Hi Greg,
> > Enable diagnostic interrupts for the A64FX.
> > This is done using a pseudo-NMI.
>
> I do not understand what this driver is, sorry. Can you please provide more
> information in the changelog text for what this is, who would use it, and how it will
> be interacted with.
I understand. I will add a description in the next version.
> > +config A64FX_DIAG
> > + bool "A64FX diag driver"
> > + depends on ARM64
>
> What about ACPI? Shouldn't this code depend on that?
Okey. I will make it dependent on ACPI.
> > + help
> > + Say Y here if you want to enable diag interrupt on A64FX.
>
> What is A64FX?
A64FX is a processor designed by Fujitsu.
For the sake of clarity, I will describe it as "Fujitsu A64FX".
> > + This driver uses pseudo-NMI if available.
>
> What does this mean?
This driver uses the pseudo-NMI feature to perform diagnostic interrupts
for A64FX. However, I felt that it was superfluous to give this explanation
here, so I will delete this sentence.
> > + If unsure, say N.
>
> No module? Why not?
request_nmi() is not EXPORT_SYMBOL. So this driver cannot be a module.
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * A64FX diag driver.
>
> No copyright information? Are you sure?
I will add copyright information.
> > +#define BMC_DIAG_INTERRUPT_STATUS_OFFSET (0x0044) #define
> > +BMC_INTERRUPT_STATUS_MASK ((1U) << 31)
>
> BIT()?
>
> > +#define BMC_DIAG_INTERRUPT_ENABLE_OFFSET (0x0040) #define
> > +BMC_INTERRUPT_ENABLE_MASK ((1U) << 31)
>
> BIT()?
Okey, I will use BIT().
> > +static irqreturn_t a64fx_diag_handler(int irq, void *dev_id) {
> > + handle_sysrq('c');
>
>
> Why is this calling this sysrq call? From an interrupt? Why?
>
> And you are hard-coding "c", are you sure?
As mentioned by Arnd, I only called panic () at first, but after receiving
his suggestion, I decided to call handle_sysrq ('c').
This driver only supports the function that causes a panic when receiving
a diagnostic interrupt from the outside, so "c" is coded.
Also, no data is added when a diagnostic interrupt is sent.
> > + if (mmsc & BMC_INTERRUPT_STATUS_MASK)
> > + writel(BMC_INTERRUPT_STATUS_MASK, (void
> *)diag_status_reg_addr);
>
> No need to wait for the write to complete?
>
> You shouldn't have to cast diag_status_reg_addr, right?
Due to the specifications of the machine, there is no problem even
if there is no write wait processing.
I will remove constant and (void *). Thank you for pointing out.
> > + enable_irq(priv->irq);
> > + priv->has_nmi = false;
> > + dev_info(dev, "registered for IRQ %d\n", priv->irq);
> > + } else {
> > + enable_nmi(priv->irq);
> > + priv->has_nmi = true;
> > + dev_info(dev, "registered for NMI %d\n", priv->irq);
>
> When drivers are successful, they are quiet. No need for the noise here.
I will remove the message for a successful NMI/IRQ registration.
Thank you.
Hitomi Hasegawa
