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Date: Wed, 15 May 2024 09:31:48 -0700
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Subject: Re: [PATCH v2 5/6] drivers/hv/vmbus: Get the irq number from
 DeviceTree
To: Saurabh Singh Sengar <ssengar@linux.microsoft.com>
Cc: arnd@arndb.de, bhelgaas@google.com, bp@alien8.de,
 catalin.marinas@arm.com, dave.hansen@linux.intel.com, decui@microsoft.com,
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 linux-arm-kernel@lists.infradead.org, linux-hyperv@vger.kernel.org,
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References: <20240514224508.212318-1-romank@linux.microsoft.com>
 <20240514224508.212318-6-romank@linux.microsoft.com>
 <20240515094225.GA22844@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
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From: Roman Kisel <romank@linux.microsoft.com>
In-Reply-To: <20240515094225.GA22844@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
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On 5/15/2024 2:42 AM, Saurabh Singh Sengar wrote:
> On Tue, May 14, 2024 at 03:43:52PM -0700, Roman Kisel wrote:
>> The vmbus driver uses ACPI for interrupt assignment on
> 
> In subject use the prefix "Drivers: hv: vmbus:".
> It is preferred to us "VMbus/VMBus" instead of "vmbus" for all the
> commit message and comments.
> 
I can see "Drivers: hv: vmbus:" as a convention from the data[1], will 
update the commit message per that.

The recent Michael Kelly's patchset where the Hyper-V documentation is 
updated to use "VMBus" instead of the incorrect one (iiuc) "VMbus" 
compels me to use "VMBus" out of the options you have enumerated, in the 
commit description.

[1]
The data mining device was

git log --all --grep='Drivers: hv: vmbus:'

and variations thereof.

>> arm64 hence it won't function in the VTL mode where only
>> DeviceTree can be used.
>>
>> Update the vmbus driver to discover interrupt configuration
>> via DeviceTree.
>>
>> Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
>> ---
>>   drivers/hv/vmbus_drv.c | 37 +++++++++++++++++++++++++++++++++++++
>>   1 file changed, 37 insertions(+)
>>
>> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
>> index e25223cee3ab..52f01bd1c947 100644
>> --- a/drivers/hv/vmbus_drv.c
>> +++ b/drivers/hv/vmbus_drv.c
>> @@ -36,6 +36,7 @@
>>   #include <linux/syscore_ops.h>
>>   #include <linux/dma-map-ops.h>
>>   #include <linux/pci.h>
>> +#include <linux/of_irq.h>
>>   #include <clocksource/hyperv_timer.h>
>>   #include <asm/mshyperv.h>
>>   #include "hyperv_vmbus.h"
>> @@ -2316,6 +2317,34 @@ static int vmbus_acpi_add(struct platform_device *pdev)
>>   }
>>   #endif
>>   
>> +static int __maybe_unused vmbus_of_set_irq(struct device_node *np)
>> +{
>> +	struct irq_desc *desc;
>> +	int irq;
>> +
>> +	irq = of_irq_get(np, 0);
>> +	if (irq == 0) {
>> +		pr_err("VMBus interrupt mapping failure\n");
>> +		return -EINVAL;
>> +	}
>> +	if (irq < 0) {
>> +		pr_err("VMBus interrupt data can't be read from DeviceTree, error %d\n", irq);
>> +		return irq;
>> +	}
>> +
>> +	desc = irq_to_desc(irq);
>> +	if (!desc) {
>> +		pr_err("VMBus interrupt description can't be found for virq %d\n", irq);
>> +		return -ENODEV;
>> +	}
>> +
>> +	vmbus_irq = irq;
>> +	vmbus_interrupt = desc->irq_data.hwirq;
>> +	pr_debug("VMBus virq %d, hwirq %d\n", vmbus_irq, vmbus_interrupt);
>> +
>> +	return 0;
>> +}
>> +
>>   static int vmbus_device_add(struct platform_device *pdev)
>>   {
>>   	struct resource **cur_res = &hyperv_mmio;
>> @@ -2324,12 +2353,20 @@ static int vmbus_device_add(struct platform_device *pdev)
>>   	struct device_node *np = pdev->dev.of_node;
>>   	int ret;
>>   
>> +	pr_debug("VMBus is present in DeviceTree\n");
>> +
>>   	hv_dev = &pdev->dev;
>>   
>>   	ret = of_range_parser_init(&parser, np);
>>   	if (ret)
>>   		return ret;
>>   
>> +#ifndef HYPERVISOR_CALLBACK_VECTOR
>> +	ret = vmbus_of_set_irq(np);
>> +	if (ret)
>> +		return ret;
>> +#endif
>> +
>>   	for_each_of_range(&parser, &range) {
>>   		struct resource *res;
>>   
>> -- 
>> 2.45.0
>>

-- 
Thank you,
Roman