Update the driver to support device tree boot as well along with ACPI.
At present the device tree parsing only provides the mmio region info
and is not the exact copy of ACPI parsing. This is sufficient to cater
all the current device tree usecases for VMBus.

Currently device tree is supported only for x86 systems.

Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
---
[V3]
- Changed the logic to use generic api (for_each_of_range) for parsing "ranges".
- Remove dependency of ACPI for HYPERV in case of x86.

 drivers/hv/Kconfig     |  4 +--
 drivers/hv/vmbus_drv.c | 60 ++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 0747a8f1fcee..7e44d4246d8d 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -4,8 +4,8 @@ menu "Microsoft Hyper-V guest support"
 
 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
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 9d6e0d02b834..5cbc541a20b5 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>
@@ -2152,7 +2153,7 @@ void vmbus_device_unregister(struct hv_device *device_obj)
 	device_unregister(&device_obj->device);
 }
 
-
+#ifdef CONFIG_ACPI
 /*
  * VMBUS is an acpi enumerated device. Get the information we
  * need from DSDT.
@@ -2262,6 +2263,7 @@ static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
 
 	return AE_OK;
 }
+#endif
 
 static int vmbus_mmio_remove(void)
 {
@@ -2282,7 +2284,7 @@ static int vmbus_mmio_remove(void)
 	}
 }
 
-static void vmbus_reserve_fb(void)
+static void __maybe_unused vmbus_reserve_fb(void)
 {
 	resource_size_t start = 0, size;
 	struct pci_dev *pdev;
@@ -2442,6 +2444,7 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size)
 }
 EXPORT_SYMBOL_GPL(vmbus_free_mmio);
 
+#ifdef CONFIG_ACPI
 static int vmbus_acpi_add(struct platform_device *pdev)
 {
 	acpi_status result;
@@ -2494,10 +2497,52 @@ static int vmbus_acpi_add(struct platform_device *pdev)
 		vmbus_mmio_remove();
 	return ret_val;
 }
+#else
+
+static int vmbus_device_add(struct platform_device *pdev)
+{
+	struct resource **cur_res = &hyperv_mmio;
+	struct of_range range;
+	struct of_range_parser parser;
+	struct device_node *np;
+	int ret = 0;
+
+	hv_dev = &pdev->dev;
+	np = pdev->dev.of_node;
+
+	ret = of_range_parser_init(&parser, np);
+	if (ret) {
+		dev_err(hv_dev, "Failed to parse resources.\n");
+		return ret;
+	}
+
+	for_each_of_range(&parser, &range) {
+		struct resource *res;
+
+		res = kzalloc(sizeof(*res), GFP_ATOMIC);
+		if (!res)
+			return -ENOMEM;
+
+		res->name = "hyperv mmio";
+		res->flags = IORESOURCE_MEM | IORESOURCE_MEM_64;
+		res->start = range.pci_addr;
+		res->end = range.pci_addr + range.size;
+
+		*cur_res = res;
+		cur_res = &res->sibling;
+	}
+
+	return ret;
+}
+#endif
 
 static int vmbus_platform_driver_probe(struct platform_device *pdev)
 {
+#ifdef CONFIG_ACPI
 	return vmbus_acpi_add(pdev);
+#else
+	return vmbus_device_add(pdev);
+#endif
 }
 
 static int vmbus_platform_driver_remove(struct platform_device *pdev)
@@ -2643,6 +2688,16 @@ static int vmbus_bus_resume(struct device *dev)
 #define vmbus_bus_resume NULL
 #endif /* CONFIG_PM_SLEEP */
 
+static const struct of_device_id vmbus_of_match[] = {
+	{
+		.compatible = "microsoft,vmbus",
+	},
+	{
+		/* sentinel */
+	},
+};
+MODULE_DEVICE_TABLE(of, vmbus_of_match);
+
 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
 	{"VMBUS", 0},
 	{"VMBus", 0},
@@ -2677,6 +2732,7 @@ static struct platform_driver vmbus_platform_driver = {
 	.driver = {
 		.name = "vmbus",
 		.acpi_match_table = ACPI_PTR(vmbus_acpi_device_ids),
+		.of_match_table = of_match_ptr(vmbus_of_match),
 		.pm = &vmbus_bus_pm,
 		.probe_type = PROBE_FORCE_SYNCHRONOUS,
 	}
-- 
2.25.1

Hi Saurabh,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on next-20230206]
[cannot apply to robh/for-next tip/timers/core brgl/gpio/for-next wsa/i2c/for-next linus/master v6.2-rc7 v6.2-rc6 v6.2-rc5 v6.2-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Saurabh-Sengar/drivers-clocksource-hyper-v-non-ACPI-support-in-hyperv-clock/20230207-015625
patch link:    https://lore.kernel.org/r/1675706060-22361-7-git-send-email-ssengar%40linux.microsoft.com
patch subject: [PATCH v3 6/6] Driver: VMBus: Add device tree support
config: i386-randconfig-a014-20230206 (https://download.01.org/0day-ci/archive/20230207/202302071011.XjQOfXVK-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
reproduce (this is a W=1 build):
        # https://github.com/intel-lab-lkp/linux/commit/121473f34bab66918912399f1cfe9e06a9ea0294
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Saurabh-Sengar/drivers-clocksource-hyper-v-non-ACPI-support-in-hyperv-clock/20230207-015625
        git checkout 121473f34bab66918912399f1cfe9e06a9ea0294
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/hv/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/hv/vmbus_drv.c: In function 'vmbus_mmio_remove':
   drivers/hv/vmbus_drv.c:2285:1: error: no return statement in function returning non-void [-Werror=return-type]
    2285 | }
         | ^
   At top level:
>> drivers/hv/vmbus_drv.c:2691:34: warning: 'vmbus_of_match' defined but not used [-Wunused-const-variable=]
    2691 | static const struct of_device_id vmbus_of_match[] = {
         |                                  ^~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/vmbus_of_match +2691 drivers/hv/vmbus_drv.c

  2690	
> 2691	static const struct of_device_id vmbus_of_match[] = {
  2692		{
  2693			.compatible = "microsoft,vmbus",
  2694		},
  2695		{
  2696			/* sentinel */
  2697		},
  2698	};
  2699	MODULE_DEVICE_TABLE(of, vmbus_of_match);
  2700	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests