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-rw-r--r--kernel/irq/ipi.c326
1 files changed, 326 insertions, 0 deletions
diff --git a/kernel/irq/ipi.c b/kernel/irq/ipi.c
new file mode 100644
index 000000000000..c37f34b00a11
--- /dev/null
+++ b/kernel/irq/ipi.c
@@ -0,0 +1,326 @@
+/*
+ * linux/kernel/irq/ipi.c
+ *
+ * Copyright (C) 2015 Imagination Technologies Ltd
+ * Author: Qais Yousef <qais.yousef@imgtec.com>
+ *
+ * This file contains driver APIs to the IPI subsystem.
+ */
+
+#define pr_fmt(fmt) "genirq/ipi: " fmt
+
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+
+/**
+ * irq_reserve_ipi() - Setup an IPI to destination cpumask
+ * @domain: IPI domain
+ * @dest: cpumask of cpus which can receive the IPI
+ *
+ * Allocate a virq that can be used to send IPI to any CPU in dest mask.
+ *
+ * On success it'll return linux irq number and 0 on failure
+ */
+unsigned int irq_reserve_ipi(struct irq_domain *domain,
+ const struct cpumask *dest)
+{
+ unsigned int nr_irqs, offset;
+ struct irq_data *data;
+ int virq, i;
+
+ if (!domain ||!irq_domain_is_ipi(domain)) {
+ pr_warn("Reservation on a non IPI domain\n");
+ return 0;
+ }
+
+ if (!cpumask_subset(dest, cpu_possible_mask)) {
+ pr_warn("Reservation is not in possible_cpu_mask\n");
+ return 0;
+ }
+
+ nr_irqs = cpumask_weight(dest);
+ if (!nr_irqs) {
+ pr_warn("Reservation for empty destination mask\n");
+ return 0;
+ }
+
+ if (irq_domain_is_ipi_single(domain)) {
+ /*
+ * If the underlying implementation uses a single HW irq on
+ * all cpus then we only need a single Linux irq number for
+ * it. We have no restrictions vs. the destination mask. The
+ * underlying implementation can deal with holes nicely.
+ */
+ nr_irqs = 1;
+ offset = 0;
+ } else {
+ unsigned int next;
+
+ /*
+ * The IPI requires a seperate HW irq on each CPU. We require
+ * that the destination mask is consecutive. If an
+ * implementation needs to support holes, it can reserve
+ * several IPI ranges.
+ */
+ offset = cpumask_first(dest);
+ /*
+ * Find a hole and if found look for another set bit after the
+ * hole. For now we don't support this scenario.
+ */
+ next = cpumask_next_zero(offset, dest);
+ if (next < nr_cpu_ids)
+ next = cpumask_next(next, dest);
+ if (next < nr_cpu_ids) {
+ pr_warn("Destination mask has holes\n");
+ return 0;
+ }
+ }
+
+ virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE);
+ if (virq <= 0) {
+ pr_warn("Can't reserve IPI, failed to alloc descs\n");
+ return 0;
+ }
+
+ virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
+ (void *) dest, true);
+
+ if (virq <= 0) {
+ pr_warn("Can't reserve IPI, failed to alloc hw irqs\n");
+ goto free_descs;
+ }
+
+ for (i = 0; i < nr_irqs; i++) {
+ data = irq_get_irq_data(virq + i);
+ cpumask_copy(data->common->affinity, dest);
+ data->common->ipi_offset = offset;
+ }
+ return virq;
+
+free_descs:
+ irq_free_descs(virq, nr_irqs);
+ return 0;
+}
+
+/**
+ * irq_destroy_ipi() - unreserve an IPI that was previously allocated
+ * @irq: linux irq number to be destroyed
+ *
+ * Return the IPIs allocated with irq_reserve_ipi() to the system destroying
+ * all virqs associated with them.
+ */
+void irq_destroy_ipi(unsigned int irq)
+{
+ struct irq_data *data = irq_get_irq_data(irq);
+ struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL;
+ struct irq_domain *domain;
+ unsigned int nr_irqs;
+
+ if (!irq || !data || !ipimask)
+ return;
+
+ domain = data->domain;
+ if (WARN_ON(domain == NULL))
+ return;
+
+ if (!irq_domain_is_ipi(domain)) {
+ pr_warn("Trying to destroy a non IPI domain!\n");
+ return;
+ }
+
+ if (irq_domain_is_ipi_per_cpu(domain))
+ nr_irqs = cpumask_weight(ipimask);
+ else
+ nr_irqs = 1;
+
+ irq_domain_free_irqs(irq, nr_irqs);
+}
+
+/**
+ * ipi_get_hwirq - Get the hwirq associated with an IPI to a cpu
+ * @irq: linux irq number
+ * @cpu: the target cpu
+ *
+ * When dealing with coprocessors IPI, we need to inform the coprocessor of
+ * the hwirq it needs to use to receive and send IPIs.
+ *
+ * Returns hwirq value on success and INVALID_HWIRQ on failure.
+ */
+irq_hw_number_t ipi_get_hwirq(unsigned int irq, unsigned int cpu)
+{
+ struct irq_data *data = irq_get_irq_data(irq);
+ struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL;
+
+ if (!data || !ipimask || cpu > nr_cpu_ids)
+ return INVALID_HWIRQ;
+
+ if (!cpumask_test_cpu(cpu, ipimask))
+ return INVALID_HWIRQ;
+
+ /*
+ * Get the real hardware irq number if the underlying implementation
+ * uses a seperate irq per cpu. If the underlying implementation uses
+ * a single hardware irq for all cpus then the IPI send mechanism
+ * needs to take care of the cpu destinations.
+ */
+ if (irq_domain_is_ipi_per_cpu(data->domain))
+ data = irq_get_irq_data(irq + cpu - data->common->ipi_offset);
+
+ return data ? irqd_to_hwirq(data) : INVALID_HWIRQ;
+}
+EXPORT_SYMBOL_GPL(ipi_get_hwirq);
+
+static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data,
+ const struct cpumask *dest, unsigned int cpu)
+{
+ struct cpumask *ipimask = irq_data_get_affinity_mask(data);
+
+ if (!chip || !ipimask)
+ return -EINVAL;
+
+ if (!chip->ipi_send_single && !chip->ipi_send_mask)
+ return -EINVAL;
+
+ if (cpu > nr_cpu_ids)
+ return -EINVAL;
+
+ if (dest) {
+ if (!cpumask_subset(dest, ipimask))
+ return -EINVAL;
+ } else {
+ if (!cpumask_test_cpu(cpu, ipimask))
+ return -EINVAL;
+ }
+ return 0;
+}
+
+/**
+ * __ipi_send_single - send an IPI to a target Linux SMP CPU
+ * @desc: pointer to irq_desc of the IRQ
+ * @cpu: destination CPU, must in the destination mask passed to
+ * irq_reserve_ipi()
+ *
+ * This function is for architecture or core code to speed up IPI sending. Not
+ * usable from driver code.
+ *
+ * Returns zero on success and negative error number on failure.
+ */
+int __ipi_send_single(struct irq_desc *desc, unsigned int cpu)
+{
+ struct irq_data *data = irq_desc_get_irq_data(desc);
+ struct irq_chip *chip = irq_data_get_irq_chip(data);
+
+#ifdef DEBUG
+ /*
+ * Minimise the overhead by omitting the checks for Linux SMP IPIs.
+ * Since the callers should be arch or core code which is generally
+ * trusted, only check for errors when debugging.
+ */
+ if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu)))
+ return -EINVAL;
+#endif
+ if (!chip->ipi_send_single) {
+ chip->ipi_send_mask(data, cpumask_of(cpu));
+ return 0;
+ }
+
+ /* FIXME: Store this information in irqdata flags */
+ if (irq_domain_is_ipi_per_cpu(data->domain) &&
+ cpu != data->common->ipi_offset) {
+ /* use the correct data for that cpu */
+ unsigned irq = data->irq + cpu - data->common->ipi_offset;
+
+ data = irq_get_irq_data(irq);
+ }
+ chip->ipi_send_single(data, cpu);
+ return 0;
+}
+
+/**
+ * ipi_send_mask - send an IPI to target Linux SMP CPU(s)
+ * @desc: pointer to irq_desc of the IRQ
+ * @dest: dest CPU(s), must be a subset of the mask passed to
+ * irq_reserve_ipi()
+ *
+ * This function is for architecture or core code to speed up IPI sending. Not
+ * usable from driver code.
+ *
+ * Returns zero on success and negative error number on failure.
+ */
+int __ipi_send_mask(struct irq_desc *desc, const struct cpumask *dest)
+{
+ struct irq_data *data = irq_desc_get_irq_data(desc);
+ struct irq_chip *chip = irq_data_get_irq_chip(data);
+ unsigned int cpu;
+
+#ifdef DEBUG
+ /*
+ * Minimise the overhead by omitting the checks for Linux SMP IPIs.
+ * Since the callers should be arch or core code which is generally
+ * trusted, only check for errors when debugging.
+ */
+ if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0)))
+ return -EINVAL;
+#endif
+ if (chip->ipi_send_mask) {
+ chip->ipi_send_mask(data, dest);
+ return 0;
+ }
+
+ if (irq_domain_is_ipi_per_cpu(data->domain)) {
+ unsigned int base = data->irq;
+
+ for_each_cpu(cpu, dest) {
+ unsigned irq = base + cpu - data->common->ipi_offset;
+
+ data = irq_get_irq_data(irq);
+ chip->ipi_send_single(data, cpu);
+ }
+ } else {
+ for_each_cpu(cpu, dest)
+ chip->ipi_send_single(data, cpu);
+ }
+ return 0;
+}
+
+/**
+ * ipi_send_single - Send an IPI to a single CPU
+ * @virq: linux irq number from irq_reserve_ipi()
+ * @cpu: destination CPU, must in the destination mask passed to
+ * irq_reserve_ipi()
+ *
+ * Returns zero on success and negative error number on failure.
+ */
+int ipi_send_single(unsigned int virq, unsigned int cpu)
+{
+ struct irq_desc *desc = irq_to_desc(virq);
+ struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL;
+ struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL;
+
+ if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu)))
+ return -EINVAL;
+
+ return __ipi_send_single(desc, cpu);
+}
+EXPORT_SYMBOL_GPL(ipi_send_single);
+
+/**
+ * ipi_send_mask - Send an IPI to target CPU(s)
+ * @virq: linux irq number from irq_reserve_ipi()
+ * @dest: dest CPU(s), must be a subset of the mask passed to
+ * irq_reserve_ipi()
+ *
+ * Returns zero on success and negative error number on failure.
+ */
+int ipi_send_mask(unsigned int virq, const struct cpumask *dest)
+{
+ struct irq_desc *desc = irq_to_desc(virq);
+ struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL;
+ struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL;
+
+ if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0)))
+ return -EINVAL;
+
+ return __ipi_send_mask(desc, dest);
+}
+EXPORT_SYMBOL_GPL(ipi_send_mask);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-11 15:02:14 +0100