diff mbox

[RFC,v2] irqchip: Add support for tango interrupt router

Message ID dfb86360-2247-65bb-602b-5c21029709fd@free.fr (mailing list archive)
State New, archived
Headers show

Commit Message

Mason July 12, 2017, 4:39 p.m. UTC
128 inputs, 24 outputs (to GIC SPI 0-23)
---
There might be a few things wrong with this driver.
When I cat /proc/interrupts the interrupt count appears
to be bogus (as if level IRQ counts are added to edge
IRQ counts). Did I mess something up with the IRQ domains?
---
 .../interrupt-controller/sigma,smp8759-intc.txt    |  18 ++
 drivers/irqchip/Makefile                           |   2 +-
 drivers/irqchip/irq-smp8759.c                      | 203 +++++++++++++++++++++
 3 files changed, 222 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/sigma,smp8759-intc.txt
 create mode 100644 drivers/irqchip/irq-smp8759.c

Comments

Mason July 15, 2017, 1:06 p.m. UTC | #1
On 12/07/2017 18:39, Mason wrote:

> 128 inputs, 24 outputs (to GIC SPI 0-23)
> 
> There might be a few things wrong with this driver. When I
> cat /proc/interrupts the interrupt count appears to be bogus
> (as if level IRQ counts are added to edge IRQ counts).

OK, I found the issue.

It occurred on the interrupt lines that stay high when
the HW block is idle, so I mishandled them on every
level interrupt.

I have two remaining issues:

1) In the ISR, I get the hwirq from the GIC. What is the
API to translate that to the SPI? I'm currently just
subtracting 32.

2) I'm currently using a single domain, with a
handle_simple_irq domain handler. That's probably
wrong. Should I define two domains, one for edge
IRQs and one for level IRQs, and use the appropriate
handler?  Should both domain have 128 entries?
(I.e. are they indexed by the hwirq?)
And should I use linear or tree?

Regards.
Mason July 15, 2017, 11:46 p.m. UTC | #2
On 15/07/2017 15:06, Mason wrote:

> I have two remaining issues:
> 
> 1) In the ISR, I get the hwirq from the GIC. What is the
> API to translate that to the SPI? I'm currently just
> subtracting 32.

gic_set_type() in drivers/irqchip/irq-gic.c

	/* SPIs have restrictions on the supported types */
	if (gicirq >= 32 && type != IRQ_TYPE_LEVEL_HIGH &&
			    type != IRQ_TYPE_EDGE_RISING)
		return -EINVAL;


gic_irq_domain_translate() in the same file:

		/* Get the interrupt number and add 16 to skip over SGIs */
		*hwirq = fwspec->param[1] + 16;

		/*
		 * For SPIs, we need to add 16 more to get the GIC irq
		 * ID number
		 */
		if (!fwspec->param[0])
			*hwirq += 16;


So it seems "acceptable" to compute spi = d->hwirq - 32;


> 2) I'm currently using a single domain, with a
> handle_simple_irq domain handler. That's probably
> wrong. Should I define two domains, one for edge
> IRQs and one for level IRQs, and use the appropriate
> handler?  Should both domain have 128 entries?
> (I.e. are they indexed by the hwirq?)
> And should I use linear or tree?

I will read this again carefully:
https://www.kernel.org/doc/Documentation/IRQ-domain.txt

Regards.
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/interrupt-controller/sigma,smp8759-intc.txt b/Documentation/devicetree/bindings/interrupt-controller/sigma,smp8759-intc.txt
new file mode 100644
index 000000000000..9ec922f3c0a4
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/sigma,smp8759-intc.txt
@@ -0,0 +1,18 @@ 
+Sigma Designs SMP8759 interrupt router
+
+Required properties:
+- compatible: "sigma,smp8759-intc"
+- reg: address/size of register area
+- interrupt-controller
+- #interrupt-cells: <2>  (hwirq and trigger_type)
+- interrupt-parent: parent phandle
+
+Example:
+
+	interrupt-controller@6f800 {
+		compatible = "sigma,smp8759-intc";
+		reg = <0x6f800 0x430>;
+		interrupt-controller;
+		#interrupt-cells = <2>;
+		interrupt-parent = <&gic>;
+	};
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index e4dbfc85abdb..013104923b71 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -47,7 +47,7 @@  obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o
 obj-$(CONFIG_ARCH_NSPIRE)		+= irq-zevio.o
 obj-$(CONFIG_ARCH_VT8500)		+= irq-vt8500.o
 obj-$(CONFIG_ST_IRQCHIP)		+= irq-st.o
-obj-$(CONFIG_TANGO_IRQ)			+= irq-tango.o
+obj-$(CONFIG_TANGO_IRQ)			+= irq-tango.o irq-smp8759.o
 obj-$(CONFIG_TB10X_IRQC)		+= irq-tb10x.o
 obj-$(CONFIG_TS4800_IRQ)		+= irq-ts4800.o
 obj-$(CONFIG_XTENSA)			+= irq-xtensa-pic.o
diff --git a/drivers/irqchip/irq-smp8759.c b/drivers/irqchip/irq-smp8759.c
new file mode 100644
index 000000000000..ec7fee4574ef
--- /dev/null
+++ b/drivers/irqchip/irq-smp8759.c
@@ -0,0 +1,203 @@ 
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+
+#define IRQ_MAX		128
+#define SPI_MAX		24 /* 24 output lines routed to SPI 0-23 */
+#define LEVEL_SPI	17
+#define IRQ_ENABLE	BIT(31)
+
+/*
+ * 128 inputs mapped to 24 outputs
+ * LEVEL_HIGH IRQs are muxed on output line 'LEVEL_SPI'
+ * EDGE_RISING IRQs get a dedicated output line
+ * gic_spi_to_tango_hwirq array maps GIC SPI hwirq to tango hwirq
+ */
+struct tango_intc {
+	DECLARE_BITMAP(enabled, IRQ_MAX);
+	spinlock_t lock;
+	void __iomem *config;
+	void __iomem *status;
+	struct irq_domain *dom;
+	u8 gic_spi_to_tango_hwirq[SPI_MAX];
+};
+
+static void tango_level_isr(struct irq_desc *desc)
+{
+	unsigned int pos, virq;
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct tango_intc *intc = irq_desc_get_handler_data(desc);
+	DECLARE_BITMAP(status, IRQ_MAX);
+
+	chained_irq_enter(chip, desc);
+
+	memcpy_fromio(status, intc->status, IRQ_MAX / BITS_PER_BYTE);
+	spin_lock(&intc->lock);
+	bitmap_and(status, status, intc->enabled, IRQ_MAX);
+	spin_unlock(&intc->lock);
+	for_each_set_bit(pos, status, IRQ_MAX) {
+		virq = irq_find_mapping(intc->dom, pos);
+		generic_handle_irq(virq);
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static void tango_edge_isr(struct irq_desc *desc)
+{
+	unsigned int virq;
+	struct irq_data *d = &desc->irq_data;
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct tango_intc *intc = irq_desc_get_handler_data(desc);
+
+	/* I don't know how to get the SPI number, d->hwirq - 32 is a hack */
+	int hwirq = intc->gic_spi_to_tango_hwirq[d->hwirq - 32];
+	//printk("%s: SPI=%lu hwirq=%d\n", __func__, d->hwirq, hwirq);
+
+	chained_irq_enter(chip, desc);
+	virq = irq_find_mapping(intc->dom, hwirq);
+	generic_handle_irq(virq);
+	chained_irq_exit(chip, desc);
+}
+
+static void tango_mask(struct irq_data *data)
+{
+	unsigned long flags;
+	struct tango_intc *intc = data->chip_data;
+
+	spin_lock_irqsave(&intc->lock, flags);
+	__clear_bit(data->hwirq, intc->enabled);
+	writel_relaxed(0, intc->config + data->hwirq * 4);
+	spin_unlock_irqrestore(&intc->lock, flags);
+}
+
+static void tango_unmask(struct irq_data *data)
+{
+	unsigned long flags;
+	struct tango_intc *intc = data->chip_data;
+
+#if 0
+	if (!in_irq() && !in_interrupt()) {
+		printk("HWIRQ=%lu mask=%u\n", data->hwirq, data->mask);
+		dump_stack();
+	}
+#endif
+
+	spin_lock_irqsave(&intc->lock, flags);
+	__set_bit(data->hwirq, intc->enabled);
+	writel_relaxed(IRQ_ENABLE | data->mask, intc->config + data->hwirq * 4);
+	spin_unlock_irqrestore(&intc->lock, flags);
+}
+
+static int find_free_output_line(struct tango_intc *intc)
+{
+	int spi;
+
+	for (spi = 0; spi < SPI_MAX; ++spi)
+		if (intc->gic_spi_to_tango_hwirq[spi] == 0)
+			return spi;
+
+	return -ENOSPC;
+}
+
+int tango_set_type(struct irq_data *data, unsigned int flow_type)
+{
+	struct tango_intc *intc = data->chip_data;
+	printk("%s: IRQ=%lu type=%x\n", __func__, data->hwirq, flow_type);
+	dump_stack();
+	if (flow_type & IRQ_TYPE_LEVEL_HIGH) {
+		data->mask = LEVEL_SPI;
+		return 0;
+	}
+
+	if (flow_type & IRQ_TYPE_EDGE_RISING) {
+		int res = find_free_output_line(intc);
+		if (res < 0)
+			return res;
+		data->mask = res;
+		intc->gic_spi_to_tango_hwirq[res] = data->hwirq;
+		printk("Map tango hwirq %lu to GIC SPI %d\n", data->hwirq, res);
+		return 0;
+	}
+
+	/* LEVEL_LOW and EDGE_FALLING are not supported */
+	return -ENOSYS;
+}
+
+static struct irq_chip tango_chip = {
+	.name		= "tango",
+	.irq_mask	= tango_mask,
+	.irq_unmask	= tango_unmask,
+	.irq_set_type	= tango_set_type,
+};
+
+static int tango_map(struct irq_domain *dom, unsigned int virq, irq_hw_number_t hw)
+{
+	struct tango_intc *intc = dom->host_data;
+	struct irq_desc *desc = irq_to_desc(virq);
+	printk("%s: dom=%p virq=%u hwirq=%lu desc=%p\n", __func__, dom, virq, hw, desc);
+	irq_domain_set_info(dom, virq, hw, &tango_chip, intc, handle_simple_irq, NULL, NULL);
+	return 0;
+}
+
+static void tango_unmap(struct irq_domain *d, unsigned int virq)
+{
+	printk("%s: dom=%p virq=%u\n", __func__, d, virq);
+	dump_stack();
+}
+
+struct irq_domain_ops dom_ops =
+{
+	.map	= tango_map,
+	.unmap	= tango_unmap,
+	.xlate	= irq_domain_xlate_twocell,
+};
+
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+static int __init map_irq(struct device_node *gic, int irq, int type)
+{
+	struct of_phandle_args irq_data = { gic, 3, { GIC_SPI, irq, type }};
+	return irq_create_of_mapping(&irq_data);
+}
+
+static int __init tango_irq_init(struct device_node *node, struct device_node *parent)
+{
+	int spi, virq;
+	struct irq_domain *irq_dom;
+	void __iomem *base;
+	struct tango_intc *intc = kzalloc(sizeof(*intc), GFP_KERNEL);
+
+	base = of_iomap(node, 0);
+	if (!base)
+		panic("%s: of_iomap failed", node->name);
+
+	virq = map_irq(parent, LEVEL_SPI, IRQ_TYPE_LEVEL_HIGH);
+	if (!virq)
+		panic("%s: Failed to map IRQ %d\n", node->name, LEVEL_SPI);
+
+	irq_set_chained_handler_and_data(virq, tango_level_isr, intc);
+
+	for (spi = 0; spi < SPI_MAX; ++spi) {
+		if (spi == LEVEL_SPI)
+			continue;
+
+		virq = map_irq(parent, spi, IRQ_TYPE_EDGE_RISING);
+		if (!virq)
+			panic("%s: Failed to map IRQ %d\n", node->name, spi);
+
+		irq_set_chained_handler_and_data(virq, tango_edge_isr, intc);
+	}
+
+	irq_dom = irq_domain_add_linear(node, IRQ_MAX, &dom_ops, intc);
+
+	spin_lock_init(&intc->lock);
+	intc->config = base;
+	intc->status = base + 0x420;
+	intc->dom = irq_dom;
+	intc->gic_spi_to_tango_hwirq[LEVEL_SPI] = ~0;
+
+	return 0;
+}
+IRQCHIP_DECLARE(tango_intc, "sigma,smp8759-intc", tango_irq_init);