[PATCH 4.19 87/88] PCI: aardvark: Fix reading MSI interrupt number

Greg Kroah-Hartman
2022-05-10T13:46:20Z

From: Pali Rohár <pali@kernel.org>

commit 805dfc18dd3d4dd97a987d4406593b5a225b1253 upstream.

In advk_pcie_handle_msi() it is expected that when bit i in the W1C
register PCIE_MSI_STATUS_REG is cleared, the PCIE_MSI_PAYLOAD_REG is
updated to contain the MSI number corresponding to index i.

Experiments show that this is not so, and instead PCIE_MSI_PAYLOAD_REG
always contains the number of the last received MSI, overall.

Do not read PCIE_MSI_PAYLOAD_REG register for determining MSI interrupt
number. Since Aardvark already forbids more than 32 interrupts and uses
own allocated hwirq numbers, the msi_idx already corresponds to the
received MSI number.

Link: https://lore.kernel.org/r/20220110015018.26359-3-kabel@kernel.org
Fixes: 8c39d710363c ("PCI: aardvark: Add Aardvark PCI host controller driver")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/pci/controller/pci-aardvark.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1035,7 +1035,7 @@ static void advk_pcie_remove_irq_domain(
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);
msi_val = advk_readl(pcie, PCIE_MSI_STATUS_REG);
@@ -1045,13 +1045,9 @@ static void advk_pcie_handle_msi(struct
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
- */
advk_writel(pcie, BIT(msi_idx), PCIE_MSI_STATUS_REG);
- msi_data = advk_readl(pcie, PCIE_MSI_PAYLOAD_REG) & PCIE_MSI_DATA_MASK;
- generic_handle_irq(msi_data);
+ virq = irq_find_mapping(pcie->msi_inner_domain, msi_idx);
+ generic_handle_irq(virq);
}

advk_writel(pcie, PCIE_ISR0_MSI_INT_PENDING,