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Subject[PATCH v2 3/5] virtio-mmio: create a generic MSI irq domain
Date
From: Liu Jiang <gerry@linux.alibaba.com>

Create a generic irq domain for all architectures which
supports virtio-mmio. The device offering VIRTIO_F_MMIO_MSI
feature bit can use this irq domain.

Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>
Co-developed-by: Zha Bin <zhabin@linux.alibaba.com>
Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
Co-developed-by: Jing Liu <jing2.liu@linux.intel.com>
Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>
Co-developed-by: Chao Peng <chao.p.peng@linux.intel.com>
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
---
drivers/base/platform-msi.c | 4 +-
drivers/virtio/Kconfig | 9 ++++
drivers/virtio/virtio_mmio_msi.h | 93 ++++++++++++++++++++++++++++++++++++++++
include/linux/msi.h | 1 +
4 files changed, 105 insertions(+), 2 deletions(-)
create mode 100644 drivers/virtio/virtio_mmio_msi.h

diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
index 8da314b..45752f1 100644
--- a/drivers/base/platform-msi.c
+++ b/drivers/base/platform-msi.c
@@ -31,12 +31,11 @@ struct platform_msi_priv_data {
/* The devid allocator */
static DEFINE_IDA(platform_msi_devid_ida);

-#ifdef GENERIC_MSI_DOMAIN_OPS
/*
* Convert an msi_desc to a globaly unique identifier (per-device
* devid + msi_desc position in the msi_list).
*/
-static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
+irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
{
u32 devid;

@@ -45,6 +44,7 @@ static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
}

+#ifdef GENERIC_MSI_DOMAIN_OPS
static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
{
arg->desc = desc;
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 078615c..551a9f7 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -84,6 +84,15 @@ config VIRTIO_MMIO

If unsure, say N.

+config VIRTIO_MMIO_MSI
+ bool "Memory-mapped virtio device MSI"
+ depends on VIRTIO_MMIO && GENERIC_MSI_IRQ_DOMAIN && GENERIC_MSI_IRQ
+ help
+ This allows device drivers to support msi interrupt handling for
+ virtio-mmio devices. It can improve performance greatly.
+
+ If unsure, say N.
+
config VIRTIO_MMIO_CMDLINE_DEVICES
bool "Memory mapped virtio devices parameter parsing"
depends on VIRTIO_MMIO
diff --git a/drivers/virtio/virtio_mmio_msi.h b/drivers/virtio/virtio_mmio_msi.h
new file mode 100644
index 0000000..27cb2af
--- /dev/null
+++ b/drivers/virtio/virtio_mmio_msi.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _DRIVERS_VIRTIO_VIRTIO_MMIO_MSI_H
+#define _DRIVERS_VIRTIO_VIRTIO_MMIO_MSI_H
+
+#ifdef CONFIG_VIRTIO_MMIO_MSI
+
+#include <linux/msi.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/platform_device.h>
+
+static irq_hw_number_t mmio_msi_hwirq;
+static struct irq_domain *mmio_msi_domain;
+
+struct irq_domain *__weak arch_msi_root_irq_domain(void)
+{
+ return NULL;
+}
+
+void __weak irq_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
+{
+}
+
+static void mmio_msi_mask_irq(struct irq_data *data)
+{
+}
+
+static void mmio_msi_unmask_irq(struct irq_data *data)
+{
+}
+
+static struct irq_chip mmio_msi_controller = {
+ .name = "VIRTIO-MMIO-MSI",
+ .irq_mask = mmio_msi_mask_irq,
+ .irq_unmask = mmio_msi_unmask_irq,
+ .irq_ack = irq_chip_ack_parent,
+ .irq_retrigger = irq_chip_retrigger_hierarchy,
+ .irq_compose_msi_msg = irq_msi_compose_msg,
+ .flags = IRQCHIP_SKIP_SET_WAKE,
+};
+
+static int mmio_msi_prepare(struct irq_domain *domain, struct device *dev,
+ int nvec, msi_alloc_info_t *arg)
+{
+ memset(arg, 0, sizeof(*arg));
+ return 0;
+}
+
+static void mmio_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+ mmio_msi_hwirq = platform_msi_calc_hwirq(desc);
+}
+
+static irq_hw_number_t mmio_msi_get_hwirq(struct msi_domain_info *info,
+ msi_alloc_info_t *arg)
+{
+ return mmio_msi_hwirq;
+}
+
+static struct msi_domain_ops mmio_msi_domain_ops = {
+ .msi_prepare = mmio_msi_prepare,
+ .set_desc = mmio_msi_set_desc,
+ .get_hwirq = mmio_msi_get_hwirq,
+};
+
+static struct msi_domain_info mmio_msi_domain_info = {
+ .flags = MSI_FLAG_USE_DEF_DOM_OPS |
+ MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_ACTIVATE_EARLY,
+ .ops = &mmio_msi_domain_ops,
+ .chip = &mmio_msi_controller,
+ .handler = handle_edge_irq,
+ .handler_name = "edge",
+};
+
+static inline void mmio_msi_create_irq_domain(void)
+{
+ struct fwnode_handle *fn;
+ struct irq_domain *parent = arch_msi_root_irq_domain();
+
+ fn = irq_domain_alloc_named_fwnode("VIRTIO-MMIO-MSI");
+ if (fn && parent) {
+ mmio_msi_domain =
+ platform_msi_create_irq_domain(fn,
+ &mmio_msi_domain_info, parent);
+ irq_domain_free_fwnode(fn);
+ }
+}
+#else
+static inline void mmio_msi_create_irq_domain(void) {}
+#endif
+
+#endif
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 8ad679e..ee5f566 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -362,6 +362,7 @@ int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
unsigned int nvec);
void *platform_msi_get_host_data(struct irq_domain *domain);
+irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc);
#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */

#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
--
1.8.3.1
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