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Message-ID: <547F2918.3070803@atmel.com>
Date: Wed, 3 Dec 2014 16:15:36 +0100
From: Nicolas Ferre <nicolas.ferre@...el.com>
To: Boris Brezillon <boris.brezillon@...e-electrons.com>,
"Jean-Christophe Plagniol-Villard" <plagnioj@...osoft.com>,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
Andrew Victor <linux@...im.org.za>,
Samuel Ortiz <sameo@...ux.intel.com>,
Lee Jones <lee.jones@...aro.org>
CC: Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
"Mark Rutland" <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
<devicetree@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, "Arnd Bergmann" <arnd@...db.de>,
Jean-Jacques Hiblot <jjhiblot@...phandler.com>
Subject: Re: [PATCH v3 06/11] memory: atmel-ebi: add DT bindings documentation
Le 03/12/2014 15:56, Nicolas Ferre a écrit :
> Le 01/12/2014 11:27, Boris Brezillon a écrit :
>> The EBI (External Bus Interface) is used to access external peripherals
>> (NOR, SRAM, NAND, and other specific devices like ethernet controllers).
>> Each device is assigned a CS line and an address range and can have its
>> own configuration (timings, access mode, bus width, ...).
>> This driver provides a generic DT binding to configure a device according
>> to its requirements.
>> For specific device controllers (like the NAND one) the SMC timings
>> should be configured by the controller driver through the matrix and smc
>> syscon regmaps.
>>
>> Signed-off-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
>> ---
>> .../bindings/memory-controllers/atmel-ebi.txt | 155 +++++++++++++++++++++
>> 1 file changed, 155 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/memory-controllers/atmel-ebi.txt
>>
>> diff --git a/Documentation/devicetree/bindings/memory-controllers/atmel-ebi.txt b/Documentation/devicetree/bindings/memory-controllers/atmel-ebi.txt
>> new file mode 100644
>> index 0000000..3749ea1
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/memory-controllers/atmel-ebi.txt
>> @@ -0,0 +1,155 @@
>> +* Device tree bindings for Atmel EBI
>> +
>> +The External Bus Interface (EBI) controller is a bus where you can connect
>> +asynchronous (NAND, NOR, SRAM, ....) and synchronous memories (SDR/DDR SDRAMs).
>> +The EBI provides a glue-less interface to asynchronous memories though the SMC
>> +(Static Memory Controller).
>> +Synchronous memories (and some asynchronous memories like NANDs) can be
>> +attached to specialized controllers which are responsible for configuring the
>> +bus appropriately according to the connected device.
>> +In the other hand, the bus interface can be automated for simple asynchronous
>> +devices.
>> +
>> +Required properties:
>> +
>> +- compatible: "atmel,at91sam9260-ebi"
>> + "atmel,at91sam9261-ebi"
>> + "atmel,at91sam9263-ebi0"
>> + "atmel,at91sam9263-ebi1"
>
> Ditto: 9263 twice.
>
>> + "atmel,at91sam9g45-ebi"
>> + "atmel,at91sam9x5-ebi"
>> + "atmel,sama5d3-ebi"
>> +
>> +- reg: Contains offset/length value for EBI memory mapping.
>> + This property might contain several entries if the EBI
>> + memory range is not contiguous
>> +
>> +- #address-cells: Must be 2.
>> + The first cell encodes the CS.
>> + The second cell encode the offset into the CS memory
>> + range.
>> +
>> +- #size-cells: Must be set to 1.
>> +
>> +- ranges: Encodes CS to memory region association.
>> +
>> +- clocks: Clock feeding the EBI controller.
>> + 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.
>> +There might be board specific devices like FPGAs.
>> +You'll define you device requirements in these child nodes.
>> +
>> +Required child cs node properties:
>> +
>> +- #address-cells: Must be 2.
>> +
>> +- #size-cells: Must be 1.
>> +
>> +- ranges: Empty property indicating that child nodes can inherit
>> + memory layout.
>> +
>> +Optional child cs node properties:
>> +- atmel,generic-dev boolean property specifying if the device is
>> + a generic device.
Well... no real information, specify right here what a "generic device" is.
>> + The following properties are only parsed if
>> + this property is present.
>> + Specialized devices are attached to specialized
>> + controllers which are responsible for
>> + configuring the bus appropriately.
>> + Here are some examples of specialized
>> + controllers: NAND, CompactFlash, SDR-SDRAM.
>> +
>> +- atmel,bus-width: width of the asynchronous device's data bus
>> + 8, 16 or 32.
>> + 8 if not present.
>> +
>> +- atmel,byte-access-type "write" or "select" (see Atmel datasheet).
>> + "select" if not present.
>> +
>> +- atmel,read-mode "nrd" or "ncs".
>> + "ncs" is not present.
>> +
>> +- atmel,write-mode "nwe" or "ncs".
>> + "ncs" is not present.
>> +
>> +- atmel,exnw-mode "disabled", "frozen" or "ready".
>> + "disabled" if not present.
>> +
>> +- atmel,page-mode enable page mode if present. The provided value
>> + defines the page size (supported values: 4, 8,
>> + 16 and 32).
>> +
>> +Optional device timings expressed in nanoseconds (if the property is not
>> +present 0 is assumed):
>> +
>> +- atmel,ncs-rd-setup-ns
>> +- atmel,nrd-setup-ns
>> +- atmel,ncs-wr-setup-ns
>> +- atmel,nwe-setup-ns
>> +- atmel,ncs-rd-pulse-ns
>> +- atmel,nrd-pulse-ns
>> +- atmel,ncs-wr-pulse-ns
>> +- atmel,nwe-pulse-ns
>> +- atmel,nwe-cycle-ns
>> +- atmel,nrd-cycle-ns
>> +- atmel,tdf-ns
>> +
>> +- atmel,tdf-optimized data float optimized mode. If present the data
>> + float time is optimized depending on the next
>> + device being accessed (next device setup
>> + time is substracted to the current devive data
>
> Typo: subtract, device
>
>> + float time).
>> +
>> +
>> +
>> +Example:
>> +
>> + ebi: ebi@...00000 {
>> + compatible = "atmel,sama5d3-ebi", "simple-bus";
>> + #address-cells = <2>;
>> + #size-cells = <1>;
>> + atmel,smc = <&hsmc>;
>> + atmel,matrix = <&matrix>;
>> + reg = <0x10000000 0x10000000
>> + 0x40000000 0x30000000>;
>> + ranges = <0x0 0x0 0x10000000 0x10000000
>> + 0x1 0x0 0x40000000 0x10000000
>> + 0x2 0x0 0x50000000 0x10000000
>> + 0x3 0x0 0x60000000 0x10000000>;
>> + clocks = <&mck>;
>> +
>> + pinctrl-names = "default";
>> + pinctrl-0 = <&pinctrl_ebi_addr>;
>> +
>> + cs@0 {
>> + #address-cells = <2>;
>> + #size-cells = <1>;
>> + ranges;
>> + atmel,generic-dev;
>> + atmel,read-mode = "nrd";
>> + atmel,write-mode = "nwe";
>> + atmel,bus-width = <16>;
>> + atmel,ncs-rd-setup-ns = <0>;
>> + atmel,ncs-wr-setup-ns = <0>;
>> + atmel,nwe-setup-ns = <8>;
>> + atmel,nrd-setup-ns = <16>;
>> + atmel,ncs-rd-pulse-ns = <84>;
>> + atmel,ncs-wr-pulse-ns = <84>;
>> + atmel,nrd-pulse-ns = <76>;
>> + atmel,nwe-pulse-ns = <76>;
>> + atmel,nrd-cycle-ns = <107>;
>> + atmel,nwe-cycle-ns = <84>;
>> + atmel,tdf-ns = <16>;
>> +
>> + nor: flash@0,0 {
>> + compatible = "cfi-flash";
>> + #address-cells = <1>;
>> + #size-cells = <1>;
>> + reg = <0x0 0x0 0x1000000>;
>> + bank-width = <2>;
>> + };
>> + };
>> + };
>> +
>>
>
>
--
Nicolas Ferre
--
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