On 1 Jan 2013, at 22:08, Andrew Turner wrote:
>> On a semi-related note: the current obstacle to moving more devices
>> over to using FDT on BERI is that our FDT implementation appears to
>> require a PIC to be configured. We're not actually using a PIC on
>> BERI currently. It works fine attached to nexus, as the implied
>> fallback for not having a PIC is to simply use the suitably numbered
>> interrupt wires direct into the MIPS. However, trying the same setup
>> described using FDT leads to an interrupt-related warning at boot,
>> and no interrupt being provided to the driver. I suspect I need to
>> provide a PIC-alike software component as a fall-back for the non-PIC
>> case. From a brief e-mail exchange with JC, it sounds like the XLP
>> FDT setup is actually not using interrupts either, currently.
>
> I'm not sure if a PIC is required. From my reading of the code it
> appears not. By the look of it if you are using the nexus to
> handle interrupts you need to put an interrupts property in the device
> and "#interrupt-cells = <1>;" in the soc node.
>
> You will also need to implement an interrupt decode function and add it
> to the fdt_pic_table array. ARM has a number of almost identical copies
> of this function you can use for inspration.
This seemed to do the trick; what do you think of the attached? This isn't a
board-specific change, so I dropped it into the common fdt_mips.c code. On the
other hand, this left it a bit open as to what the right compatible= line to
use was, so feedback there most welcome.
Robert
Change 219933 by rwatson@rwatson_zenith_cl_cam_ac_uk on 2013/01/02 09:32:16
Implement an FDT PIC decode routine to use when no PIC has been
configured, which assumes a cascade back to the nexus bus (e.g.,
the on-board CP0 interrupt management parts on the MIPS). If the
soc bus in a MIPS DTS file is declared as "mips4k,cp0"-compatible,
then this will be enabled. This is sufficient to allow IRQs to be
configured on BERI.
Affected files ...
.. //depot/projects/ctsrd/beribsd/src/sys/dev/fdt/fdt_mips.c#2 edit
Differences ...
==== //depot/projects/ctsrd/beribsd/src/sys/dev/fdt/fdt_mips.c#2 (text+ko) ====
@@ -49,8 +49,26 @@
{ NULL, NULL }
};
+/*
+ * For PIC-free boards, provide a PIC decoder to be used with mips4k CP0
+ * interrupt control directly.
+ */
+static int
+fdt_pic_decode_mips4k_cp0(phandle_t node, pcell_t *intr, int *interrupt,
+ int *trig, int *pol)
+{
+
+ if (!fdt_is_compatible(node, "mips4k,cp0"))
+ return (ENXIO);
+
+ *interrupt = fdt32_to_cpu(intr[0]);
+ *trig = INTR_TRIGGER_CONFORM;
+ *pol = INTR_POLARITY_CONFORM;
+
+ return (0);
+}
+
fdt_pic_decode_t fdt_pic_table[] = {
- NULL,
- NULL,
+ &fdt_pic_decode_mips4k_cp0,
NULL
};
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