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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..9592717 --- /dev/null +++ b/Documentation/devicetree/bindings/memory-controllers/ti-aemif.txt @@ -0,0 +1,210 @@ +* Device tree bindings for Texas instruments AEMIF controller + +The Async External Memory Interface (EMIF16/AEMIF) controller is intended to +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 (DA850) - 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,da850-aemif" + +- reg: contains offset/length value for AEMIF control registers + space. + +- #address-cells: Must be 2. The partition number has to be encoded in the + first address cell and it may accept values 0..N-1 + (N - total number of partitions). It's recommended to + assign N-1 number for the control partition. The second + cell is the offset into the partition. + +- #size-cells: Must be set to 1. + +- ranges: Contains memory regions. There are two types of + ranges/partitions: + - CS-specific partition/range. If continuous, must be + set up to reflect the memory layout for 4 chipselects, + if not then additional range/partition can be added and + child device can select the proper one. + - control partition which is common for all CS + interfaces. + +- clocks: the clock feeding 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: + +- #address-cells: Must be 2. + +- #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. + +- ti,cs-chipselect: number of chipselect. Indicates on the aemif driver + which chipselect is used for accessing the memory. For + compatibles "ti,davinci-aemif" and "ti,keystone-aemif" + it can be in range [0-3]. For compatible + "ti,da850-aemif" range is [2-5]. + +Optional child cs node properties: + +- ti,cs-bus-width: width of the asynchronous device's data bus + 8 or 16 if not preset 8 + +- ti,cs-select-strobe-mode: 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-extended-wait-mode: 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-min-turnaround-ns: 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-read-setup-ns: 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-read-strobe-ns: read strobe width, ns + Time between the activation and deactivation of + the read strobe. + Minimum value is 1 (0 treated as 1). + +- ti,cs-read-hold-ns: 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-write-setup-ns: 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-write-strobe-ns: write strobe width, ns + Time between the activation and deactivation of + the write strobe. + Minimum value is 1 (0 treated as 1). + +- ti,cs-write-hold-ns: 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. + +Example for aemif, davinci nand and nor flash chip select shown below. + +memory-controller@21000A00 { + compatible = "ti,davinci-aemif"; + #address-cells = <2>; + #size-cells = <1>; + clocks = <&clkaemif 0>; + clock-names = "aemif"; + clock-ranges; + reg = <0x21000A00 0x00000100>; + ranges = <0 0 0x70000000 0x10000000 + 1 0 0x21000A00 0x00000100>; + /* + * Partition0: CS-specific memory range which is + * implemented as continuous physical memory region + * Partition1: control memory range + */ + + nand:cs2 { + #address-cells = <2>; + #size-cells = <1>; + clock-ranges; + ranges; + + ti,cs-chipselect = <2>; + /* all timings in nanoseconds */ + ti,cs-min-turnaround-ns = <0>; + ti,cs-read-hold-ns = <7>; + ti,cs-read-strobe-ns = <42>; + ti,cs-read-setup-ns = <14>; + ti,cs-write-hold-ns = <7>; + ti,cs-write-strobe-ns = <42>; + ti,cs-write-setup-ns = <14>; + + nand@0,0x8000000 { + compatible = "ti,davinci-nand"; + reg = <0 0x8000000 0x4000000 + 1 0x0000000 0x0000100>; + /* + * Partition0, offset 0x8000000, size 0x4000000 + * Partition1, offset 0x0000000, size 0x0000100 + */ + + .. see davinci-nand.txt + }; + }; + + nor:cs0 { + #address-cells = <2>; + #size-cells = <1>; + clock-ranges; + ranges; + + ti,cs-chipselect = <0>; + /* all timings in nanoseconds */ + ti,cs-min-turnaround-ns = <0>; + ti,cs-read-hold-ns = <8>; + ti,cs-read-strobe-ns = <40>; + ti,cs-read-setup-ns = <14>; + ti,cs-write-hold-ns = <7>; + ti,cs-write-strobe-ns = <40>; + ti,cs-write-setup-ns = <14>; + ti,cs-bus-width = <16>; + + flash@0,0x0000000 { + compatible = "cfi-flash"; + reg = <0 0x0000000 0x4000000>; + + ... + }; + }; +}; |
