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Message-ID: <baf3ad72a9ea4f07bad56abcbb89bce4@BL2PR03MB467.namprd03.prod.outlook.com>
Date: Fri, 17 Jan 2014 02:58:47 +0000
From: Jingchang Lu <jingchang.lu@...escale.com>
To: Mark Rutland <mark.rutland@....com>
CC: "vinod.koul@...el.com" <vinod.koul@...el.com>,
"dan.j.williams@...el.com" <dan.j.williams@...el.com>,
"arnd@...db.de" <arnd@...db.de>,
"shawn.guo@...aro.org" <shawn.guo@...aro.org>,
Pawel Moll <Pawel.Moll@....com>,
"swarren@...dotorg.org" <swarren@...dotorg.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: RE: [PATCHv9 2/2] dma: Add Freescale eDMA engine driver support
> -----Original Message-----
> From: Mark Rutland [mailto:mark.rutland@....com]
> Sent: Thursday, January 16, 2014 7:12 PM
> To: Lu Jingchang-B35083
> Cc: vinod.koul@...el.com; dan.j.williams@...el.com; arnd@...db.de;
> shawn.guo@...aro.org; Pawel Moll; swarren@...dotorg.org; linux-
> kernel@...r.kernel.org; linux-arm-kernel@...ts.infradead.org;
> devicetree@...r.kernel.org; Wang Huan-B18965
> Subject: Re: [PATCHv9 2/2] dma: Add Freescale eDMA engine driver support
>
> On Thu, Jan 16, 2014 at 02:30:00AM +0000, Jingchang Lu wrote:
> > Add Freescale enhanced direct memory(eDMA) controller support.
> > This module can be found on Vybrid and LS-1 SoCs.
> >
> > Signed-off-by: Alison Wang <b18965@...escale.com>
> > Signed-off-by: Jingchang Lu <b35083@...escale.com>
> > ---
> > changes in v9:
> > define endian's operating functions instead of macro definition.
> > remove the filter function, using dma_get_slave_channel instead.
> >
> > changes in v8:
> > change the edma driver according eDMA dts change.
> > add big-endian and little-endian handling.
> >
> > no changes in v4 ~ v7.
> >
> > changes in v3:
> > add vf610 edma dt-bindings namespace with prefix VF610_*.
> >
> > changes in v2:
> > using generic dma-channels property instead of fsl,dma-channels.
> >
> >
> > Documentation/devicetree/bindings/dma/fsl-edma.txt | 66 ++
> > drivers/dma/Kconfig | 10 +
> > drivers/dma/Makefile | 1 +
> > drivers/dma/fsl-edma.c | 957
> +++++++++++++++++++++
> > 4 files changed, 1034 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/dma/fsl-edma.txt
> > create mode 100644 drivers/dma/fsl-edma.c
> >
> > diff --git a/Documentation/devicetree/bindings/dma/fsl-edma.txt
> b/Documentation/devicetree/bindings/dma/fsl-edma.txt
> > new file mode 100644
> > index 0000000..5a5fb61
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/dma/fsl-edma.txt
> > @@ -0,0 +1,66 @@
> > +* Freescale enhanced Direct Memory Access(eDMA) Controller
> > +
> > + The eDMA channels have multiplex capability by programmble memory-
> mapped
> > +registers. channels are split into two groups, called DMAMUX0 and
> DMAMUX1,
> > +specific DMA request source can only be multiplexed by any channel of
> certain
> > +group, DMAMUX0 or DMAMUX1, but not both.
> > +
> > +* eDMA Controller
> > +Required properties:
> > +- compatible :
> > + - "fsl,vf610-edma" for eDMA used similar to that on Vybrid
> vf610 SoC
> > +- reg : Specifies base physical address(s) and size of the eDMA
> registers.
> > + The 1st region is eDMA control register's address and size.
> > + The 2nd and the 3rd regions are programmable channel
> multiplexing
> > + control register's address and size.
> > +- interrupts : Should contain eDMA interrupt
> > +- interrupt-names : Should be "edma-tx" for transmission interrupt and
> > + "edma-err" for error interrupt
>
> The description of interrupts and interrupt-names is a bit odd. How
> about:
>
> - interrupts: a list of interrupt-specifiers, one for each entry in
> interrupt-names.
>
> - interrupt names: should contain:
> * "edma-tx" - the transmission interrupt.
> * "edma-err" - the error interrupt.
>
> > +- #dma-cells : Must be <2>.
> > + The 1st cell specifies the DMAMUX(0 for DMAMUX0 and 1 for
> DMAMUX1).
> > + Specific request source can only be multiplexed by specific
> channels
> > + group called DMAMUX.
> > + The 2nd cell specifies the request source(slot) ID.
> > + See the SoC's reference manual for all the supported request
> sources.
> > +- dma-channels : Number of channels supported by the controller
> > +- clock-names : The channel group block clock names
> > +- clocks : eDMA module clock
>
> The set of expected clock-names should be well defined, and the example
> has more than one clock..
>
> This should be something like:
>
> - clocks: a list of phandle + clock-specifier pairs, one for each entry
> in clock-names.
>
> - clock-names: a list of clock names. Should contain:
> * "dmamux0" - <insert description here>
> * "dmamux1" - <insert description here>
Your suggestion for the interrupt and clock binding is much clearer, I will take this, thanks.
>
> > +
> > +
> > +Examples:
> > +
> > +edma0: dma-controller@...18000 {
> > + #dma-cells = <2>;
> > + compatible = "fsl,vf610-edma";
> > + reg = <0x40018000 0x2000>,
> > + <0x40024000 0x1000>,
> > + <0x40025000 0x1000>;
> > + interrupts = <0 8 IRQ_TYPE_LEVEL_HIGH>,
> > + <0 9 IRQ_TYPE_LEVEL_HIGH>;
> > + interrupt-names = "edma-tx", "edma-err";
> > + dma-channels = <32>;
> > + clock-names = "dmamux0", "dmamux1";
> > + clocks = <&clks VF610_CLK_DMAMUX0>,
> > + <&clks VF610_CLK_DMAMUX1>;
> > +};
>
> [...]
>
> > + for (i = 0; i < DMAMUX_NR; i++) {
> > + char clkname[32];
> > +
> > + res = platform_get_resource(pdev, IORESOURCE_MEM, 1 +
> i);
> > + fsl_edma->muxbase[i] = devm_ioremap_resource(&pdev->dev,
> res);
> > + if (IS_ERR(fsl_edma->muxbase[i]))
> > + return PTR_ERR(fsl_edma->muxbase[i]);
> > +
> > + sprintf(clkname, "dmamux%d", i);
> > + fsl_edma->muxclk[i] = of_clk_get(np, i);
> > + fsl_edma->muxclk[i] = devm_clk_get(&pdev->dev, clkname);
>
> The of_clk_get should disappear. It's always overwritten and
> devm_clk_get will do what you want.
It's my mistake in substituting devm_clk_get() for of_clk_get(), I will remove it, thanks.
>
> > + if (IS_ERR(fsl_edma->muxclk[i])) {
> > + dev_err(&pdev->dev, "Missing DMAMUX block
> clock.\n");
> > + return PTR_ERR(fsl_edma->muxclk[i]);
> > + }
> > +
> > + ret = clk_prepare_enable(fsl_edma->muxclk[i]);
> > + if (ret) {
> > + dev_err(&pdev->dev, "DMAMUX clk block
> failed.\n");
> > + return ret;
> > + }
> > +
> > + }
> > +
> > + ret = fsl_edma_irq_init(pdev, fsl_edma);
> > + if (ret)
> > + return ret;
> > +
> > + fsl_edma->big_endian = of_property_read_bool(np, "big-endian");
>
> This isn't in the binding.
I will add its binding, thanks.
Best Regards,
Jingchang
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