Re: [3/3] PCI: designware: Move interrupt acking into the proper callback

From: Niklas Cassel <niklas.cassel@linaro.org>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Trent Piepho <tpiepho@impinj.com>,
	Jingoo Han <jingoohan1@gmail.com>,
	Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
	faiz_abbas@ti.com, Joao Pinto <Joao.Pinto@synopsys.com>,
	Vignesh R <vigneshr@ti.com>
Subject: Re: [3/3] PCI: designware: Move interrupt acking into the proper callback
Date: Mon, 3 Dec 2018 19:02:40 +0100	[thread overview]
Message-ID: <20181203180240.GC18985@centauri.lan> (raw)
In-Reply-To: <20181113225734.8026-4-marc.zyngier@arm.com>

On Tue, Nov 13, 2018 at 10:57:34PM +0000, Marc Zyngier wrote:
> The write to the status register is really an ACK for the HW,
> and should be treated as such by the driver. Let's move it to the
> irq_ack callback, which will prevent people from moving it around
> in order to paper over other bugs.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 0a76948ed49e..f06e67c60593 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -99,9 +99,6 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  					       (i * MAX_MSI_IRQS_PER_CTRL) +
>  					       pos);
>  			generic_handle_irq(irq);
> -			dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS +
> -						(i * MSI_REG_CTRL_BLOCK_SIZE),
> -					    4, 1 << pos);
>  			pos++;
>  		}
>  	}
> @@ -200,14 +197,18 @@ static void dw_pci_bottom_unmask(struct irq_data *data)
>  
>  static void dw_pci_bottom_ack(struct irq_data *d)
>  {
> -	struct msi_desc *msi = irq_data_get_msi_desc(d);
> -	struct pcie_port *pp;
> +	struct pcie_port *pp  = irq_data_get_irq_chip_data(d);
> +	unsigned int res, bit, ctrl;
>  	unsigned long flags;
>  
> -	pp = msi_desc_to_pci_sysdata(msi);
> +	ctrl = d->hwirq / MAX_MSI_IRQS_PER_CTRL;
> +	res = ctrl * MSI_REG_CTRL_BLOCK_SIZE;
> +	bit = d->hwirq % MAX_MSI_IRQS_PER_CTRL;
>  
>  	raw_spin_lock_irqsave(&pp->lock, flags);
>  
> +	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS + res, 4, 1 << bit);
> +
>  	if (pp->ops->msi_irq_ack)
>  		pp->ops->msi_irq_ack(d->hwirq, pp);
>  

Tested-by: Niklas Cassel <niklas.cassel@linaro.org>