[PATCH v3 2/4] ACPI: LoongArch: Add acpi_arch_[late]_init()
From: Bibo Mao
Date: Mon Sep 14 2026 - 23:35:55 EST
LoongArch IOMMU scanning flow is similar with virtio-iommu,
there is early init and late_init. In early init function, PCI
ACS is enabled if there is IOMMU table, and late_init is called
after PCI device scanning, where IOVT table scanning function is
executed.
Here add acpi_arch_init() and acpi_arch_late_init() API on LoongArch,
function acpi_iovt_init() is to enable PCI ACS function if IOMMU device
exists in IOVT table, and function acpi_iovt_late_init() is to scan
IOVT table, add IOMMU devices.
Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
---
drivers/acpi/Kconfig | 4 +
drivers/acpi/Makefile | 2 +-
drivers/acpi/bus.c | 2 +
drivers/acpi/loongarch/Kconfig | 7 +
drivers/acpi/loongarch/Makefile | 3 +
drivers/acpi/loongarch/init.c | 16 +++
drivers/acpi/loongarch/init.h | 5 +
drivers/acpi/loongarch/iovt.c | 219 ++++++++++++++++++++++++++++++++
include/linux/acpi.h | 1 +
9 files changed, 258 insertions(+), 1 deletion(-)
create mode 100644 drivers/acpi/loongarch/Kconfig
create mode 100644 drivers/acpi/loongarch/Makefile
create mode 100644 drivers/acpi/loongarch/init.c
create mode 100644 drivers/acpi/loongarch/init.h
create mode 100644 drivers/acpi/loongarch/iovt.c
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index f165d14cf61a..192e6f18eda1 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -550,6 +550,10 @@ if ARM64
source "drivers/acpi/arm64/Kconfig"
endif
+if LOONGARCH
+source "drivers/acpi/loongarch/Kconfig"
+endif
+
if RISCV
source "drivers/acpi/riscv/Kconfig"
endif
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index d1b0affb844f..91584a3c1e01 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -131,6 +131,6 @@ obj-y += dptf/
obj-$(CONFIG_ARM64) += arm64/
obj-$(CONFIG_ACPI_VIOT) += viot.o
-
+obj-$(CONFIG_LOONGARCH) += loongarch/
obj-$(CONFIG_RISCV) += riscv/
obj-$(CONFIG_X86) += x86/
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 808c6746be14..33d752eacde3 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -1465,6 +1465,7 @@ struct kobject *acpi_kobj;
EXPORT_SYMBOL_GPL(acpi_kobj);
void __weak __init acpi_arch_init(void) { }
+void __weak __init acpi_arch_late_init(void) { }
static int __init acpi_init(void)
{
@@ -1503,6 +1504,7 @@ static int __init acpi_init(void)
acpi_wakeup_device_init();
acpi_debugger_init();
acpi_setup_sb_notify_handler();
+ acpi_arch_late_init();
acpi_viot_init();
return 0;
}
diff --git a/drivers/acpi/loongarch/Kconfig b/drivers/acpi/loongarch/Kconfig
new file mode 100644
index 000000000000..91ba3c35b9bf
--- /dev/null
+++ b/drivers/acpi/loongarch/Kconfig
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# ACPI Configuration for LOONGARCH
+#
+
+config ACPI_IOVT
+ bool
diff --git a/drivers/acpi/loongarch/Makefile b/drivers/acpi/loongarch/Makefile
new file mode 100644
index 000000000000..c338d3102fc1
--- /dev/null
+++ b/drivers/acpi/loongarch/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-y += init.o
+obj-$(CONFIG_ACPI_IOVT) += iovt.o
diff --git a/drivers/acpi/loongarch/init.c b/drivers/acpi/loongarch/init.c
new file mode 100644
index 000000000000..e7272ee197c7
--- /dev/null
+++ b/drivers/acpi/loongarch/init.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/acpi.h>
+#include "init.h"
+
+void __init acpi_arch_init(void)
+{
+ if (IS_ENABLED(CONFIG_ACPI_IOVT))
+ acpi_iovt_init();
+}
+
+void __init acpi_arch_late_init(void)
+{
+ if (IS_ENABLED(CONFIG_ACPI_IOVT))
+ acpi_iovt_late_init();
+}
diff --git a/drivers/acpi/loongarch/init.h b/drivers/acpi/loongarch/init.h
new file mode 100644
index 000000000000..85e5197553ad
--- /dev/null
+++ b/drivers/acpi/loongarch/init.h
@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#include <linux/init.h>
+
+void __init acpi_iovt_init(void);
+void __init acpi_iovt_late_init(void);
diff --git a/drivers/acpi/loongarch/iovt.c b/drivers/acpi/loongarch/iovt.c
new file mode 100644
index 000000000000..302ca6a75905
--- /dev/null
+++ b/drivers/acpi/loongarch/iovt.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/acpi.h>
+#include <linux/pci.h>
+#include "init.h"
+
+struct iovt_device_entry {
+ struct list_head list;
+ int start_devid;
+ int end_devid;
+};
+
+struct iovt_fwnode {
+ struct list_head list;
+ struct fwnode_handle *fwnode;
+ int flag;
+ int segment;
+ int devid;
+ int nid;
+ struct list_head ep_list;
+};
+
+/* Root pointer to the mapped IOVT table */
+static LIST_HEAD(iovt_fwnode_list);
+static DEFINE_SPINLOCK(iovt_fwnode_lock);
+
+#ifdef CONFIG_PCI
+static void __init iovt_enable_acs(struct acpi_iovt_iommu *iommu)
+{
+ static bool acs_enabled __initdata;
+
+ if (acs_enabled)
+ return;
+
+ /* IOMMU V1 only supports PCI device management */
+ if ((iommu->header.type == ACPI_IOVT_IOMMU_V1) ||
+ (iommu->flags & (ACPI_IOVT_IOMMU_PCI_DEVICE | ACPI_IOVT_IOMMU_MAGAGE_BY_SEGMENT))) {
+ pci_request_acs();
+ acs_enabled = true;
+ }
+}
+#else
+static inline void iovt_enable_acs(struct acpi_iovt_iommu *iommu) { }
+#endif
+
+static int __init iovt_get_pci_iommu_fwnode(struct iovt_fwnode *np, u16 segment, u16 bdf)
+{
+ struct pci_dev *pdev;
+ struct fwnode_handle *fwnode;
+
+ pdev = pci_get_domain_bus_and_slot(segment, PCI_BUS_NUM(bdf), bdf & 0xff);
+ if (!pdev) {
+ pr_err("No PCI IOMMU found for segment 0x%x bdf 0x%x\n", segment, bdf);
+ return -ENODEV;
+ }
+
+ fwnode = dev_fwnode(&pdev->dev);
+ if (!fwnode) {
+ /*
+ * PCI devices aren't necessarily described by ACPI. Create a
+ * fwnode so the IOMMU subsystem can identify this device.
+ */
+ fwnode = acpi_alloc_fwnode_static();
+ if (!fwnode) {
+ pci_dev_put(pdev);
+ return -ENOMEM;
+ }
+ set_primary_fwnode(&pdev->dev, fwnode);
+ }
+
+ np->fwnode = dev_fwnode(&pdev->dev);
+ if (np->flag & ACPI_IOVT_IOMMU_PXM_VALID)
+ set_dev_node(&pdev->dev, np->nid);
+ pci_dev_put(pdev);
+ return 0;
+}
+
+static int __init iovt_add_iommu(struct acpi_iovt_iommu *iommu)
+{
+ struct iovt_fwnode *np;
+ struct fwnode_handle *fwnode;
+ struct acpi_iovt_device_entry *ep;
+ struct iovt_device_entry *entry;
+ int i, ret, start_devid;
+ bool is_start = false;
+
+ np = kzalloc_obj(struct iovt_fwnode, GFP_ATOMIC);
+ if (WARN_ON(!np))
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&np->list);
+ np->flag = iommu->flags;
+ np->segment = iommu->segment;
+ if (np->flag & ACPI_IOVT_IOMMU_PXM_VALID)
+ np->nid = pxm_to_node(iommu->proximity_domain);
+
+ if (np->flag & ACPI_IOVT_IOMMU_PCI_DEVICE) {
+ np->devid = iommu->device_id;
+ ret = iovt_get_pci_iommu_fwnode(np, np->segment, np->devid);
+ if (ret) {
+ kfree(np);
+ return ret;
+ }
+
+ } else {
+ fwnode = acpi_alloc_fwnode_static();
+ if (!fwnode) {
+ kfree(np);
+ return -ENOMEM;
+ }
+
+ np->fwnode = fwnode;
+ }
+
+ /* All devices in the segment are managed by this IOMMU */
+ if (np->flag & ACPI_IOVT_IOMMU_MAGAGE_BY_SEGMENT)
+ goto skip;
+
+ INIT_LIST_HEAD(&np->ep_list);
+ ep = ACPI_ADD_PTR(struct acpi_iovt_device_entry, iommu, iommu->device_entry_offset);
+ for (i = 0; i < iommu->device_entry_num; i++) {
+ switch (ep->type) {
+ case ACPI_IOVT_DEVICE_ENTRY_START:
+ is_start = true;
+ start_devid = ep->device_id;
+ break;
+ case ACPI_IOVT_DEVICE_ENTRY_END:
+ if (!is_start)
+ break;
+
+ entry = kzalloc_obj(struct iovt_device_entry, GFP_ATOMIC);
+ if (!entry)
+ return -ENOMEM;
+
+ entry->start_devid = start_devid;
+ entry->end_devid = ep->device_id;
+ list_add_tail(&entry->list, &np->ep_list);
+ is_start = false;
+ break;
+ case ACPI_IOVT_DEVICE_ENTRY_SINGLE:
+ entry = kzalloc_obj(struct iovt_device_entry, GFP_ATOMIC);
+ if (!entry)
+ return -ENOMEM;
+
+ entry->start_devid = ep->device_id;
+ entry->end_devid = ep->device_id;
+ list_add_tail(&entry->list, &np->ep_list);
+ is_start = false;
+ break;
+ default:
+ break;
+ }
+ ep = ACPI_ADD_PTR(struct acpi_iovt_device_entry, ep, ep->length);
+ }
+
+skip:
+ spin_lock(&iovt_fwnode_lock);
+ list_add_tail(&np->list, &iovt_fwnode_list);
+ spin_unlock(&iovt_fwnode_lock);
+ return 0;
+}
+
+static void __init iovt_init_devices(struct acpi_table_header *header)
+{
+ struct acpi_iovt_iommu *iommu;
+ struct acpi_table_iovt *iovt;
+ int i;
+
+ /* Get the first IOVT node */
+ iovt = (struct acpi_table_iovt *)header;
+ iommu = ACPI_ADD_PTR(struct acpi_iovt_iommu, iovt, iovt->iommu_offset);
+ for (i = 0; i < iovt->iommu_count; i++) {
+ iovt_add_iommu(iommu);
+ iommu = ACPI_ADD_PTR(struct acpi_iovt_iommu, iommu, iommu->header.length);
+ }
+}
+
+void __init acpi_iovt_init(void)
+{
+ acpi_status status;
+ struct acpi_table_header *hdr;
+ struct acpi_table_iovt *iovt;
+ struct acpi_iovt_iommu *iommu;
+ int i;
+
+ status = acpi_get_table(ACPI_SIG_IOVT, 0, &hdr);
+ if (ACPI_FAILURE(status)) {
+ if (status != AE_NOT_FOUND)
+ pr_err("Failed to get table, %s\n", acpi_format_exception(status));
+
+ return;
+ }
+
+ iovt = (struct acpi_table_iovt *)&hdr;
+ iommu = ACPI_ADD_PTR(struct acpi_iovt_iommu, iovt, iovt->iommu_offset);
+ for (i = 0; i < iovt->iommu_count; i++) {
+ iovt_enable_acs(iommu);
+ iommu = ACPI_ADD_PTR(struct acpi_iovt_iommu, iommu, iommu->header.length);
+ }
+
+ acpi_put_table(hdr);
+}
+
+void __init acpi_iovt_late_init(void)
+{
+ acpi_status status;
+ struct acpi_table_header *hdr;
+
+ status = acpi_get_table(ACPI_SIG_IOVT, 0, &hdr);
+ if (ACPI_FAILURE(status)) {
+ if (status != AE_NOT_FOUND)
+ pr_err("Failed to get table, %s\n", acpi_format_exception(status));
+
+ return;
+ }
+
+ iovt_init_devices(hdr);
+ acpi_put_table(hdr);
+}
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index ddacac812094..2a621c095b8b 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1642,6 +1642,7 @@ static inline int acpi_pptt_get_cpumask_from_cache_id(u32 cache_id,
#endif
void acpi_arch_init(void);
+void acpi_arch_late_init(void);
#ifdef CONFIG_ACPI_PCC
void acpi_init_pcc(void);
--
2.39.3