ARM GIC / PL061 error on uni-processor system

[Christopher Horler]

chorler@linux-foxtrot:~/projects/src/qemu> git describe
v2.2.0-369-gab0302e

When booting Linux 3.19.1 (default buildroot), configured for realview-pb-a8 on qemu from git (as above).

The following message appears (line 253/ 254 of attached log):
"GIC CPU mask not found - kernel will fail to boot."

The kernel does boot - so perhaps this is a misleading error message?
(though temporarily tweaking commit 6b9680bb does remove the message)

later the following three lines appear when pl061 is probed (resulting in ENODEV):
pl061_gpio dev:gpio0: invalid IRQ base in pdata
pl061_gpio dev:gpio1: invalid IRQ base in pdata
pl061_gpio dev:gpio2: invalid IRQ base in pdata

(from linux-3.18.1/drivers/gpio/gpio-pl061.c line 253)

qemu/hw/arm/realview.c
has some code that suggests to me pl061 is required for the MMC.

Where should I look to see how to initialise the irq_base member of the platform data in QEmu?

[Christopher Horler (cshorler)]

now I look further I notice that the pl061_platform_data structures are not fully initialised in the kernel

linux-3.18.1/arch/arm/mach-realview/realview_pba8.c

so this probably isn't a qemu bug

[Christopher Horler (cshorler)]

confirmed - not a bug, patching the kernel fixes the problem.

[Christopher Horler (cshorler)]

In arch/arm/mach-realview/realview_*.c pl061_platform_data irq_base members are statically (default) initialised to 0 (whereas for versatile they are explicitly set via defines in the platform headers).

In pl061_probe, -ENODEV is returned for irq_base <= 0.

Changing this to < 0, results in irq_domain_add_simple dynamically allocating irqs - and in the case of qemu resolves booting from MMC / SD, where pl061 is linked to pl181 in realview.c

I assume this is also valid for real hardware, but have no way to test.

I have not figured out what stops the 2.6 kernel booting, which is what I actually need... (seems to be coupled to mmci.c, or possibly the ext2 filesystem)