linux-kernel - Re: [PATCH v3 07/13] PCI: apple: Move away from INTMSK{SET,CLR} for INTx and private interrupts

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Message-ID: <sbudn32sbw6d3z7n2yomlzdsbtumckw4o576zfe5nlvwpt22j4@hf2zpld7tvcb>
Date: Sun, 13 Apr 2025 22:39:52 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Marc Zyngier <maz@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, linux-pci@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, asahi@...ts.linux.dev, 
	Alyssa Rosenzweig <alyssa@...enzweig.io>, Janne Grunau <j@...nau.net>, Hector Martin <marcan@...can.st>, 
	Sven Peter <sven@...npeter.dev>, Bjorn Helgaas <bhelgaas@...gle.com>, 
	Lorenzo Pieralisi <lpieralisi@...nel.org>, Krzysztof Wilczyński <kw@...ux.com>, 
	Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
	Mark Kettenis <mark.kettenis@...all.nl>
Subject: Re: [PATCH v3 07/13] PCI: apple: Move away from INTMSK{SET,CLR} for
 INTx and private interrupts

On Tue, Apr 01, 2025 at 10:17:07AM +0100, Marc Zyngier wrote:
> T602x seems to have dropped the rather useful SET/CLR accessors
> to the masking register.
> 
> Instead, let's use the mask register directly, and wrap it with
> a brand new spinlock. No, this isn't moving in the right direction.
> 
> Reviewed-by: Rob Herring (Arm) <robh@...nel.org>
> Acked-by: Alyssa Rosenzweig <alyssa@...enzweig.io>
> Tested-by: Janne Grunau <j@...nau.net>
> Signed-off-by: Marc Zyngier <maz@...nel.org>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>

- Mani

> ---
>  drivers/pci/controller/pcie-apple.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
> index 6d3aa186d9c5f..6b04bf0b41dcc 100644
> --- a/drivers/pci/controller/pcie-apple.c
> +++ b/drivers/pci/controller/pcie-apple.c
> @@ -142,6 +142,7 @@ struct apple_pcie {
>  };
>  
>  struct apple_pcie_port {
> +	raw_spinlock_t		lock;
>  	struct apple_pcie	*pcie;
>  	struct device_node	*np;
>  	void __iomem		*base;
> @@ -261,14 +262,16 @@ static void apple_port_irq_mask(struct irq_data *data)
>  {
>  	struct apple_pcie_port *port = irq_data_get_irq_chip_data(data);
>  
> -	writel_relaxed(BIT(data->hwirq), port->base + PORT_INTMSKSET);
> +	guard(raw_spinlock_irqsave)(&port->lock);
> +	rmw_set(BIT(data->hwirq), port->base + PORT_INTMSK);
>  }
>  
>  static void apple_port_irq_unmask(struct irq_data *data)
>  {
>  	struct apple_pcie_port *port = irq_data_get_irq_chip_data(data);
>  
> -	writel_relaxed(BIT(data->hwirq), port->base + PORT_INTMSKCLR);
> +	guard(raw_spinlock_irqsave)(&port->lock);
> +	rmw_clear(BIT(data->hwirq), port->base + PORT_INTMSK);
>  }
>  
>  static bool hwirq_is_intx(unsigned int hwirq)
> @@ -387,7 +390,7 @@ static int apple_pcie_port_setup_irq(struct apple_pcie_port *port)
>  		return -ENOMEM;
>  
>  	/* Disable all interrupts */
> -	writel_relaxed(~0, port->base + PORT_INTMSKSET);
> +	writel_relaxed(~0, port->base + PORT_INTMSK);
>  	writel_relaxed(~0, port->base + PORT_INTSTAT);
>  
>  	irq_set_chained_handler_and_data(irq, apple_port_irq_handler, port);
> @@ -537,6 +540,8 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
>  	port->pcie = pcie;
>  	port->np = np;
>  
> +	raw_spin_lock_init(&port->lock);
> +
>  	port->base = devm_platform_ioremap_resource(platform, port->idx + 2);
>  	if (IS_ERR(port->base))
>  		return PTR_ERR(port->base);
> -- 
> 2.39.2
> 

-- 
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