[PATCH RFC v2 02/18] irq/dev-msi: Add support for a new DEV_MSI irq domain
From: Dave Jiang
Date: Tue Jul 21 2020 - 12:02:38 EST
From: Megha Dey <megha.dey@xxxxxxxxx>
Add support for the creation of a new DEV_MSI irq domain. It creates a
new irq chip associated with the DEV_MSI domain and adds the necessary
domain operations to it.
Add a new config option DEV_MSI which must be enabled by any
driver that wants to support device-specific message-signaled-interrupts
outside of PCI-MSI(-X).
Lastly, add device specific mask/unmask callbacks in addition to a write
function to the platform_msi_ops.
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Megha Dey <megha.dey@xxxxxxxxx>
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
arch/x86/include/asm/hw_irq.h | 5 ++
drivers/base/Kconfig | 7 +++
drivers/base/Makefile | 1
drivers/base/dev-msi.c | 95 +++++++++++++++++++++++++++++++++++++++++
drivers/base/platform-msi.c | 45 +++++++++++++------
drivers/base/platform-msi.h | 23 ++++++++++
include/linux/msi.h | 8 +++
7 files changed, 168 insertions(+), 16 deletions(-)
create mode 100644 drivers/base/dev-msi.c
create mode 100644 drivers/base/platform-msi.h
diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index 74c12437401e..8ecd7570589d 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -61,6 +61,11 @@ struct irq_alloc_info {
irq_hw_number_t msi_hwirq;
};
#endif
+#ifdef CONFIG_DEV_MSI
+ struct {
+ irq_hw_number_t hwirq;
+ };
+#endif
#ifdef CONFIG_X86_IO_APIC
struct {
int ioapic_id;
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 8d7001712062..f00901bac056 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -210,4 +210,11 @@ config GENERIC_ARCH_TOPOLOGY
appropriate scaling, sysfs interface for reading capacity values at
runtime.
+config DEV_MSI
+ bool "Device Specific Interrupt Messages"
+ select IRQ_DOMAIN_HIERARCHY
+ select GENERIC_MSI_IRQ_DOMAIN
+ help
+ Allow device drivers to generate device-specific interrupt messages
+ for devices independent of PCI MSI/-X.
endmenu
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 157452080f3d..ca1e4d39164e 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_REGMAP) += regmap/
obj-$(CONFIG_SOC_BUS) += soc.o
obj-$(CONFIG_PINCTRL) += pinctrl.o
obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
+obj-$(CONFIG_DEV_MSI) += dev-msi.o
obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o
obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o
diff --git a/drivers/base/dev-msi.c b/drivers/base/dev-msi.c
new file mode 100644
index 000000000000..240ccc353933
--- /dev/null
+++ b/drivers/base/dev-msi.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright  2020 Intel Corporation.
+ *
+ * Author: Megha Dey <megha.dey@xxxxxxxxx>
+ */
+
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+#include "platform-msi.h"
+
+struct irq_domain *dev_msi_default_domain;
+
+static irq_hw_number_t dev_msi_get_hwirq(struct msi_domain_info *info,
+ msi_alloc_info_t *arg)
+{
+ return arg->hwirq;
+}
+
+static irq_hw_number_t dev_msi_calc_hwirq(struct msi_desc *desc)
+{
+ u32 devid;
+
+ devid = desc->platform.msi_priv_data->devid;
+
+ return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
+}
+
+static void dev_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+ arg->hwirq = dev_msi_calc_hwirq(desc);
+}
+
+static int dev_msi_prepare(struct irq_domain *domain, struct device *dev,
+ int nvec, msi_alloc_info_t *arg)
+{
+ memset(arg, 0, sizeof(*arg));
+
+ return 0;
+}
+
+static struct msi_domain_ops dev_msi_domain_ops = {
+ .get_hwirq = dev_msi_get_hwirq,
+ .set_desc = dev_msi_set_desc,
+ .msi_prepare = dev_msi_prepare,
+};
+
+static struct irq_chip dev_msi_controller = {
+ .name = "DEV-MSI",
+ .irq_unmask = platform_msi_unmask_irq,
+ .irq_mask = platform_msi_mask_irq,
+ .irq_write_msi_msg = platform_msi_write_msg,
+ .irq_ack = irq_chip_ack_parent,
+ .irq_retrigger = irq_chip_retrigger_hierarchy,
+ .flags = IRQCHIP_SKIP_SET_WAKE,
+};
+
+static struct msi_domain_info dev_msi_domain_info = {
+ .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS,
+ .ops = &dev_msi_domain_ops,
+ .chip = &dev_msi_controller,
+ .handler = handle_edge_irq,
+ .handler_name = "edge",
+};
+
+static int __init create_dev_msi_domain(void)
+{
+ struct irq_domain *parent = NULL;
+ struct fwnode_handle *fn;
+
+ /*
+ * Modern code should never have to use irq_get_default_host. But since
+ * dev-msi is invisible to DT/ACPI, this is an exception case.
+ */
+ parent = irq_get_default_host();
+ if (!parent)
+ return -ENXIO;
+
+ fn = irq_domain_alloc_named_fwnode("DEV_MSI");
+ if (!fn)
+ return -ENXIO;
+
+ dev_msi_default_domain = msi_create_irq_domain(fn, &dev_msi_domain_info, parent);
+ if (!dev_msi_default_domain) {
+ pr_warn("failed to initialize irqdomain for DEV-MSI.\n");
+ return -ENXIO;
+ }
+
+ irq_domain_update_bus_token(dev_msi_default_domain, DOMAIN_BUS_PLATFORM_MSI);
+ irq_domain_free_fwnode(fn);
+
+ return 0;
+}
+device_initcall(create_dev_msi_domain);
diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
index 9d94cd699468..5e1f210d65ee 100644
--- a/drivers/base/platform-msi.c
+++ b/drivers/base/platform-msi.c
@@ -12,21 +12,7 @@
#include <linux/irqdomain.h>
#include <linux/msi.h>
#include <linux/slab.h>
-
-#define DEV_ID_SHIFT 21
-#define MAX_DEV_MSIS (1 << (32 - DEV_ID_SHIFT))
-
-/*
- * Internal data structure containing a (made up, but unique) devid
- * and the platform-msi ops
- */
-struct platform_msi_priv_data {
- struct device *dev;
- void *host_data;
- msi_alloc_info_t arg;
- const struct platform_msi_ops *ops;
- int devid;
-};
+#include "platform-msi.h"
/* The devid allocator */
static DEFINE_IDA(platform_msi_devid_ida);
@@ -76,7 +62,7 @@ static void platform_msi_update_dom_ops(struct msi_domain_info *info)
ops->set_desc = platform_msi_set_desc;
}
-static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
+void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
{
struct msi_desc *desc = irq_data_get_msi_desc(data);
struct platform_msi_priv_data *priv_data;
@@ -86,6 +72,33 @@ static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
priv_data->ops->write_msg(desc, msg);
}
+static void __platform_msi_desc_mask_unmask_irq(struct msi_desc *desc, u32 mask)
+{
+ const struct platform_msi_ops *ops;
+
+ ops = desc->platform.msi_priv_data->ops;
+ if (!ops)
+ return;
+
+ if (mask) {
+ if (ops->irq_mask)
+ ops->irq_mask(desc);
+ } else {
+ if (ops->irq_unmask)
+ ops->irq_unmask(desc);
+ }
+}
+
+void platform_msi_mask_irq(struct irq_data *data)
+{
+ __platform_msi_desc_mask_unmask_irq(irq_data_get_msi_desc(data), 1);
+}
+
+void platform_msi_unmask_irq(struct irq_data *data)
+{
+ __platform_msi_desc_mask_unmask_irq(irq_data_get_msi_desc(data), 0);
+}
+
static void platform_msi_update_chip_ops(struct msi_domain_info *info)
{
struct irq_chip *chip = info->chip;
diff --git a/drivers/base/platform-msi.h b/drivers/base/platform-msi.h
new file mode 100644
index 000000000000..1de8c2874218
--- /dev/null
+++ b/drivers/base/platform-msi.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright  2020 Intel Corporation.
+ *
+ * Author: Megha Dey <megha.dey@xxxxxxxxx>
+ */
+
+#include <linux/msi.h>
+
+#define DEV_ID_SHIFT 21
+#define MAX_DEV_MSIS (1 << (32 - DEV_ID_SHIFT))
+
+/*
+ * Data structure containing a (made up, but unique) devid
+ * and the platform-msi ops.
+ */
+struct platform_msi_priv_data {
+ struct device *dev;
+ void *host_data;
+ msi_alloc_info_t arg;
+ const struct platform_msi_ops *ops;
+ int devid;
+};
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 7f6a8eb51aca..1da97f905720 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -323,9 +323,13 @@ enum {
/*
* platform_msi_ops - Callbacks for platform MSI ops
+ * @irq_mask: mask an interrupt source
+ * @irq_unmask: unmask an interrupt source
* @write_msg: write message content
*/
struct platform_msi_ops {
+ unsigned int (*irq_mask)(struct msi_desc *desc);
+ unsigned int (*irq_unmask)(struct msi_desc *desc);
irq_write_msi_msg_t write_msg;
};
@@ -370,6 +374,10 @@ 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);
+
+void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg);
+void platform_msi_unmask_irq(struct irq_data *data);
+void platform_msi_mask_irq(struct irq_data *data);
#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN