Re: [PATCH v4 1/2] bcma: register bcma as device tree driver

Hauke Mehrtens
2014-09-23T22:04:18Z

On 09/22/2014 09:26 AM, Arnd Bergmann wrote:
> On Monday 22 September 2014 00:38:27 Hauke Mehrtens wrote:
>> +
>> +- reg : iomem address range of chipcommon core
>> +
>> +The cores on the AXI bus are automatically detected by bcma with the
>> +memory ranges they are using and they get registered afterwards.
>> +Automatic detection of the IRQ number is not reliable on
>> +BCM47xx/BCM53xx ARM SoCs. To assign IRQ numbers to the cores, provide
>> +them manually through device tree. The IRQ number and the device tree
>> +child entry will get assigned to the core with the matching reg address.
>> +
>> +Example:
>> +
>> + axi@18000000 {
>> + compatible = "brcm,bus-axi";
>> + reg = <0x18000000 0x1000>;
>> + ranges = <0x00000000 0x18000000 0x00100000>;
>> + #address-cells = <1>;
>> + #size-cells = <1>;
>> +
>> + pcie@12000 {
>> + reg = <0x00012000 0x1000>;
>> + interrupts = <GIC_SPI 131 IRQ_TYPE_LEVEL_HIGH>;
>> + };
>> +
>> + ethernet@24000 {
>> + reg = <0x00024000 0x1000>;
>> + interrupts = <GIC_SPI 147 IRQ_TYPE_LEVEL_HIGH>;
>> + };
>> +
>> + ethernet@25000 {
>> + reg = <0x00025000 0x1000>;
>> + interrupts = <GIC_SPI 148 IRQ_TYPE_LEVEL_HIGH>;
>> + };
>> + };
>>
>
> While reading through this new version, I had a new idea about how
> this could be handled better for any machines that have a unique
> number in the interrupt field: If you do the same thing as PCI
> and add an interrupt-map property [1], you can translate that
> number into a real interrupt specifier for the child nodes.
>
> This can work even if every device lists the local interrupt
> as '0', since you can have device-specific lookup entries if you
> use the correct interrupt-map-mask property.
>
> Arnd
>
> [1] http://www.openfirmware.org/1275/practice/imap/imap0_9d.pdf
>

I assume this should then look somehow like this:

axi@18000000 {
compatible = "brcm,bus-axi";
reg = <0x18000000 0x1000>;
ranges = <0x00000000 0x18000000 0x00100000>;
#address-cells = <1>;
#size-cells = <1>;

#interrupt-cells = <1>;
interrupt-map = <
/* ChipCommon */
0x00000000 0 &gic GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH

/* PCIe Controller 0 */
0x00012000 0 &gic GIC_SPI 126 IRQ_TYPE_LEVEL_HIGH
0x00012000 1 &gic GIC_SPI 127 IRQ_TYPE_LEVEL_HIGH
0x00012000 2 &gic GIC_SPI 128 IRQ_TYPE_LEVEL_HIGH
0x00012000 3 &gic GIC_SPI 129 IRQ_TYPE_LEVEL_HIGH
0x00012000 4 &gic GIC_SPI 130 IRQ_TYPE_LEVEL_HIGH
0x00012000 5 &gic GIC_SPI 131 IRQ_TYPE_LEVEL_HIGH

/* USB 2.0 Controller */
0x00021000 0 &gic GIC_SPI 79 IRQ_TYPE_LEVEL_HIGH
>;
};

How does the mapping of these interrupts to the devices work?

Do I have to add a device tree entry for every device after all?

Do you have some example code where this is handled in code, I could not
find the code doing this for PCI.

Hauke