Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20220123033306.29799-1-qizhong.cheng@mediatek.com>
In-Reply-To: <20220123033306.29799-1-qizhong.cheng@mediatek.com>
From:   Chen-Yu Tsai <wenst@chromium.org>
Date:   Mon, 24 Jan 2022 11:12:49 +0800
Message-ID: <CAGXv+5EcAXFTnjkbeU4f3J2s4Ue5zxrN4QgS=t54BnLX8Gkw2w@mail.gmail.com>
Subject: Re: [PATCH] PCI: mediatek: Change MSI interrupt processing sequence
To:     qizhong cheng <qizhong.cheng@mediatek.com>
Cc:     Ryder Lee <ryder.lee@mediatek.com>,
        Jianjun Wang <jianjun.wang@mediatek.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, chuanjia.liu@mediatek.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi,

On Sun, Jan 23, 2022 at 11:34 AM qizhong cheng
<qizhong.cheng@mediatek.com> wrote:
>
> As an edge-triggered interrupts, its interrupt status should be cleared
> before dispatch to the handler of device.

I'm curious, is this just a code correction or are there real world
cases where something fails?

Also, please add a Fixes tag and maybe Cc stable so this gets backported
automatically.

ChenYu

> Signed-off-by: qizhong cheng <qizhong.cheng@mediatek.com>
> ---
>  drivers/pci/controller/pcie-mediatek.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> index 2f3f974977a3..705ea33758b1 100644
> --- a/drivers/pci/controller/pcie-mediatek.c
> +++ b/drivers/pci/controller/pcie-mediatek.c
> @@ -624,12 +624,12 @@ static void mtk_pcie_intr_handler(struct irq_desc *desc)
>                 if (status & MSI_STATUS){
>                         unsigned long imsi_status;
>
> +                       /* Clear MSI interrupt status */
> +                       writel(MSI_STATUS, port->base + PCIE_INT_STATUS);
>                         while ((imsi_status = readl(port->base + PCIE_IMSI_STATUS))) {
>                                 for_each_set_bit(bit, &imsi_status, MTK_MSI_IRQS_NUM)
>                                         generic_handle_domain_irq(port->inner_domain, bit);
>                         }
> -                       /* Clear MSI interrupt status */
> -                       writel(MSI_STATUS, port->base + PCIE_INT_STATUS);
>                 }
>         }
>
> --
> 2.25.1
>
>
> _______________________________________________
> Linux-mediatek mailing list
> Linux-mediatek@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-mediatek