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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2016 IBM Corporation.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/irq.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/of.h>
#include <asm/smp.h>
#include <asm/irq.h>
#include <asm/errno.h>
#include <asm/xics.h>
#include <asm/io.h>
#include <asm/opal.h>
#include <asm/kvm_ppc.h>
static void icp_opal_teardown_cpu(void)
{
int hw_cpu = hard_smp_processor_id();
/* Clear any pending IPI */
opal_int_set_mfrr(hw_cpu, 0xff);
}
static void icp_opal_flush_ipi(void)
{
/*
* We take the ipi irq but and never return so we need to EOI the IPI,
* but want to leave our priority 0.
*
* Should we check all the other interrupts too?
* Should we be flagging idle loop instead?
* Or creating some task to be scheduled?
*/
if (opal_int_eoi((0x00 << 24) | XICS_IPI) > 0)
force_external_irq_replay();
}
static unsigned int icp_opal_get_xirr(void)
{
unsigned int kvm_xirr;
__be32 hw_xirr;
int64_t rc;
/* Handle an interrupt latched by KVM first */
kvm_xirr = kvmppc_get_xics_latch();
if (kvm_xirr)
return kvm_xirr;
/* Then ask OPAL */
rc = opal_int_get_xirr(&hw_xirr, false);
if (rc < 0)
return 0;
return be32_to_cpu(hw_xirr);
}
static unsigned int icp_opal_get_irq(void)
{
unsigned int xirr;
unsigned int vec;
unsigned int irq;
xirr = icp_opal_get_xirr();
vec = xirr & 0x00ffffff;
if (vec == XICS_IRQ_SPURIOUS)
return 0;
irq = irq_find_mapping(xics_host, vec);
if (likely(irq)) {
xics_push_cppr(vec);
return irq;
}
/* We don't have a linux mapping, so have rtas mask it. */
xics_mask_unknown_vec(vec);
/* We might learn about it later, so EOI it */
if (opal_int_eoi(xirr) > 0)
force_external_irq_replay();
return 0;
}
static void icp_opal_set_cpu_priority(unsigned char cppr)
{
/*
* Here be dragons. The caller has asked to allow only IPI's and not
* external interrupts. But OPAL XIVE doesn't support that. So instead
* of allowing no interrupts allow all. That's still not right, but
* currently the only caller who does this is xics_migrate_irqs_away()
* and it works in that case.
*/
if (cppr >= DEFAULT_PRIORITY)
cppr = LOWEST_PRIORITY;
xics_set_base_cppr(cppr);
opal_int_set_cppr(cppr);
iosync();
}
static void icp_opal_eoi(struct irq_data *d)
{
unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
int64_t rc;
iosync();
rc = opal_int_eoi((xics_pop_cppr() << 24) | hw_irq);
/*
* EOI tells us whether there are more interrupts to fetch.
*
* Some HW implementations might not be able to send us another
* external interrupt in that case, so we force a replay.
*/
if (rc > 0)
force_external_irq_replay();
}
#ifdef CONFIG_SMP
static void icp_opal_cause_ipi(int cpu)
{
int hw_cpu = get_hard_smp_processor_id(cpu);
kvmppc_set_host_ipi(cpu);
opal_int_set_mfrr(hw_cpu, IPI_PRIORITY);
}
static irqreturn_t icp_opal_ipi_action(int irq, void *dev_id)
{
int cpu = smp_processor_id();
kvmppc_clear_host_ipi(cpu);
opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff);
return smp_ipi_demux();
}
/*
* Called when an interrupt is received on an off-line CPU to
* clear the interrupt, so that the CPU can go back to nap mode.
*/
void icp_opal_flush_interrupt(void)
{
unsigned int xirr;
unsigned int vec;
do {
xirr = icp_opal_get_xirr();
vec = xirr & 0x00ffffff;
if (vec == XICS_IRQ_SPURIOUS)
break;
if (vec == XICS_IPI) {
/* Clear pending IPI */
int cpu = smp_processor_id();
kvmppc_clear_host_ipi(cpu);
opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff);
} else {
pr_err("XICS: hw interrupt 0x%x to offline cpu, "
"disabling\n", vec);
xics_mask_unknown_vec(vec);
}
/* EOI the interrupt */
} while (opal_int_eoi(xirr) > 0);
}
#endif /* CONFIG_SMP */
static const struct icp_ops icp_opal_ops = {
.get_irq = icp_opal_get_irq,
.eoi = icp_opal_eoi,
.set_priority = icp_opal_set_cpu_priority,
.teardown_cpu = icp_opal_teardown_cpu,
.flush_ipi = icp_opal_flush_ipi,
#ifdef CONFIG_SMP
.ipi_action = icp_opal_ipi_action,
.cause_ipi = icp_opal_cause_ipi,
#endif
};
int icp_opal_init(void)
{
struct device_node *np;
np = of_find_compatible_node(NULL, NULL, "ibm,opal-intc");
if (!np)
return -ENODEV;
icp_ops = &icp_opal_ops;
printk("XICS: Using OPAL ICP fallbacks\n");
of_node_put(np);
return 0;
}
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