On Wed, 05 Jan 2022 15:02:38 +0000, Pali Rohár <pali@xxxxxxxxxx> wrote: > > This adds support for legacy INTx interrupts received from other PCIe > devices and which are reported by a new INTx irq chip. > > With this change, kernel can distinguish between INTA, INTB, INTC and INTD > interrupts. > > Note that for this support, device tree files has to be properly adjusted > to provide "interrupts" or "interrupts-extended" property with intx > interrupt source, "interrupt-names" property with "intx" string and also > 'interrupt-controller' subnode must be defined. > > If device tree files do not provide these nodes then driver would work as > before. > > Signed-off-by: Pali Rohár <pali@xxxxxxxxxx> > --- > drivers/pci/controller/pci-mvebu.c | 182 +++++++++++++++++++++++++++-- > 1 file changed, 174 insertions(+), 8 deletions(-) > > diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c > index 1e90ab888075..04bcdd7b7a6d 100644 > --- a/drivers/pci/controller/pci-mvebu.c > +++ b/drivers/pci/controller/pci-mvebu.c > @@ -54,9 +54,10 @@ > PCIE_CONF_ADDR_EN) > #define PCIE_CONF_DATA_OFF 0x18fc > #define PCIE_INT_CAUSE_OFF 0x1900 > +#define PCIE_INT_UNMASK_OFF 0x1910 > +#define PCIE_INT_INTX(i) BIT(24+i) > #define PCIE_INT_PM_PME BIT(28) > -#define PCIE_MASK_OFF 0x1910 > -#define PCIE_MASK_ENABLE_INTS 0x0f000000 > +#define PCIE_INT_ALL_MASK GENMASK(31, 0) > #define PCIE_CTRL_OFF 0x1a00 > #define PCIE_CTRL_X1_MODE 0x0001 > #define PCIE_CTRL_RC_MODE BIT(1) > @@ -110,6 +111,10 @@ struct mvebu_pcie_port { > struct mvebu_pcie_window iowin; > u32 saved_pcie_stat; > struct resource regs; > + struct irq_domain *intx_irq_domain; > + struct irq_chip intx_irq_chip; Why is this structure per port? It really should be global. Printing the port number in the name isn't enough of a reason. > + raw_spinlock_t irq_lock; > + int intx_irq; > }; > > static inline void mvebu_writel(struct mvebu_pcie_port *port, u32 val, u32 reg) > @@ -235,7 +240,7 @@ static void mvebu_pcie_setup_wins(struct mvebu_pcie_port *port) > > static void mvebu_pcie_setup_hw(struct mvebu_pcie_port *port) > { > - u32 ctrl, lnkcap, cmd, dev_rev, mask; > + u32 ctrl, lnkcap, cmd, dev_rev, unmask; > > /* Setup PCIe controller to Root Complex mode. */ > ctrl = mvebu_readl(port, PCIE_CTRL_OFF); > @@ -288,10 +293,30 @@ static void mvebu_pcie_setup_hw(struct mvebu_pcie_port *port) > /* Point PCIe unit MBUS decode windows to DRAM space. */ > mvebu_pcie_setup_wins(port); > > - /* Enable interrupt lines A-D. */ > - mask = mvebu_readl(port, PCIE_MASK_OFF); > - mask |= PCIE_MASK_ENABLE_INTS; > - mvebu_writel(port, mask, PCIE_MASK_OFF); > + /* Mask all interrupt sources. */ > + mvebu_writel(port, ~PCIE_INT_ALL_MASK, PCIE_INT_UNMASK_OFF); > + > + /* Clear all interrupt causes. */ > + mvebu_writel(port, ~PCIE_INT_ALL_MASK, PCIE_INT_CAUSE_OFF); > + > + if (port->intx_irq <= 0) { > + /* > + * When neither "summary" interrupt, nor "intx" interrupt was > + * specified in DT then unmask all legacy INTx interrupts as in > + * this case driver does not provide a way for masking and > + * unmasking of individual legacy INTx interrupts. In this case > + * all interrupts, including legacy INTx are reported via one > + * shared GIC source and therefore kernel cannot distinguish > + * which individual legacy INTx was triggered. These interrupts > + * are shared, so it should not cause any issue. Just > + * performance penalty as every PCIe interrupt handler needs to > + * be called when some interrupt is triggered. > + */ > + unmask = mvebu_readl(port, PCIE_INT_UNMASK_OFF); > + unmask |= PCIE_INT_INTX(0) | PCIE_INT_INTX(1) | > + PCIE_INT_INTX(2) | PCIE_INT_INTX(3); > + mvebu_writel(port, unmask, PCIE_INT_UNMASK_OFF); Maybe worth printing a warning here, so that the user knows they are on thin ice. > + } > } > > static struct mvebu_pcie_port *mvebu_pcie_find_port(struct mvebu_pcie *pcie, > @@ -924,6 +949,109 @@ static struct pci_ops mvebu_pcie_ops = { > .write = mvebu_pcie_wr_conf, > }; > > +static void mvebu_pcie_intx_irq_mask(struct irq_data *d) > +{ > + struct mvebu_pcie_port *port = d->domain->host_data; > + irq_hw_number_t hwirq = irqd_to_hwirq(d); > + unsigned long flags; > + u32 unmask; > + > + raw_spin_lock_irqsave(&port->irq_lock, flags); > + unmask = mvebu_readl(port, PCIE_INT_UNMASK_OFF); > + unmask &= ~PCIE_INT_INTX(hwirq); > + mvebu_writel(port, unmask, PCIE_INT_UNMASK_OFF); > + raw_spin_unlock_irqrestore(&port->irq_lock, flags); > +} > + > +static void mvebu_pcie_intx_irq_unmask(struct irq_data *d) > +{ > + struct mvebu_pcie_port *port = d->domain->host_data; > + irq_hw_number_t hwirq = irqd_to_hwirq(d); > + unsigned long flags; > + u32 unmask; > + > + raw_spin_lock_irqsave(&port->irq_lock, flags); > + unmask = mvebu_readl(port, PCIE_INT_UNMASK_OFF); > + unmask |= PCIE_INT_INTX(hwirq); > + mvebu_writel(port, unmask, PCIE_INT_UNMASK_OFF); > + raw_spin_unlock_irqrestore(&port->irq_lock, flags); > +} > + > +static int mvebu_pcie_intx_irq_map(struct irq_domain *h, > + unsigned int virq, irq_hw_number_t hwirq) > +{ > + struct mvebu_pcie_port *port = h->host_data; > + > + irq_set_status_flags(virq, IRQ_LEVEL); > + irq_set_chip_and_handler(virq, &port->intx_irq_chip, handle_level_irq); > + irq_set_chip_data(virq, port); > + > + return 0; > +} > + > +static const struct irq_domain_ops mvebu_pcie_intx_irq_domain_ops = { > + .map = mvebu_pcie_intx_irq_map, > + .xlate = irq_domain_xlate_onecell, > +}; > + > +static int mvebu_pcie_init_irq_domain(struct mvebu_pcie_port *port) > +{ > + struct device *dev = &port->pcie->pdev->dev; > + struct device_node *pcie_intc_node; > + > + raw_spin_lock_init(&port->irq_lock); > + > + port->intx_irq_chip.name = devm_kasprintf(dev, GFP_KERNEL, > + "mvebu-%s-INTx", > + port->name); That's exactly what I really don't want to see. It prevents sharing of the irq_chip structure, and gets in the way of making it const in the future. Yes, I know that some drivers do that. I can't fix those, because /proc/interrupts is ABI. But I really don't want to see more of these. /sys/kernel/debug/irqs already has all the information you need, as it will happily give you the domain name and the interrupt topology. > + port->intx_irq_chip.irq_mask = mvebu_pcie_intx_irq_mask; > + port->intx_irq_chip.irq_unmask = mvebu_pcie_intx_irq_unmask; > + > + pcie_intc_node = of_get_next_child(port->dn, NULL); > + if (!pcie_intc_node) { > + dev_err(dev, "No PCIe Intc node found for %s\n", port->name); > + return -ENODEV; > + } > + > + port->intx_irq_domain = irq_domain_add_linear(pcie_intc_node, PCI_NUM_INTX, > + &mvebu_pcie_intx_irq_domain_ops, > + port); > + of_node_put(pcie_intc_node); > + if (!port->intx_irq_domain) { > + devm_kfree(dev, port->intx_irq_chip.name); > + dev_err(dev, "Failed to get INTx IRQ domain for %s\n", port->name); > + return -ENOMEM; > + } > + > + return 0; > +} > + > +static void mvebu_pcie_irq_handler(struct irq_desc *desc) > +{ > + struct mvebu_pcie_port *port = irq_desc_get_handler_data(desc); > + struct irq_chip *chip = irq_desc_get_chip(desc); > + struct device *dev = &port->pcie->pdev->dev; > + u32 cause, unmask, status; > + int i; > + > + chained_irq_enter(chip, desc); > + > + cause = mvebu_readl(port, PCIE_INT_CAUSE_OFF); > + unmask = mvebu_readl(port, PCIE_INT_UNMASK_OFF); Why do you need to read this? If the CAUSE register also returns the masked interrupts that are pending, it may be worth keeping a shadow copy of the this register, as you end-up having an extra MMIO read on each and every interrupt, which can't be great for performance. > + status = cause & unmask; > + > + /* Process legacy INTx interrupts */ > + for (i = 0; i < PCI_NUM_INTX; i++) { > + if (!(status & PCIE_INT_INTX(i))) > + continue; > + > + if (generic_handle_domain_irq(port->intx_irq_domain, i) == -EINVAL) > + dev_err_ratelimited(dev, "unexpected INT%c IRQ\n", (char)i+'A'); > + } > + > + chained_irq_exit(chip, desc); > +} > + > static int mvebu_pcie_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) > { > /* Interrupt support on mvebu emulated bridges is not implemented yet */ > @@ -1121,6 +1249,16 @@ static int mvebu_pcie_parse_port(struct mvebu_pcie *pcie, > port->io_attr = -1; > } > > + /* > + * Old DT bindings do not contain "intx" interrupt > + * so do not fail probing driver when interrupt does not exist. > + */ > + port->intx_irq = of_irq_get_byname(child, "intx"); > + if (port->intx_irq == -EPROBE_DEFER) { > + ret = port->intx_irq; > + goto err; > + } > + > reset_gpio = of_get_named_gpio_flags(child, "reset-gpios", 0, &flags); > if (reset_gpio == -EPROBE_DEFER) { > ret = reset_gpio; > @@ -1317,6 +1455,7 @@ static int mvebu_pcie_probe(struct platform_device *pdev) > > for (i = 0; i < pcie->nports; i++) { > struct mvebu_pcie_port *port = &pcie->ports[i]; > + int irq = port->intx_irq; > > child = port->dn; > if (!child) > @@ -1344,6 +1483,22 @@ static int mvebu_pcie_probe(struct platform_device *pdev) > continue; > } > > + if (irq > 0) { > + ret = mvebu_pcie_init_irq_domain(port); > + if (ret) { > + dev_err(dev, "%s: cannot init irq domain\n", > + port->name); > + pci_bridge_emul_cleanup(&port->bridge); > + devm_iounmap(dev, port->base); > + port->base = NULL; > + mvebu_pcie_powerdown(port); > + continue; > + } > + irq_set_chained_handler_and_data(irq, > + mvebu_pcie_irq_handler, > + port); > + } > + > /* > * PCIe topology exported by mvebu hw is quite complicated. In > * reality has something like N fully independent host bridges > @@ -1448,6 +1603,7 @@ static int mvebu_pcie_remove(struct platform_device *pdev) > > for (i = 0; i < pcie->nports; i++) { > struct mvebu_pcie_port *port = &pcie->ports[i]; > + int irq = port->intx_irq; > > if (!port->base) > continue; > @@ -1458,7 +1614,17 @@ static int mvebu_pcie_remove(struct platform_device *pdev) > mvebu_writel(port, cmd, PCIE_CMD_OFF); > > /* Mask all interrupt sources. */ > - mvebu_writel(port, 0, PCIE_MASK_OFF); > + mvebu_writel(port, ~PCIE_INT_ALL_MASK, PCIE_INT_UNMASK_OFF); > + > + /* Clear all interrupt causes. */ > + mvebu_writel(port, ~PCIE_INT_ALL_MASK, PCIE_INT_CAUSE_OFF); > + > + /* Remove IRQ domains. */ > + if (port->intx_irq_domain) > + irq_domain_remove(port->intx_irq_domain); > + > + if (irq > 0) > + irq_set_chained_handler_and_data(irq, NULL, NULL); > > /* Free config space for emulated root bridge. */ > pci_bridge_emul_cleanup(&port->bridge); Thanks, M. -- Without deviation from the norm, progress is not possible.