Hi Zubair,
On Wed, Oct 14, 2015 at 5:51 AM, Zubair Lutfullah Kakakhel
<Zubair.Kakakhel@xxxxxxxxxx> wrote:
> Xilfpga boots only with device-tree. Document the required properties
> and the unique boot style
>
> Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@xxxxxxxxxx>
> ---
> .../devicetree/bindings/mips/img/xilfpga.txt | 76 ++++++++++++++++++++++
> 1 file changed, 76 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mips/img/xilfpga.txt
>
> diff --git a/Documentation/devicetree/bindings/mips/img/xilfpga.txt b/Documentation/devicetree/bindings/mips/img/xilfpga.txt
> new file mode 100644
> index 0000000..1e7084c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mips/img/xilfpga.txt
> @@ -0,0 +1,76 @@
> +Imagination University Program MIPSFpga
> +=======================================
> +
> +Under the Imagination University Program, a microAptiv UP core has been released for academic usage.
> +
> +As we are dealing with a mips core instantiated on an FPGA, specifications are fluid and can be varied in RTL.
> +
> +This binding document is provided as baseline guidance for the example project provided by IMG.
> +
> +The example project runs on the Nexys4DDR board by Digilent powered by the ARTIX-7 FPGA by Xilinx.
> +
> +Relevant details about the example project and the Nexys4DDR board:
> +
> +- microAptiv UP core m14Kc
> +- 50MHz clock speed
> +- 128Mbyte DDR RAM at 0x0000_0000
> +- 8Kbyte RAM at 0x1000_0000
> +- axi_intc at 0x1020_0000
> +- axi_uart16550 at 0x1040_0000
> +- axi_gpio at 0x1060_0000
> +- axi_i2c at 0x10A0_0000
> +- custom_gpio at 0x10C0_0000
> +- axi_ethernetlite at 0x10E0_0000
> +- 8Kbyte BootRAM at 0x1FC0_0000
> +
> +Required properties:
> +--------------------
> + - compatible: Must include "img,xilfpga".
> +
> +CPU nodes:
> +----------
> +A "cpus" node is required. Required properties:
> + - #address-cells: Must be 1.
> + - #size-cells: Must be 0.
> +A CPU sub-node is also required for at least CPU 0. Required properties:
> + - device_type: Must be "cpu".
> + - compatible: Must be "mips,m14Kc".
> + - reg: Must be <0>.
> + - clocks: Must include the CPU clock. See ../../clock/clock-bindings.txt for
> + details on clock bindings.
I think the reference to clock binding docs is not required.
> + - ext clock handle for fixed-clock received by MIPS core.
> +Example:
> + cpus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + cpu0: cpu@0 {
> + device_type = "cpu";
> + compatible = "mips,m14Kc";
> + reg = <0>;
> + clocks = <&ext>;
> + };
> + };
> +
> + ext: ext {
> + compatible = "fixed-clock";
> + #clock-cells = <0>;
> + clock-frequency = <50000000>;
> + };
> +
> +Boot protocol:
> +--------------
> +
> +The BootRAM is a writeable "RAM" in FPGA at 0x1FC0_0000. This is for easy reprogrammibility via JTAG.
> +
> +The BootRAM inializes the cache and the axi_uart peripheral.
> +
> +DDR initialiation is already handled by a HW IP block.
> +
> +When the example project bitstream is loaded, the cpu_reset button needs to be pressed.
> +
> +The bootram initializes the cache and axi_uart. Then outputs MIPSFPGA\n\r on the serial port
> +on the Nexys4DDR board.
> +
> +At this point, the board is ready to load the Linux kernel vmlinux file via JTAG.
> +
> --
> 1.9.1
>
> --
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Cheers,
Moritz
