On Tue, Apr 05, 2022 at 12:17:51PM +0100, daire.mcnamara@xxxxxxxxxxxxx wrote: > From: Daire McNamara <daire.mcnamara@xxxxxxxxxxxxx> > > Clear MSI bit in ISTATUS register after reading it before > handling individual MSI bits That explains nothing. If you are fixing a bug please describe the issue and how the patch is fixing it. > This fixes a potential race condition pointed out by Bjorn Helgaas: > https://lore.kernel.org/linux-pci/20220127202000.GA126335@bhelgaas/ > > Fixes: 6f15a9c9f941 ("PCI: microchip: Add Microchip PolarFire PCIe controller driver") > Signed-off-by: Daire McNamara <daire.mcnamara@xxxxxxxxxxxxx> > --- > Adding linux-pci mailing list > drivers/pci/controller/pcie-microchip-host.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/drivers/pci/controller/pcie-microchip-host.c b/drivers/pci/controller/pcie-microchip-host.c > index 29d8e81e4181..da8e3fdc97b3 100644 > --- a/drivers/pci/controller/pcie-microchip-host.c > +++ b/drivers/pci/controller/pcie-microchip-host.c > @@ -416,6 +416,7 @@ static void mc_handle_msi(struct irq_desc *desc) > > status = readl_relaxed(bridge_base_addr + ISTATUS_LOCAL); > if (status & PM_MSI_INT_MSI_MASK) { > + writel_relaxed(status & PM_MSI_INT_MSI_MASK, bridge_base_addr + ISTATUS_LOCAL); What does ISTATUS_LOCAL contain vs ISTATUS_MSI ? If you explain that to me I could help you write the commit log. Thanks, Lorenzo > status = readl_relaxed(bridge_base_addr + ISTATUS_MSI); > for_each_set_bit(bit, &status, msi->num_vectors) { > ret = generic_handle_domain_irq(msi->dev_domain, bit); > @@ -432,13 +433,8 @@ static void mc_msi_bottom_irq_ack(struct irq_data *data) > void __iomem *bridge_base_addr = > port->axi_base_addr + MC_PCIE_BRIDGE_ADDR; > u32 bitpos = data->hwirq; > - unsigned long status; > > writel_relaxed(BIT(bitpos), bridge_base_addr + ISTATUS_MSI); > - status = readl_relaxed(bridge_base_addr + ISTATUS_MSI); > - if (!status) > - writel_relaxed(BIT(PM_MSI_INT_MSI_SHIFT), > - bridge_base_addr + ISTATUS_LOCAL); > } > > static void mc_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) > -- > 2.25.1 >
