linux-kernel - Re: [PATCH 6/7] PCI: aardvark: Correctly clear and unmask all MSI interrupts

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Message-ID: <fb3a7ef15397292692b6d5dd0d2e439e@kernel.org>
Date:   Fri, 06 Aug 2021 09:32:24 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Pali Rohár <pali@...nel.org>
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Rob Herring <robh@...nel.org>,
        Marek Behún <kabel@...nel.org>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/7] PCI: aardvark: Correctly clear and unmask all MSI
 interrupts

On 2021-06-25 10:03, Pali Rohár wrote:
> Define a new macro PCIE_MSI_ALL_MASK and use it for masking, unmasking 
> and
> clearing all MSI interrupts.
> 
> Signed-off-by: Pali Rohár <pali@...nel.org>
> Reviewed-by: Marek Behún <kabel@...nel.org>
> Cc: stable@...r.kernel.org
> ---
>  drivers/pci/controller/pci-aardvark.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-aardvark.c
> b/drivers/pci/controller/pci-aardvark.c
> index 0e81d89f307d..7cad6d989f6c 100644
> --- a/drivers/pci/controller/pci-aardvark.c
> +++ b/drivers/pci/controller/pci-aardvark.c
> @@ -117,6 +117,7 @@
>  #define PCIE_MSI_ADDR_HIGH_REG			(CONTROL_BASE_ADDR + 0x54)
>  #define PCIE_MSI_STATUS_REG			(CONTROL_BASE_ADDR + 0x58)
>  #define PCIE_MSI_MASK_REG			(CONTROL_BASE_ADDR + 0x5C)
> +#define     PCIE_MSI_ALL_MASK			GENMASK(31, 0)
>  #define PCIE_MSI_PAYLOAD_REG			(CONTROL_BASE_ADDR + 0x9C)
>  #define     PCIE_MSI_DATA_MASK			GENMASK(15, 0)
> 
> @@ -470,19 +471,22 @@ static void advk_pcie_setup_hw(struct advk_pcie 
> *pcie)
>  	advk_writel(pcie, reg, PCIE_CORE_CTRL2_REG);
> 
>  	/* Clear all interrupts */
> +	advk_writel(pcie, PCIE_MSI_ALL_MASK, PCIE_MSI_STATUS_REG);
>  	advk_writel(pcie, PCIE_ISR0_ALL_MASK, PCIE_ISR0_REG);
>  	advk_writel(pcie, PCIE_ISR1_ALL_MASK, PCIE_ISR1_REG);
>  	advk_writel(pcie, PCIE_IRQ_ALL_MASK, HOST_CTRL_INT_STATUS_REG);
> 
>  	/* Disable All ISR0/1 Sources */
> -	reg = PCIE_ISR0_ALL_MASK;
> -	reg &= ~PCIE_ISR0_MSI_INT_PENDING;
> -	advk_writel(pcie, reg, PCIE_ISR0_MASK_REG);
> -
> +	advk_writel(pcie, PCIE_ISR0_ALL_MASK, PCIE_ISR0_MASK_REG);
>  	advk_writel(pcie, PCIE_ISR1_ALL_MASK, PCIE_ISR1_MASK_REG);
> 
>  	/* Unmask all MSIs */
> -	advk_writel(pcie, 0, PCIE_MSI_MASK_REG);
> +	advk_writel(pcie, ~(u32)PCIE_MSI_ALL_MASK, PCIE_MSI_MASK_REG);
> +
> +	/* Unmask summary MSI interrupt */
> +	reg = advk_readl(pcie, PCIE_ISR0_MASK_REG);
> +	reg &= ~PCIE_ISR0_MSI_INT_PENDING;
> +	advk_writel(pcie, reg, PCIE_ISR0_MASK_REG);
> 
>  	/* Enable summary interrupt for GIC SPI source */
>  	reg = PCIE_IRQ_ALL_MASK & (~PCIE_IRQ_ENABLE_INTS_MASK);
> @@ -1177,7 +1181,7 @@ static void advk_pcie_handle_msi(struct advk_pcie 
> *pcie)
> 
>  	msi_mask = advk_readl(pcie, PCIE_MSI_MASK_REG);
>  	msi_val = advk_readl(pcie, PCIE_MSI_STATUS_REG);
> -	msi_status = msi_val & ~msi_mask;
> +	msi_status = msi_val & ((~msi_mask) & PCIE_MSI_ALL_MASK);
> 
>  	for (msi_idx = 0; msi_idx < MSI_IRQ_NUM; msi_idx++) {
>  		if (!(BIT(msi_idx) & msi_status))

This still begs the question: why would you ever enable all
MSIs the first place? They should be enabled on request only.

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