linux-kernel - Re: [PATCH v3] PCI: aardvark: Fix PCI_EXP

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Message-ID: <20190806162811.GB15498@e121166-lin.cambridge.arm.com>
Date:   Tue, 6 Aug 2019 17:28:11 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Remi Pommarel <repk@...plefau.lt>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Cc:     Bjorn Helgaas <helgaas@...nel.org>,
        Ellie Reeves <ellierevves@...il.com>,
        linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] PCI: aardvark: Fix PCI_EXP_RTCTL register
 configuration

On Fri, Jun 14, 2019 at 12:10:59PM +0200, Remi Pommarel wrote:
> PCI_EXP_RTCTL is used to activate PME interrupt only, so writing into it
> should not modify other interrupts' mask. The ISR mask polarity was also
> inverted, when PCI_EXP_RTCTL_PMEIE is set PCIE_MSG_PM_PME_MASK mask bit
> should actually be cleared.
> 
> Fixes: 8a3ebd8de328 ("PCI: aardvark: Implement emulated root PCI bridge config space")
> Signed-off-by: Remi Pommarel <repk@...plefau.lt>
> ---
> Changes since v1:
>  * Improve code readability
>  * Fix mask polarity
>  * PME_MASK shift was off by one
> Changes since v2:
>  * Modify patch title
>  * Change Fixes tag to commit that actually introduces the bug
> ---
>  drivers/pci/controller/pci-aardvark.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)

Thomas, are you OK with this patch ?

Thanks,
Lorenzo

> diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> index 134e0306ff00..f6e55c4597b1 100644
> --- a/drivers/pci/controller/pci-aardvark.c
> +++ b/drivers/pci/controller/pci-aardvark.c
> @@ -415,7 +415,7 @@ advk_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge,
>  
>  	case PCI_EXP_RTCTL: {
>  		u32 val = advk_readl(pcie, PCIE_ISR0_MASK_REG);
> -		*value = (val & PCIE_MSG_PM_PME_MASK) ? PCI_EXP_RTCTL_PMEIE : 0;
> +		*value = (val & PCIE_MSG_PM_PME_MASK) ? 0 : PCI_EXP_RTCTL_PMEIE;
>  		return PCI_BRIDGE_EMUL_HANDLED;
>  	}
>  
> @@ -451,10 +451,15 @@ advk_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge,
>  		advk_writel(pcie, new, PCIE_CORE_PCIEXP_CAP + reg);
>  		break;
>  
> -	case PCI_EXP_RTCTL:
> -		new = (new & PCI_EXP_RTCTL_PMEIE) << 3;
> -		advk_writel(pcie, new, PCIE_ISR0_MASK_REG);
> +	case PCI_EXP_RTCTL: {
> +		/* Only mask/unmask PME interrupt */
> +		u32 val = advk_readl(pcie, PCIE_ISR0_MASK_REG) &
> +			~PCIE_MSG_PM_PME_MASK;
> +		if ((new & PCI_EXP_RTCTL_PMEIE) == 0)
> +			val |= PCIE_MSG_PM_PME_MASK;
> +		advk_writel(pcie, val, PCIE_ISR0_MASK_REG);
>  		break;
> +	}
>  
>  	case PCI_EXP_RTSTA:
>  		new = (new & PCI_EXP_RTSTA_PME) >> 9;
> -- 
> 2.20.1
>