[PATCH 1/6] irqchip: add the Alpine MSIX interrupt controller

Antoine Tenart
2016-02-08T09:16:06Z

This patch adds the Alpine MSIX interrupt controller driver.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Tsahee Zidenberg <tsahee@annapurnalabs.com>
---
drivers/irqchip/Kconfig | 6 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-alpine-msi.c | 297 +++++++++++++++++++++++++++++++++++++++
3 files changed, 304 insertions(+)
create mode 100644 drivers/irqchip/irq-alpine-msi.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 715923d5236c..f20e5b28eb5f 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -60,6 +60,12 @@ config ARM_VIC_NR
The maximum number of VICs available in the system, for
power management.

+config ALPINE_MSI
+ bool
+ depends on PCI && PCI_MSI
+ select GENERIC_IRQ_CHIP
+ select PCI_MSI_IRQ_DOMAIN
+
config ATMEL_AIC_IRQ
bool
select GENERIC_IRQ_CHIP
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 18caacb60d58..57f68e0eea74 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -1,5 +1,6 @@
obj-$(CONFIG_IRQCHIP) += irqchip.o

+obj-$(CONFIG_ALPINE_MSI) += irq-alpine-msi.o
obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2835.o
obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2836.o
obj-$(CONFIG_ARCH_EXYNOS) += exynos-combiner.o
diff --git a/drivers/irqchip/irq-alpine-msi.c b/drivers/irqchip/irq-alpine-msi.c
new file mode 100644
index 000000000000..435dd4ab3626
--- /dev/null
+++ b/drivers/irqchip/irq-alpine-msi.c
@@ -0,0 +1,297 @@
+/*
+ * Annapurna Labs MSIX support services
+ *
+ * Copyright (C) 2016, Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Antoine Tenart <antoine.tenart@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/irqchip.h>
+#include <linux/irqchip/arm-gic.h>
+#include <linux/msi.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+
+#include <asm/irq.h>
+#include <asm-generic/msi.h>
+
+/* MSIX message address format: local GIC target */
+#define ALPINE_MSIX_SPI_TARGET_CLUSTER0 BIT(16)
+
+struct alpine_msix_data {
+ spinlock_t msi_map_lock;
+ u32 addr_high;
+ u32 addr_low;
+ u32 spi_first; /* The SGI number that MSIs start */
+ u32 num_spis; /* The number of SGIs for MSIs */
+ unsigned long *msi_map;
+};
+
+static void alpine_msix_mask_msi_irq(struct irq_data *d)
+{
+ pci_msi_mask_irq(d);
+ irq_chip_mask_parent(d);
+}
+
+static void alpine_msix_unmask_msi_irq(struct irq_data *d)
+{
+ pci_msi_unmask_irq(d);
+ irq_chip_unmask_parent(d);
+}
+
+static int alpine_msix_set_affinity(struct irq_data *irq_data,
+ const struct cpumask *mask, bool force)
+{
+ int ret;
+
+ ret = irq_chip_set_affinity_parent(irq_data, mask, force);
+ return ret == IRQ_SET_MASK_OK ? IRQ_SET_MASK_OK_DONE : ret;
+}
+
+static struct irq_chip alpine_msix_irq_chip = {
+ .name = "MSIx",
+ .irq_mask = alpine_msix_mask_msi_irq,
+ .irq_unmask = alpine_msix_unmask_msi_irq,
+ .irq_eoi = irq_chip_eoi_parent,
+ .irq_set_affinity = alpine_msix_set_affinity,
+};
+
+static int alpine_msix_allocate_sgi(struct alpine_msix_data *priv, int num_req)
+{
+ int first, i;
+
+ spin_lock(&priv->msi_map_lock);
+
+ first = bitmap_find_next_zero_area(priv->msi_map, priv->num_spis, 0,
+ num_req, 0);
+ if (first >= priv->num_spis) {
+ spin_unlock(&priv->msi_map_lock);
+ return -ENOSPC;
+ }
+
+ for (i = 0; i < num_req; i++)
+ set_bit(first + i, priv->msi_map);
+
+ spin_unlock(&priv->msi_map_lock);
+
+ return priv->spi_first + first;
+}
+
+static void alpine_msix_free_sgi(struct alpine_msix_data *priv, unsigned sgi,
+ int num_req)
+{
+ int i, first;
+
+ first = sgi - priv->spi_first;
+
+ spin_lock(&priv->msi_map_lock);
+
+ for (i = 0; i < num_req; i++)
+ clear_bit(first + i, priv->msi_map);
+
+ spin_unlock(&priv->msi_map_lock);
+}
+
+static void alpine_msix_compose_msi_msg(struct irq_data *data,
+ struct msi_msg *msg)
+{
+ struct alpine_msix_data *priv = irq_data_get_irq_chip_data(data);
+
+ msg->address_hi = priv->addr_high;
+ msg->address_lo = priv->addr_low + (data->hwirq << 3);
+ msg->data = 0;
+}
+
+static struct msi_domain_info alpine_msix_domain_info = {
+ .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_PCI_MSIX,
+ .chip = &alpine_msix_irq_chip,
+};
+
+static struct irq_chip middle_irq_chip = {
+ .name = "alpine_msix_middle",
+ .irq_mask = irq_chip_mask_parent,
+ .irq_unmask = irq_chip_unmask_parent,
+ .irq_eoi = irq_chip_eoi_parent,
+ .irq_set_affinity = irq_chip_set_affinity_parent,
+ .irq_compose_msi_msg = alpine_msix_compose_msi_msg,
+};
+
+static int alpine_msix_gic_domain_alloc(struct irq_domain *domain,
+ unsigned int virq, int sgi)
+{
+ struct irq_fwspec fwspec;
+ struct irq_data *d;
+ int ret;
+
+ if (!is_of_node(domain->parent->fwnode))
+ return -EINVAL;
+
+ fwspec.fwnode = domain->parent->fwnode;
+ fwspec.param_count = 3;
+ fwspec.param[0] = 0;
+ fwspec.param[1] = sgi;
+ fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+
+ ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+ if (ret)
+ return ret;
+
+ d = irq_domain_get_irq_data(domain->parent, virq);
+ d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
+
+ return 0;
+}
+
+static int alpine_msix_middle_domain_alloc(struct irq_domain *domain,
+ unsigned int virq,
+ unsigned int nr_irqs, void *args)
+{
+ struct alpine_msix_data *priv = domain->host_data;
+ int sgi, err, i;
+
+ sgi = alpine_msix_allocate_sgi(priv, nr_irqs);
+ if (sgi < 0)
+ return sgi;
+
+ for (i = 0; i < nr_irqs; i++) {
+ err = alpine_msix_gic_domain_alloc(domain, virq + i, sgi + i);
+ if (err)
+ goto err_sgi;
+
+ irq_domain_set_hwirq_and_chip(domain, virq + i, sgi + i,
+ &middle_irq_chip, priv);
+ }
+
+ return 0;
+
+err_sgi:
+ while (--i >= 0)
+ irq_domain_free_irqs_parent(domain, virq, i);
+ alpine_msix_free_sgi(priv, sgi, nr_irqs);
+ return err;
+}
+
+static void alpine_msix_middle_domain_free(struct irq_domain *domain,
+ unsigned int virq,
+ unsigned int nr_irqs)
+{
+ struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+ struct alpine_msix_data *priv = irq_data_get_irq_chip_data(d);
+
+ irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+ alpine_msix_free_sgi(priv, d->hwirq, nr_irqs);
+}
+
+static const struct irq_domain_ops alpine_msix_middle_domain_ops = {
+ .alloc = alpine_msix_middle_domain_alloc,
+ .free = alpine_msix_middle_domain_free,
+};
+
+static int alpine_msix_init_domains(struct alpine_msix_data *priv,
+ struct device_node *node)
+{
+ struct irq_domain *middle_domain, *msi_domain, *gic_domain;
+ struct device_node *gic_node;
+
+ gic_node = of_irq_find_parent(node);
+ if (!gic_node) {
+ pr_err("Failed to find the GIC node\n");
+ return -ENODEV;
+ }
+
+ gic_domain = irq_find_host(gic_node);
+ if (!gic_domain) {
+ pr_err("Failed to find the GIC domain\n");
+ return -ENXIO;
+ }
+
+ middle_domain = irq_domain_add_tree(NULL,
+ &alpine_msix_middle_domain_ops,
+ priv);
+ if (!middle_domain) {
+ pr_err("Failed to create the MSIX middle domain\n");
+ return -ENOMEM;
+ }
+
+ middle_domain->parent = gic_domain;
+
+ msi_domain = pci_msi_create_irq_domain(of_node_to_fwnode(node),
+ &alpine_msix_domain_info,
+ middle_domain);
+ if (!msi_domain) {
+ pr_err("Failed to create MSI domain\n");
+ irq_domain_remove(msi_domain);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int alpine_msix_init(struct device_node *node,
+ struct device_node *parent)
+{
+ struct alpine_msix_data *priv;
+ struct resource res;
+ int ret;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ spin_lock_init(&priv->msi_map_lock);
+
+ ret = of_address_to_resource(node, 0, &res);
+ if (ret) {
+ pr_err("Failed to allocate resource\n");
+ goto err_priv;
+ }
+
+ priv->addr_high = upper_32_bits((u64)res.start);
+ priv->addr_low = lower_32_bits(res.start) + ALPINE_MSIX_SPI_TARGET_CLUSTER0;
+
+ if (of_property_read_u32(node, "al,msi-base-spi", &priv->spi_first)) {
+ pr_err("Unable to parse MSI base\n");
+ ret = -EINVAL;
+ goto err_priv;
+ }
+
+ if (of_property_read_u32(node, "al,msi-num-spis", &priv->num_spis)) {
+ pr_err("Unable to parse MSI numbers\n");
+ ret = -EINVAL;
+ goto err_priv;
+ }
+
+ priv->msi_map = kzalloc(sizeof(*priv->msi_map) * BITS_TO_LONGS(priv->num_spis),
+ GFP_KERNEL);
+ if (!priv->msi_map) {
+ ret = -ENOMEM;
+ goto err_priv;
+ }
+
+ pr_debug("Registering %d msixs, starting at %d\n",
+ priv->num_spis, priv->spi_first);
+
+ ret = alpine_msix_init_domains(priv, node);
+ if (ret)
+ goto err_map;
+
+ return 0;
+
+err_map:
+ kfree(priv->msi_map);
+err_priv:
+ kfree(priv);
+ return ret;
+}
+IRQCHIP_DECLARE(alpine_msix, "al,alpine-msix", alpine_msix_init);
--
2.7.0