ACPI: LoongArch: Add acpi_arch_[late]_init()

LoongArch IOMMU scanning flow is similar with virtio-iommu, there is an
early init phase and a late init phase. In the early init function, PCI
ACS is enabled if there is IOMMU table, and the late init function is
called after PCI device scanning, where IOVT table scanning function is
executed.

Here add acpi_arch_init() and acpi_arch_late_init() API for LoongArch:
the acpi_iovt_init() function is to enable PCI ACS function if the IOMMU
device exists in IOVT table; while the acpi_iovt_late_init() function is
to scan IOVT table and add IOMMU devices.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/Kconfig

@@ -6,6 +6,7 @@ config LOONGARCH
 	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_MCFG if ACPI
 	select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU
+	select ACPI_IOVT if ACPI
 	select ACPI_PPTT if ACPI
 	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
 	select ARCH_BINFMT_ELF_STATE

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

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/

drivers/acpi/bus.c

@@ -1449,6 +1449,7 @@ 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)
 {
@@ -1487,6 +1488,7 @@ 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;
 }

drivers/acpi/loongarch/Kconfig

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# ACPI Configuration for LOONGARCH
+#
+
+config ACPI_IOVT
+	bool

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

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();
+}

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);

drivers/acpi/loongarch/iovt.c

@@ -0,0 +1,211 @@
+// 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, end_devid;
+};
+
+struct iovt_fwnode {
+	struct list_head list;
+	struct fwnode_handle *fwnode;
+	int flag;
+	int nid, segment, devid;
+	struct list_head ep_list;
+};
+
+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)
+{
+	int i, ret;
+	bool is_start = false;
+	struct iovt_fwnode *np;
+	struct iovt_device_entry *entry;
+	struct acpi_iovt_device_entry *ep;
+
+	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 < 0) {
+			kfree(np);
+			return ret;
+		}
+	} else {
+		np->fwnode = acpi_alloc_fwnode_static();
+		if (!np->fwnode) {
+			kfree(np);
+			return -ENOMEM;
+		}
+	}
+
+	/* 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;
+			entry->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;
+
+			is_start = false;
+			entry->end_devid = ep->device_id;
+			list_add_tail(&entry->list, &np->ep_list);
+			break;
+		case ACPI_IOVT_DEVICE_ENTRY_SINGLE:
+			entry = kzalloc_obj(struct iovt_device_entry, GFP_ATOMIC);
+			if (!entry)
+				return -ENOMEM;
+
+			is_start = false;
+			entry->start_devid = ep->device_id;
+			entry->end_devid = ep->device_id;
+			list_add_tail(&entry->list, &np->ep_list);
+			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)
+{
+	int i;
+	struct acpi_table_iovt *iovt;
+	struct acpi_iovt_iommu *iommu;
+
+	/* 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)
+{
+	int i;
+	acpi_status status;
+	struct acpi_table_header *hdr;
+	struct acpi_table_iovt *iovt;
+	struct acpi_iovt_iommu *iommu;
+
+	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);
+}

include/linux/acpi.h

@@ -1637,6 +1637,7 @@ 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);