From: Marc Zyngier marc.zyngier@arm.com
The write to the status register is really an ACK for the HW, and should be treated as such by the driver. Let's move it to the irq_ack() callback, which will prevent people from moving it around in order to paper over other bugs.
Fixes: 8c934095fa2f ("PCI: dwc: Clear MSI interrupt status after it is handled, not before") Fixes: 7c5925afbc58 ("PCI: dwc: Move MSI IRQs allocation to IRQ domains hierarchical API") Link: https://lore.kernel.org/linux-pci/20181113225734.8026-1-marc.zyngier@arm.com... Reported-by: Trent Piepho tpiepho@impinj.com Tested-by: Niklas Cassel niklas.cassel@linaro.org Tested-by: Gustavo Pimentel gustavo.pimentel@synopsys.com Tested-by: Stanimir Varbanov svarbanov@mm-sol.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com [lorenzo.pieralisi@arm.com: updated commit log] Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Cc: stable@vger.kernel.org --- Original upstream commit SHA1: 3f7bb2ec20ce07c02b2002349d256c91a463fcc5
Sending a backport (which is authored by Marc, just like the original commit), for 4.14-stable, since the original commit failed to apply there.
Not sure if Tested-by tags should remain. Mine can be kept, since I've tested the backport.
drivers/pci/dwc/pcie-designware-host.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c index bc3e2d8d0cce..58b38c54a7cf 100644 --- a/drivers/pci/dwc/pcie-designware-host.c +++ b/drivers/pci/dwc/pcie-designware-host.c @@ -45,8 +45,19 @@ static int dw_pcie_wr_own_conf(struct pcie_port *pp, int where, int size, return dw_pcie_write(pci->dbi_base + where, size, val); }
+static void dwc_irq_ack(struct irq_data *d) +{ + struct msi_desc *msi = irq_data_get_msi_desc(d); + struct pcie_port *pp = msi_desc_to_pci_sysdata(msi); + int pos = d->hwirq % 32; + int i = d->hwirq / 32; + + dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS + i * 12, 4, BIT(pos)); +} + static struct irq_chip dw_msi_irq_chip = { .name = "PCI-MSI", + .irq_ack = dwc_irq_ack, .irq_enable = pci_msi_unmask_irq, .irq_disable = pci_msi_mask_irq, .irq_mask = pci_msi_mask_irq, @@ -72,8 +83,6 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) pos)) != 32) { irq = irq_find_mapping(pp->irq_domain, i * 32 + pos); generic_handle_irq(irq); - dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS + i * 12, - 4, 1 << pos); pos++; } } @@ -263,7 +272,7 @@ static struct msi_controller dw_pcie_msi_chip = { static int dw_pcie_msi_map(struct irq_domain *domain, unsigned int irq, irq_hw_number_t hwirq) { - irq_set_chip_and_handler(irq, &dw_msi_irq_chip, handle_simple_irq); + irq_set_chip_and_handler(irq, &dw_msi_irq_chip, handle_edge_irq); irq_set_chip_data(irq, domain->host_data);
return 0;