RE: [[LINUX PATCH v10] 1/4] Devicetree: Add pl353 smc controller devicetree binding information

[Naga Sureshkumar Relli]

Hi Boris,


> -----Original Message-----
> From: Boris Brezillon [mailto:boris.brezillon@xxxxxxxxxxx]
> Sent: Monday, June 25, 2018 2:10 AM
> To: Naga Sureshkumar Relli <nagasure@xxxxxxxxxx>
> Cc: richard@xxxxxx; dwmw2@xxxxxxxxxxxxx; computersforpeace@xxxxxxxxx;
> marek.vasut@xxxxxxxxx; f.fainelli@xxxxxxxxx; mmayer@xxxxxxxxxxxx; rogerq@xxxxxx;
> ladis@xxxxxxxxxxxxxx; ada@xxxxxxxxxxx; honghui.zhang@xxxxxxxxxxxx;
> miquel.raynal@xxxxxxxxxxx; nagasureshkumarrelli@xxxxxxxxx; Michal Simek
> <michals@xxxxxxxxxx>; linux-mtd@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [[LINUX PATCH v10] 1/4] Devicetree: Add pl353 smc controller devicetree
> binding information
> 
> Hi Naga,
> 
> Subject prefix should be "dt-bindings: memory: " not "Devicetree: ".
Ok, I will change it.

> 
> On Thu, 21 Jun 2018 12:12:28 +0530
> Naga Sureshkumar Relli <naga.sureshkumar.relli@xxxxxxxxxx> wrote:
> 
> > Add pl353 static memory controller devicetree binding information.
> >
> > Signed-off-by: Naga Sureshkumar Relli
> > <naga.sureshkumar.relli@xxxxxxxxxx>
> > ---
> > Changes in v10:
> >  - Corrected the typos like "should be" to "Must be" and nand to NAND etc..
> >  - Removed padding to describe size-cells and address-cells
> >  - Removed timing parameters from DT, and added ->setup_data_interface() hook
> >    to the driver to read the SDR timings
> >  - Modified label name from "pl353smcc_0: pl353smcc@e000e000" to
> >    "smcc: memory-controller@e000e000" as suggested by Miquel Changes
> > in v9:
> >  - Addressed below comments given by Randy Dunlap and Miquel Raynal
> >  - Typos
> >  - Added extra documentation that explains the HW ECC limitation with SMC
> >    (Comments given to v8: https://lkml.org/lkml/2018/3/22/23)
> > Changes in v8:
> >  - None
> > Changes in v7:
> >  - Corrected clocks description
> >  - prefixed '#' for address and size cells Changes in v6:
> >  - None
> > Changes in v5:
> >  - Removed timing properties
> > Changes in v4:
> >  - none
> > Changes in v3:
> >  - none
> > Changes in v2:
> >  - modified timing binding info as per onfi timing parameters
> >  - add suffix nano second as timing unit
> >  - modified the clock names as per the IP spec
> > ---
> >  .../bindings/memory-controllers/pl353-smc.txt      | 41
> ++++++++++++++++++++++
> >  1 file changed, 41 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt
> >
> > diff --git
> > a/Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt
> > b/Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt
> > new file mode 100644
> > index 0000000..8b4c65e
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/memory-controllers/pl353-smc.t
> > +++ xt
> > @@ -0,0 +1,41 @@
> > +Device tree bindings for ARM PL353 static memory controller
> > +
> > +PL353 static memory controller supports two kinds of memory
> > +interfaces.i.e NAND and SRAM/NOR interfaces.
> > +The actual devices are instantiated from the child nodes of pl353 smc node.
> > +
> > +Required properties:
> > +- compatible		: Must be "arm,pl353-smc-r2p1"
> > +- reg			: Controller registers map and length.
> > +- clock-names		: List of input clock names - "ref_clk", "aper_clk"
> > +			  (See clock bindings for details).
> > +- clocks		: Clock phandles (see clock bindings for details).
> > +- address-cells		: Must be 1.
> > +- size-cells		: Must be 1.
> > +
> > +Child nodes:
> > + For NAND the "arm,pl353-nand-r2p1" and for NOR the "cfi-flash"
> > +drivers are supported as child nodes.
> > +
> > +for NAND partition information please refer the below file
> > +Documentation/devicetree/bindings/mtd/partition.txt
> > +
> > +Example:
> > +	smcc: memory-controller@e000e000
> > +			compatible = "arm,pl353-smc-r2p1"
> > +			clock-names = "memclk", "aclk";
> > +			clocks = <&clkc 11>, <&clkc 44>;
> > +			reg = <0xe000e000 0x1000>;
> > +			#address-cells = <1>;
> > +			#size-cells = <1>;
> > +			ranges;
> > +			nand_0: flash@e1000000 {
> > +				compatible = "arm,pl353-nand-r2p1"
> > +				reg = <0xe1000000 0x1000000>;
> > +				(...)
> > +			};
> > +			nor0: flash@e2000000 {
> > +				compatible = "cfi-flash";
> > +				reg = <0xe2000000 0x2000000>;
> > +			};
> > +	};
> 
> I had a look at the PL353 TRM, and the block diagram looks very similar to the atmel
> EBI/SMC one. AHB/AXI memory ranges that are used to interact with the memories are
> assigned CS ids, which can then be used to configure the timings (and other kind of stuff). I
> think you should have #address-cells = <2>, the first cell encoding the CS id, and the second
> one, the memory offset within the reserved range for this CS id.
> See the atmel,ebi binding [1].
> 
To my previous patch, as per your comments, I modified reading timing parameters from dts
To nand_setup_data_interface() hook,
But I didn't see the CS implementation as per atmel EBI driver.
Sure, I will update like that and will send v11.

Thanks,
Naga Sureshkumar Relli

> Regards,
> 
> Boris
> 
> [1]https://elixir.bootlin.com/linux/v4.18-
> rc2/source/Documentation/devicetree/bindings/memory-controllers/atmel,ebi.txt