// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2017 Thomas Gleixner <tglx@linutronix.de>
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#include <linux/spinlock.h>
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#include <linux/seq_file.h>
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#include <linux/bitmap.h>
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#include <linux/percpu.h>
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#include <linux/cpu.h>
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#include <linux/irq.h>
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#define IRQ_MATRIX_SIZE (BITS_TO_LONGS(IRQ_MATRIX_BITS))
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struct cpumap {
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unsigned int available;
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unsigned int allocated;
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unsigned int managed;
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unsigned int managed_allocated;
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bool initialized;
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bool online;
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unsigned long alloc_map[IRQ_MATRIX_SIZE];
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unsigned long managed_map[IRQ_MATRIX_SIZE];
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};
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struct irq_matrix {
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unsigned int matrix_bits;
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unsigned int alloc_start;
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unsigned int alloc_end;
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unsigned int alloc_size;
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unsigned int global_available;
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unsigned int global_reserved;
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unsigned int systembits_inalloc;
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unsigned int total_allocated;
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unsigned int online_maps;
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struct cpumap __percpu *maps;
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unsigned long scratch_map[IRQ_MATRIX_SIZE];
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unsigned long system_map[IRQ_MATRIX_SIZE];
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};
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#define CREATE_TRACE_POINTS
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#include <trace/events/irq_matrix.h>
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/**
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* irq_alloc_matrix - Allocate a irq_matrix structure and initialize it
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* @matrix_bits: Number of matrix bits must be <= IRQ_MATRIX_BITS
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* @alloc_start: From which bit the allocation search starts
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* @alloc_end: At which bit the allocation search ends, i.e first
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* invalid bit
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*/
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__init struct irq_matrix *irq_alloc_matrix(unsigned int matrix_bits,
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unsigned int alloc_start,
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unsigned int alloc_end)
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{
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struct irq_matrix *m;
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if (matrix_bits > IRQ_MATRIX_BITS)
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return NULL;
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m = kzalloc(sizeof(*m), GFP_KERNEL);
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if (!m)
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return NULL;
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m->matrix_bits = matrix_bits;
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m->alloc_start = alloc_start;
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m->alloc_end = alloc_end;
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m->alloc_size = alloc_end - alloc_start;
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m->maps = alloc_percpu(*m->maps);
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if (!m->maps) {
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kfree(m);
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return NULL;
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}
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return m;
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}
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/**
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* irq_matrix_online - Bring the local CPU matrix online
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* @m: Matrix pointer
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*/
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void irq_matrix_online(struct irq_matrix *m)
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{
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struct cpumap *cm = this_cpu_ptr(m->maps);
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BUG_ON(cm->online);
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if (!cm->initialized) {
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cm->available = m->alloc_size;
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cm->available -= cm->managed + m->systembits_inalloc;
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cm->initialized = true;
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}
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m->global_available += cm->available;
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cm->online = true;
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m->online_maps++;
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trace_irq_matrix_online(m);
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}
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/**
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* irq_matrix_offline - Bring the local CPU matrix offline
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* @m: Matrix pointer
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*/
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void irq_matrix_offline(struct irq_matrix *m)
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{
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struct cpumap *cm = this_cpu_ptr(m->maps);
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/* Update the global available size */
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m->global_available -= cm->available;
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cm->online = false;
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m->online_maps--;
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trace_irq_matrix_offline(m);
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}
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static unsigned int matrix_alloc_area(struct irq_matrix *m, struct cpumap *cm,
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unsigned int num, bool managed)
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{
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unsigned int area, start = m->alloc_start;
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unsigned int end = m->alloc_end;
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bitmap_or(m->scratch_map, cm->managed_map, m->system_map, end);
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bitmap_or(m->scratch_map, m->scratch_map, cm->alloc_map, end);
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area = bitmap_find_next_zero_area(m->scratch_map, end, start, num, 0);
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if (area >= end)
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return area;
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if (managed)
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bitmap_set(cm->managed_map, area, num);
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else
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bitmap_set(cm->alloc_map, area, num);
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return area;
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}
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/* Find the best CPU which has the lowest vector allocation count */
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static unsigned int matrix_find_best_cpu(struct irq_matrix *m,
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const struct cpumask *msk)
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{
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unsigned int cpu, best_cpu, maxavl = 0;
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struct cpumap *cm;
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best_cpu = UINT_MAX;
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for_each_cpu(cpu, msk) {
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cm = per_cpu_ptr(m->maps, cpu);
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if (!cm->online || cm->available <= maxavl)
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continue;
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best_cpu = cpu;
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maxavl = cm->available;
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}
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return best_cpu;
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}
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/* Find the best CPU which has the lowest number of managed IRQs allocated */
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static unsigned int matrix_find_best_cpu_managed(struct irq_matrix *m,
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const struct cpumask *msk)
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{
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unsigned int cpu, best_cpu, allocated = UINT_MAX;
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struct cpumap *cm;
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best_cpu = UINT_MAX;
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for_each_cpu(cpu, msk) {
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cm = per_cpu_ptr(m->maps, cpu);
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if (!cm->online || cm->managed_allocated > allocated)
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continue;
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best_cpu = cpu;
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allocated = cm->managed_allocated;
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}
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return best_cpu;
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}
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/**
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* irq_matrix_assign_system - Assign system wide entry in the matrix
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* @m: Matrix pointer
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* @bit: Which bit to reserve
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* @replace: Replace an already allocated vector with a system
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* vector at the same bit position.
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*
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* The BUG_ON()s below are on purpose. If this goes wrong in the
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* early boot process, then the chance to survive is about zero.
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* If this happens when the system is life, it's not much better.
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*/
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void irq_matrix_assign_system(struct irq_matrix *m, unsigned int bit,
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bool replace)
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{
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struct cpumap *cm = this_cpu_ptr(m->maps);
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BUG_ON(bit > m->matrix_bits);
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BUG_ON(m->online_maps > 1 || (m->online_maps && !replace));
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set_bit(bit, m->system_map);
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if (replace) {
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BUG_ON(!test_and_clear_bit(bit, cm->alloc_map));
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cm->allocated--;
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m->total_allocated--;
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}
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if (bit >= m->alloc_start && bit < m->alloc_end)
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m->systembits_inalloc++;
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trace_irq_matrix_assign_system(bit, m);
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}
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/**
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* irq_matrix_reserve_managed - Reserve a managed interrupt in a CPU map
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* @m: Matrix pointer
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* @msk: On which CPUs the bits should be reserved.
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*
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* Can be called for offline CPUs. Note, this will only reserve one bit
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* on all CPUs in @msk, but it's not guaranteed that the bits are at the
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* same offset on all CPUs
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*/
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int irq_matrix_reserve_managed(struct irq_matrix *m, const struct cpumask *msk)
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{
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unsigned int cpu, failed_cpu;
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for_each_cpu(cpu, msk) {
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struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
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unsigned int bit;
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bit = matrix_alloc_area(m, cm, 1, true);
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if (bit >= m->alloc_end)
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goto cleanup;
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cm->managed++;
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if (cm->online) {
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cm->available--;
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m->global_available--;
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}
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trace_irq_matrix_reserve_managed(bit, cpu, m, cm);
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}
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return 0;
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cleanup:
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failed_cpu = cpu;
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for_each_cpu(cpu, msk) {
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if (cpu == failed_cpu)
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break;
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irq_matrix_remove_managed(m, cpumask_of(cpu));
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}
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return -ENOSPC;
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}
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/**
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* irq_matrix_remove_managed - Remove managed interrupts in a CPU map
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* @m: Matrix pointer
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* @msk: On which CPUs the bits should be removed
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*
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* Can be called for offline CPUs
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*
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* This removes not allocated managed interrupts from the map. It does
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* not matter which one because the managed interrupts free their
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* allocation when they shut down. If not, the accounting is screwed,
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* but all what can be done at this point is warn about it.
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*/
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void irq_matrix_remove_managed(struct irq_matrix *m, const struct cpumask *msk)
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{
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unsigned int cpu;
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for_each_cpu(cpu, msk) {
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struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
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unsigned int bit, end = m->alloc_end;
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if (WARN_ON_ONCE(!cm->managed))
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continue;
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/* Get managed bit which are not allocated */
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bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
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bit = find_first_bit(m->scratch_map, end);
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if (WARN_ON_ONCE(bit >= end))
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continue;
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clear_bit(bit, cm->managed_map);
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cm->managed--;
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if (cm->online) {
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cm->available++;
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m->global_available++;
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}
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trace_irq_matrix_remove_managed(bit, cpu, m, cm);
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}
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}
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/**
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* irq_matrix_alloc_managed - Allocate a managed interrupt in a CPU map
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* @m: Matrix pointer
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* @cpu: On which CPU the interrupt should be allocated
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*/
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int irq_matrix_alloc_managed(struct irq_matrix *m, const struct cpumask *msk,
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unsigned int *mapped_cpu)
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{
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unsigned int bit, cpu, end = m->alloc_end;
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struct cpumap *cm;
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if (cpumask_empty(msk))
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return -EINVAL;
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cpu = matrix_find_best_cpu_managed(m, msk);
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if (cpu == UINT_MAX)
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return -ENOSPC;
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cm = per_cpu_ptr(m->maps, cpu);
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end = m->alloc_end;
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/* Get managed bit which are not allocated */
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bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
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bit = find_first_bit(m->scratch_map, end);
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if (bit >= end)
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return -ENOSPC;
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set_bit(bit, cm->alloc_map);
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cm->allocated++;
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cm->managed_allocated++;
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m->total_allocated++;
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*mapped_cpu = cpu;
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trace_irq_matrix_alloc_managed(bit, cpu, m, cm);
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return bit;
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}
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/**
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* irq_matrix_assign - Assign a preallocated interrupt in the local CPU map
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* @m: Matrix pointer
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* @bit: Which bit to mark
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*
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* This should only be used to mark preallocated vectors
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*/
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void irq_matrix_assign(struct irq_matrix *m, unsigned int bit)
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{
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struct cpumap *cm = this_cpu_ptr(m->maps);
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if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
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return;
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if (WARN_ON_ONCE(test_and_set_bit(bit, cm->alloc_map)))
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return;
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cm->allocated++;
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m->total_allocated++;
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cm->available--;
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m->global_available--;
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trace_irq_matrix_assign(bit, smp_processor_id(), m, cm);
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}
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/**
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* irq_matrix_reserve - Reserve interrupts
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* @m: Matrix pointer
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*
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* This is merily a book keeping call. It increments the number of globally
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* reserved interrupt bits w/o actually allocating them. This allows to
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* setup interrupt descriptors w/o assigning low level resources to it.
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* The actual allocation happens when the interrupt gets activated.
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*/
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void irq_matrix_reserve(struct irq_matrix *m)
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{
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if (m->global_reserved <= m->global_available &&
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m->global_reserved + 1 > m->global_available)
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pr_warn("Interrupt reservation exceeds available resources\n");
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m->global_reserved++;
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trace_irq_matrix_reserve(m);
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}
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/**
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* irq_matrix_remove_reserved - Remove interrupt reservation
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* @m: Matrix pointer
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*
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* This is merily a book keeping call. It decrements the number of globally
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* reserved interrupt bits. This is used to undo irq_matrix_reserve() when the
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* interrupt was never in use and a real vector allocated, which undid the
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* reservation.
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*/
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void irq_matrix_remove_reserved(struct irq_matrix *m)
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{
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m->global_reserved--;
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trace_irq_matrix_remove_reserved(m);
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}
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/**
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* irq_matrix_alloc - Allocate a regular interrupt in a CPU map
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* @m: Matrix pointer
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* @msk: Which CPUs to search in
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* @reserved: Allocate previously reserved interrupts
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* @mapped_cpu: Pointer to store the CPU for which the irq was allocated
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*/
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int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
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bool reserved, unsigned int *mapped_cpu)
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{
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unsigned int cpu, bit;
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struct cpumap *cm;
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/*
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* Not required in theory, but matrix_find_best_cpu() uses
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* for_each_cpu() which ignores the cpumask on UP .
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*/
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if (cpumask_empty(msk))
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return -EINVAL;
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cpu = matrix_find_best_cpu(m, msk);
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if (cpu == UINT_MAX)
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return -ENOSPC;
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cm = per_cpu_ptr(m->maps, cpu);
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bit = matrix_alloc_area(m, cm, 1, false);
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if (bit >= m->alloc_end)
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return -ENOSPC;
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cm->allocated++;
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cm->available--;
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m->total_allocated++;
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m->global_available--;
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if (reserved)
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m->global_reserved--;
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*mapped_cpu = cpu;
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trace_irq_matrix_alloc(bit, cpu, m, cm);
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return bit;
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}
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/**
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* irq_matrix_free - Free allocated interrupt in the matrix
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* @m: Matrix pointer
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* @cpu: Which CPU map needs be updated
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* @bit: The bit to remove
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* @managed: If true, the interrupt is managed and not accounted
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* as available.
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*/
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void irq_matrix_free(struct irq_matrix *m, unsigned int cpu,
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unsigned int bit, bool managed)
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{
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struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
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if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
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return;
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if (WARN_ON_ONCE(!test_and_clear_bit(bit, cm->alloc_map)))
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return;
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cm->allocated--;
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if(managed)
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cm->managed_allocated--;
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if (cm->online)
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m->total_allocated--;
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if (!managed) {
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cm->available++;
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if (cm->online)
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m->global_available++;
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}
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trace_irq_matrix_free(bit, cpu, m, cm);
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}
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/**
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* irq_matrix_available - Get the number of globally available irqs
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* @m: Pointer to the matrix to query
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* @cpudown: If true, the local CPU is about to go down, adjust
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* the number of available irqs accordingly
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*/
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unsigned int irq_matrix_available(struct irq_matrix *m, bool cpudown)
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{
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struct cpumap *cm = this_cpu_ptr(m->maps);
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if (!cpudown)
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return m->global_available;
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return m->global_available - cm->available;
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}
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/**
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* irq_matrix_reserved - Get the number of globally reserved irqs
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* @m: Pointer to the matrix to query
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*/
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unsigned int irq_matrix_reserved(struct irq_matrix *m)
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{
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return m->global_reserved;
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}
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/**
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* irq_matrix_allocated - Get the number of allocated irqs on the local cpu
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* @m: Pointer to the matrix to search
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*
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* This returns number of allocated irqs
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*/
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unsigned int irq_matrix_allocated(struct irq_matrix *m)
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{
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struct cpumap *cm = this_cpu_ptr(m->maps);
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return cm->allocated;
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}
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#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
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/**
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* irq_matrix_debug_show - Show detailed allocation information
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* @sf: Pointer to the seq_file to print to
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* @m: Pointer to the matrix allocator
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* @ind: Indentation for the print format
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*
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* Note, this is a lockless snapshot.
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*/
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void irq_matrix_debug_show(struct seq_file *sf, struct irq_matrix *m, int ind)
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{
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unsigned int nsys = bitmap_weight(m->system_map, m->matrix_bits);
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int cpu;
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seq_printf(sf, "Online bitmaps: %6u\n", m->online_maps);
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seq_printf(sf, "Global available: %6u\n", m->global_available);
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seq_printf(sf, "Global reserved: %6u\n", m->global_reserved);
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seq_printf(sf, "Total allocated: %6u\n", m->total_allocated);
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seq_printf(sf, "System: %u: %*pbl\n", nsys, m->matrix_bits,
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m->system_map);
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seq_printf(sf, "%*s| CPU | avl | man | mac | act | vectors\n", ind, " ");
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cpus_read_lock();
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for_each_online_cpu(cpu) {
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struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
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seq_printf(sf, "%*s %4d %4u %4u %4u %4u %*pbl\n", ind, " ",
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cpu, cm->available, cm->managed,
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cm->managed_allocated, cm->allocated,
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m->matrix_bits, cm->alloc_map);
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}
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cpus_read_unlock();
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}
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#endif
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