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Subject[PATCH v1 1/2] x86/msi: Enhance x86 to support platform_msi
Date
From: Liu Jiang <gerry@linux.alibaba.com>

The x86 platform currently only supports specific MSI/MSI-x for PCI
devices. To enable MSI to the platform devices such as virtio-mmio
device, this patch enhances x86 with platform MSI by leveraging the
already built-in platform-msi driver (drivers/base/platform-msi.c)
and makes it as a configurable option.

Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>
Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>
---
arch/x86/Kconfig | 6 ++++
arch/x86/include/asm/hw_irq.h | 5 +++
arch/x86/include/asm/irqdomain.h | 9 +++++
arch/x86/kernel/apic/msi.c | 74 ++++++++++++++++++++++++++++++++++++++++
drivers/base/platform-msi.c | 4 +--
include/linux/msi.h | 1 +
6 files changed, 97 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5e89499..c1178f2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1074,6 +1074,12 @@ config X86_IO_APIC
def_bool y
depends on X86_LOCAL_APIC || X86_UP_IOAPIC

+config X86_PLATFORM_MSI
+ def_bool y
+ depends on X86_LOCAL_APIC && X86_64
+ select GENERIC_MSI_IRQ
+ select GENERIC_MSI_IRQ_DOMAIN
+
config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
bool "Reroute for broken boot IRQs"
depends on X86_IO_APIC
diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index 4154bc5..5c96b49 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -113,6 +113,11 @@ struct irq_alloc_info {
struct msi_desc *desc;
};
#endif
+#ifdef CONFIG_X86_PLATFORM_MSI
+ struct {
+ irq_hw_number_t platform_msi_hwirq;
+ };
+#endif
};
};

diff --git a/arch/x86/include/asm/irqdomain.h b/arch/x86/include/asm/irqdomain.h
index c066ffa..b53f51f 100644
--- a/arch/x86/include/asm/irqdomain.h
+++ b/arch/x86/include/asm/irqdomain.h
@@ -56,4 +56,13 @@ extern void mp_irqdomain_deactivate(struct irq_domain *domain,
static inline void arch_init_msi_domain(struct irq_domain *domain) { }
#endif

+#ifdef CONFIG_X86_PLATFORM_MSI
+extern struct irq_domain *platform_msi_get_def_irq_domain(void);
+#else
+static inline struct irq_domain *platform_msi_get_def_irq_domain(void)
+{
+ return NULL;
+}
+#endif
+
#endif
diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
index 7f75334..ef558c7 100644
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -22,6 +22,10 @@
#include <asm/irq_remapping.h>

static struct irq_domain *msi_default_domain;
+#ifdef CONFIG_X86_PLATFORM_MSI
+static struct irq_domain *platform_msi_default_domain;
+static struct msi_domain_info platform_msi_domain_info;
+#endif

static void irq_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
{
@@ -146,6 +150,17 @@ void __init arch_init_msi_domain(struct irq_domain *parent)
}
if (!msi_default_domain)
pr_warn("failed to initialize irqdomain for MSI/MSI-x.\n");
+#ifdef CONFIG_X86_PLATFORM_MSI
+ fn = irq_domain_alloc_named_fwnode("PLATFORM-MSI");
+ if (fn) {
+ platform_msi_default_domain =
+ platform_msi_create_irq_domain(fn,
+ &platform_msi_domain_info, parent);
+ irq_domain_free_fwnode(fn);
+ }
+ if (!platform_msi_default_domain)
+ pr_warn("failed to initialize irqdomain for PLATFORM-MSI.\n");
+#endif
}

#ifdef CONFIG_IRQ_REMAP
@@ -384,3 +399,62 @@ int hpet_assign_irq(struct irq_domain *domain, struct hpet_channel *hc,
return irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, &info);
}
#endif
+
+#ifdef CONFIG_X86_PLATFORM_MSI
+static void platform_msi_mask_irq(struct irq_data *data)
+{
+}
+
+static void platform_msi_unmask_irq(struct irq_data *data)
+{
+}
+
+static struct irq_chip platform_msi_controller = {
+ .name = "PLATFORM-MSI",
+ .irq_mask = platform_msi_mask_irq,
+ .irq_unmask = platform_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 platform_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 platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+ arg->platform_msi_hwirq = platform_msi_calc_hwirq(desc);
+}
+
+static irq_hw_number_t platform_msi_get_hwirq(struct msi_domain_info *info,
+ msi_alloc_info_t *arg)
+{
+ return arg->platform_msi_hwirq;
+}
+
+static struct msi_domain_ops platform_msi_domain_ops = {
+ .msi_prepare = platform_msi_prepare,
+ .set_desc = platform_msi_set_desc,
+ .get_hwirq = platform_msi_get_hwirq,
+};
+
+static struct msi_domain_info platform_msi_domain_info = {
+ .flags = MSI_FLAG_USE_DEF_DOM_OPS |
+ MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_ACTIVATE_EARLY,
+ .ops = &platform_msi_domain_ops,
+ .chip = &platform_msi_controller,
+ .handler = handle_edge_irq,
+ .handler_name = "edge",
+};
+
+struct irq_domain *platform_msi_get_def_irq_domain(void)
+{
+ return platform_msi_default_domain;
+}
+#endif
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/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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