In the subject, "legacy_irq_handler" looks like it's supposed to be a function name, but it's not. Maybe something like: PCI: keystone: Check INTA/B/C/D IRQ_STATUS in ks_pcie_legacy_irq_handler() On Thu, Feb 07, 2019 at 04:39:17PM +0530, Kishon Vijay Abraham I wrote: > The legacy interrupt handler directly checks the IRQ_STATUS register > corresponding to a interrupt line inorder to invoke generic_handle_irq. s/The legacy interrupt handler/ks_pcie_handle_legacy_irq()/ ? s/to a/to an/ s/inorder/in order/ s/generic_handle_irq/generic_handle_irq()/ > While this is okay for K2G platform which has separate interrupt line for > each of the 4 legacy interrupts, AM654 which uses the same PCIe wrapper > has a single interrupt line for all the legacy interrupts. So for AM654 > the interrupt handler won't be able to directly check the IRQ_STATUS > register corresponding to the interrupt line. s/platform which/platform, which/ s/separate interrupt line/separate interrupt lines/ s/AM654 which/AM654, which/ s/PCIe wrapper/PCIe wrapper,/ s/interrupt line for all/interrupt line shared by all/ > Also the legacy interrupt handler uses 'virq' obtained from > irq_of_parse_and_map to find the correct interrupt line which raised the > interrupt. There is no guarantee that virq assigned for contiguous hardware > irq will be contiguous and the interrupt handler might end up checking > the wrong IRQ_STATUS register. s/irq_of_parse_and_map/irq_of_parse_and_map() s/irq will/IRQ will/ > In order to overcome the above issues, read the IRQ_STATUS register of > all the 4 legacy interrupts to determine which interrupt was raised. > > Link: https://lkml.kernel.org/r/bb081d21-7c03-0357-4294-7e92d95d838c@xxxxxxx > Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx> > --- > drivers/pci/controller/dwc/pci-keystone.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c > index 5286a480f76b..4cf9849d5a1d 100644 > --- a/drivers/pci/controller/dwc/pci-keystone.c > +++ b/drivers/pci/controller/dwc/pci-keystone.c > @@ -214,16 +214,11 @@ static void ks_pcie_handle_legacy_irq(struct keystone_pcie *ks_pcie, > { > struct dw_pcie *pci = ks_pcie->pci; > struct device *dev = pci->dev; > - u32 pending; > int virq; > > - pending = ks_pcie_app_readl(ks_pcie, IRQ_STATUS(offset)); > - > - if (BIT(0) & pending) { > - virq = irq_linear_revmap(ks_pcie->legacy_irq_domain, offset); > - dev_dbg(dev, ": irq: irq_offset %d, virq %d\n", offset, virq); > - generic_handle_irq(virq); > - } > + virq = irq_linear_revmap(ks_pcie->legacy_irq_domain, offset); > + dev_dbg(dev, ": irq: irq_offset %d, virq %d\n", offset, virq); > + generic_handle_irq(virq); > > /* EOI the INTx interrupt */ > ks_pcie_app_writel(ks_pcie, IRQ_EOI, offset); > @@ -607,8 +602,9 @@ static void ks_pcie_legacy_irq_handler(struct irq_desc *desc) > struct keystone_pcie *ks_pcie = irq_desc_get_handler_data(desc); > struct dw_pcie *pci = ks_pcie->pci; > struct device *dev = pci->dev; > - u32 irq_offset = irq - ks_pcie->legacy_host_irqs[0]; > struct irq_chip *chip = irq_desc_get_chip(desc); > + unsigned int irq_no; > + u32 reg; > > dev_dbg(dev, ": Handling legacy irq %d\n", irq); > > @@ -618,7 +614,13 @@ static void ks_pcie_legacy_irq_handler(struct irq_desc *desc) > * ack operation. > */ > chained_irq_enter(chip, desc); > - ks_pcie_handle_legacy_irq(ks_pcie, irq_offset); > + for (irq_no = 0; irq_no < PCI_NUM_INTX; irq_no++) { > + reg = ks_pcie_app_readl(ks_pcie, IRQ_STATUS(irq_no)); > + if (!(reg & INTx_EN)) > + continue; > + ks_pcie_handle_legacy_irq(ks_pcie, irq_no); It's too bad that reading IRQ_STATUS and writing IRQ_EOI are now in separate functions. It's nice to have them together for code auditing purposes. Could maybe accumulate a mask of which INTx bits are set and call ks_pcie_handle_legacy_irq() only once with that mask? Of course, then you'd need another loop in ks_pcie_handle_legacy_irq(). > + } > + > chained_irq_exit(chip, desc); > } > > -- > 2.17.1 >
