Re: [PATCH V6] gpio: virtio: Add IRQ support

On Thu, Oct 21, 2021 at 7:34 AM Viresh Kumar [off-list ref] wrote:

On 20-10-21, 18:10, Andy Shevchenko wrote:

quoted

On Wednesday, October 20, 2021, Viresh Kumar [off-list ref]
wrote:

...

quoted

quoted

+       case IRQ_TYPE_NONE:
+               type = VIRTIO_GPIO_IRQ_TYPE_NONE;
+               break;

IIRC you add dead code. IRQ framework never calls this if type is not set.

Yes, but it is allowed to call

irq_set_irq_type(irq, IRQ_TYPE_NONE);

and the irq framework won't disallow it AFAICT.

That's true, but how you may end up in this callback with a such?
What the meaning of that call to the user?

...

quoted

quoted

 struct virtio_gpio_config {
        __le16 ngpio;
        __u8 padding[2];

@@ -44,4 +56,17 @@ struct virtio_gpio_response_get_names {
        __u8 value[];
 };

+/* Virtio GPIO IRQ Request / Response */
+struct virtio_gpio_irq_request {
+       __le16 gpio;
+};
+
+struct virtio_gpio_irq_response {
+       __u8 status;
+};

I’m wondering if those above should be packed.

You are talking about the newly added ones or the ones before ?

In any case, they are all already packed (i.e. they have explicit
padding wherever required) and properly aligned. Compiler won't add
any other padding to them.

Is it only for 64-bit to 64-bit communications?
If there is a possibility to have 32-bit to 64-bit or vice versa
communication you have a problem.

-- 
With Best Regards,
Andy Shevchenko
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