Re: [PATCH v1 3/3] xen/common: move device initialization code to common code

[Jan Beulich <jbeulich@xxxxxxxx>]

On 11.09.2024 12:04, Oleksii Kurochko wrote:
> --- a/xen/common/Makefile
> +++ b/xen/common/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_HYPFS_CONFIG) += config_data.o
>  obj-$(CONFIG_CORE_PARKING) += core_parking.o
>  obj-y += cpu.o
>  obj-$(CONFIG_DEBUG_TRACE) += debugtrace.o
> +obj-$(call or,$(CONFIG_HAS_DEVICE_TREE),$(CONFIG_HAS_ACPI)) += device.o

I can't spot any HAS_ACPI in the tree. And if this was switched to CONFIG_ACPI
I'd further ask why the file needs building on x86.

Also I think I'd prefer to avoid the of the "or" macro here:

obj-$(CONFIG_ACPI) += device.o
obj-$(CONFIG_HAS_DEVICE_TREE) += device.o

ought to be quite fine. There's de-duplication somewhere for what $(obj-y) 
lists.

> --- /dev/null
> +++ b/xen/common/device.c
> @@ -0,0 +1,82 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Based on the code from:
> + *   xen/arch/arm/device.c
> + */
> +
> +#include <xen/bug.h>
> +#include <xen/device_tree.h>
> +#include <xen/errno.h>
> +#include <xen/init.h>
> +
> +#include <asm-generic/device.h>
> +
> +#ifdef CONFIG_ACPI
> +extern const struct acpi_device_desc _asdevice[], _aedevice[];

Why does this live separately here, rather than ...

> +#endif
> +
> +#ifdef CONFIG_HAS_DEVICE_TREE
> +
> +extern const struct device_desc _sdevice[], _edevice[];

... like this ...

> +int __init device_init(struct dt_device_node *dev, enum device_class class,
> +                       const void *data)
> +{
> +    const struct device_desc *desc;
> +
> +    ASSERT(dev != NULL);
> +
> +    if ( !dt_device_is_available(dev) || dt_device_for_passthrough(dev) )
> +        return  -ENODEV;
> +
> +    for ( desc = _sdevice; desc != _edevice; desc++ )
> +    {
> +        if ( desc->class != class )
> +            continue;
> +
> +        if ( dt_match_node(desc->dt_match, dev) )
> +        {
> +            ASSERT(desc->init != NULL);
> +
> +            return desc->init(dev, data);
> +        }
> +    }
> +
> +    return -EBADF;
> +}
> +
> +enum device_class device_get_class(const struct dt_device_node *dev)
> +{
> +    const struct device_desc *desc;
> +
> +    ASSERT(dev != NULL);
> +
> +    for ( desc = _sdevice; desc != _edevice; desc++ )
> +    {
> +        if ( dt_match_node(desc->dt_match, dev) )
> +            return desc->class;
> +    }
> +
> +    return DEVICE_UNKNOWN;
> +}
> +
> +#endif
> +
> +#ifdef CONFIG_ACPI

... in the section where it's needed? Leaving just one #ifdef for ACPI.

Jan