From:   "Michael Kelley (LINUX)" <mikelley@microsoft.com>
To:     Saurabh Sengar <ssengar@linux.microsoft.com>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        "wei.liu@kernel.org" <wei.liu@kernel.org>,
        Dexuan Cui <decui@microsoft.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>
Subject: RE: [PATCH v9 5/5] Driver: VMBus: Add Devicetree support
Thread-Topic: [PATCH v9 5/5] Driver: VMBus: Add Devicetree support
Thread-Index: AQHZWwBDpvUkyd9oQUaDzsOlV6PYEq8D9mMA
Date:   Mon, 20 Mar 2023 18:04:16 +0000
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References: <1679298460-11855-1-git-send-email-ssengar@linux.microsoft.com>
 <1679298460-11855-6-git-send-email-ssengar@linux.microsoft.com>
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From: Saurabh Sengar <ssengar@linux.microsoft.com> Sent: Monday, March 20, =
2023 12:48 AM
>=20
> Update the driver to support Devicetree boot as well along with ACPI.
> At present the Devicetree parsing only provides the mmio region info
> and is not the exact copy of ACPI parsing. This is sufficient to cater
> all the current Devicetree usecases for VMBus.
>=20
> Currently Devicetree is supported only for x86 systems.
>=20
> Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> ---
> [V9]
> - Add vmbus_mmio_remove for error handling
> - Remove logic from !acpi_disabled to acpi_disabled
>=20
>  drivers/hv/Kconfig     |  5 ++--
>  drivers/hv/vmbus_drv.c | 66 +++++++++++++++++++++++++++++++++++++++---
>  2 files changed, 65 insertions(+), 6 deletions(-)
>=20
> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> index 0747a8f1fcee..47132b30b7ee 100644
> --- a/drivers/hv/Kconfig
> +++ b/drivers/hv/Kconfig
> @@ -4,11 +4,12 @@ menu "Microsoft Hyper-V guest support"
>=20
>  config HYPERV
>  	tristate "Microsoft Hyper-V client drivers"
> -	depends on ACPI && ((X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
> -		|| (ARM64 && !CPU_BIG_ENDIAN))
> +	depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
> +		|| (ACPI && ARM64 && !CPU_BIG_ENDIAN)
>  	select PARAVIRT
>  	select X86_HV_CALLBACK_VECTOR if X86
>  	select VMAP_PFN
> +	select OF_EARLY_FLATTREE if OF
>  	help
>  	  Select this option to run Linux as a Hyper-V client operating
>  	  system.
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 3ad2fa2b92e7..5de2d3bb8289 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -20,6 +20,7 @@
>  #include <linux/completion.h>
>  #include <linux/hyperv.h>
>  #include <linux/kernel_stat.h>
> +#include <linux/of_address.h>
>  #include <linux/clockchips.h>
>  #include <linux/cpu.h>
>  #include <linux/sched/isolation.h>
> @@ -2143,7 +2144,7 @@ void vmbus_device_unregister(struct hv_device
> *device_obj)
>  	device_unregister(&device_obj->device);
>  }
>=20
> -
> +#ifdef CONFIG_ACPI
>  /*
>   * VMBUS is an acpi enumerated device. Get the information we
>   * need from DSDT.
> @@ -2253,6 +2254,7 @@ static acpi_status vmbus_walk_resources(struct
> acpi_resource *res, void *ctx)
>=20
>  	return AE_OK;
>  }
> +#endif
>=20
>  static void vmbus_mmio_remove(void)
>  {
> @@ -2273,7 +2275,7 @@ static void vmbus_mmio_remove(void)
>  	}
>  }
>=20
> -static void vmbus_reserve_fb(void)
> +static void __maybe_unused vmbus_reserve_fb(void)
>  {
>  	resource_size_t start =3D 0, size;
>  	struct pci_dev *pdev;
> @@ -2433,6 +2435,7 @@ void vmbus_free_mmio(resource_size_t start,
> resource_size_t size)
>  }
>  EXPORT_SYMBOL_GPL(vmbus_free_mmio);
>=20
> +#ifdef CONFIG_ACPI
>  static int vmbus_acpi_add(struct platform_device *pdev)
>  {
>  	acpi_status result;
> @@ -2485,10 +2488,54 @@ static int vmbus_acpi_add(struct platform_device =
*pdev)
>  		vmbus_mmio_remove();
>  	return ret_val;
>  }
> +#else
> +static int vmbus_acpi_add(struct platform_device *pdev)
> +{
> +	return 0;
> +}
> +#endif
> +
> +static int vmbus_device_add(struct platform_device *pdev)
> +{
> +	struct resource **cur_res =3D &hyperv_mmio;
> +	struct of_range range;
> +	struct of_range_parser parser;
> +	struct device_node *np =3D pdev->dev.of_node;
> +	int ret;
> +
> +	hv_dev =3D &pdev->dev;
> +
> +	ret =3D of_range_parser_init(&parser, np);
> +	if (ret)
> +		return ret;
> +
> +	for_each_of_range(&parser, &range) {
> +		struct resource *res;
> +
> +		res =3D kzalloc(sizeof(*res), GFP_KERNEL);
> +		if (!res) {
> +			vmbus_mmio_remove();
> +			return -ENOMEM;
> +		}
> +
> +		res->name =3D "hyperv mmio";
> +		res->flags =3D range.flags;
> +		res->start =3D range.cpu_addr;
> +		res->end =3D range.cpu_addr + range.size;
> +
> +		*cur_res =3D res;
> +		cur_res =3D &res->sibling;
> +	}
> +
> +	return ret;
> +}
>=20
>  static int vmbus_platform_driver_probe(struct platform_device *pdev)
>  {
> -	return vmbus_acpi_add(pdev);
> +	if (acpi_disabled)
> +		return vmbus_device_add(pdev);
> +	else
> +		return vmbus_acpi_add(pdev);
>  }
>=20
>  static int vmbus_platform_driver_remove(struct platform_device *pdev)
> @@ -2634,7 +2681,17 @@ static int vmbus_bus_resume(struct device *dev)
>  #define vmbus_bus_resume NULL
>  #endif /* CONFIG_PM_SLEEP */
>=20
> -static const struct acpi_device_id vmbus_acpi_device_ids[] =3D {
> +static const __maybe_unused struct of_device_id vmbus_of_match[] =3D {
> +	{
> +		.compatible =3D "microsoft,vmbus",
> +	},
> +	{
> +		/* sentinel */
> +	},
> +};
> +MODULE_DEVICE_TABLE(of, vmbus_of_match);
> +
> +static const __maybe_unused struct acpi_device_id vmbus_acpi_device_ids[=
] =3D {
>  	{"VMBUS", 0},
>  	{"VMBus", 0},
>  	{"", 0},
> @@ -2668,6 +2725,7 @@ static struct platform_driver vmbus_platform_driver=
 =3D {
>  	.driver =3D {
>  		.name =3D "vmbus",
>  		.acpi_match_table =3D ACPI_PTR(vmbus_acpi_device_ids),
> +		.of_match_table =3D of_match_ptr(vmbus_of_match),
>  		.pm =3D &vmbus_bus_pm,
>  		.probe_type =3D PROBE_FORCE_SYNCHRONOUS,
>  	}
> --
> 2.34.1

Reviewed-by: Michael Kelley <mikelley@microsoft.com>