wrote:
The register area of the JZ4780 DMA core can be split into different
sections for different purposes:
* one set of registers is used to perform actions at the DMA core
level,
that will generally affect all channels;
* one set of registers per DMA channel, to perform actions at the
DMA
channel level, that will only affect the channel in question.
The problem rises when trying to support new versions of the JZ47xx
Ingenic SoC. For instance, the JZ4770 has two DMA cores, each one
with six DMA channels, and the register sets are interleaved:
<DMA0 chan regs> <DMA1 chan regs> <DMA0 ctrl regs> <DMA1 ctrl regs>
By using one memory resource for the channel-specific registers and
one memory resource for the core-specific registers, we can support
the JZ4770, by initializing the driver once per DMA core with
different
addresses.
Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
---
.../devicetree/bindings/dma/jz4780-dma.txt | 6 +-
Pls move to separate patch.
OK.
drivers/dma/dma-jz4780.c | 106
+++++++++++-------
2 files changed, 69 insertions(+), 43 deletions(-)
diff --git a/Documentation/devicetree/bindings/dma/jz4780-dma.txt
b/Documentation/devicetree/bindings/dma/jz4780-dma.txt
index f25feee62b15..f9b1864f5b77 100644
--- a/Documentation/devicetree/bindings/dma/jz4780-dma.txt
+++ b/Documentation/devicetree/bindings/dma/jz4780-dma.txt
@@ -3,7 +3,8 @@
Required properties:
- compatible: Should be "ingenic,jz4780-dma"
-- reg: Should contain the DMA controller registers location and
length.
+- reg: Should contain the DMA channel registers location and
length, followed
+ by the DMA controller registers location and length.
- interrupts: Should contain the interrupt specifier of the DMA
controller.
- interrupt-parent: Should be the phandle of the interrupt
controller that
- clocks: Should contain a clock specifier for the JZ4780 PDMA
clock.
@@ -22,7 +23,8 @@ Example:
dma: dma@13420000 {
compatible = "ingenic,jz4780-dma";
- reg = <0x13420000 0x10000>;
+ reg = <0x13420000 0x400
+ 0x13421000 0x40>;
Second should be optional or we break platform which may not have
updated DT..
See comment below.
- jzdma->base = devm_ioremap_resource(dev, res);
- if (IS_ERR(jzdma->base))
- return PTR_ERR(jzdma->base);
+ jzdma->chn_base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(jzdma->chn_base))
+ return PTR_ERR(jzdma->chn_base);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ if (!res) {
+ dev_err(dev, "failed to get I/O memory\n");
+ return -EINVAL;
+ }
okay and this breaks if you happen to get probed on older DT. I think
DT
is treated as ABI so you need to continue support older method while
finding if DT has split resources
See my response to PrasannaKumar. All the Ingenic-based boards do
compile
the devicetree within the kernel, so I think it's still fine to add
breaking
changes. I'll wait on @Rob to give his point of view on this, though.
(It's not something hard to change, but I'd like to know what's the
policy
in that case. I have other DT-breaking patches to submit)
--
~Vinod
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