[PATCH V11 10/10] irqchip: Add Loongson PCH LPC controller support

Huacai Chen
2022-04-30T09:03:52Z

with old MIPS-based Loongson) support. This patch add Loongson PCH LPC
interrupt controller support.

PCH-LPC stands for "LPC Interrupts" that described in Section 24.3 of
"Loongson 7A1000 Bridge User Manual". For more information please refer
Documentation/loongarch/irq-chip-model.rst.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
drivers/irqchip/Kconfig | 8 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-loongson-pch-lpc.c | 225 +++++++++++++++++++++++++
3 files changed, 234 insertions(+)
create mode 100644 drivers/irqchip/irq-loongson-pch-lpc.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index eea0c15562cf..c56a8dbb51cc 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -610,6 +610,14 @@ config LOONGSON_PCH_MSI
help
Support for the Loongson PCH MSI Controller.

+config LOONGSON_PCH_LPC
+ bool "Loongson PCH LPC Controller"
+ depends on MACH_LOONGSON64
+ default (MACH_LOONGSON64 && LOONGARCH)
+ select IRQ_DOMAIN_HIERARCHY
+ help
+ Support for the Loongson PCH LPC Controller.
+
config MST_IRQ
bool "MStar Interrupt Controller"
depends on ARCH_MEDIATEK || ARCH_MSTARV7 || COMPILE_TEST
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index e5e546a8195c..71d9bc551d5b 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -112,6 +112,7 @@ obj-$(CONFIG_LOONGSON_HTPIC) += irq-loongson-htpic.o
obj-$(CONFIG_LOONGSON_HTVEC) += irq-loongson-htvec.o
obj-$(CONFIG_LOONGSON_PCH_PIC) += irq-loongson-pch-pic.o
obj-$(CONFIG_LOONGSON_PCH_MSI) += irq-loongson-pch-msi.o
+obj-$(CONFIG_LOONGSON_PCH_LPC) += irq-loongson-pch-lpc.o
obj-$(CONFIG_MST_IRQ) += irq-mst-intc.o
obj-$(CONFIG_SL28CPLD_INTC) += irq-sl28cpld.o
obj-$(CONFIG_MACH_REALTEK_RTL) += irq-realtek-rtl.o
diff --git a/drivers/irqchip/irq-loongson-pch-lpc.c b/drivers/irqchip/irq-loongson-pch-lpc.c
new file mode 100644
index 000000000000..55ef72bfdfea
--- /dev/null
+++ b/drivers/irqchip/irq-loongson-pch-lpc.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Loongson LPC Interrupt Controller support
+ *
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+
+#define pr_fmt(fmt) "lpc: " fmt
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/syscore_ops.h>
+
+/* Registers */
+#define LPC_INT_CTL 0x00
+#define LPC_INT_ENA 0x04
+#define LPC_INT_STS 0x08
+#define LPC_INT_CLR 0x0c
+#define LPC_INT_POL 0x10
+#define LPC_COUNT 16
+
+struct pch_lpc {
+ void __iomem *base;
+ struct irq_domain *lpc_domain;
+ struct fwnode_handle *domain_handle;
+ raw_spinlock_t lpc_lock;
+ u32 saved_reg_ctl;
+ u32 saved_reg_ena;
+ u32 saved_reg_pol;
+};
+
+static struct pch_lpc *pch_lpc_priv;
+
+static void ack_lpc_irq(struct irq_data *d)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&pch_lpc_priv->lpc_lock, flags);
+ writel(0x1 << d->irq, pch_lpc_priv->base + LPC_INT_CLR);
+ raw_spin_unlock_irqrestore(&pch_lpc_priv->lpc_lock, flags);
+}
+static void mask_lpc_irq(struct irq_data *d)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&pch_lpc_priv->lpc_lock, flags);
+ writel(readl(pch_lpc_priv->base + LPC_INT_ENA) & (~(0x1 << (d->irq))),
+ pch_lpc_priv->base + LPC_INT_ENA);
+ raw_spin_unlock_irqrestore(&pch_lpc_priv->lpc_lock, flags);
+}
+
+static void mask_ack_lpc_irq(struct irq_data *d)
+{
+}
+
+static void unmask_lpc_irq(struct irq_data *d)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&pch_lpc_priv->lpc_lock, flags);
+ writel(readl(pch_lpc_priv->base + LPC_INT_ENA) | (0x1 << (d->irq)),
+ pch_lpc_priv->base + LPC_INT_ENA);
+ raw_spin_unlock_irqrestore(&pch_lpc_priv->lpc_lock, flags);
+}
+
+static int lpc_set_type(struct irq_data *d, unsigned int type)
+{
+ u32 val;
+ u32 mask = 0x1 << (d->hwirq);
+
+ if (!(type & IRQ_TYPE_LEVEL_MASK))
+ return 0;
+
+ val = readl(pch_lpc_priv->base + LPC_INT_POL);
+
+ if (type == IRQ_TYPE_LEVEL_HIGH)
+ val |= mask;
+ else
+ val &= ~mask;
+
+ writel(val, pch_lpc_priv->base + LPC_INT_POL);
+
+ return 0;
+}
+
+static struct irq_chip pch_lpc_irq_chip = {
+ .name = "PCH LPC",
+ .irq_mask = mask_lpc_irq,
+ .irq_unmask = unmask_lpc_irq,
+ .irq_ack = ack_lpc_irq,
+ .irq_mask_ack = mask_ack_lpc_irq,
+ .irq_eoi = unmask_lpc_irq,
+ .irq_set_type = lpc_set_type,
+ .flags = IRQCHIP_SKIP_SET_WAKE,
+};
+
+static void lpc_irq_dispatch(struct irq_desc *desc)
+{
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ u32 pending;
+
+ chained_irq_enter(chip, desc);
+
+ pending = readl(pch_lpc_priv->base + LPC_INT_ENA);
+ pending &= readl(pch_lpc_priv->base + LPC_INT_STS);
+ if (!pending)
+ spurious_interrupt();
+
+ while (pending) {
+ int bit = __ffs(pending);
+
+ generic_handle_irq(bit);
+ pending &= ~BIT(bit);
+ }
+ chained_irq_exit(chip, desc);
+}
+
+static int pch_lpc_map(struct irq_domain *d, unsigned int irq,
+ irq_hw_number_t hw)
+{
+ irq_set_chip_and_handler(irq, &pch_lpc_irq_chip, handle_level_irq);
+ return 0;
+}
+
+static const struct irq_domain_ops pch_lpc_domain_ops = {
+ .map = pch_lpc_map,
+ .translate = irq_domain_translate_twocell,
+};
+
+static void pch_lpc_reset(struct pch_lpc *priv)
+{
+ /* Enable the LPC interrupt, bit31: en bit30: edge */
+ writel(0x80000000, priv->base + LPC_INT_CTL);
+ writel(0, priv->base + LPC_INT_ENA);
+ /* Clear all 18-bit interrpt bit */
+ writel(0x3ffff, priv->base + LPC_INT_CLR);
+}
+
+static int pch_lpc_disabled(struct pch_lpc *priv)
+{
+ return (readl(priv->base + LPC_INT_ENA) == 0xffffffff) &&
+ (readl(priv->base + LPC_INT_STS) == 0xffffffff);
+}
+
+static int pch_lpc_suspend(void)
+{
+ pch_lpc_priv->saved_reg_ctl = readl(pch_lpc_priv->base + LPC_INT_CTL);
+ pch_lpc_priv->saved_reg_ena = readl(pch_lpc_priv->base + LPC_INT_ENA);
+ pch_lpc_priv->saved_reg_pol = readl(pch_lpc_priv->base + LPC_INT_POL);
+ return 0;
+}
+
+static void pch_lpc_resume(void)
+{
+ writel(pch_lpc_priv->saved_reg_ctl, pch_lpc_priv->base + LPC_INT_CTL);
+ writel(pch_lpc_priv->saved_reg_ena, pch_lpc_priv->base + LPC_INT_ENA);
+ writel(pch_lpc_priv->saved_reg_pol, pch_lpc_priv->base + LPC_INT_POL);
+}
+
+static struct syscore_ops pch_lpc_syscore_ops = {
+ .suspend = pch_lpc_suspend,
+ .resume = pch_lpc_resume,
+};
+
+struct irq_domain *pch_lpc_acpi_init(struct irq_domain *parent,
+ struct acpi_madt_lpc_pic *acpi_pchlpc)
+{
+ int parent_irq;
+ struct pch_lpc *priv;
+ struct irq_fwspec fwspec;
+
+ if (!acpi_pchlpc)
+ return NULL;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return NULL;
+
+ raw_spin_lock_init(&priv->lpc_lock);
+
+ priv->base = ioremap(acpi_pchlpc->address, acpi_pchlpc->size);
+ if (!priv->base)
+ goto free_priv;
+
+ if (pch_lpc_disabled(priv)) {
+ pr_err("Failed to get LPC status\n");
+ goto iounmap_base;
+ }
+
+ priv->domain_handle = irq_domain_alloc_fwnode((phys_addr_t *)acpi_pchlpc);
+ if (!priv->domain_handle) {
+ pr_err("Unable to allocate domain handle\n");
+ goto iounmap_base;
+ }
+ priv->lpc_domain = irq_domain_add_legacy(NULL, LPC_COUNT, 0, 0,
+ &pch_lpc_domain_ops, priv);
+ if (!priv->lpc_domain) {
+ pr_err("Failed to create IRQ domain\n");
+ goto iounmap_base;
+ }
+ pch_lpc_reset(priv);
+
+ fwspec.fwnode = parent->fwnode;
+ fwspec.param[0] = acpi_pchlpc->cascade;
+ fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
+ fwspec.param_count = 2;
+ parent_irq = irq_create_fwspec_mapping(&fwspec);
+ irq_set_chained_handler_and_data(parent_irq, lpc_irq_dispatch, priv);
+ pch_lpc_priv = priv;
+
+ register_syscore_ops(&pch_lpc_syscore_ops);
+
+ return irq_find_matching_fwnode(priv->domain_handle, DOMAIN_BUS_ANY);
+
+iounmap_base:
+ iounmap(priv->base);
+free_priv:
+ kfree(priv);
+
+ return NULL;
+}
--
2.27.0