[PATCH 1/6] irqchip: Add Loongson HyperTransport Vector support

Jiaxun Yang
2020-04-22T14:26:22Z

This controller appears on Loongson-3 chips for receiving interrupt
vectors from PCH's PIC and PCH's PCIe MSI interrupts. It usually act
as the top of irq hierarchy.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
drivers/irqchip/Kconfig | 8 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-loongson-htvec.c | 217 +++++++++++++++++++++++++++
3 files changed, 226 insertions(+)
create mode 100644 drivers/irqchip/irq-loongson-htvec.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index a85aada04a64..de4564e2ea88 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -532,4 +532,12 @@ config LOONGSON_HTPIC
help
Support for the Loongson-3 HyperTransport PIC Controller.

+config LOONGSON_HTVEC
+ bool "Loongson3 HyperTransport Interrupt Vector Controller"
+ depends on MACH_LOONGSON64 || COMPILE_TEST
+ default MACH_LOONGSON64
+ select IRQ_DOMAIN_HIERARCHY
+ help
+ Support for the Loongson3 HyperTransport Interrupt Vector Controller.
+
endmenu
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 37bbe39bf909..74561879f5a7 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -107,3 +107,4 @@ obj-$(CONFIG_TI_SCI_INTR_IRQCHIP) += irq-ti-sci-intr.o
obj-$(CONFIG_TI_SCI_INTA_IRQCHIP) += irq-ti-sci-inta.o
obj-$(CONFIG_LOONGSON_LIOINTC) += irq-loongson-liointc.o
obj-$(CONFIG_LOONGSON_HTPIC) += irq-loongson-htpic.o
+obj-$(CONFIG_LOONGSON_HTVEC) += irq-loongson-htvec.o
diff --git a/drivers/irqchip/irq-loongson-htvec.c b/drivers/irqchip/irq-loongson-htvec.c
new file mode 100644
index 000000000000..e155ebb99efb
--- /dev/null
+++ b/drivers/irqchip/irq-loongson-htvec.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
+ * Loongson HyperTransport Interrupt Vector support
+ */
+
+#define pr_fmt(fmt) "htvec: " fmt
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+
+/* Registers */
+#define HTVEC_EN_OFF 0x20
+#define HTVEC_MAX_PARENT_IRQ 4
+
+#define VEC_COUNT_PER_REG 32
+#define VEC_REG_COUNT 4
+#define VEC_COUNT (VEC_COUNT_PER_REG * VEC_REG_COUNT)
+#define VEC_REG_IDX(irq_id) ((irq_id) / VEC_COUNT_PER_REG)
+#define VEC_REG_BIT(irq_id) ((irq_id) % VEC_COUNT_PER_REG)
+
+struct htvec {
+ void __iomem *base;
+ struct irq_domain *htvec_domain;
+ raw_spinlock_t htvec_lock;
+};
+
+static void htvec_irq_dispatch(struct irq_desc *desc)
+{
+ struct htvec *priv = irq_desc_get_handler_data(desc);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ uint32_t pending;
+ bool handled = false;
+ int i;
+
+ chained_irq_enter(chip, desc);
+
+ for (i = 0; i < VEC_REG_COUNT; i++) {
+ pending = readl(priv->base + 4 * i);
+ /* Ack all IRQs at once, otherwise IRQ flood might happen */
+ writel(pending, priv->base + 4 * i);
+ while (pending) {
+ int bit = __ffs(pending);
+
+ generic_handle_irq(irq_linear_revmap(priv->htvec_domain,
+ bit + 32 * i));
+ pending &= ~BIT(bit);
+ handled = true;
+ }
+ }
+
+ if (!handled)
+ spurious_interrupt();
+
+ chained_irq_exit(chip, desc);
+}
+
+static void htvec_bitset(void __iomem *addr, int bit)
+{
+ u32 reg;
+
+ addr += VEC_REG_IDX(bit) * 4;
+ reg = readl(addr);
+ reg |= BIT(VEC_REG_BIT(bit));
+ writel(reg, addr);
+}
+
+static void htvec_bitclr(void __iomem *addr, int bit)
+{
+ u32 reg;
+
+ addr += VEC_REG_IDX(bit) * 4;
+ reg = readl(addr);
+ reg &= ~BIT(VEC_REG_BIT(bit));
+ writel(reg, addr);
+}
+
+static void htvec_mask_irq(struct irq_data *d)
+{
+ struct htvec *priv = irq_data_get_irq_chip_data(d);
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&priv->htvec_lock, flags);
+ htvec_bitclr(priv->base + HTVEC_EN_OFF, d->hwirq);
+ raw_spin_unlock_irqrestore(&priv->htvec_lock, flags);
+}
+
+static void htvec_unmask_irq(struct irq_data *d)
+{
+ struct htvec *priv = irq_data_get_irq_chip_data(d);
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&priv->htvec_lock, flags);
+ htvec_bitset(priv->base + HTVEC_EN_OFF, d->hwirq);
+ raw_spin_unlock_irqrestore(&priv->htvec_lock, flags);
+}
+
+static struct irq_chip htvec_irq_chip = {
+ .name = "LOONGSON_HTVEC",
+ .irq_mask = htvec_mask_irq,
+ .irq_unmask = htvec_unmask_irq,
+};
+
+static int htvec_domain_alloc(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs, void *arg)
+{
+ struct htvec *priv = domain->host_data;
+ unsigned long hwirq;
+ unsigned int type;
+
+ irq_domain_translate_onecell(domain, arg, &hwirq, &type);
+
+ /* Not much to do, just setup the irqdata */
+ irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+ &htvec_irq_chip, priv);
+
+ return 0;
+}
+
+static void htvec_domain_free(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs)
+{
+ int i;
+
+ for (i = 0; i < nr_irqs; i++) {
+ struct irq_data *d = irq_domain_get_irq_data(domain, virq + i);
+
+ irq_set_handler(virq + i, NULL);
+ irq_domain_reset_irq_data(d);
+ }
+}
+
+static const struct irq_domain_ops htvec_domain_ops = {
+ .translate = irq_domain_translate_onecell,
+ .alloc = htvec_domain_alloc,
+ .free = htvec_domain_free,
+};
+
+static void htvec_reset(struct htvec *priv)
+{
+ u32 idx;
+
+ /* Clear IRQ cause registers, mask all interrupts */
+ for (idx = 0; idx < VEC_REG_COUNT; idx++) {
+ writel_relaxed(0x0, priv->base + HTVEC_EN_OFF + 4 * idx);
+ writel_relaxed(0xFFFFFFFF, priv->base);
+ }
+}
+
+static int htvec_of_init(struct device_node *node,
+ struct device_node *parent)
+{
+ struct htvec *priv;
+ int err, parent_irq[4], num_parents = 0, i;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ raw_spin_lock_init(&priv->htvec_lock);
+ priv->base = of_iomap(node, 0);
+ if (!priv->base) {
+ err = -ENOMEM;
+ goto free_priv;
+ }
+
+ /* Interrupt may come from any of the 4 interrupt line */
+ for (i = 0; i < HTVEC_MAX_PARENT_IRQ; i++) {
+ parent_irq[i] = irq_of_parse_and_map(node, i);
+ if (parent_irq[i] <= 0)
+ break;
+
+ num_parents++;
+ }
+
+ if (!num_parents) {
+ pr_err("Failed to get parent irqs\n");
+ err = -ENODEV;
+ goto iounmap_base;
+ }
+
+ priv->htvec_domain = irq_domain_create_linear(of_node_to_fwnode(node),
+ VEC_COUNT,
+ &htvec_domain_ops,
+ priv);
+ if (!priv->htvec_domain) {
+ pr_err("Failed to create IRQ domain\n");
+ err = -ENOMEM;
+ goto iounmap_base;
+ }
+
+ htvec_reset(priv);
+
+ for (i = 0; i < num_parents; i++) {
+ irq_set_chained_handler_and_data(parent_irq[i],
+ htvec_irq_dispatch, priv);
+ }
+
+ return 0;
+
+iounmap_base:
+ iounmap(priv->base);
+free_priv:
+ kfree(priv);
+
+ return err;
+}
+
+IRQCHIP_DECLARE(htvec, "loongson,htvec-1.0", htvec_of_init);
--
2.26.0.rc2