irqchip: RISC-V per-HART local interrupt controller driver

The RISC-V per-HART local interrupt controller manages software
interrupts, timer interrupts, external interrupts (which are routed
via the platform level interrupt controller) and other per-HART
local interrupts.

We add a driver for the RISC-V local interrupt controller, which
eventually replaces the RISC-V architecture code, allowing for a
better split between arch code and drivers.

The driver is compliant with RISC-V Hart-Level Interrupt Controller
DT bindings located at:
Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt

Co-developed-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
[Palmer: Cleaned up warnings]
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
This commit is contained in:
Anup Patel 2020-06-01 14:45:40 +05:30 committed by Palmer Dabbelt
parent d175d699df
commit 6b7ce8927b
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
9 changed files with 188 additions and 43 deletions

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@ -40,6 +40,7 @@ config RISCV
select GENERIC_SMP_IDLE_THREAD
select GENERIC_STRNCPY_FROM_USER if MMU
select GENERIC_STRNLEN_USER if MMU
select HANDLE_DOMAIN_IRQ
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_KASAN if MMU && 64BIT
select HAVE_ARCH_KGDB

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@ -10,8 +10,6 @@
#include <linux/interrupt.h>
#include <linux/linkage.h>
#define NR_IRQS 0
void riscv_timer_interrupt(void);
#include <asm-generic/irq.h>

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@ -7,7 +7,6 @@
#include <linux/interrupt.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/seq_file.h>
#include <asm/smp.h>
@ -19,39 +18,13 @@ int arch_show_interrupts(struct seq_file *p, int prec)
asmlinkage __visible void __irq_entry do_IRQ(struct pt_regs *regs)
{
struct pt_regs *old_regs;
switch (regs->cause & ~CAUSE_IRQ_FLAG) {
case RV_IRQ_TIMER:
old_regs = set_irq_regs(regs);
irq_enter();
riscv_timer_interrupt();
irq_exit();
set_irq_regs(old_regs);
break;
#ifdef CONFIG_SMP
case RV_IRQ_SOFT:
/*
* We only use software interrupts to pass IPIs, so if a non-SMP
* system gets one, then we don't know what to do.
*/
handle_IPI(regs);
break;
#endif
case RV_IRQ_EXT:
old_regs = set_irq_regs(regs);
irq_enter();
if (handle_arch_irq)
handle_arch_irq(regs);
irq_exit();
set_irq_regs(old_regs);
break;
default:
pr_alert("unexpected interrupt cause 0x%lx", regs->cause);
BUG();
}
}
void __init init_IRQ(void)
{
irqchip_init();
if (!handle_arch_irq)
panic("No interrupt controller found.");
}

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@ -183,6 +183,4 @@ void trap_init(void)
csr_write(CSR_SCRATCH, 0);
/* Set the exception vector address */
csr_write(CSR_TVEC, &handle_exception);
/* Enable interrupts */
csr_write(CSR_IE, IE_SIE);
}

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@ -493,6 +493,19 @@ config TI_SCI_INTA_IRQCHIP
If you wish to use interrupt aggregator irq resources managed by the
TI System Controller, say Y here. Otherwise, say N.
config RISCV_INTC
bool "RISC-V Local Interrupt Controller"
depends on RISCV
default y
help
This enables support for the per-HART local interrupt controller
found in standard RISC-V systems. The per-HART local interrupt
controller handles timer interrupts, software interrupts, and
hardware interrupts. Without a per-HART local interrupt controller,
a RISC-V system will be unable to handle any interrupts.
If you don't know what to do here, say Y.
config SIFIVE_PLIC
bool "SiFive Platform-Level Interrupt Controller"
depends on RISCV

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@ -98,6 +98,7 @@ obj-$(CONFIG_NDS32) += irq-ativic32.o
obj-$(CONFIG_QCOM_PDC) += qcom-pdc.o
obj-$(CONFIG_CSKY_MPINTC) += irq-csky-mpintc.o
obj-$(CONFIG_CSKY_APB_INTC) += irq-csky-apb-intc.o
obj-$(CONFIG_RISCV_INTC) += irq-riscv-intc.o
obj-$(CONFIG_SIFIVE_PLIC) += irq-sifive-plic.o
obj-$(CONFIG_IMX_IRQSTEER) += irq-imx-irqsteer.o
obj-$(CONFIG_IMX_INTMUX) += irq-imx-intmux.o

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@ -0,0 +1,146 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2012 Regents of the University of California
* Copyright (C) 2017-2018 SiFive
* Copyright (C) 2020 Western Digital Corporation or its affiliates.
*/
#define pr_fmt(fmt) "riscv-intc: " fmt
#include <linux/atomic.h>
#include <linux/bits.h>
#include <linux/cpu.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/smp.h>
static struct irq_domain *intc_domain;
static asmlinkage void riscv_intc_irq(struct pt_regs *regs)
{
struct pt_regs *old_regs;
unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG;
if (unlikely(cause >= BITS_PER_LONG))
panic("unexpected interrupt cause");
switch (cause) {
case RV_IRQ_TIMER:
old_regs = set_irq_regs(regs);
irq_enter();
riscv_timer_interrupt();
irq_exit();
set_irq_regs(old_regs);
break;
#ifdef CONFIG_SMP
case RV_IRQ_SOFT:
/*
* We only use software interrupts to pass IPIs, so if a
* non-SMP system gets one, then we don't know what to do.
*/
handle_IPI(regs);
break;
#endif
default:
handle_domain_irq(intc_domain, cause, regs);
break;
}
}
/*
* On RISC-V systems local interrupts are masked or unmasked by writing
* the SIE (Supervisor Interrupt Enable) CSR. As CSRs can only be written
* on the local hart, these functions can only be called on the hart that
* corresponds to the IRQ chip.
*/
static void riscv_intc_irq_mask(struct irq_data *d)
{
csr_clear(CSR_IE, BIT(d->hwirq));
}
static void riscv_intc_irq_unmask(struct irq_data *d)
{
csr_set(CSR_IE, BIT(d->hwirq));
}
static int riscv_intc_cpu_starting(unsigned int cpu)
{
csr_set(CSR_IE, BIT(RV_IRQ_SOFT));
return 0;
}
static int riscv_intc_cpu_dying(unsigned int cpu)
{
csr_clear(CSR_IE, BIT(RV_IRQ_SOFT));
return 0;
}
static struct irq_chip riscv_intc_chip = {
.name = "RISC-V INTC",
.irq_mask = riscv_intc_irq_mask,
.irq_unmask = riscv_intc_irq_unmask,
};
static int riscv_intc_domain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
irq_set_percpu_devid(irq);
irq_domain_set_info(d, irq, hwirq, &riscv_intc_chip, d->host_data,
handle_percpu_devid_irq, NULL, NULL);
return 0;
}
static const struct irq_domain_ops riscv_intc_domain_ops = {
.map = riscv_intc_domain_map,
.xlate = irq_domain_xlate_onecell,
};
static int __init riscv_intc_init(struct device_node *node,
struct device_node *parent)
{
int rc, hartid;
hartid = riscv_of_parent_hartid(node);
if (hartid < 0) {
pr_warn("unable to fine hart id for %pOF\n", node);
return 0;
}
/*
* The DT will have one INTC DT node under each CPU (or HART)
* DT node so riscv_intc_init() function will be called once
* for each INTC DT node. We only need to do INTC initialization
* for the INTC DT node belonging to boot CPU (or boot HART).
*/
if (riscv_hartid_to_cpuid(hartid) != smp_processor_id())
return 0;
intc_domain = irq_domain_add_linear(node, BITS_PER_LONG,
&riscv_intc_domain_ops, NULL);
if (!intc_domain) {
pr_err("unable to add IRQ domain\n");
return -ENXIO;
}
rc = set_handle_irq(&riscv_intc_irq);
if (rc) {
pr_err("failed to set irq handler\n");
return rc;
}
cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_STARTING,
"irqchip/riscv/intc:starting",
riscv_intc_cpu_starting,
riscv_intc_cpu_dying);
pr_info("%d local interrupts mapped\n", BITS_PER_LONG);
return 0;
}
IRQCHIP_DECLARE(riscv, "riscv,cpu-intc", riscv_intc_init);

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@ -9,6 +9,7 @@
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
@ -76,6 +77,7 @@ struct plic_handler {
void __iomem *enable_base;
struct plic_priv *priv;
};
static int plic_parent_irq;
static bool plic_cpuhp_setup_done;
static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
@ -219,15 +221,17 @@ static const struct irq_domain_ops plic_irqdomain_ops = {
* that source ID back to the same claim register. This automatically enables
* and disables the interrupt, so there's nothing else to do.
*/
static void plic_handle_irq(struct pt_regs *regs)
static void plic_handle_irq(struct irq_desc *desc)
{
struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
struct irq_chip *chip = irq_desc_get_chip(desc);
void __iomem *claim = handler->hart_base + CONTEXT_CLAIM;
irq_hw_number_t hwirq;
WARN_ON_ONCE(!handler->present);
csr_clear(CSR_IE, IE_EIE);
chained_irq_enter(chip, desc);
while ((hwirq = readl(claim))) {
int irq = irq_find_mapping(handler->priv->irqdomain, hwirq);
@ -237,7 +241,8 @@ static void plic_handle_irq(struct pt_regs *regs)
else
generic_handle_irq(irq);
}
csr_set(CSR_IE, IE_EIE);
chained_irq_exit(chip, desc);
}
static void plic_set_threshold(struct plic_handler *handler, u32 threshold)
@ -248,10 +253,8 @@ static void plic_set_threshold(struct plic_handler *handler, u32 threshold)
static int plic_dying_cpu(unsigned int cpu)
{
struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
csr_clear(CSR_IE, IE_EIE);
plic_set_threshold(handler, PLIC_DISABLE_THRESHOLD);
if (plic_parent_irq)
disable_percpu_irq(plic_parent_irq);
return 0;
}
@ -260,7 +263,11 @@ static int plic_starting_cpu(unsigned int cpu)
{
struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
csr_set(CSR_IE, IE_EIE);
if (plic_parent_irq)
enable_percpu_irq(plic_parent_irq,
irq_get_trigger_type(plic_parent_irq));
else
pr_warn("cpu%d: parent irq not available\n", cpu);
plic_set_threshold(handler, PLIC_ENABLE_THRESHOLD);
return 0;
@ -328,6 +335,14 @@ static int __init plic_init(struct device_node *node,
continue;
}
/* Find parent domain and register chained handler */
if (!plic_parent_irq && irq_find_host(parent.np)) {
plic_parent_irq = irq_of_parse_and_map(node, i);
if (plic_parent_irq)
irq_set_chained_handler(plic_parent_irq,
plic_handle_irq);
}
/*
* When running in M-mode we need to ignore the S-mode handler.
* Here we assume it always comes later, but that might be a
@ -368,7 +383,6 @@ done:
pr_info("%pOFP: mapped %d interrupts with %d handlers for"
" %d contexts.\n", node, nr_irqs, nr_handlers, nr_contexts);
set_handle_irq(plic_handle_irq);
return 0;
out_iounmap:

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@ -102,6 +102,7 @@ enum cpuhp_state {
CPUHP_AP_IRQ_ARMADA_XP_STARTING,
CPUHP_AP_IRQ_BCM2836_STARTING,
CPUHP_AP_IRQ_MIPS_GIC_STARTING,
CPUHP_AP_IRQ_RISCV_STARTING,
CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
CPUHP_AP_ARM_MVEBU_COHERENCY,
CPUHP_AP_MICROCODE_LOADER,