Message-ID: <aJN8jOQ8VeDjmwil@lizhi-Precision-Tower-5810>
Date: Wed, 6 Aug 2025 12:02:20 -0400
From: Frank Li <Frank.li@....com>
To: Lorenzo Pieralisi <lpieralisi@...nel.org>
Cc: linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Thomas Gleixner <tglx@...utronix.de>, Rob Herring <robh@...nel.org>,
	Marc Zyngier <maz@...nel.org>
Subject: Re: [PATCH] of/irq: Convert of_msi_map_id() callers to of_msi_xlate()

On Tue, Aug 05, 2025 at 03:34:43PM +0200, Lorenzo Pieralisi wrote:
> With the introduction of the of_msi_xlate() function, the OF layer
> provides an API to map a device ID and retrieve the MSI controller
> node the ID is mapped to with a single call.
>
> of_msi_map_id() is currently used to map a deviceID to a specific
> MSI controller node; of_msi_xlate() can be used for that purpose
> too, there is no need to keep the two functions.
>
> Convert of_msi_map_id() to of_msi_xlate() calls and update the
> of_msi_xlate() documentation to describe how the struct device_node
> pointer passed in should be set-up to either provide the MSI controller
> node target or receive its pointer upon mapping completion.
>
> Signed-off-by: Lorenzo Pieralisi <lpieralisi@...nel.org>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Rob Herring <robh@...nel.org>
> Cc: Marc Zyngier <maz@...nel.org>

Reviewed-by: Frank Li <Frank.Li@....com>

> ---
> As suggested by RobH:
>
> https://lore.kernel.org/lkml/20250627213241.GA168190-robh@kernel.org/
>
>  drivers/irqchip/irq-gic-v3-its-fsl-mc-msi.c |  2 +-
>  drivers/of/irq.c                            | 25 +++++----------------
>  drivers/pci/msi/irqdomain.c                 |  2 +-
>  include/linux/of_irq.h                      |  6 -----
>  4 files changed, 7 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its-fsl-mc-msi.c b/drivers/irqchip/irq-gic-v3-its-fsl-mc-msi.c
> index 11549d85f23b..b5785472765a 100644
> --- a/drivers/irqchip/irq-gic-v3-its-fsl-mc-msi.c
> +++ b/drivers/irqchip/irq-gic-v3-its-fsl-mc-msi.c
> @@ -30,7 +30,7 @@ static u32 fsl_mc_msi_domain_get_msi_id(struct irq_domain *domain,
>  	u32 out_id;
>
>  	of_node = irq_domain_get_of_node(domain);
> -	out_id = of_node ? of_msi_map_id(&mc_dev->dev, of_node, mc_dev->icid) :
> +	out_id = of_node ? of_msi_xlate(&mc_dev->dev, &of_node, mc_dev->icid) :
>  			iort_msi_map_id(&mc_dev->dev, mc_dev->icid);
>
>  	return out_id;
> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> index 74aaea61de13..e7c12abd10ab 100644
> --- a/drivers/of/irq.c
> +++ b/drivers/of/irq.c
> @@ -673,13 +673,14 @@ void __init of_irq_init(const struct of_device_id *matches)
>  /**
>   * of_msi_xlate - map a MSI ID and find relevant MSI controller node
>   * @dev: device for which the mapping is to be done.
> - * @msi_np: Pointer to store the MSI controller node
> + * @msi_np: Pointer to target MSI controller node
>   * @id_in: Device ID.
>   *
>   * Walk up the device hierarchy looking for devices with a "msi-map"
> - * property. If found, apply the mapping to @id_in. @msi_np pointed
> - * value must be NULL on entry, if an MSI controller is found @msi_np is
> - * initialized to the MSI controller node with a reference held.
> + * property. If found, apply the mapping to @id_in.
> + * If @msi_np points to a non-NULL device node pointer, only entries targeting
> + * that node will be matched; if it points to a NULL value, it will receive the
> + * device node of the first matching target phandle, with a reference held.
>   *
>   * Returns: The mapped MSI id.
>   */
> @@ -699,22 +700,6 @@ u32 of_msi_xlate(struct device *dev, struct device_node **msi_np, u32 id_in)
>  	return id_out;
>  }
>
> -/**
> - * of_msi_map_id - Map a MSI ID for a device.
> - * @dev: device for which the mapping is to be done.
> - * @msi_np: device node of the expected msi controller.
> - * @id_in: unmapped MSI ID for the device.
> - *
> - * Walk up the device hierarchy looking for devices with a "msi-map"
> - * property.  If found, apply the mapping to @id_in.
> - *
> - * Return: The mapped MSI ID.
> - */
> -u32 of_msi_map_id(struct device *dev, struct device_node *msi_np, u32 id_in)
> -{
> -	return of_msi_xlate(dev, &msi_np, id_in);
> -}
> -
>  /**
>   * of_msi_map_get_device_domain - Use msi-map to find the relevant MSI domain
>   * @dev: device for which the mapping is to be done.
> diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
> index 0938ef7ebabf..555c61b1fc36 100644
> --- a/drivers/pci/msi/irqdomain.c
> +++ b/drivers/pci/msi/irqdomain.c
> @@ -422,7 +422,7 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
>  	pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
>
>  	of_node = irq_domain_get_of_node(domain);
> -	rid = of_node ? of_msi_map_id(&pdev->dev, of_node, rid) :
> +	rid = of_node ? of_msi_xlate(&pdev->dev, &of_node, rid) :
>  			iort_msi_map_id(&pdev->dev, rid);
>
>  	return rid;
> diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
> index a480063c9cb1..1db8543dfc8a 100644
> --- a/include/linux/of_irq.h
> +++ b/include/linux/of_irq.h
> @@ -55,7 +55,6 @@ extern struct irq_domain *of_msi_map_get_device_domain(struct device *dev,
>  							u32 bus_token);
>  extern void of_msi_configure(struct device *dev, const struct device_node *np);
>  extern u32 of_msi_xlate(struct device *dev, struct device_node **msi_np, u32 id_in);
> -u32 of_msi_map_id(struct device *dev, struct device_node *msi_np, u32 id_in);
>  #else
>  static inline void of_irq_init(const struct of_device_id *matches)
>  {
> @@ -105,11 +104,6 @@ static inline u32 of_msi_xlate(struct device *dev, struct device_node **msi_np,
>  {
>  	return id_in;
>  }
> -static inline u32 of_msi_map_id(struct device *dev,
> -				 struct device_node *msi_np, u32 id_in)
> -{
> -	return id_in;
> -}
>  #endif
>
>  #if defined(CONFIG_OF_IRQ) || defined(CONFIG_SPARC)
> --
> 2.48.0
>

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