Re: [PATCH v2 5/7] arm: qemu: Enable ramfb by default

[Alper Nebi Yasak <alpernebiyasak@gmail.com>]

On 2023-08-28 20:54 +03:00, Simon Glass wrote:
> Hi Alper,
> On Mon, 28 Aug 2023 at 09:46, Alper Nebi Yasak <alpernebiyasak@gmail.com> wrote:
>>
>> On 2023-08-22 21:56 +03:00, Simon Glass wrote:
>>> Hi Alper,
>>>
>>> On Tue, 22 Aug 2023 at 06:10, Alper Nebi Yasak <alpernebiyasak@gmail.com> wrote:
>>>>
>>>> From: Alexander Graf <agraf@csgraf.de>
>>>>
>>>> Now that we have everything in place to support ramfb, let's wire it up
>>>> by default in the ARM QEMU targets. That way, you can easily use a
>>>> graphical console by just passing -device ramfb to the QEMU command line.
>>>>
>>>> Signed-off-by: Alexander Graf <agraf@csgraf.de>
>>>> [Alper: Rebase on bochs changes, add pre-reloc init, error handling]
>>>> Co-developed-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
>>>> Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
>>>> ---
>>>>
>>>> Changes in v2:
>>>> - Rebase on "qemu: arm: Enable Bochs, console buffering, USB keyboard"
>>>> - Drop env changes from ARM (necessary but in prerequisite series)
>>>> - Drop imply VIDEO, SYS_CONSOLE_IN_ENV changes from ARM (in prereq.)
>>>> - Probe QFW in ARM QEMU board_early_init_f to bind ramfb pre-reloc
>>>> - Add IS_ENABLED(CONFIG_QFW) check and error handling to ARM QEMU
>>>>
>>>>  arch/arm/Kconfig                    |  3 +++
>>>>  board/emulation/qemu-arm/qemu-arm.c | 41 +++++++++++++++++++++++++++++
>>>>  2 files changed, 44 insertions(+)
>>>>
>>>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>>>> index 1fd3ccd1607f..7afe26ac804f 100644
>>>> --- a/arch/arm/Kconfig
>>>> +++ b/arch/arm/Kconfig
>>>> @@ -1046,6 +1046,9 @@ config ARCH_QEMU
>>>>         imply USB_XHCI_PCI
>>>>         imply USB_KEYBOARD
>>>>         imply CMD_USB
>>>> +       imply VIDEO_RAMFB
>>>> +       imply BOARD_EARLY_INIT_F
>>>> +       imply BOARD_EARLY_INIT_R
>>>>
>>>>  config ARCH_RMOBILE
>>>>         bool "Renesas ARM SoCs"
>>>> diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c
>>>> index 942f1fff5717..23ef31cb7feb 100644
>>>> --- a/board/emulation/qemu-arm/qemu-arm.c
>>>> +++ b/board/emulation/qemu-arm/qemu-arm.c
>>>> @@ -11,6 +11,7 @@
>>>>  #include <fdtdec.h>
>>>>  #include <init.h>
>>>>  #include <log.h>
>>>> +#include <qfw.h>
>>>>  #include <usb.h>
>>>>  #include <virtio_types.h>
>>>>  #include <virtio.h>
>>>> @@ -102,6 +103,46 @@ static struct mm_region qemu_arm64_mem_map[] = {
>>>>  struct mm_region *mem_map = qemu_arm64_mem_map;
>>>>  #endif
>>>>
>>>> +int board_early_init_f(void)
>>>> +{
>>>> +       struct udevice *dev;
>>>> +       int ret;
>>>> +
>>>> +       /*
>>>> +        * Make sure we enumerate the QEMU Firmware device to bind ramfb
>>>> +        * so video_reserve() can reserve memory for it.
>>>> +        */
>>>> +       if (IS_ENABLED(CONFIG_QFW)) {
>>>> +               ret = qfw_get_dev(&dev);
>>>> +               if (ret) {
>>>> +                       log_err("Failed to get QEMU FW device: %d\n", ret);
>>>
>>> We should only present an error if the device is present but
>>> failed...so if the user doesn't provide the flag, all should be well.
>>
>> I don't understand what you mean by "user doesn't provide the flag". But
>> I assume this should ignore the error (unless what?) so that we can
>> continue to boot. Would that apply for board_early_init_r below as well?
> 
> I thought you said there was a qemu flag to enable ramfb? So add it to
> the DT and then the device can (in its bind routine) decide not to be
> bound by returning -ENODEV

Ah. I'm not used to calling them flags, especially those that have
values as in "-device ramfb". My mind jumped to DM_FLAG_PRE_RELOC /
bootph-some-ram.

But note that what this code tries to probe here is not the ramfb
device, it's the bus/parent of that. If this fails, we can't know if the
user specified "-device ramfb" or not.

Is the parent node's device probed by the time .bind() is called? Or,
can I have it probed by calling qfw_get_dev() (which is just
uclass_first_device_err(UCLASS_QFW, ...))?