PCI: aardvark: Read all 16-bits from PCIE_MSI_PAYLOAD_REG

commit 95997723b6402cd6c53e0f9e7ac640ec64eaaff8 upstream.

The PCIE_MSI_PAYLOAD_REG contains 16-bit MSI number, not only lower
8 bits. Fix reading content of this register and add a comment
describing the access to this register.

Link: https://lore.kernel.org/r/20211028185659.20329-4-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>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 1a0f4dcfb328fb1868726cd25de44aeea3020661..e5ac846e2a20fe724d7d809bfc75eea4c0dbccb8 100644 (file)
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -111,6 +111,7 @@
 #define PCIE_MSI_STATUS_REG                    (CONTROL_BASE_ADDR + 0x58)
 #define PCIE_MSI_MASK_REG                      (CONTROL_BASE_ADDR + 0x5C)
 #define PCIE_MSI_PAYLOAD_REG                   (CONTROL_BASE_ADDR + 0x9C)
+#define     PCIE_MSI_DATA_MASK                 GENMASK(15, 0)
 
 /* LMI registers base address and register offsets */
 #define LMI_BASE_ADDR                          0x6000
@@ -805,8 +806,12 @@ 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
+                */
                advk_writel(pcie, BIT(msi_idx), PCIE_MSI_STATUS_REG);
-               msi_data = advk_readl(pcie, PCIE_MSI_PAYLOAD_REG) & 0xFF;
+               msi_data = advk_readl(pcie, PCIE_MSI_PAYLOAD_REG) & PCIE_MSI_DATA_MASK;
                generic_handle_irq(msi_data);
        }