Re: [PATCH v3 07/23] mailbox: Add RISC-V SBI message proxy (MPXY) based mailbox driver

From: Thomas Gleixner <tglx@linutronix.de>
To: "Anup Patel" <apatel@ventanamicro.com>,
	"Michael Turquette" <mturquette@baylibre.com>,
	"Stephen Boyd" <sboyd@kernel.org>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Jassi Brar" <jassisinghbrar@gmail.com>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	"Mika Westerberg" <mika.westerberg@linux.intel.com>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Bartosz Golaszewski" <brgl@bgdev.pl>,
	"Uwe Kleine-König" <ukleinek@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Len Brown <lenb@kernel.org>, Sunil V L <sunilvl@ventanamicro.com>,
	Rahul Pathak <rpathak@ventanamicro.com>,
	Leyfoon Tan <leyfoon.tan@starfivetech.com>,
	Atish Patra <atish.patra@linux.dev>,
	Andrew Jones <ajones@ventanamicro.com>,
	Samuel Holland <samuel.holland@sifive.com>,
	Anup Patel <anup@brainfault.org>,
	linux-clk@vger.kernel.org, devicetree@vger.kernel.org,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	Anup Patel <apatel@ventanamicro.com>
Subject: Re: [PATCH v3 07/23] mailbox: Add RISC-V SBI message proxy (MPXY) based mailbox driver
Date: Mon, 12 May 2025 20:54:23 +0200	[thread overview]
Message-ID: <8734d9lkww.ffs@tglx> (raw)
In-Reply-To: <20250511133939.801777-8-apatel@ventanamicro.com>

On Sun, May 11 2025 at 19:09, Anup Patel wrote:
> +
> +static irqreturn_t mpxy_mbox_irq_event(int irq, void *dev_id)
> +{
> +	/* We only have MSI for notification so just wakeup IRQ thread */
> +	return IRQ_WAKE_THREAD;

I was idly reading through this because I looked at the irq chip.

This function is competely pointless.

> +}
> +
> +static irqreturn_t mpxy_mbox_irq_thread(int irq, void *dev_id)
> +{
> +	mpxy_mbox_peek_data(dev_id);
> +	return IRQ_HANDLED;
> +}
> +
> +static int mpxy_mbox_setup_msi(struct mbox_chan *chan,
> +			       struct mpxy_mbox_channel *mchan)
> +{
> +	struct device *dev = mchan->mbox->dev;
> +	int rc;
> +
> +	/* Do nothing if MSI not supported */
> +	if (mchan->msi_irq == U32_MAX)
> +		return 0;
> +
> +	/* Fail if MSI already enabled */
> +	if (mchan->attrs.msi_control)
> +		return -EALREADY;
> +
> +	/* Request channel MSI handler */
> +	rc = request_threaded_irq(mchan->msi_irq,
> +				  mpxy_mbox_irq_event,
> +				  mpxy_mbox_irq_thread,
> +				  0, dev_name(dev), chan);

Just do:

	rc = request_threaded_irq(mchan->msi_irq, NULL, mpxy_mbox_irq_thread,
				  0, dev_name(dev), chan);

and be done with it. The core code will happily wake up your thread.