Add PCI legacy interrupt support for AM654. AM654 has a single HW
interrupt line for all the four legacy interrupts INTA/INTB/INTC/INTD.
The HW interrupt line connected to GIC is a pulse interrupt whereas
the legacy interrupts by definition is level interrupt. In order to
provide level interrupt functionality to edge interrupt line, PCIe
in AM654 has provided IRQ_EOI register. When the SW writes to IRQ_EOI
register after handling the interrupt, the IP checks the state of
legacy interrupt and re-triggers pulse interrupt invoking the handler
again.
Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
---
drivers/pci/controller/dwc/pci-keystone.c | 87 +++++++++++++++++++++--
1 file changed, 82 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index dfa9a7fcf9b7..84a25207d0d3 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -118,6 +118,7 @@ struct keystone_pcie {
/* PCI Device ID */
u32 device_id;
struct device_node *legacy_intc_np;
+ struct irq_domain *legacy_irq_domain;
int msi_host_irq;
int num_lanes;
@@ -289,6 +290,29 @@ static irqreturn_t ks_pcie_handle_error_irq(struct keystone_pcie *ks_pcie)
return IRQ_HANDLED;
}
+static void ks_pcie_am654_legacy_irq_handler(struct irq_desc *desc)
+{
+ struct keystone_pcie *ks_pcie = irq_desc_get_handler_data(desc);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ int virq, i;
+ u32 reg;
+
+ chained_irq_enter(chip, desc);
+
+ for (i = 0; i < PCI_NUM_INTX; i++) {
+ reg = ks_pcie_app_readl(ks_pcie, IRQ_STATUS(i));
+ if (!(reg & INTx_EN))
+ continue;
+
+ virq = irq_linear_revmap(ks_pcie->legacy_irq_domain, i);
+ generic_handle_irq(virq);
+ ks_pcie_app_writel(ks_pcie, IRQ_STATUS(i), INTx_EN);
+ ks_pcie_app_writel(ks_pcie, IRQ_EOI, i);
+ }
+
+ chained_irq_exit(chip, desc);
+}
+
void ks_pcie_irq_eoi(struct irq_data *data)
{
struct keystone_pcie *ks_pcie = irq_data_get_irq_chip_data(data);
@@ -728,6 +752,54 @@ static int ks_pcie_config_msi_irq(struct keystone_pcie *ks_pcie)
return ret;
}
+static int ks_pcie_am654_intx_map(struct irq_domain *domain, unsigned int irq,
+ irq_hw_number_t hwirq)
+{
+ irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
+ irq_set_chip_data(irq, domain->host_data);
+
+ return 0;
+}
+
+static const struct irq_domain_ops ks_pcie_am654_irq_domain_ops = {
+ .map = ks_pcie_am654_intx_map,
+};
+
+static int ks_pcie_am654_config_legacy_irq(struct keystone_pcie *ks_pcie)
+{
+ struct device *dev = ks_pcie->pci->dev;
+ struct irq_domain *legacy_irq_domain;
+ struct device_node *np = ks_pcie->np;
+ struct device_node *intc_np;
+ int ret = 0;
+ int irq;
+ int i;
+
+ intc_np = of_get_child_by_name(np, "interrupt-controller");
+ if (!intc_np) {
+ dev_warn(dev, "legacy interrupt-controller node is absent\n");
+ return -EINVAL;
+ }
+
+ irq = irq_of_parse_and_map(intc_np, 0);
+ if (!irq)
+ return -EINVAL;
+
+ irq_set_chained_handler_and_data(irq, ks_pcie_am654_legacy_irq_handler, ks_pcie);
+ legacy_irq_domain = irq_domain_add_linear(intc_np, PCI_NUM_INTX,
+ &ks_pcie_am654_irq_domain_ops, ks_pcie);
+ if (!legacy_irq_domain) {
+ dev_err(dev, "Failed to add irq domain for legacy irqs\n");
+ return -EINVAL;
+ }
+ ks_pcie->legacy_irq_domain = legacy_irq_domain;
+
+ for (i = 0; i < PCI_NUM_INTX; i++)
+ ks_pcie_app_writel(ks_pcie, IRQ_ENABLE_SET(i), INTx_EN);
+
+ return ret;
+}
+
static int ks_pcie_config_legacy_irq(struct keystone_pcie *ks_pcie)
{
struct device *dev = ks_pcie->pci->dev;
@@ -835,12 +907,17 @@ static int __init ks_pcie_host_init(struct pcie_port *pp)
int ret;
pp->bridge->ops = &ks_pcie_ops;
- if (!ks_pcie->is_am6)
- pp->bridge->child_ops = &ks_child_pcie_ops;
- ret = ks_pcie_config_legacy_irq(ks_pcie);
- if (ret)
- return ret;
+ if (!ks_pcie->is_am6) {
+ pp->bridge->child_ops = &ks_child_pcie_ops;
+ ret = ks_pcie_config_legacy_irq(ks_pcie);
+ if (ret)
+ return ret;
+ } else {
+ ret = ks_pcie_am654_config_legacy_irq(ks_pcie);
+ if (ret)
+ return ret;
+ }
ret = ks_pcie_config_msi_irq(ks_pcie);
if (ret)
--
2.17.1
