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Diffstat (limited to 'arch/powerpc/sysdev/xive/common.c')
| -rw-r--r-- | arch/powerpc/sysdev/xive/common.c | 1474 |
1 files changed, 1474 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c new file mode 100644 index 000000000..2aa9f3de2 --- /dev/null +++ b/arch/powerpc/sysdev/xive/common.c @@ -0,0 +1,1474 @@ +/* + * Copyright 2016,2017 IBM Corporation. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#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 <linux/vmalloc.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); + +/* 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 + */ +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 (unlikely(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) { + unmap_kernel_range((unsigned long)xd->eoi_mmio, + 1u << xd->esb_shift); + iounmap(xd->eoi_mmio); + if (xd->eoi_mmio == xd->trig_mmio) + xd->trig_mmio = NULL; + xd->eoi_mmio = NULL; + } + if (xd->trig_mmio) { + unmap_kernel_range((unsigned long)xd->trig_mmio, + 1u << xd->esb_shift); + 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); + + /* + * Turn OFF by default the interrupt being mapped. A side + * effect of this check is the mapping the ESB page of the + * interrupt in the Linux address space. This prevents page + * fault issues in the crash handler which masks all + * interrupts. + */ + xive_esb_read(xd, XIVE_ESB_SET_PQ_01); + + 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 != XIVE_BAD_IRQ) + 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 == XIVE_BAD_IRQ) + 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); + xc->hw_ipi = XIVE_BAD_IRQ; + + 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); |