Re: [PATCH v5 5/5] Driver: VMBus: Add device tree support

Saurabh Singh Sengar
2023-02-09T17:46:47Z

On Thu, Feb 09, 2023 at 09:50:31AM -0600, Rob Herring wrote:
> On Thu, Feb 9, 2023 at 6:15 AM Saurabh Sengar
> <ssengar@linux.microsoft.com> wrote:
> >
> > Update the driver to support device tree boot as well along with ACPI.
>
> Devicetree
>
> > At present the device tree parsing only provides the mmio region info
>
> Devicetree
>
> And anywhere else.

OK

>
> > 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>
> > ---
> > - Removed #else for device tree parsing code. This should help better
> > test coverage.
> > - Fix macro '__maybe_unused' warning
> > - Added below options in Kconfig to enable device tree options for HYPERV
> > select OF if !ACPI
> > select OF_EARLY_FLATTREE if !ACPI
> >
> > drivers/hv/Kconfig | 6 +++--
> > drivers/hv/vmbus_drv.c | 60 ++++++++++++++++++++++++++++++++++++++++--
> > 2 files changed, 62 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> > index 0747a8f1fcee..1a55bf32d195 100644
> > --- a/drivers/hv/Kconfig
> > +++ b/drivers/hv/Kconfig
> > @@ -4,11 +4,13 @@ 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
> > + select OF if !ACPI
> > + select OF_EARLY_FLATTREE if !ACPI
> > 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 73497157a23a..02f6bab61c37 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 void vmbus_mmio_remove(void)
> > {
> > @@ -2282,7 +2284,7 @@ static void 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 +2497,50 @@ static int vmbus_acpi_add(struct platform_device *pdev)
> > vmbus_mmio_remove();
> > return ret_val;
> > }
> > +#endif
> > +
> > +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;
>
> No need to initialize.

OK

>
> > +
> > + hv_dev = &pdev->dev;
> > + np = pdev->dev.of_node;
>
> Set this on the declaration.

OK

>
> > +
> > + ret = of_range_parser_init(&parser, np);
> > + if (ret) {
> > + dev_err(hv_dev, "Failed to parse resources.\n");
>
> If a print is needed, put it in of_range_parser_init().

Will remove the print

>
> > + 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;
>
> This is not PCI. It's a union, so use 'bus_addr' instead.
>
> But wait, resources and IORESOURCE_MEM are *CPU* addresses. You need
> cpu_addr here. Your DT happens to do 1:1 addresses so it happens to
> work either way.

bus_addr works for us, will send V6

Regards,
Saurabh

>
> Rob