// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2016,2017 IBM Corporation.
*/
#define pr_fmt(fmt) "xive: " fmt
#include <linux/types.h>
#include <linux/threads.h>
#include <linux/kernel.h>
#include <linux/irq.h>
#include <linux/debugfs.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/msi.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/irq.h>
#include <asm/errno.h>
#include <asm/xive.h>
#include <asm/xive-regs.h>
#include <asm/xmon.h>
#include "xive-internal.h"
#undef DEBUG_FLUSH
#undef DEBUG_ALL
#ifdef DEBUG_ALL
#define DBG_VERBOSE(fmt, ...) pr_devel("cpu %d - " fmt, \
smp_processor_id(), ## __VA_ARGS__)
#else
#define DBG_VERBOSE(fmt...) do { } while(0)
#endif
bool __xive_enabled;
EXPORT_SYMBOL_GPL(__xive_enabled);
bool xive_cmdline_disabled;
/* We use only one priority for now */
static u8 xive_irq_priority;
/* TIMA exported to KVM */
void __iomem *xive_tima;
EXPORT_SYMBOL_GPL(xive_tima);
u32 xive_tima_offset;
/* Backend ops */
static const struct xive_ops *xive_ops;
/* Our global interrupt domain */
static struct irq_domain *xive_irq_domain;
#ifdef CONFIG_SMP
/* The IPIs all use the same logical irq number */
static u32 xive_ipi_irq;
#endif
/* Xive state for each CPU */
static DEFINE_PER_CPU(struct xive_cpu *, xive_cpu);
/*
* A "disabled" interrupt should never fire, to catch problems
* we set its logical number to this
*/
#define XIVE_BAD_IRQ 0x7fffffff
#define XIVE_MAX_IRQ (XIVE_BAD_IRQ - 1)
/* An invalid CPU target */
#define XIVE_INVALID_TARGET (-1)
/*
* Read the next entry in a queue, return its content if it's valid
* or 0 if there is no new entry.
*
* The queue pointer is moved forward unless "just_peek" is set
*/
static u32 xive_read_eq(struct xive_q *q, bool just_peek)
{
u32 cur;
if (!q->qpage)
return 0;
cur = be32_to_cpup(q->qpage + q->idx);
/* Check valid bit (31) vs current toggle polarity */
if ((cur >> 31) == q->toggle)
return 0;
/* If consuming from the queue ... */
if (!just_peek) {
/* Next entry */
q->idx = (q->idx + 1) & q->msk;
/* Wrap around: flip valid toggle */
if (q->idx == 0)
q->toggle ^= 1;
}
/* Mask out the valid bit (31) */
return cur & 0x7fffffff;
}
/*
* Scans all the queue that may have interrupts in them
* (based on "pending_prio") in priority order until an
* interrupt is found or all the queues are empty.
*
* Then updates the CPPR (Current Processor Priority
* Register) based on the most favored interrupt found
* (0xff if none) and return what was found (0 if none).
*
* If just_peek is set, return the most favored pending
* interrupt if any but don't update the queue pointers.
*
* Note: This function can operate generically on any number
* of queues (up to 8). The current implementation of the XIVE
* driver only uses a single queue however.
*
* Note2: This will also "flush" "the pending_count" of a queue
* into the "count" when that queue is observed to be empty.
* This is used to keep track of the amount of interrupts
* targetting a queue. When an interrupt is moved away from
* a queue, we only decrement that queue count once the queue
* has been observed empty to avoid races.
*/
static u32 xive_scan_interrupts(struct xive_cpu *xc, bool just_peek)
{
u32 irq = 0;
u8 prio;
/* Find highest pending priority */
while (xc->pending_prio != 0) {
struct xive_q *q;
prio = ffs(xc->pending_prio) - 1;
DBG_VERBOSE("scan_irq: trying prio %d\n", prio);
/* Try to fetch */
irq = xive_read_eq(&xc->queue[prio], just_peek);
/* Found something ? That's it */
if (irq)
break;
/* Clear pending bits */
xc->pending_prio &= ~(1 << prio);
/*
* Check if the queue count needs adjusting due to
* interrupts being moved away. See description of
* xive_dec_target_count()
*/
q = &xc->queue[prio];
if (atomic_read(&q->pending_count)) {
int p = atomic_xchg(&q->pending_count, 0);
if (p) {
WARN_ON(p > atomic_read(&q->count));
atomic_sub(p, &q->count);
}
}
}
/* If nothing was found, set CPPR to 0xff */
if (irq == 0)
prio = 0xff;
/* Update HW CPPR to match if necessary */
if (prio != xc->cppr) {
DBG_VERBOSE("scan_irq: adjusting CPPR to %d\n", prio);
xc->cppr = prio;
out_8(xive_tima + xive_tima_offset + TM_CPPR, prio);
}
return irq;
}
/*
* This is used to perform the magic loads from an ESB
* described in xive.h
*/
static notrace u8 xive_esb_read(struct xive_irq_data *xd, u32 offset)
{
u64 val;
/* Handle HW errata */
if (xd->flags & XIVE_IRQ_FLAG_SHIFT_BUG)
offset |= offset << 4;
if ((xd->flags & XIVE_IRQ_FLAG_H_INT_ESB) && xive_ops->esb_rw)
val = xive_ops->esb_rw(xd->hw_irq, offset, 0, 0);
else
val = in_be64(xd->eoi_mmio + offset);
return (u8)val;
}
static void xive_esb_write(struct xive_irq_data *xd, u32 offset, u64 data)
{
/* Handle HW errata */
if (xd->flags & XIVE_IRQ_FLAG_SHIFT_BUG)
offset |= offset << 4;
if ((xd->flags & XIVE_IRQ_FLAG_H_INT_ESB) && xive_ops->esb_rw)
xive_ops->esb_rw(xd->hw_irq, offset, data, 1);
else
out_be64(xd->eoi_mmio + offset, data);
}
#ifdef CONFIG_XMON
static notrace void xive_dump_eq(const char *name, struct xive_q *q)
{
u32 i0, i1, idx;
if (!q->qpage)
return;
idx = q->idx;
i0 = be32_to_cpup(q->qpage + idx);
idx = (idx + 1) & q->msk;
i1 = be32_to_cpup(q->qpage + idx);
xmon_printf(" %s Q T=%d %08x %08x ...\n", name,
q->toggle, i0, i1);
}
notrace void xmon_xive_do_dump(int cpu)
{
struct xive_cpu *xc = per_cpu(xive_cpu, cpu);
xmon_printf("XIVE state for CPU %d:\n", cpu);
xmon_printf(" pp=%02x cppr=%02x\n", xc->pending_prio, xc->cppr);
xive_dump_eq("IRQ", &xc->queue[xive_irq_priority]);
#ifdef CONFIG_SMP
{
u64 val = xive_esb_read(&xc->ipi_data, XIVE_ESB_GET);
xmon_printf(" IPI state: %x:%c%c\n", xc->hw_ipi,
val & XIVE_ESB_VAL_P ? 'P' : 'p',
val & XIVE_ESB_VAL_Q ? 'Q' : 'q');
}
#endif
}
#endif /* CONFIG_XMON */
static unsigned int xive_get_irq(void)
{
struct xive_cpu *xc = __this_cpu_read(xive_cpu);
u32 irq;
/*
* This can be called either as a result of a HW interrupt or
* as a "replay" because EOI decided there was still something
* in one of the queues.
*
* First we perform an ACK cycle in order to update our mask
* of pending priorities. This will also have the effect of
* updating the CPPR to the most favored pending interrupts.
*
* In the future, if we have a way to differentiate a first
* entry (on HW interrupt) from a replay triggered by EOI,
* we could skip this on replays unless we soft-mask tells us
* that a new HW interrupt occurred.
*/
xive_ops->update_pending(xc);
DBG_VERBOSE("get_irq: pending=%02x\n", xc->pending_prio);
/* Scan our queue(s) for interrupts */
irq = xive_scan_interrupts(xc, false);
DBG_VERBOSE("get_irq: got irq 0x%x, new pending=0x%02x\n",
irq, xc->pending_prio);
/* Return pending interrupt if any */
if (irq == XIVE_BAD_IRQ)
return 0;
return irq;
}
/*
* After EOI'ing an interrupt, we need to re-check the queue
* to see if another interrupt is pending since multiple
* interrupts can coalesce into a single notification to the
* CPU.
*
* If we find that there is indeed more in there, we call
* force_external_irq_replay() to make Linux synthetize an
* external interrupt on the next call to local_irq_restore().
*/
static void xive_do_queue_eoi(struct xive_cpu *xc)
{
if (xive_scan_interrupts(xc, true) != 0) {
DBG_VERBOSE("eoi: pending=0x%02x\n", xc->pending_prio);
force_external_irq_replay();
}
}
/*
* EOI an interrupt at the source. There are several methods
* to do this depending on the HW version and source type
*/
static void xive_do_source_eoi(u32 hw_irq, struct xive_irq_data *xd)
{
/* If the XIVE supports the new "store EOI facility, use it */
if (xd->flags & XIVE_IRQ_FLAG_STORE_EOI)
xive_esb_write(xd, XIVE_ESB_STORE_EOI, 0);
else if (hw_irq && xd->flags & XIVE_IRQ_FLAG_EOI_FW) {
/*
* The FW told us to call it. This happens for some
* interrupt sources that need additional HW whacking
* beyond the ESB manipulation. For example LPC interrupts
* on P9 DD1.0 needed a latch to be clared in the LPC bridge
* itself. The Firmware will take care of it.
*/
if (WARN_ON_ONCE(!xive_ops->eoi))
return;
xive_ops->eoi(hw_irq);
} else {
u8 eoi_val;
/*
* Otherwise for EOI, we use the special MMIO that does
* a clear of both P and Q and returns the old Q,
* except for LSIs where we use the "EOI cycle" special
* load.
*
* This allows us to then do a re-trigger if Q was set
* rather than synthesizing an interrupt in software
*
* For LSIs the HW EOI cycle is used rather than PQ bits,
* as they are automatically re-triggred in HW when still
* pending.
*/
if (xd->flags & XIVE_IRQ_FLAG_LSI)
xive_esb_read(xd, XIVE_ESB_LOAD_EOI);
else {
eoi_val = xive_esb_read(xd, XIVE_ESB_SET_PQ_00);
DBG_VERBOSE("eoi_val=%x\n", eoi_val);
/* Re-trigger if needed */
if ((eoi_val & XIVE_ESB_VAL_Q) && xd->trig_mmio)
out_be64(xd->trig_mmio, 0);
}
}
}
/* irq_chip eoi callback */
static void xive_irq_eoi(struct irq_data *d)
{
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
struct xive_cpu *xc = __this_cpu_read(xive_cpu);
DBG_VERBOSE("eoi_irq: irq=%d [0x%lx] pending=%02x\n",
d->irq, irqd_to_hwirq(d), xc->pending_prio);
/*
* EOI the source if it hasn't been disabled and hasn't
* been passed-through to a KVM guest
*/
if (!irqd_irq_disabled(d) && !irqd_is_forwarded_to_vcpu(d) &&
!(xd->flags & XIVE_IRQ_NO_EOI))
xive_do_source_eoi(irqd_to_hwirq(d), xd);
/*
* Clear saved_p to indicate that it's no longer occupying
* a queue slot on the target queue
*/
xd->saved_p = false;
/* Check for more work in the queue */
xive_do_queue_eoi(xc);
}
/*
* Helper used to mask and unmask an interrupt source. This
* is only called for normal interrupts that do not require
* masking/unmasking via firmware.
*/
static void xive_do_source_set_mask(struct xive_irq_data *xd,
bool mask)
{
u64 val;
/*
* If the interrupt had P set, it may be in a queue.
*
* We need to make sure we don't re-enable it until it
* has been fetched from that queue and EOId. We keep
* a copy of that P state and use it to restore the
* ESB accordingly on unmask.
*/
if (mask) {
val = xive_esb_read(xd, XIVE_ESB_SET_PQ_01);
xd->saved_p = !!(val & XIVE_ESB_VAL_P);
} else if (xd->saved_p)
xive_esb_read(xd, XIVE_ESB_SET_PQ_10);
else
xive_esb_read(xd, XIVE_ESB_SET_PQ_00);
}
/*
* Try to chose "cpu" as a new interrupt target. Increments
* the queue accounting for that target if it's not already
* full.
*/
static bool xive_try_pick_target(int cpu)
{
struct xive_cpu *xc = per_cpu(xive_cpu, cpu);
struct xive_q *q = &xc->queue[xive_irq_priority];
int max;
/*
* Calculate max number of interrupts in that queue.
*
* We leave a gap of 1 just in case...
*/
max = (q->msk + 1) - 1;
return !!atomic_add_unless(&q->count, 1, max);
}
/*
* Un-account an interrupt for a target CPU. We don't directly
* decrement q->count since the interrupt might still be present
* in the queue.
*
* Instead increment a separate counter "pending_count" which
* will be substracted from "count" later when that CPU observes
* the queue to be empty.
*/
static void xive_dec_target_count(int cpu)
{
struct xive_cpu *xc = per_cpu(xive_cpu, cpu);
struct xive_q *q = &xc->queue[xive_irq_priority];
if (WARN_ON(cpu < 0 || !xc)) {
pr_err("%s: cpu=%d xc=%p\n", __func__, cpu, xc);
return;
}
/*
* We increment the "pending count" which will be used
* to decrement the target queue count whenever it's next
* processed and found empty. This ensure that we don't
* decrement while we still have the interrupt there
* occupying a slot.
*/
atomic_inc(&q->pending_count);
}
/* Find a tentative CPU target in a CPU mask */
static int xive_find_target_in_mask(const struct cpumask *mask,
unsigned int fuzz)
{
int cpu, first, num, i;
/* Pick up a starting point CPU in the mask based on fuzz */
num = min_t(int, cpumask_weight(mask), nr_cpu_ids);
first = fuzz % num;
/* Locate it */
cpu = cpumask_first(mask);
for (i = 0; i < first && cpu < nr_cpu_ids; i++)
cpu = cpumask_next(cpu, mask);
/* Sanity check */
if (WARN_ON(cpu >= nr_cpu_ids))
cpu = cpumask_first(cpu_online_mask);
/* Remember first one to handle wrap-around */
first = cpu;
/*
* Now go through the entire mask until we find a valid
* target.
*/
do {
/*
* We re-check online as the fallback case passes us
* an untested affinity mask
*/
if (cpu_online(cpu) && xive_try_pick_target(cpu))
return cpu;
cpu = cpumask_next(cpu, mask);
/* Wrap around */
if (cpu >= nr_cpu_ids)
cpu = cpumask_first(mask);
} while (cpu != first);
return -1;
}
/*
* Pick a target CPU for an interrupt. This is done at
* startup or if the affinity is changed in a way that
* invalidates the current target.
*/
static int xive_pick_irq_target(struct irq_data *d,
const struct cpumask *affinity)
{
static unsigned int fuzz;
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
cpumask_var_t mask;
int cpu = -1;
/*
* If we have chip IDs, first we try to build a mask of
* CPUs matching the CPU and find a target in there
*/
if (xd->src_chip != XIVE_INVALID_CHIP_ID &&
zalloc_cpumask_var(&mask, GFP_ATOMIC)) {
/* Build a mask of matching chip IDs */
for_each_cpu_and(cpu, affinity, cpu_online_mask) {
struct xive_cpu *xc = per_cpu(xive_cpu, cpu);
if (xc->chip_id == xd->src_chip)
cpumask_set_cpu(cpu, mask);
}
/* Try to find a target */
if (cpumask_empty(mask))
cpu = -1;
else
cpu = xive_find_target_in_mask(mask, fuzz++);
free_cpumask_var(mask);
if (cpu >= 0)
return cpu;
fuzz--;
}
/* No chip IDs, fallback to using the affinity mask */
return xive_find_target_in_mask(affinity, fuzz++);
}
static unsigned int xive_irq_startup(struct irq_data *d)
{
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
int target, rc;
pr_devel("xive_irq_startup: irq %d [0x%x] data @%p\n",
d->irq, hw_irq, d);
#ifdef CONFIG_PCI_MSI
/*
* The generic MSI code returns with the interrupt disabled on the
* card, using the MSI mask bits. Firmware doesn't appear to unmask
* at that level, so we do it here by hand.
*/
if (irq_data_get_msi_desc(d))
pci_msi_unmask_irq(d);
#endif
/* Pick a target */
target = xive_pick_irq_target(d, irq_data_get_affinity_mask(d));
if (target == XIVE_INVALID_TARGET) {
/* Try again breaking affinity */
target = xive_pick_irq_target(d, cpu_online_mask);
if (target == XIVE_INVALID_TARGET)
return -ENXIO;
pr_warn("irq %d started with broken affinity\n", d->irq);
}
/* Sanity check */
if (WARN_ON(target == XIVE_INVALID_TARGET ||
target >= nr_cpu_ids))
target = smp_processor_id();
xd->target = target;
/*
* Configure the logical number to be the Linux IRQ number
* and set the target queue
*/
rc = xive_ops->configure_irq(hw_irq,
get_hard_smp_processor_id(target),
xive_irq_priority, d->irq);
if (rc)
return rc;
/* Unmask the ESB */
xive_do_source_set_mask(xd, false);
return 0;
}
static void xive_irq_shutdown(struct irq_data *d)
{
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
pr_devel("xive_irq_shutdown: irq %d [0x%x] data @%p\n",
d->irq, hw_irq, d);
if (WARN_ON(xd->target == XIVE_INVALID_TARGET))
return;
/* Mask the interrupt at the source */
xive_do_source_set_mask(xd, true);
/*
* The above may have set saved_p. We clear it otherwise it
* will prevent re-enabling later on. It is ok to forget the
* fact that the interrupt might be in a queue because we are
* accounting that already in xive_dec_target_count() and will
* be re-routing it to a new queue with proper accounting when
* it's started up again
*/
xd->saved_p = false;
/*
* Mask the interrupt in HW in the IVT/EAS and set the number
* to be the "bad" IRQ number
*/
xive_ops->configure_irq(hw_irq,
get_hard_smp_processor_id(xd->target),
0xff, XIVE_BAD_IRQ);
xive_dec_target_count(xd->target);
xd->target = XIVE_INVALID_TARGET;
}
static void xive_irq_unmask(struct irq_data *d)
{
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
pr_devel("xive_irq_unmask: irq %d data @%p\n", d->irq, xd);
/*
* This is a workaround for PCI LSI problems on P9, for
* these, we call FW to set the mask. The problems might
* be fixed by P9 DD2.0, if that is the case, firmware
* will no longer set that flag.
*/
if (xd->flags & XIVE_IRQ_FLAG_MASK_FW) {
unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
xive_ops->configure_irq(hw_irq,
get_hard_smp_processor_id(xd->target),
xive_irq_priority, d->irq);
return;
}
xive_do_source_set_mask(xd, false);
}
static void xive_irq_mask(struct irq_data *d)
{
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
pr_devel("xive_irq_mask: irq %d data @%p\n", d->irq, xd);
/*
* This is a workaround for PCI LSI problems on P9, for
* these, we call OPAL to set the mask. The problems might
* be fixed by P9 DD2.0, if that is the case, firmware
* will no longer set that flag.
*/
if (xd->flags & XIVE_IRQ_FLAG_MASK_FW) {
unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
xive_ops->configure_irq(hw_irq,
get_hard_smp_processor_id(xd->target),
0xff, d->irq);
return;
}
xive_do_source_set_mask(xd, true);
}
static int xive_irq_set_affinity(struct irq_data *d,
const struct cpumask *cpumask,
bool force)
{
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
u32 target, old_target;
int rc = 0;
pr_devel("xive_irq_set_affinity: irq %d\n", d->irq);
/* Is this valid ? */
if (cpumask_any_and(cpumask, cpu_online_mask) >= nr_cpu_ids)
return -EINVAL;
/* Don't do anything if the interrupt isn't started */
if (!irqd_is_started(d))
return IRQ_SET_MASK_OK;
/*
* If existing target is already in the new mask, and is
* online then do nothing.
*/
if (xd->target != XIVE_INVALID_TARGET &&
cpu_online(xd->target) &&
cpumask_test_cpu(xd->target, cpumask))
return IRQ_SET_MASK_OK;
/* Pick a new target */
target = xive_pick_irq_target(d, cpumask);
/* No target found */
if (target == XIVE_INVALID_TARGET)
return -ENXIO;
/* Sanity check */
if (WARN_ON(target >= nr_cpu_ids))
target = smp_processor_id();
old_target = xd->target;
/*
* Only configure the irq if it's not currently passed-through to
* a KVM guest
*/
if (!irqd_is_forwarded_to_vcpu(d))
rc = xive_ops->configure_irq(hw_irq,
get_hard_smp_processor_id(target),
xive_irq_priority, d->irq);
if (rc < 0) {
pr_err("Error %d reconfiguring irq %d\n", rc, d->irq);
return rc;
}
pr_devel(" target: 0x%x\n", target);
xd->target = target;
/* Give up previous target */
if (old_target != XIVE_INVALID_TARGET)
xive_dec_target_count(old_target);
return IRQ_SET_MASK_OK;
}
static int xive_irq_set_type(struct irq_data *d, unsigned int flow_type)
{
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
/*
* We only support these. This has really no effect other than setting
* the corresponding descriptor bits mind you but those will in turn
* affect the resend function when re-enabling an edge interrupt.
*
* Set set the default to edge as explained in map().
*/
if (flow_type == IRQ_TYPE_DEFAULT || flow_type == IRQ_TYPE_NONE)
flow_type = IRQ_TYPE_EDGE_RISING;
if (flow_type != IRQ_TYPE_EDGE_RISING &&
flow_type != IRQ_TYPE_LEVEL_LOW)
return -EINVAL;
irqd_set_trigger_type(d, flow_type);
/*
* Double check it matches what the FW thinks
*
* NOTE: We don't know yet if the PAPR interface will provide
* the LSI vs MSI information apart from the device-tree so
* this check might have to move into an optional backend call
* that is specific to the native backend
*/
if ((flow_type == IRQ_TYPE_LEVEL_LOW) !=
!!(xd->flags & XIVE_IRQ_FLAG_LSI)) {
pr_warn("Interrupt %d (HW 0x%x) type mismatch, Linux says %s, FW says %s\n",
d->irq, (u32)irqd_to_hwirq(d),
(flow_type == IRQ_TYPE_LEVEL_LOW) ? "Level" : "Edge",
(xd->flags & XIVE_IRQ_FLAG_LSI) ? "Level" : "Edge");
}
return IRQ_SET_MASK_OK_NOCOPY;
}
static int xive_irq_retrigger(struct irq_data *d)
{
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
/* This should be only for MSIs */
if (WARN_ON(xd->flags & XIVE_IRQ_FLAG_LSI))
return 0;
/*
* To perform a retrigger, we first set the PQ bits to
* 11, then perform an EOI.
*/
xive_esb_read(xd, XIVE_ESB_SET_PQ_11);
/*
* Note: We pass "0" to the hw_irq argument in order to
* avoid calling into the backend EOI code which we don't
* want to do in the case of a re-trigger. Backends typically
* only do EOI for LSIs anyway.
*/
xive_do_source_eoi(0, xd);
return 1;
}
static int xive_irq_set_vcpu_affinity(struct irq_data *d, void *state)
{
struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
int rc;
u8 pq;
/*
* We only support this on interrupts that do not require
* firmware calls for masking and unmasking
*/
if (xd->flags & XIVE_IRQ_FLAG_MASK_FW)
return -EIO;
/*
* This is called by KVM with state non-NULL for enabling
* pass-through or NULL for disabling it
*/
if (state) {
irqd_set_forwarded_to_vcpu(d);
/* Set it to PQ=10 state to prevent further sends */
pq = xive_esb_read(xd, XIVE_ESB_SET_PQ_10);
/* No target ? nothing to do */
if (xd->target == XIVE_INVALID_TARGET) {
/*
* An untargetted interrupt should have been
* also masked at the source
*/
WARN_ON(pq & 2);
return 0;
}
/*
* If P was set, adjust state to PQ=11 to indicate
* that a resend is needed for the interrupt to reach
* the guest. Also remember the value of P.
*
* This also tells us that it's in flight to a host queue
* or has already been fetched but hasn't been EOIed yet
* by the host. This it's potentially using up a host
* queue slot. This is important to know because as long
* as this is the case, we must not hard-unmask it when
* "returning" that interrupt to the host.
*
* This saved_p is cleared by the host EOI, when we know
* for sure the queue slot is no longer in use.
*/
if (pq & 2) {
pq = xive_esb_read(xd, XIVE_ESB_SET_PQ_11);
xd->saved_p = true;
/*
* Sync the XIVE source HW to ensure the interrupt
* has gone through the EAS before we change its
* target to the guest. That should guarantee us
* that we *will* eventually get an EOI for it on
* the host. Otherwise there would be a small window
* for P to be seen here but the interrupt going
* to the guest queue.
*/
if (xive_ops->sync_source)
xive_ops->sync_source(hw_irq);
} else
xd->saved_p = false;
} else {
irqd_clr_forwarded_to_vcpu(d);
/* No host target ? hard mask and return */
if (xd->target == XIVE_INVALID_TARGET) {
xive_do_source_set_mask(xd, true);
return 0;
}
/*
* Sync the XIVE source HW to ensure the interrupt
* has gone through the EAS before we change its
* target to the host.
*/
if (xive_ops->sync_source)
xive_ops->sync_source(hw_irq);
/*
* By convention we are called with the interrupt in
* a PQ=10 or PQ=11 state, ie, it won't fire and will
* have latched in Q whether there's a pending HW
* interrupt or not.
*
* First reconfigure the target.
*/
rc = xive_ops->configure_irq(hw_irq,
get_hard_smp_processor_id(xd->target),
xive_irq_priority, d->irq);
if (rc)
return rc;
/*
* Then if saved_p is not set, effectively re-enable the
* interrupt with an EOI. If it is set, we know there is
* still a message in a host queue somewhere that will be
* EOId eventually.
*
* Note: We don't check irqd_irq_disabled(). Effectively,
* we *will* let the irq get through even if masked if the
* HW is still firing it in order to deal with the whole
* saved_p business properly. If the interrupt triggers
* while masked, the generic code will re-mask it anyway.
*/
if (!xd->saved_p)
xive_do_source_eoi(hw_irq, xd);
}
return 0;
}
static struct irq_chip xive_irq_chip = {
.name = "XIVE-IRQ",
.irq_startup = xive_irq_startup,
.irq_shutdown = xive_irq_shutdown,
.irq_eoi = xive_irq_eoi,
.irq_mask = xive_irq_mask,
.irq_unmask = xive_irq_unmask,
.irq_set_affinity = xive_irq_set_affinity,
.irq_set_type = xive_irq_set_type,
.irq_retrigger = xive_irq_retrigger,
.irq_set_vcpu_affinity = xive_irq_set_vcpu_affinity,
};
bool is_xive_irq(struct irq_chip *chip)
{
return chip == &xive_irq_chip;
}
EXPORT_SYMBOL_GPL(is_xive_irq);
void xive_cleanup_irq_data(struct xive_irq_data *xd)
{
if (xd->eoi_mmio) {
iounmap(xd->eoi_mmio);
if (xd->eoi_mmio == xd->trig_mmio)
xd->trig_mmio = NULL;
xd->eoi_mmio = NULL;
}
if (xd->trig_mmio) {
iounmap(xd->trig_mmio);
xd->trig_mmio = NULL;
}
}
EXPORT_SYMBOL_GPL(xive_cleanup_irq_data);
static int xive_irq_alloc_data(unsigned int virq, irq_hw_number_t hw)
{
struct xive_irq_data *xd;
int rc;
xd = kzalloc(sizeof(struct xive_irq_data), GFP_KERNEL);
if (!xd)
return -ENOMEM;
rc = xive_ops->populate_irq_data(hw, xd);
if (rc) {
kfree(xd);
return rc;
}
xd->target = XIVE_INVALID_TARGET;
irq_set_handler_data(virq, xd);
return 0;
}
static void xive_irq_free_data(unsigned int virq)
{
struct xive_irq_data *xd = irq_get_handler_data(virq);
if (!xd)
return;
irq_set_handler_data(virq, NULL);
xive_cleanup_irq_data(xd);
kfree(xd);
}
#ifdef CONFIG_SMP
static void xive_cause_ipi(int cpu)
{
struct xive_cpu *xc;
struct xive_irq_data *xd;
xc = per_cpu(xive_cpu, cpu);
DBG_VERBOSE("IPI CPU %d -> %d (HW IRQ 0x%x)\n",
smp_processor_id(), cpu, xc->hw_ipi);
xd = &xc->ipi_data;
if (WARN_ON(!xd->trig_mmio))
return;
out_be64(xd->trig_mmio, 0);
}
static irqreturn_t xive_muxed_ipi_action(int irq, void *dev_id)
{
return smp_ipi_demux();
}
static void xive_ipi_eoi(struct irq_data *d)
{
struct xive_cpu *xc = __this_cpu_read(xive_cpu);
/* Handle possible race with unplug and drop stale IPIs */
if (!xc)
return;
DBG_VERBOSE("IPI eoi: irq=%d [0x%lx] (HW IRQ 0x%x) pending=%02x\n",
d->irq, irqd_to_hwirq(d), xc->hw_ipi, xc->pending_prio);
xive_do_source_eoi(xc->hw_ipi, &xc->ipi_data);
xive_do_queue_eoi(xc);
}
static void xive_ipi_do_nothing(struct irq_data *d)
{
/*
* Nothing to do, we never mask/unmask IPIs, but the callback
* has to exist for the struct irq_chip.
*/
}
static struct irq_chip xive_ipi_chip = {
.name = "XIVE-IPI",
.irq_eoi = xive_ipi_eoi,
.irq_mask = xive_ipi_do_nothing,
.irq_unmask = xive_ipi_do_nothing,
};
static void __init xive_request_ipi(void)
{
unsigned int virq;
/*
* Initialization failed, move on, we might manage to
* reach the point where we display our errors before
* the system falls appart
*/
if (!xive_irq_domain)
return;
/* Initialize it */
virq = irq_create_mapping(xive_irq_domain, 0);
xive_ipi_irq = virq;
WARN_ON(request_irq(virq, xive_muxed_ipi_action,
IRQF_PERCPU | IRQF_NO_THREAD, "IPI", NULL));
}
static int xive_setup_cpu_ipi(unsigned int cpu)
{
struct xive_cpu *xc;
int rc;
pr_debug("Setting up IPI for CPU %d\n", cpu);
xc = per_cpu(xive_cpu, cpu);
/* Check if we are already setup */
if (xc->hw_ipi != 0)
return 0;
/* Grab an IPI from the backend, this will populate xc->hw_ipi */
if (xive_ops->get_ipi(cpu, xc))
return -EIO;
/*
* Populate the IRQ data in the xive_cpu structure and
* configure the HW / enable the IPIs.
*/
rc = xive_ops->populate_irq_data(xc->hw_ipi, &xc->ipi_data);
if (rc) {
pr_err("Failed to populate IPI data on CPU %d\n", cpu);
return -EIO;
}
rc = xive_ops->configure_irq(xc->hw_ipi,
get_hard_smp_processor_id(cpu),
xive_irq_priority, xive_ipi_irq);
if (rc) {
pr_err("Failed to map IPI CPU %d\n", cpu);
return -EIO;
}
pr_devel("CPU %d HW IPI %x, virq %d, trig_mmio=%p\n", cpu,
xc->hw_ipi, xive_ipi_irq, xc->ipi_data.trig_mmio);
/* Unmask it */
xive_do_source_set_mask(&xc->ipi_data, false);
return 0;
}
static void xive_cleanup_cpu_ipi(unsigned int cpu, struct xive_cpu *xc)
{
/* Disable the IPI and free the IRQ data */
/* Already cleaned up ? */
if (xc->hw_ipi == 0)
return;
/* Mask the IPI */
xive_do_source_set_mask(&xc->ipi_data, true);
/*
* Note: We don't call xive_cleanup_irq_data() to free
* the mappings as this is called from an IPI on kexec
* which is not a safe environment to call iounmap()
*/
/* Deconfigure/mask in the backend */
xive_ops->configure_irq(xc->hw_ipi, hard_smp_processor_id(),
0xff, xive_ipi_irq);
/* Free the IPIs in the backend */
xive_ops->put_ipi(cpu, xc);
}
void __init xive_smp_probe(void)
{
smp_ops->cause_ipi = xive_cause_ipi;
/* Register the IPI */
xive_request_ipi();
/* Allocate and setup IPI for the boot CPU */
xive_setup_cpu_ipi(smp_processor_id());
}
#endif /* CONFIG_SMP */
static int xive_irq_domain_map(struct irq_domain *h, unsigned int virq,
irq_hw_number_t hw)
{
int rc;
/*
* Mark interrupts as edge sensitive by default so that resend
* actually works. Will fix that up below if needed.
*/
irq_clear_status_flags(virq, IRQ_LEVEL);
#ifdef CONFIG_SMP
/* IPIs are special and come up with HW number 0 */
if (hw == 0) {
/*
* IPIs are marked per-cpu. We use separate HW interrupts under
* the hood but associated with the same "linux" interrupt
*/
irq_set_chip_and_handler(virq, &xive_ipi_chip,
handle_percpu_irq);
return 0;
}
#endif
rc = xive_irq_alloc_data(virq, hw);
if (rc)
return rc;
irq_set_chip_and_handler(virq, &xive_irq_chip, handle_fasteoi_irq);
return 0;
}
static void xive_irq_domain_unmap(struct irq_domain *d, unsigned int virq)
{
struct irq_data *data = irq_get_irq_data(virq);
unsigned int hw_irq;
/* XXX Assign BAD number */
if (!data)
return;
hw_irq = (unsigned int)irqd_to_hwirq(data);
if (hw_irq)
xive_irq_free_data(virq);
}
static int xive_irq_domain_xlate(struct irq_domain *h, struct device_node *ct,
const u32 *intspec, unsigned int intsize,
irq_hw_number_t *out_hwirq, unsigned int *out_flags)
{
*out_hwirq = intspec[0];
/*
* If intsize is at least 2, we look for the type in the second cell,
* we assume the LSB indicates a level interrupt.
*/
if (intsize > 1) {
if (intspec[1] & 1)
*out_flags = IRQ_TYPE_LEVEL_LOW;
else
*out_flags = IRQ_TYPE_EDGE_RISING;
} else
*out_flags = IRQ_TYPE_LEVEL_LOW;
return 0;
}
static int xive_irq_domain_match(struct irq_domain *h, struct device_node *node,
enum irq_domain_bus_token bus_token)
{
return xive_ops->match(node);
}
static const struct irq_domain_ops xive_irq_domain_ops = {
.match = xive_irq_domain_match,
.map = xive_irq_domain_map,
.unmap = xive_irq_domain_unmap,
.xlate = xive_irq_domain_xlate,
};
static void __init xive_init_host(void)
{
xive_irq_domain = irq_domain_add_nomap(NULL, XIVE_MAX_IRQ,
&xive_irq_domain_ops, NULL);
if (WARN_ON(xive_irq_domain == NULL))
return;
irq_set_default_host(xive_irq_domain);
}
static void xive_cleanup_cpu_queues(unsigned int cpu, struct xive_cpu *xc)
{
if (xc->queue[xive_irq_priority].qpage)
xive_ops->cleanup_queue(cpu, xc, xive_irq_priority);
}
static int xive_setup_cpu_queues(unsigned int cpu, struct xive_cpu *xc)
{
int rc = 0;
/* We setup 1 queues for now with a 64k page */
if (!xc->queue[xive_irq_priority].qpage)
rc = xive_ops->setup_queue(cpu, xc, xive_irq_priority);
return rc;
}
static int xive_prepare_cpu(unsigned int cpu)
{
struct xive_cpu *xc;
xc = per_cpu(xive_cpu, cpu);
if (!xc) {
struct device_node *np;
xc = kzalloc_node(sizeof(struct xive_cpu),
GFP_KERNEL, cpu_to_node(cpu));
if (!xc)
return -ENOMEM;
np = of_get_cpu_node(cpu, NULL);
if (np)
xc->chip_id = of_get_ibm_chip_id(np);
of_node_put(np);
per_cpu(xive_cpu, cpu) = xc;
}
/* Setup EQs if not already */
return xive_setup_cpu_queues(cpu, xc);
}
static void xive_setup_cpu(void)
{
struct xive_cpu *xc = __this_cpu_read(xive_cpu);
/* The backend might have additional things to do */
if (xive_ops->setup_cpu)
xive_ops->setup_cpu(smp_processor_id(), xc);
/* Set CPPR to 0xff to enable flow of interrupts */
xc->cppr = 0xff;
out_8(xive_tima + xive_tima_offset + TM_CPPR, 0xff);
}
#ifdef CONFIG_SMP
void xive_smp_setup_cpu(void)
{
pr_devel("SMP setup CPU %d\n", smp_processor_id());
/* This will have already been done on the boot CPU */
if (smp_processor_id() != boot_cpuid)
xive_setup_cpu();
}
int xive_smp_prepare_cpu(unsigned int cpu)
{
int rc;
/* Allocate per-CPU data and queues */
rc = xive_prepare_cpu(cpu);
if (rc)
return rc;
/* Allocate and setup IPI for the new CPU */
return xive_setup_cpu_ipi(cpu);
}
#ifdef CONFIG_HOTPLUG_CPU
static void xive_flush_cpu_queue(unsigned int cpu, struct xive_cpu *xc)
{
u32 irq;
/* We assume local irqs are disabled */
WARN_ON(!irqs_disabled());
/* Check what's already in the CPU queue */
while ((irq = xive_scan_interrupts(xc, false)) != 0) {
/*
* We need to re-route that interrupt to its new destination.
* First get and lock the descriptor
*/
struct irq_desc *desc = irq_to_desc(irq);
struct irq_data *d = irq_desc_get_irq_data(desc);
struct xive_irq_data *xd;
unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
/*
* Ignore anything that isn't a XIVE irq and ignore
* IPIs, so can just be dropped.
*/
if (d->domain != xive_irq_domain || hw_irq == 0)
continue;
/*
* The IRQ should have already been re-routed, it's just a
* stale in the old queue, so re-trigger it in order to make
* it reach is new destination.
*/
#ifdef DEBUG_FLUSH
pr_info("CPU %d: Got irq %d while offline, re-sending...\n",
cpu, irq);
#endif
raw_spin_lock(&desc->lock);
xd = irq_desc_get_handler_data(desc);
/*
* For LSIs, we EOI, this will cause a resend if it's
* still asserted. Otherwise do an MSI retrigger.
*/
if (xd->flags & XIVE_IRQ_FLAG_LSI)
xive_do_source_eoi(irqd_to_hwirq(d), xd);
else
xive_irq_retrigger(d);
raw_spin_unlock(&desc->lock);
}
}
void xive_smp_disable_cpu(void)
{
struct xive_cpu *xc = __this_cpu_read(xive_cpu);
unsigned int cpu = smp_processor_id();
/* Migrate interrupts away from the CPU */
irq_migrate_all_off_this_cpu();
/* Set CPPR to 0 to disable flow of interrupts */
xc->cppr = 0;
out_8(xive_tima + xive_tima_offset + TM_CPPR, 0);
/* Flush everything still in the queue */
xive_flush_cpu_queue(cpu, xc);
/* Re-enable CPPR */
xc->cppr = 0xff;
out_8(xive_tima + xive_tima_offset + TM_CPPR, 0xff);
}
void xive_flush_interrupt(void)
{
struct xive_cpu *xc = __this_cpu_read(xive_cpu);
unsigned int cpu = smp_processor_id();
/* Called if an interrupt occurs while the CPU is hot unplugged */
xive_flush_cpu_queue(cpu, xc);
}
#endif /* CONFIG_HOTPLUG_CPU */
#endif /* CONFIG_SMP */
void xive_teardown_cpu(void)
{
struct xive_cpu *xc = __this_cpu_read(xive_cpu);
unsigned int cpu = smp_processor_id();
/* Set CPPR to 0 to disable flow of interrupts */
xc->cppr = 0;
out_8(xive_tima + xive_tima_offset + TM_CPPR, 0);
if (xive_ops->teardown_cpu)
xive_ops->teardown_cpu(cpu, xc);
#ifdef CONFIG_SMP
/* Get rid of IPI */
xive_cleanup_cpu_ipi(cpu, xc);
#endif
/* Disable and free the queues */
xive_cleanup_cpu_queues(cpu, xc);
}
void xive_shutdown(void)
{
xive_ops->shutdown();
}
bool __init xive_core_init(const struct xive_ops *ops, void __iomem *area, u32 offset,
u8 max_prio)
{
xive_tima = area;
xive_tima_offset = offset;
xive_ops = ops;
xive_irq_priority = max_prio;
ppc_md.get_irq = xive_get_irq;
__xive_enabled = true;
pr_devel("Initializing host..\n");
xive_init_host();
pr_devel("Initializing boot CPU..\n");
/* Allocate per-CPU data and queues */
xive_prepare_cpu(smp_processor_id());
/* Get ready for interrupts */
xive_setup_cpu();
pr_info("Interrupt handling initialized with %s backend\n",
xive_ops->name);
pr_info("Using priority %d for all interrupts\n", max_prio);
return true;
}
__be32 *xive_queue_page_alloc(unsigned int cpu, u32 queue_shift)
{
unsigned int alloc_order;
struct page *pages;
__be32 *qpage;
alloc_order = xive_alloc_order(queue_shift);
pages = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, alloc_order);
if (!pages)
return ERR_PTR(-ENOMEM);
qpage = (__be32 *)page_address(pages);
memset(qpage, 0, 1 << queue_shift);
return qpage;
}
static int __init xive_off(char *arg)
{
xive_cmdline_disabled = true;
return 0;
}
__setup("xive=off", xive_off);
