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[v2,1/3] PCI: aardvark: Fix reading MSI interrupt number

Message ID 20210823164033.27491-2-pali@kernel.org (mailing list archive)
State Changes Requested
Delegated to: Lorenzo Pieralisi
Headers show
Series PCI: aardvark: MSI interrupt fixes | expand

Commit Message

Pali Rohár Aug. 23, 2021, 4:40 p.m. UTC
Experiments showed that in register PCIE_MSI_PAYLOAD_REG is stored number
of the last received MSI interrupt and not number of MSI interrupt which
belongs to msi_idx bit. Therefore this implies that aardvark HW can cache
only bits [4:0] of received MSI interrupts with effectively means that it
supports only MSI interrupts with numbers 0-31.

Do not read PCIE_MSI_PAYLOAD_REG register for determining MSI interrupt
number. Instead ensure that pci-aardvark.c configures only MSI numbers in
range 0-31 and then msi_idx contains correct received MSI number.

Signed-off-by: Pali Rohár <pali@kernel.org>
Cc: stable@vger.kernel.org
---
 drivers/pci/controller/pci-aardvark.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

Comments

Marc Zyngier Aug. 23, 2021, 4:52 p.m. UTC | #1
On Mon, 23 Aug 2021 17:40:31 +0100,
Pali Rohár <pali@kernel.org> wrote:
> 
> Experiments showed that in register PCIE_MSI_PAYLOAD_REG is stored number
> of the last received MSI interrupt and not number of MSI interrupt which
> belongs to msi_idx bit. Therefore this implies that aardvark HW can cache
> only bits [4:0] of received MSI interrupts with effectively means that it
> supports only MSI interrupts with numbers 0-31.
> 
> Do not read PCIE_MSI_PAYLOAD_REG register for determining MSI interrupt
> number. Instead ensure that pci-aardvark.c configures only MSI numbers in
> range 0-31 and then msi_idx contains correct received MSI number.
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> Cc: stable@vger.kernel.org
> ---
>  drivers/pci/controller/pci-aardvark.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> index 48fbfa7eb24c..81c4a9ff91a3 100644
> --- a/drivers/pci/controller/pci-aardvark.c
> +++ b/drivers/pci/controller/pci-aardvark.c
> @@ -1232,7 +1232,6 @@ static void advk_pcie_remove_irq_domain(struct advk_pcie *pcie)
>  static void advk_pcie_handle_msi(struct advk_pcie *pcie)
>  {
>  	u32 msi_val, msi_mask, msi_status, msi_idx;
> -	u16 msi_data;
>  	int virq;
>  
>  	msi_mask = advk_readl(pcie, PCIE_MSI_MASK_REG);
> @@ -1243,17 +1242,13 @@ static void advk_pcie_handle_msi(struct advk_pcie *pcie)
>  		if (!(BIT(msi_idx) & msi_status))
>  			continue;
>  
> -		/*
> -		 * msi_idx contains bits [4:0] of the msi_data and msi_data
> -		 * contains 16bit MSI interrupt number from MSI inner domain
> -		 */
>  		advk_writel(pcie, BIT(msi_idx), PCIE_MSI_STATUS_REG);
> -		msi_data = advk_readl(pcie, PCIE_MSI_PAYLOAD_REG) & PCIE_MSI_DATA_MASK;
> -		virq = irq_find_mapping(pcie->msi_inner_domain, msi_data);
> +
> +		virq = irq_find_mapping(pcie->msi_inner_domain, msi_idx);
>  		if (virq)
>  			generic_handle_irq(virq);

NAK.

As I have explained before, I want this API dead, and I don't feel
like doing another pass at the whole of the kernel tree to remove
these patterns.

A patch targeting stable is not a mandate for using deprecated
APIs. You can always send another patch for stable versions before
5.14.

	M.
diff mbox series

Patch

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 48fbfa7eb24c..81c4a9ff91a3 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1232,7 +1232,6 @@  static void advk_pcie_remove_irq_domain(struct advk_pcie *pcie)
 static void advk_pcie_handle_msi(struct advk_pcie *pcie)
 {
 	u32 msi_val, msi_mask, msi_status, msi_idx;
-	u16 msi_data;
 	int virq;
 
 	msi_mask = advk_readl(pcie, PCIE_MSI_MASK_REG);
@@ -1243,17 +1242,13 @@  static void advk_pcie_handle_msi(struct advk_pcie *pcie)
 		if (!(BIT(msi_idx) & msi_status))
 			continue;
 
-		/*
-		 * msi_idx contains bits [4:0] of the msi_data and msi_data
-		 * contains 16bit MSI interrupt number from MSI inner domain
-		 */
 		advk_writel(pcie, BIT(msi_idx), PCIE_MSI_STATUS_REG);
-		msi_data = advk_readl(pcie, PCIE_MSI_PAYLOAD_REG) & PCIE_MSI_DATA_MASK;
-		virq = irq_find_mapping(pcie->msi_inner_domain, msi_data);
+
+		virq = irq_find_mapping(pcie->msi_inner_domain, msi_idx);
 		if (virq)
 			generic_handle_irq(virq);
 		else
-			dev_err_ratelimited(&pcie->pdev->dev, "unexpected MSI 0x%04hx\n", msi_data);
+			dev_err_ratelimited(&pcie->pdev->dev, "unexpected MSI 0x%02x\n", msi_idx);
 	}
 
 	advk_writel(pcie, PCIE_ISR0_MSI_INT_PENDING,