Re: [PATCH v3 2/2] memory: ti-aemif: add bindings for AEMIF driver

Santosh Shilimkar
2013-12-14T19:16:35Z

Kumar,

On Wednesday 11 December 2013 05:59 AM, Ivan Khoronzhuk wrote:
> Add bindings for TI Async External Memory Interface (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 via 4 chip selects with 64M byte access per chip select.
>
> We are not encoding CS number in reg property, it's memory partition number.
> The CS number is encoded for Davinci NAND node using standalone property
> "ti,davinci-chipselect" and we need to provide two memory ranges to it,
> as result we can't encode CS number in "reg" for AEMIF child devices
> (NAND/NOR/etc), as it will break bindings compatibility.
>
> In this patch, NAND node is used just as an example of child node.
>
> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
> ---
Can you please check if you are happy with the updated version. Your ack
is needed to take the series forward. Thanks

> .../bindings/memory-controllers/ti-aemif.txt | 210 ++++++++++++++++++++
> 1 file changed, 210 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..d1466dc
> --- /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,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.
> +
> +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 = <0x2100A00 0x00000100>;
> + ranges = <0 0 0x70000000 0x10000000
> + 1 0 0x21000A00 0x0000100>;
> + /*
> + * 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-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>;
> + /*
> + * 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-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>;
> +
> + ...
> + };
> + };
> +};
>