Message-ID: <5294CE7F.3060607@ti.com>
Date:	Tue, 26 Nov 2013 18:38:23 +0200
From:	"ivan.khoronzhuk" <ivan.khoronzhuk@...com>
To:	Kumar Gala <galak@...nel.crashing.org>
CC:	Santosh Shilimkar <santosh.shilimkar@...com>,
	Rob Landley <rob@...dley.net>,
	Russell King <linux@....linux.org.uk>,
	devicetree <devicetree@...r.kernel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Rob Herring <rob.herring@...xeda.com>,
	Stephen Warren <swarren@...dotorg.org>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-mtd@...ts.infradead.org>, <grygorii.strashko@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH 2/2] memory: ti-aemif: add bindings for AEMIF driver

On 11/22/2013 11:04 PM, Kumar Gala wrote:
>
> On Nov 20, 2013, at 9:46 AM, Ivan Khoronzhuk <ivan.khoronzhuk@...com> wrote:
>
>> Add bindings for AEMIF controller drivers/memory/ti-aemif.c
>>
>
> Binding shouldn’t normally refer to code.
>
> Just saying something like:
>
> Adding binging for TI Async External Memory Interface (AEMIF) controller.
>
>

Ok

>> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@...com>
>> ---
>> .../bindings/memory-controllers/ti-aemif.txt       |  198 ++++++++++++++++++++
>> 1 file changed, 198 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/memory-controllers/ti-aemif.txt
>>
>> diff --git a/Documentation/devicetree/bindings/memory-controllers/ti-aemif.txt b/Documentation/devicetree/bindings/memory-controllers/ti-aemif.txt
>> new file mode 100644
>> index 0000000..be0c0cb
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/memory-controllers/ti-aemif.txt
>> @@ -0,0 +1,198 @@
>> +* Device tree bindings for Texas instruments AEMIF controller
>> +
>> +Th Async External Memory Interface (EMIF16/AEMIF) controller is intended to
>
> The?
>

The

>> +provide a glue-less interface to a variety of asynchronous memory devices like
>> +ASRA M, NOR and NAND memory. A total of 256M bytes of any of these memories
>> +can be accessed at any given time via four chip selects with 64M byte access
>> +per chip select. Synchronous memories such as DDR1 SD RAM, SDR SDRAM
>> +and Mobile SDR are not supported.
>> +
>> +Documentation:
>> +Davinci DM646x - http://www.ti.com/lit/ug/sprueq7c/sprueq7c.pdf
>> +OMAP-L138 - http://www.ti.com/lit/ug/spruh77a/spruh77a.pdf
>> +Kestone - http://www.ti.com/lit/ug/sprugz3a/sprugz3a.pdf
>> +
>> +Required properties:
>> +
>> +- compatible:		"ti,davinci-aemif"
>> +			"ti,keystone-aemif"
>> +			"ti,omap-L138-aemif"
>> +
>> +- #address-cells:	Must be 2. The first cell is the memory partition
>> +			number. The 0 partition is for chip selects. And the
>> +			second cell is the offset into the partition, for the 0
>> +			partition it corresponds to chip select offset.
>> +
>
> Is the first cell just the chip select number?
>
> I’m wondering if this is similar to FSL Localbus controller, see the binding:
>
> bindings/powerpc/fsl/lbc.txt
>

No, it is a memory range number

>> +- #size-cells:		Must be set to 1.
>> +
>> +- reg:			contains offset/length value for AEMIF control registers
>> +			space.
>> +
>> +- ranges:		Must be set up to reflect the memory layout for 4
>> +			chipselects and for AEMIF control range.
>> +
>> +- clocks:		phandle reference to the controller clock. Required only
>> +			if clock tree data present in device tree.
>> +			See clock-bindings.txt
>> +
>> +- clock-names:		clock name. It has to be "aemif". Required only if clock
>> +			tree data present in device tree, in another case don't
>> +			use it.
>> +			See clock-bindings.txt
>> +
>> +- clock-ranges:		Empty property indicating that child nodes can inherit
>> +			named clocks. Required only if clock tree data present
>> +			in device tree.
>> +			See clock-bindings.txt
>> +
>> +
>> +Child chip-select (cs) nodes contain the memory devices nodes connected to
>> +such as NOR (e.g. cfi-flash) and NAND (ti,davinci-nand, see davinci-nand.txt).
>> +There might be board specific devices like FPGAs.
>> +
>> +Required child cs node properties:
>> +
>> +- compatible:		"ti,aemif-cs"
>> +
>> +- #address-cells:	Must be 2. The first cell is the memory partition
>> +			number. The 0 partition is for chip selects. And the
>> +			second cell is the offset into the partition, for the 0
>> +			partition it corresponds to chip select offset.
>> +
>> +- #size-cells:		Must be 1.
>> +
>> +- ranges:		Empty property indicating that child nodes can inherit
>> +			memory layout.
>> +
>> +- clock-ranges:		Empty property indicating that child nodes can inherit
>> +			named clocks. Required only if clock tree data present
>> +			in device tree.
>> +
>> +Optional child cs node properties:
>> +
>> +
>> +- ti,bus-width:			width of the asynchronous device's data bus
>> +				8 or 16 if not preset 8
>> +
>> +- ti,cs-ss:		enable/disable select strobe mode
>> +				In select strobe mode chip select behaves as
>> +				the strobe and is active only during the strobe
>> +				period. If present then enable.
>> +
>> +- ti,cs-ew:		enable/disable extended wait mode
>> +				if set, the controller monitors the EMIFWAIT pin
>> +				mapped to that chip select to determine if the
>> +				device wants to extend the strobe period. If
>> +				present then enable.
>> +
>> +- ti,cs-ta:		minimum turn around time, ns
>> +				Time between the end of one asynchronous memory
>> +				access and the start of another asynchronous
>> +				memory access. This delay is not incurred
>> +				between a read followed by read or a write
>> +				followed by a write to same chip select.
>> +
>> +- ti,cs-rsetup:		read setup width, ns
>> +				Time between the beginning of a memory cycle
>> +				and the activation of read strobe.
>> +				Minimum value is 1 (0 treated as 1).
>> +
>> +- ti,cs-rstobe:		read strobe width, ns
>> +				Time between the activation and deactivation of
>> +				the read strobe.
>> +				Minimum value is 1 (0 treated as 1).
>> +
>> +- ti,cs-rhold:		read hold width, ns
>> +				Time between the deactivation of the read
>> +				strobe and the end of the cycle (which may be
>> +				either an address change or the deactivation of
>> +				the chip select signal.
>> +				Minimum value is 1 (0 treated as 1).
>> +
>> +- ti,cs-wsetup:		write setup width, ns
>> +				Time between the beginning of a memory cycle
>> +				and the activation of write strobe.
>> +				Minimum value is 1 (0 treated as 1).
>> +
>> +- ti,cs-wstrobe:	write strobe width, ns
>> +				Time between the activation and deactivation of
>> +				the write strobe.
>> +				Minimum value is 1 (0 treated as 1).
>> +
>> +- ti,cs-whold:		write hold width, ns
>> +				Time between the deactivation of the write
>> +				strobe and the end of the cycle (which may be
>> +				either an address change or the deactivation of
>> +				the chip select signal.
>> +				Minimum value is 1 (0 treated as 1).
>> +
>> +If any of the above parameters are absent, current parameter value will be taken
>> +from the corresponding HW reg.
>> +
>> +The name for cs node must be in format csN, where N is the cs number.
>> +For compatibles "ti,davinci-aemif" and "ti,keystone-aemif" N = [0-3].
>> +For compatible "ti,omap-L138-aemif" N = [2-5].
>> +
>> +Example for aemif, davinci nand and nor flash chip select shown below.
>> +
>> +memory-controller@...00A00 {
>> +	compatible = "ti,keystone-aemif";
>> +	#address-cells = <2>;
>> +	#size-cells = <1>;
>> +	clocks = <&clkaemif 0>;
>> +	clock-names = "aemif";
>> +	clock-ranges;
>> +	reg = <0x2100A00 0x00000100>;
>> +	ranges = <0 0 0x70000000 0x10000000
>> +		  1 0 0x21000A00 0x0000100>;
>> +
>> +	nand:cs2 {
>> +		compatible = "ti,aemif-cs";
>> +		#address-cells = <2>;
>> +		#size-cells = <1>;
>> +		clock-ranges;
>> +		ranges;
>> +
>> +		/* all timings in nanoseconds */
>> +		ti,cs-ta = <0>;
>> +		ti,cs-rhold = <7>;
>> +		ti,cs-rstrobe = <42>;
>> +		ti,cs-rsetup = <14>;
>> +		ti,cs-whold = <7>;
>> +		ti,cs-wstrobe = <42>;
>> +		ti,cs-wsetup = <14>;
>> +
>> +		nand@0,0x8000000 {
>> +			compatible = "ti,davinci-nand";
>> +			reg = <0 0x8000000 0x4000000
>> +			       1 0x0000000 0x0000100>;
>> +
>> +			.. see davinci-nand.txt
>> +		};
>> +	};
>> +
>> +	nor:cs0 {
>> +		compatible = "ti,aemif-cs";
>> +		#address-cells = <2>;
>> +		#size-cells = <1>;
>> +		clock-ranges;
>> +		ranges;
>> +
>> +		/* all timings in nanoseconds */
>> +		ti,cs-ta = <0>;
>> +		ti,cs-rhold = <8>;
>> +		ti,cs-rstrobe = <40>;
>> +		ti,cs-rsetup = <14>;
>> +		ti,cs-whold = <7>;
>> +		ti,cs-wstrobe = <40>;
>> +		ti,cs-wsetup = <14>;
>> +		ti,cs-asize = <1>;
>> +
>> +		flash@0,0x0000000 {
>> +			compatible = "cfi-flash";
>> +			reg = <0 0x0000000 0x4000000>;
>> +
>> +			...
>> +		};
>> +	};
>> +};
>> --
>> 1.7.9.5
>>
>> --
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>


-- 
Regards,
Ivan Khoronzhuk
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