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irqchip: mips-cpu: Introduce IPI IRQ domain support 

Introduce support for registering an IPI IRQ domain suitable for use by
systems using the MIPS MT (multithreading) ASE within a single core.
This will allow for such systems to be supported generically, without
the current kludge of IPI code split between the MIPS arch & the malta
board support code.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15836/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
hifive-unleashed-5.1
Paul Burton 2017-03-30 12:06:11 -07:00 committed by Ralf Baechle
parent 131735afc1
commit 3838a547fd
2 changed files with 119 additions and 8 deletions
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2
drivers/irqchip/Kconfig
View File

@ -128,7 +128,9 @@ config IMGPDC_IRQ
config IRQ_MIPS_CPU
bool
select GENERIC_IRQ_CHIP
select GENERIC_IRQ_IPI if SYS_SUPPORTS_MULTITHREADING
select IRQ_DOMAIN
select IRQ_DOMAIN_HIERARCHY if GENERIC_IRQ_IPI
config CLPS711X_IRQCHIP
bool

125
drivers/irqchip/irq-mips-cpu.c
View File

@ -17,15 +17,14 @@
/*
* Almost all MIPS CPUs define 8 interrupt sources. They are typically
* level triggered (i.e., cannot be cleared from CPU; must be cleared from
* device). The first two are software interrupts which we don't really
* use or support. The last one is usually the CPU timer interrupt if
* counter register is present or, for CPUs with an external FPU, by
* convention it's the FPU exception interrupt.
* device).
*
* Don't even think about using this on SMP. You have been warned.
* The first two are software interrupts (i.e. not exposed as pins) which
* may be used for IPIs in multi-threaded single-core systems.
*
* This file exports one global function:
* void mips_cpu_irq_init(void);
* The last one is usually the CPU timer interrupt if the counter register
* is present, or for old CPUs with an external FPU by convention it's the
* FPU exception interrupt.
*/
#include <linux/init.h>
#include <linux/interrupt.h>
@ -40,6 +39,7 @@
#include <asm/setup.h>
static struct irq_domain *irq_domain;
static struct irq_domain *ipi_domain;
static inline void unmask_mips_irq(struct irq_data *d)
{
@ -90,6 +90,29 @@ static void mips_mt_cpu_irq_ack(struct irq_data *d)
mask_mips_irq(d);
}
#ifdef CONFIG_GENERIC_IRQ_IPI
static void mips_mt_send_ipi(struct irq_data *d, unsigned int cpu)
{
irq_hw_number_t hwirq = irqd_to_hwirq(d);
unsigned long flags;
int vpflags;
local_irq_save(flags);
/* We can only send IPIs to VPEs within the local core */
WARN_ON(cpu_data[cpu].core != current_cpu_data.core);
vpflags = dvpe();
settc(cpu_vpe_id(&cpu_data[cpu]));
write_vpe_c0_cause(read_vpe_c0_cause() | (C_SW0 << hwirq));
evpe(vpflags);
local_irq_restore(flags);
}
#endif /* CONFIG_GENERIC_IRQ_IPI */
static struct irq_chip mips_mt_cpu_irq_controller = {
.name = "MIPS",
.irq_startup = mips_mt_cpu_irq_startup,
@ -100,6 +123,9 @@ static struct irq_chip mips_mt_cpu_irq_controller = {
.irq_eoi = unmask_mips_irq,
.irq_disable = mask_mips_irq,
.irq_enable = unmask_mips_irq,
#ifdef CONFIG_GENERIC_IRQ_IPI
.ipi_send_single = mips_mt_send_ipi,
#endif
};
asmlinkage void __weak plat_irq_dispatch(void)
@ -116,7 +142,10 @@ asmlinkage void __weak plat_irq_dispatch(void)
pending >>= CAUSEB_IP;
while (pending) {
irq = fls(pending) - 1;
virq = irq_linear_revmap(irq_domain, irq);
if (IS_ENABLED(CONFIG_GENERIC_IRQ_IPI) && irq < 2)
virq = irq_linear_revmap(ipi_domain, irq);
else
virq = irq_linear_revmap(irq_domain, irq);
do_IRQ(virq);
pending &= ~BIT(irq);
}
@ -147,6 +176,79 @@ static const struct irq_domain_ops mips_cpu_intc_irq_domain_ops = {
.xlate = irq_domain_xlate_onecell,
};
#ifdef CONFIG_GENERIC_IRQ_IPI
struct cpu_ipi_domain_state {
DECLARE_BITMAP(allocated, 2);
};
static int mips_cpu_ipi_alloc(struct irq_domain *domain, unsigned int virq,
unsigned int nr_irqs, void *arg)
{
struct cpu_ipi_domain_state *state = domain->host_data;
unsigned int i, hwirq;
int ret;
for (i = 0; i < nr_irqs; i++) {
hwirq = find_first_zero_bit(state->allocated, 2);
if (hwirq == 2)
return -EBUSY;
bitmap_set(state->allocated, hwirq, 1);
ret = irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq,
&mips_mt_cpu_irq_controller,
NULL);
if (ret)
return ret;
ret = irq_set_irq_type(virq + i, IRQ_TYPE_LEVEL_HIGH);
if (ret)
return ret;
}
return 0;
}
static int mips_cpu_ipi_match(struct irq_domain *d, struct device_node *node,
enum irq_domain_bus_token bus_token)
{
bool is_ipi;
switch (bus_token) {
case DOMAIN_BUS_IPI:
is_ipi = d->bus_token == bus_token;
return (!node || (to_of_node(d->fwnode) == node)) && is_ipi;
default:
return 0;
}
}
static const struct irq_domain_ops mips_cpu_ipi_chip_ops = {
.alloc = mips_cpu_ipi_alloc,
.match = mips_cpu_ipi_match,
};
static void mips_cpu_register_ipi_domain(struct device_node *of_node)
{
struct cpu_ipi_domain_state *ipi_domain_state;
ipi_domain_state = kzalloc(sizeof(*ipi_domain_state), GFP_KERNEL);
ipi_domain = irq_domain_add_hierarchy(irq_domain,
IRQ_DOMAIN_FLAG_IPI_SINGLE,
2, of_node,
&mips_cpu_ipi_chip_ops,
ipi_domain_state);
if (!ipi_domain)
panic("Failed to add MIPS CPU IPI domain");
ipi_domain->bus_token = DOMAIN_BUS_IPI;
}
#else /* !CONFIG_GENERIC_IRQ_IPI */
static inline void mips_cpu_register_ipi_domain(struct device_node *of_node) {}
#endif /* !CONFIG_GENERIC_IRQ_IPI */
static void __init __mips_cpu_irq_init(struct device_node *of_node)
{
/* Mask interrupts. */
@ -158,6 +260,13 @@ static void __init __mips_cpu_irq_init(struct device_node *of_node)
NULL);
if (!irq_domain)
panic("Failed to add irqdomain for MIPS CPU");
/*
* Only proceed to register the software interrupt IPI implementation
* for CPUs which implement the MIPS MT (multi-threading) ASE.
*/
if (cpu_has_mipsmt)
mips_cpu_register_ipi_domain(of_node);
}
void __init mips_cpu_irq_init(void)