Re: [v7,4/7] PCI: mediatek-gen3: Add INTx support
From: Marc Zyngier
Date: Tue Jan 26 2021 - 07:26:38 EST
On 2021-01-13 11:39, Jianjun Wang wrote:
Add INTx support for MediaTek Gen3 PCIe controller.
Signed-off-by: Jianjun Wang <jianjun.wang@xxxxxxxxxxxx>
Acked-by: Ryder Lee <ryder.lee@xxxxxxxxxxxx>
---
drivers/pci/controller/pcie-mediatek-gen3.c | 163 ++++++++++++++++++++
1 file changed, 163 insertions(+)
diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c
b/drivers/pci/controller/pcie-mediatek-gen3.c
index c00ea7c167de..7979a2856c35 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -9,6 +9,9 @@
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/iopoll.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_address.h>
@@ -49,6 +52,12 @@
#define PCIE_LINK_STATUS_REG 0x154
#define PCIE_PORT_LINKUP BIT(8)
+#define PCIE_INT_ENABLE_REG 0x180
+#define PCIE_INTX_SHIFT 24
+#define PCIE_INTX_MASK GENMASK(27, 24)
I guess this '24' is actually PCIE_INTX_SHIFT? In this case,
please write it as
GENMASK(PCIE_INTX_SHIFT + PCI_NUM_INTX - 1, PCIE_INTX_SHIFT)
to make it clear that you are dealing with one bit per INTx.
+
+#define PCIE_INT_STATUS_REG 0x184
+
#define PCIE_TRANS_TABLE_BASE_REG 0x800
#define PCIE_ATR_SRC_ADDR_MSB_OFFSET 0x4
#define PCIE_ATR_TRSL_ADDR_LSB_OFFSET 0x8
@@ -77,6 +86,8 @@
* @phy: PHY controller block
* @clks: PCIe clocks
* @num_clks: PCIe clocks count for this port
+ * @irq: PCIe controller interrupt number
+ * @intx_domain: legacy INTx IRQ domain
*/
struct mtk_pcie_port {
struct device *dev;
@@ -87,6 +98,9 @@ struct mtk_pcie_port {
struct phy *phy;
struct clk_bulk_data *clks;
int num_clks;
+
+ int irq;
+ struct irq_domain *intx_domain;
};
/**
@@ -266,6 +280,149 @@ static int mtk_pcie_startup_port(struct
mtk_pcie_port *port)
return 0;
}
+static int mtk_pcie_set_affinity(struct irq_data *data,
+ const struct cpumask *mask, bool force)
+{
+ return -EINVAL;
+}
+
+static void mtk_intx_mask(struct irq_data *data)
+{
+ struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
+ u32 val;
+
+ val = readl_relaxed(port->base + PCIE_INT_ENABLE_REG);
+ val &= ~BIT(data->hwirq + PCIE_INTX_SHIFT);
+ writel_relaxed(val, port->base + PCIE_INT_ENABLE_REG);
This is missing some locking. Otherwise, two concurrent mask/unmask
for different interrupts will corrupt each other's state.
+}
+
+static void mtk_intx_unmask(struct irq_data *data)
+{
+ struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
+ u32 val;
+
+ val = readl_relaxed(port->base + PCIE_INT_ENABLE_REG);
+ val |= BIT(data->hwirq + PCIE_INTX_SHIFT);
+ writel_relaxed(val, port->base + PCIE_INT_ENABLE_REG);
Same thing here.
+}
+
+/**
+ * mtk_intx_eoi
+ * @data: pointer to chip specific data
+ *
+ * As an emulated level IRQ, its interrupt status will remain
+ * until the corresponding de-assert message is received; hence that
+ * the status can only be cleared when the interrupt has been
serviced.
+ */
+static void mtk_intx_eoi(struct irq_data *data)
+{
+ struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
+ unsigned long hwirq;
+
+ hwirq = data->hwirq + PCIE_INTX_SHIFT;
+ writel_relaxed(BIT(hwirq), port->base + PCIE_INT_STATUS_REG);
+}
+
+static struct irq_chip mtk_intx_irq_chip = {
+ .irq_mask = mtk_intx_mask,
+ .irq_unmask = mtk_intx_unmask,
+ .irq_eoi = mtk_intx_eoi,
+ .irq_set_affinity = mtk_pcie_set_affinity,
+ .name = "PCIe",
nit: "PCIe" is not really descriptive. "INTx" would be a bit better.
+};
+
+static int mtk_pcie_intx_map(struct irq_domain *domain, unsigned int
irq,
+ irq_hw_number_t hwirq)
+{
+ irq_set_chip_and_handler_name(irq, &mtk_intx_irq_chip,
+ handle_fasteoi_irq, "INTx");
+ irq_set_chip_data(irq, domain->host_data);
You probably want to set the chip_data *before* wiring
the handler, as otherwise you could end-up with a NULL
pointer in any of the callbacks if the interrupt fires
between the two.
+
+ return 0;
+}
+
+static const struct irq_domain_ops intx_domain_ops = {
+ .map = mtk_pcie_intx_map,
+};
+
+static int mtk_pcie_init_irq_domains(struct mtk_pcie_port *port,
+ struct device_node *node)
+{
+ struct device *dev = port->dev;
+ struct device_node *intc_node;
+
+ /* Setup INTx */
+ intc_node = of_get_child_by_name(node, "interrupt-controller");
+ if (!intc_node) {
+ dev_err(dev, "missing PCIe Intc node\n");
+ return -ENODEV;
+ }
+
+ port->intx_domain = irq_domain_add_linear(intc_node, PCI_NUM_INTX,
+ &intx_domain_ops, port);
+ if (!port->intx_domain) {
+ dev_err(dev, "failed to get INTx IRQ domain\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static void mtk_pcie_irq_teardown(struct mtk_pcie_port *port)
+{
+ irq_set_chained_handler_and_data(port->irq, NULL, NULL);
+
+ if (port->intx_domain)
+ irq_domain_remove(port->intx_domain);
+
+ irq_dispose_mapping(port->irq);
+}
+
+static void mtk_pcie_irq_handler(struct irq_desc *desc)
+{
+ struct mtk_pcie_port *port = irq_desc_get_handler_data(desc);
+ struct irq_chip *irqchip = irq_desc_get_chip(desc);
+ unsigned long status;
+ unsigned int virq;
+ irq_hw_number_t irq_bit = PCIE_INTX_SHIFT;
+
+ chained_irq_enter(irqchip, desc);
+
+ status = readl_relaxed(port->base + PCIE_INT_STATUS_REG);
+ if (status & PCIE_INTX_MASK) {
This "if (status & PCIE_INTX_MASK)" is already implicit from
the for_each_set_bit_from() iterator, and you can drop it.
+ for_each_set_bit_from(irq_bit, &status, PCI_NUM_INTX +
+ PCIE_INTX_SHIFT) {
+ virq = irq_find_mapping(port->intx_domain,
+ irq_bit - PCIE_INTX_SHIFT);
+ generic_handle_irq(virq);
+ }
+ }
+
+ chained_irq_exit(irqchip, desc);
+}
+
+static int mtk_pcie_setup_irq(struct mtk_pcie_port *port,
+ struct device_node *node)
+{
+ struct device *dev = port->dev;
+ struct platform_device *pdev = to_platform_device(dev);
+ int err;
+
+ err = mtk_pcie_init_irq_domains(port, node);
+ if (err) {
+ dev_err(dev, "failed to init PCIe IRQ domain\n");
+ return err;
+ }
+
+ port->irq = platform_get_irq(pdev, 0);
+ if (port->irq < 0)
+ return port->irq;
+
+ irq_set_chained_handler_and_data(port->irq, mtk_pcie_irq_handler,
port);
You seem to be missing something that will mask all INTx interrupts
as an initial state.
+
+ return 0;
+}
+
static int mtk_pcie_clk_init(struct mtk_pcie_port *port)
{
int ret;
@@ -388,6 +545,10 @@ static int mtk_pcie_setup(struct mtk_pcie_port
*port)
goto err_setup;
}
+ err = mtk_pcie_setup_irq(port, dev->of_node);
+ if (err)
+ goto err_setup;
+
dev_info(dev, "PCIe link up success!\n");
return 0;
@@ -423,6 +584,7 @@ static int mtk_pcie_probe(struct platform_device
*pdev)
err = pci_host_probe(host);
if (err) {
+ mtk_pcie_irq_teardown(port);
mtk_pcie_power_down(port);
return err;
}
@@ -440,6 +602,7 @@ static int mtk_pcie_remove(struct platform_device
*pdev)
pci_remove_root_bus(host->bus);
pci_unlock_rescan_remove();
+ mtk_pcie_irq_teardown(port);
mtk_pcie_power_down(port);
return 0;
Thanks,
M.
--
Jazz is not dead. It just smells funny...