On Thu, Sep 12, 2013 at 11:17:50AM +0100, Peter Maydell wrote:
> This patch series adds a 'virt' platform which uses the
> kernel's mach-virt (fully device-tree driven) support
> to create a simple minimalist platform intended for
> use for KVM VM guests.
looks good to me. fwiw
Reviewed-by: Chritoffer Dall <christoffer.dall@xxxxxxxxxx>
>
> The major change here is that I've added a PL011 UART.
>
> Sample command line:
>
> qemu-system-arm -machine type=virt -display none \
> -kernel zImage \
> -append 'root=/dev/vda rw console=ttyAMA0 rootwait'
> -cpu cortex-a15 \
> -device virtio-blk-device,drive=foo \
> -drive if=none,file=arm-wheezy.img,id=foo \
> -m 2048 -serial stdio
>
> Note that there is no earlyprintk via the PL011 because
> there's no defined device tree binding for "hey, here
> is your earlyprintk UART".
>
>
> *** NOTE *** to get the PL011 to work you'll need to
> tweak the kernel a bit:
>
> diff --git a/arch/arm/mach-virt/virt.c b/arch/arm/mach-virt/virt.c
> index b184e57..2b6aceb 100644
> --- a/arch/arm/mach-virt/virt.c
> +++ b/arch/arm/mach-virt/virt.c
> @@ -21,11 +21,13 @@
> #include <linux/of_irq.h>
> #include <linux/of_platform.h>
> #include <linux/smp.h>
> +#include <linux/clk-provider.h>
>
> #include <asm/mach/arch.h>
>
> static void __init virt_init(void)
> {
> + of_clk_init(NULL);
> of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
> }
>
>
> Otherwise the kernel doesn't ever add the clock to its
> list, and then it refuses to probe for the PL011.
> (I'm told this isn't really the right fix, though, and
> ideally the call should be done in some generic location
> rather than in every machine's init function.)
>
> The alternative would be for the kernel to be fixed to
> follow its own device tree binding documentation and not
> require clocks/clock-names properties on the pl011 node.
Is anyone taking a look at a proper fix as far as you know?
-Christoffer
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