From 735a4ac9782b96fbe1543c578aa8334364f21abd Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pali=20Roh=C3=A1r?= Date: Fri, 2 Apr 2021 14:05:24 +0200 Subject: [PATCH] PCI: aardvark: Enable MSI-X support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit According to PCI 3.0 specification, sending both MSI and MSI-X interrupts is done by DWORD memory write operation to doorbell message address. The write operation for MSI has zero upper 16 bits and the MSI interrupt number in the lower 16 bits, while the write operation for MSI-X contains a 32-bit value from MSI-X table. Since the driver only uses interrupt numbers from range 0..31, the upper 16 bits of the DWORD memory write operation to doorbell message address are zero even for MSI-X interrupts. Thus we can enable MSI-X interrupts. Testing proves that kernel can correctly receive MSI-X interrupts from PCIe cards which supports both MSI and MSI-X interrupts. Signed-off-by: Pali Rohár Signed-off-by: Marek Behún --- drivers/pci/controller/pci-aardvark.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -1346,7 +1346,7 @@ static struct irq_chip advk_msi_irq_chip static struct msi_domain_info advk_msi_domain_info = { .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS | - MSI_FLAG_MULTI_PCI_MSI, + MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX, .chip = &advk_msi_irq_chip, };