Re: [Qemu-devel] [PATCH v3 0/5] Raspberry Pi framebuffer, DMA and Windows support

[Peter Maydell <peter.maydell@linaro.org>]

On 8 March 2016 at 20:05, Andrew Baumann <Andrew.Baumann@microsoft.com> wrote:
> This patch series adds support for the AUX (second UART), framebuffer
> and DMA controller on Raspberry Pi 2, and enables booting Windows on
> this device. As with the previous series, it is heavily based on the
> original (out of tree) work of Gregory Estrade, Stefan Weil and others
> to support Raspberry Pi 1.
>
> After this series, it is possible to boot Windows by following the
> instructions at https://github.com/0xabu/qemu/wiki. You also boot
> Raspbian to the GUI using a command such as:
>
>   qemu-system-arm -M raspi2 -kernel raspbian-boot/kernel7.img -sd
>   2015-09-24-raspbian-jessie.img -append "rw earlyprintk loglevel=8
>   console=ttyAMA0 dwc_otg.lpm_enable=0 root=/dev/mmcblk0p2 rootwait"
>   -dtb raspbian-boot/bcm2709-rpi-2-b.dtb -serial stdio

So I tried something like this, and the kernel gives a WARNING with
a backtrace, and then hangs:

[    5.413943] VFP support v0.3: implementor 41 architecture 4 part 30
variant f rev 0
[    5.976888] pinctrl core: initialized pinctrl subsystem
[    6.171197] NET: Registered protocol family 16
[    6.286799] DMA: preallocated 4096 KiB pool for atomic coherent allocations
[    6.366889] cpuidle: using governor ladder
[    6.391665] cpuidle: using governor menu
[    6.401604] bcm2709.uart_clock = 3000000
[    6.478063] ------------[ cut here ]------------
[    6.481052] WARNING: CPU: 0 PID: 1 at
/build/buildd/linux-3.18.0/arch/arm/mach-bcm2709/armctrl.c:148
armctrl_xlate+0x188/0x274()
[    6.484474] Modules linked in:
[    6.489783] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
3.18.0-20-rpi2 #21-Ubuntu
[    6.502781] [<80016ab0>] (unwind_backtrace) from [<800129d0>]
(show_stack+0x10/0x14)
[    6.506355] [<800129d0>] (show_stack) from [<805fee10>]
(dump_stack+0x9c/0xd4)
[    6.508946] [<805fee10>] (dump_stack) from [<80026ed8>]
(warn_slowpath_common+0x70/0x8c)
[    6.511251] [<80026ed8>] (warn_slowpath_common) from [<80026f90>]
(warn_slowpath_null+0x1c/0x24)
[    6.512797] [<80026f90>] (warn_slowpath_null) from [<80022044>]
(armctrl_xlate+0x188/0x274)
[    6.514558] [<80022044>] (armctrl_xlate) from [<8007399c>]
(irq_create_of_mapping+0x64/0x110)
[    6.517173] [<8007399c>] (irq_create_of_mapping) from [<804c4ef4>]
(irq_of_parse_and_map+0x24/0x2c)
[    6.518741] [<804c4ef4>] (irq_of_parse_and_map) from [<804c4f14>]
(of_irq_to_resource+0x18/0xb8)
[    6.520209] [<804c4f14>] (of_irq_to_resource) from [<804c4ff0>]
(of_irq_to_resource_table+0x3c/0x54)
[    6.523598] [<804c4ff0>] (of_irq_to_resource_table) from
[<804c25b8>] (of_device_alloc+0xd8/0x180)
[    6.528838] [<804c25b8>] (of_device_alloc) from [<804c26a8>]
(of_platform_device_create_pdata+0x48/0x98)
[    6.535352] [<804c26a8>] (of_platform_device_create_pdata) from
[<804c27f0>] (of_platform_bus_create+0xec/0x3ac)
[    6.539440] [<804c27f0>] (of_platform_bus_create) from [<804c2860>]
(of_platform_bus_create+0x15c/0x3ac)
[    6.541217] [<804c2860>] (of_platform_bus_create) from [<804c2c28>]
(of_platform_populate+0x5c/0xa0)
[    6.542770] [<804c2c28>] (of_platform_populate) from [<8088cad8>]
(bcm2709_init+0x64/0x3fc)
[    6.546211] [<8088cad8>] (bcm2709_init) from [<80888870>]
(customize_machine+0x20/0x40)
[    6.547711] [<80888870>] (customize_machine) from [<800088bc>]
(do_one_initcall+0xd8/0x208)
[    6.549200] [<800088bc>] (do_one_initcall) from [<80885ef4>]
(kernel_init_freeable+0x1fc/0x29c)
[    6.551771] [<80885ef4>] (kernel_init_freeable) from [<805f9298>]
(kernel_init+0x8/0xf0)
[    6.553319] [<805f9298>] (kernel_init) from [<8000efe8>]
(ret_from_fork+0x14/0x2c)
[    6.556670] ---[ end trace 088ba587f0a009cc ]---
[    6.649948] No ATAGs?
[    6.658029] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4
watchpoint registers.
[    6.660393] hw-breakpoint: maximum watchpoint size is 8 bytes.
[    6.664206] mailbox: Broadcom VideoCore Mailbox driver
[    6.693912] bcm2708_vcio: mailbox at f300b880
[    6.703745] bcm_power: Broadcom power driver
[    6.707642] bcm_power_open() -> 0
[    6.708671] bcm_power_request(0, 8)

Does that look familiar? (My first guess is just that it wants some
bit of hardware we haven't got a device model for yet. I haven't
tried to investigate at all yet.)

thanks
-- PMM