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Subject[PATCH V15 06/15] irqchip: Add Loongson PCH LPC controller support
Date
From: Huacai Chen <chenhuacai@loongson.cn>

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.

Co-developed-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
arch/loongarch/include/asm/irq.h | 4 +-
arch/loongarch/kernel/irq.c | 1 -
drivers/irqchip/Kconfig | 8 ++
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-loongson-pch-lpc.c | 208 +++++++++++++++++++++++++++++++++
5 files changed, 219 insertions(+), 3 deletions(-)
create mode 100644 drivers/irqchip/irq-loongson-pch-lpc.c

diff --git a/arch/loongarch/include/asm/irq.h b/arch/loongarch/include/asm/irq.h
index ace3ea6..48c0ce4 100644
--- a/arch/loongarch/include/asm/irq.h
+++ b/arch/loongarch/include/asm/irq.h
@@ -104,7 +104,7 @@ struct irq_domain *eiointc_acpi_init(struct irq_domain *parent,

struct irq_domain *htvec_acpi_init(struct irq_domain *parent,
struct acpi_madt_ht_pic *acpi_htvec);
-struct irq_domain *pch_lpc_acpi_init(struct irq_domain *parent,
+int pch_lpc_acpi_init(struct irq_domain *parent,
struct acpi_madt_lpc_pic *acpi_pchlpc);
struct irq_domain *pch_msi_acpi_init(struct irq_domain *parent,
struct acpi_madt_msi_pic *acpi_pchmsi);
@@ -121,7 +121,7 @@ struct irq_domain *pch_pic_acpi_init(struct irq_domain *parent,

extern struct irq_domain *cpu_domain;
extern struct irq_domain *liointc_domain;
-extern struct irq_domain *pch_lpc_domain;
+extern struct fwnode_handle *pch_lpc_handle;
extern struct irq_domain *pch_msi_domain[MAX_IO_PICS];
extern struct irq_domain *pch_pic_domain[MAX_IO_PICS];

diff --git a/arch/loongarch/kernel/irq.c b/arch/loongarch/kernel/irq.c
index b34b8d7..07d6059 100644
--- a/arch/loongarch/kernel/irq.c
+++ b/arch/loongarch/kernel/irq.c
@@ -27,7 +27,6 @@

struct irq_domain *cpu_domain;
struct irq_domain *liointc_domain;
-struct irq_domain *pch_lpc_domain;
struct irq_domain *pch_msi_domain[MAX_IO_PICS];
struct irq_domain *pch_pic_domain[MAX_IO_PICS];

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 1f23a6b..c1d527f 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -591,6 +591,14 @@ 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 5b67450..242b8b3 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -108,6 +108,7 @@ 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 0000000..3f51184
--- /dev/null
+++ b/drivers/irqchip/irq-loongson-pch-lpc.c
@@ -0,0 +1,208 @@
+// 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>
+
+/* 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
+
+/* LPC_INT_CTL */
+#define LPC_INT_CTL_EN BIT(31)
+
+struct pch_lpc {
+ void __iomem *base;
+ struct irq_domain *lpc_domain;
+ raw_spinlock_t lpc_lock;
+ u32 saved_reg_ctl;
+ u32 saved_reg_ena;
+ u32 saved_reg_pol;
+};
+
+struct fwnode_handle *pch_lpc_handle;
+
+static void lpc_irq_ack(struct irq_data *d)
+{
+ unsigned long flags;
+ struct pch_lpc *priv = d->domain->host_data;
+
+ raw_spin_lock_irqsave(&priv->lpc_lock, flags);
+ writel(0x1 << d->hwirq, priv->base + LPC_INT_CLR);
+ raw_spin_unlock_irqrestore(&priv->lpc_lock, flags);
+}
+
+static void lpc_irq_mask(struct irq_data *d)
+{
+ unsigned long flags;
+ struct pch_lpc *priv = d->domain->host_data;
+
+ raw_spin_lock_irqsave(&priv->lpc_lock, flags);
+ writel(readl(priv->base + LPC_INT_ENA) & (~(0x1 << (d->hwirq))),
+ priv->base + LPC_INT_ENA);
+ raw_spin_unlock_irqrestore(&priv->lpc_lock, flags);
+}
+
+static void lpc_irq_unmask(struct irq_data *d)
+{
+ unsigned long flags;
+ struct pch_lpc *priv = d->domain->host_data;
+
+ raw_spin_lock_irqsave(&priv->lpc_lock, flags);
+ writel(readl(priv->base + LPC_INT_ENA) | (0x1 << (d->hwirq)),
+ priv->base + LPC_INT_ENA);
+ raw_spin_unlock_irqrestore(&priv->lpc_lock, flags);
+}
+
+static int lpc_irq_set_type(struct irq_data *d, unsigned int type)
+{
+ u32 val;
+ u32 mask = 0x1 << (d->hwirq);
+ struct pch_lpc *priv = d->domain->host_data;
+
+ if (!(type & IRQ_TYPE_LEVEL_MASK))
+ return 0;
+
+ val = readl(priv->base + LPC_INT_POL);
+
+ if (type == IRQ_TYPE_LEVEL_HIGH)
+ val |= mask;
+ else
+ val &= ~mask;
+
+ writel(val, priv->base + LPC_INT_POL);
+
+ return 0;
+}
+
+static const struct irq_chip pch_lpc_irq_chip = {
+ .name = "PCH LPC",
+ .irq_mask = lpc_irq_mask,
+ .irq_unmask = lpc_irq_unmask,
+ .irq_ack = lpc_irq_ack,
+ .irq_set_type = lpc_irq_set_type,
+ .flags = IRQCHIP_SKIP_SET_WAKE,
+};
+
+static void lpc_irq_dispatch(struct irq_desc *desc)
+{
+ u32 pending, bit;
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct pch_lpc *priv = irq_desc_get_handler_data(desc);
+
+ chained_irq_enter(chip, desc);
+
+ pending = readl(priv->base + LPC_INT_ENA);
+ pending &= readl(priv->base + LPC_INT_STS);
+ if (!pending)
+ spurious_interrupt();
+
+ while (pending) {
+ bit = __ffs(pending);
+
+ generic_handle_domain_irq(priv->lpc_domain, 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(LPC_INT_CTL_EN, priv->base + LPC_INT_CTL);
+ writel(0, priv->base + LPC_INT_ENA);
+ /* Clear all 18-bit interrpt bit */
+ writel(GENMASK(17, 0), 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);
+}
+
+int __init 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;
+ struct fwnode_handle *irq_handle;
+
+ if (!acpi_pchlpc)
+ return -EINVAL;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ 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;
+ }
+
+ irq_handle = irq_domain_alloc_named_fwnode("lpcintc");
+ if (!irq_handle) {
+ pr_err("Unable to allocate domain handle\n");
+ goto iounmap_base;
+ }
+
+ priv->lpc_domain = irq_domain_create_linear(irq_handle, LPC_COUNT,
+ &pch_lpc_domain_ops, priv);
+ if (!priv->lpc_domain) {
+ pr_err("Failed to create IRQ domain\n");
+ goto free_irq_handle;
+ }
+ pch_lpc_reset(priv);
+
+ fwspec.fwnode = parent->fwnode;
+ fwspec.param[0] = acpi_pchlpc->cascade + GSI_MIN_PCH_IRQ;
+ 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_handle = irq_handle;
+ return 0;
+
+free_irq_handle:
+ irq_domain_free_fwnode(irq_handle);
+iounmap_base:
+ iounmap(priv->base);
+free_priv:
+ kfree(priv);
+
+ return -ENOMEM;
+}
--
1.8.3.1
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