[PATCH v4 5/6] irqchip: Add Loongson PCH MSI controller

Jiaxun Yang
2020-05-16T08:30:03Z

This controller appears on Loongson LS7A family of PCH to transform
interrupts from PCI MSI into HyperTransport vectorized interrrupts
and send them to procrssor's HT vector controller.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
--
v2:
- Style clean-ups
- Add ack callback
- Use bitmap_find_free_region
v3:
- Style clean-ups
- mutex lock instead of spin lock
- correct bitmap usage
v4:
- Fix table layout
- Make mask parent symetric
---
drivers/irqchip/Kconfig | 10 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-loongson-pch-msi.c | 255 +++++++++++++++++++++++++
3 files changed, 266 insertions(+)
create mode 100644 drivers/irqchip/irq-loongson-pch-msi.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 5524a621638c..0b6b826dd843 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -549,4 +549,14 @@ config LOONGSON_PCH_PIC
help
Support for the Loongson PCH PIC Controller.

+config LOONGSON_PCH_MSI
+ bool "Loongson PCH PIC Controller"
+ depends on MACH_LOONGSON64 || COMPILE_TEST
+ depends on PCI
+ default MACH_LOONGSON64
+ select IRQ_DOMAIN_HIERARCHY
+ select PCI_MSI
+ help
+ Support for the Loongson PCH MSI Controller.
+
endmenu
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index acc72331cec8..3a4ce283189a 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -109,3 +109,4 @@ obj-$(CONFIG_LOONGSON_LIOINTC) += irq-loongson-liointc.o
obj-$(CONFIG_LOONGSON_HTPIC) += irq-loongson-htpic.o
obj-$(CONFIG_LOONGSON_HTVEC) += irq-loongson-htvec.o
obj-$(CONFIG_LOONGSON_PCH_PIC) += irq-loongson-pch-pic.o
+obj-$(CONFIG_LOONGSON_PCH_MSI) += irq-loongson-pch-msi.o
diff --git a/drivers/irqchip/irq-loongson-pch-msi.c b/drivers/irqchip/irq-loongson-pch-msi.c
new file mode 100644
index 000000000000..50becd21008c
--- /dev/null
+++ b/drivers/irqchip/irq-loongson-pch-msi.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
+ * Loongson PCH MSI support
+ */
+
+#define pr_fmt(fmt) "pch-msi: " fmt
+
+#include <linux/irqchip.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>
+
+struct pch_msi_data {
+ struct mutex msi_map_lock;
+ phys_addr_t doorbell;
+ u32 irq_first; /* The vector number that MSIs starts */
+ u32 num_irqs; /* The number of vectors for MSIs */
+ unsigned long *msi_map;
+};
+
+static void pch_msi_mask_msi_irq(struct irq_data *d)
+{
+ pci_msi_mask_irq(d);
+ irq_chip_mask_parent(d);
+}
+
+static void pch_msi_unmask_msi_irq(struct irq_data *d)
+{
+ irq_chip_unmask_parent(d);
+ pci_msi_unmask_irq(d);
+}
+
+static struct irq_chip pch_msi_irq_chip = {
+ .name = "PCH PCI MSI",
+ .irq_mask = pch_msi_mask_msi_irq,
+ .irq_unmask = pch_msi_unmask_msi_irq,
+ .irq_ack = irq_chip_ack_parent,
+ .irq_set_affinity = irq_chip_set_affinity_parent,
+};
+
+static int pch_msi_allocate_hwirq(struct pch_msi_data *priv, int num_req)
+{
+ int first;
+
+ mutex_lock(&priv->msi_map_lock);
+
+ first = bitmap_find_free_region(priv->msi_map, priv->num_irqs,
+ get_count_order(num_req));
+ if (first < 0) {
+ mutex_unlock(&priv->msi_map_lock);
+ return -ENOSPC;
+ }
+
+ mutex_unlock(&priv->msi_map_lock);
+
+ return priv->irq_first + first;
+}
+
+static void pch_msi_free_hwirq(struct pch_msi_data *priv,
+ int hwirq, int num_req)
+{
+ int first = hwirq - priv->irq_first;
+
+ mutex_lock(&priv->msi_map_lock);
+ bitmap_release_region(priv->msi_map, first, get_count_order(num_req));
+ mutex_unlock(&priv->msi_map_lock);
+}
+
+static void pch_msi_compose_msi_msg(struct irq_data *data,
+ struct msi_msg *msg)
+{
+ struct pch_msi_data *priv = irq_data_get_irq_chip_data(data);
+
+ msg->address_hi = upper_32_bits(priv->doorbell);
+ msg->address_lo = lower_32_bits(priv->doorbell);
+ msg->data = data->hwirq;
+}
+
+static struct msi_domain_info pch_msi_domain_info = {
+ .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX,
+ .chip = &pch_msi_irq_chip,
+};
+
+static struct irq_chip middle_irq_chip = {
+ .name = "PCH MSI",
+ .irq_mask = irq_chip_mask_parent,
+ .irq_unmask = irq_chip_unmask_parent,
+ .irq_ack = irq_chip_ack_parent,
+ .irq_set_affinity = irq_chip_set_affinity_parent,
+ .irq_compose_msi_msg = pch_msi_compose_msi_msg,
+};
+
+static int pch_msi_parent_domain_alloc(struct irq_domain *domain,
+ unsigned int virq, int hwirq)
+{
+ struct irq_fwspec fwspec;
+ int ret;
+
+ fwspec.fwnode = domain->parent->fwnode;
+ fwspec.param_count = 1;
+ fwspec.param[0] = hwirq;
+
+ ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int pch_msi_middle_domain_alloc(struct irq_domain *domain,
+ unsigned int virq,
+ unsigned int nr_irqs, void *args)
+{
+ struct pch_msi_data *priv = domain->host_data;
+ int hwirq, err, i;
+
+ hwirq = pch_msi_allocate_hwirq(priv, nr_irqs);
+ if (hwirq < 0)
+ return hwirq;
+
+ for (i = 0; i < nr_irqs; i++) {
+ err = pch_msi_parent_domain_alloc(domain, virq + i, hwirq + i);
+ if (err)
+ goto err_hwirq;
+
+ irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+ &middle_irq_chip, priv);
+ }
+
+ return 0;
+
+err_hwirq:
+ pch_msi_free_hwirq(priv, hwirq, nr_irqs);
+ irq_domain_free_irqs_parent(domain, virq, i - 1);
+
+ return err;
+}
+
+static void pch_msi_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 pch_msi_data *priv = irq_data_get_irq_chip_data(d);
+
+ irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+ pch_msi_free_hwirq(priv, d->hwirq, nr_irqs);
+}
+
+static const struct irq_domain_ops pch_msi_middle_domain_ops = {
+ .alloc = pch_msi_middle_domain_alloc,
+ .free = pch_msi_middle_domain_free,
+};
+
+static int pch_msi_init_domains(struct pch_msi_data *priv,
+ struct device_node *node,
+ struct irq_domain *parent)
+{
+ struct irq_domain *middle_domain, *msi_domain;
+
+ middle_domain = irq_domain_create_linear(of_node_to_fwnode(node),
+ priv->num_irqs,
+ &pch_msi_middle_domain_ops,
+ priv);
+ if (!middle_domain) {
+ pr_err("Failed to create the MSI middle domain\n");
+ return -ENOMEM;
+ }
+
+ middle_domain->parent = parent;
+ irq_domain_update_bus_token(middle_domain, DOMAIN_BUS_NEXUS);
+
+ msi_domain = pci_msi_create_irq_domain(of_node_to_fwnode(node),
+ &pch_msi_domain_info,
+ middle_domain);
+ if (!msi_domain) {
+ pr_err("Failed to create PCI MSI domain\n");
+ irq_domain_remove(middle_domain);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int pch_msi_init(struct device_node *node,
+ struct device_node *parent)
+{
+ struct pch_msi_data *priv;
+ struct irq_domain *parent_domain;
+ struct resource res;
+ int ret;
+
+ parent_domain = irq_find_host(parent);
+ if (!parent_domain) {
+ pr_err("Failed to find the parent domain\n");
+ return -ENXIO;
+ }
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ mutex_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->doorbell = res.start;
+
+ if (of_property_read_u32(node, "loongson,msi-base-vec",
+ &priv->irq_first)) {
+ pr_err("Unable to parse MSI vec base\n");
+ ret = -EINVAL;
+ goto err_priv;
+ }
+
+ if (of_property_read_u32(node, "loongson,msi-num-vecs",
+ &priv->num_irqs)) {
+ pr_err("Unable to parse MSI vec number\n");
+ ret = -EINVAL;
+ goto err_priv;
+ }
+
+ priv->msi_map = bitmap_alloc(priv->num_irqs, GFP_KERNEL);
+ if (!priv->msi_map) {
+ ret = -ENOMEM;
+ goto err_priv;
+ }
+
+ pr_debug("Registering %d MSIs, starting at %d\n",
+ priv->num_irqs, priv->irq_first);
+
+ ret = pch_msi_init_domains(priv, node, parent_domain);
+ if (ret)
+ goto err_map;
+
+ return 0;
+
+err_map:
+ kfree(priv->msi_map);
+err_priv:
+ kfree(priv);
+ return ret;
+}
+
+IRQCHIP_DECLARE(pch_msi, "loongson,pch-msi-1.0", pch_msi_init);
--
2.26.2