linux-kernel - Re: [PATCH v3 1/6] PCI: dwc: Add msi_host

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Date:   Wed, 03 Jun 2020 12:15:04 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Jingoo Han <jingoohan1@...il.com>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Rob Herring <robh+dt@...nel.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-pci@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Masami Hiramatsu <masami.hiramatsu@...aro.org>,
        Jassi Brar <jaswinder.singh@...aro.org>
Subject: Re: [PATCH v3 1/6] PCI: dwc: Add msi_host_isr() callback

On 2020-06-03 09:54, Kunihiko Hayashi wrote:
> This adds msi_host_isr() callback function support to describe
> SoC-dependent service triggered by MSI.
> 
> For example, when AER interrupt is triggered by MSI, the callback 
> function
> reads SoC-dependent registers and detects that the interrupt is from 
> AER,
> and invoke AER interrupts related to MSI.
> 
> Cc: Marc Zyngier <maz@...nel.org>
> Cc: Jingoo Han <jingoohan1@...il.com>
> Cc: Gustavo Pimentel <gustavo.pimentel@...opsys.com>
> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 8 ++++----
>  drivers/pci/controller/dwc/pcie-designware.h      | 1 +
>  2 files changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c
> b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 0a4a5aa..9b628a2 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -112,13 +112,13 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port 
> *pp)
>  static void dw_chained_msi_isr(struct irq_desc *desc)
>  {
>  	struct irq_chip *chip = irq_desc_get_chip(desc);
> -	struct pcie_port *pp;
> +	struct pcie_port *pp = irq_desc_get_handler_data(desc);
> 
> -	chained_irq_enter(chip, desc);
> +	if (pp->ops->msi_host_isr)
> +		pp->ops->msi_host_isr(pp);

Why is this call outside of the enter/exit guards?
Do you still need to execute the standard handler?

> 
> -	pp = irq_desc_get_handler_data(desc);
> +	chained_irq_enter(chip, desc);
>  	dw_handle_msi_irq(pp);
> -
>  	chained_irq_exit(chip, desc);
>  }
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h
> b/drivers/pci/controller/dwc/pcie-designware.h
> index 656e00f..e741967 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -170,6 +170,7 @@ struct dw_pcie_host_ops {
>  	void (*scan_bus)(struct pcie_port *pp);
>  	void (*set_num_vectors)(struct pcie_port *pp);
>  	int (*msi_host_init)(struct pcie_port *pp);
> +	void (*msi_host_isr)(struct pcie_port *pp);
>  };
> 
>  struct pcie_port {

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...