Re: FAILED: patch "[PATCH] PCI: dwc: Move interrupt acking into the proper callback" failed to apply to 4.14-stable tree

[Niklas Cassel <niklas.cassel@linaro.org>]

On Tue, Jan 15, 2019 at 09:24:37AM +0100, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 4.14-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

Hello Marc,

You said that you were going to backport this to 4.14, right?

IIRC, you said something about creating a simple dw_pci_bottom_ack()
(since 4.14 lacks a ack() function).


Kind regards,
Niklas


> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From 3f7bb2ec20ce07c02b2002349d256c91a463fcc5 Mon Sep 17 00:00:00 2001
> From: Marc Zyngier <marc.zyngier@arm.com>
> Date: Tue, 13 Nov 2018 22:57:34 +0000
> Subject: [PATCH] PCI: dwc: Move interrupt acking into the proper callback
> 
> 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.
> 
> Fixes: 8c934095fa2f ("PCI: dwc: Clear MSI interrupt status after it is handled,
> not before")
> Fixes: 7c5925afbc58 ("PCI: dwc: Move MSI IRQs allocation to IRQ domains
> hierarchical API")
> Link: https://lore.kernel.org/linux-pci/20181113225734.8026-1-marc.zyngier@arm.com/
> Reported-by: Trent Piepho <tpiepho@impinj.com>
> Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
> Tested-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> Tested-by: Stanimir Varbanov <svarbanov@mm-sol.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> [lorenzo.pieralisi@arm.com: updated commit log]
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: stable@vger.kernel.org
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 610a5e018d27..0fa9e8fdce66 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);
>  
>