Hi everybody, I'm (at last) trying to move from ARCH=ppc to ARCH=powerpc. After reading Documentation/powerpc/booting-without-of.txt and various device trees in arch/powerpc/boot/dts, I still don't know how to express some devices in the device tree.
The target board has several devices on the processor local bus, as described
in the following device tree fragment.
[EMAIL PROTECTED] {
compatible = "fsl,mpc8260-localbus",
"fsl,pq2-localbus";
#address-cells = <2>;
#size-cells = <1>;
reg = <f0010100 60>;
ranges = <0 0 40000000 01000000
2 0 f2000000 00100000
3 0 f3000000 00100000
4 0 f4000000 00100000>;
[EMAIL PROTECTED],0 {
compatible = "cfi-flash";
reg = <0 0 01000000>;
bank-width = <2>;
};
[EMAIL PROTECTED],0 {
compatible = "mtd-ram";
reg = <2 0 00100000>;
bank-width = <2>;
};
[EMAIL PROTECTED],0 {
device_type = "board-control";
reg = <3 0 00000020>;
};
[EMAIL PROTECTED],0 {
reg = <4 0 00010000>;
};
};
The fourth device is a FPGA that contains several IP cores such as an
interrupt controller and a SD/MMC host controller. If I understand things
correctly, each IP core should have its own node in the device tree to allow
proper binding with device drivers. As booting-without-of.txt describes the
localbus node ranges as corresponding to a single chipselect and covering the
entire chipselect access window, I can't have nodes for each IP core as
children of the localbus node.
Should I put IP core nodes as children of the FPGA node ? If so, how do I map
addresses at the FPGA level ? A ranges property in the FPGA node would let me
map addresses in the FPGA scope to the localbus scope. However, as the
localbus scope use the chipselect number as its first address cell and 0 as
its second address cell, I don't see how I could translate offsets in the
FPGA into an address at the localbus scope.
Could anyone advice me regarding how to properly describe my hardware in the
device tree ?
Best regards,
--
Laurent Pinchart
CSE Semaphore Belgium
Chaussée de Bruxelles, 732A
B-1410 Waterloo
Belgium
T +32 (2) 387 42 59
F +32 (2) 387 42 75
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