[PATCH V5 1/7] ARM64, ACPI, PCI: I/O Remapping Table (IORT) initial support.

Tomasz Nowicki
2016-05-31T11:21:44Z

IORT shows representation of IO topology for ARM based systems.
It describes how various components are connected together on
parent-child basis e.g. PCI RC -> SMMU -> ITS. Also see IORT spec.

Initial support allows to:
- register ITS MSI chip along with ITS translation ID and domain token
- deregister ITS MSI chip based on ITS translation ID
- find registered domain token based on ITS translation ID
- map MSI RID based on PCI device and requester ID
- find domain token based on PCI device and requester ID

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
---
drivers/acpi/Kconfig | 3 +
drivers/acpi/Makefile | 1 +
drivers/acpi/iort.c | 344 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/iort.h | 38 ++++++
4 files changed, 386 insertions(+)
create mode 100644 drivers/acpi/iort.c
create mode 100644 include/linux/iort.h

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index b7e2e77..848471f 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -57,6 +57,9 @@ config ACPI_SYSTEM_POWER_STATES_SUPPORT
config ACPI_CCA_REQUIRED
bool

+config IORT_TABLE
+ bool
+
config ACPI_DEBUGGER
bool "AML debugger interface"
select ACPI_DEBUG
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 251ce85..c7c9b29 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
obj-$(CONFIG_ACPI_BGRT) += bgrt.o
obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o
obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o
+obj-$(CONFIG_IORT_TABLE) += iort.o

# processor has its own "processor." module_param namespace
processor-y := processor_driver.o
diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c
new file mode 100644
index 0000000..226eb6d
--- /dev/null
+++ b/drivers/acpi/iort.c
@@ -0,0 +1,344 @@
+/*
+ * Copyright (C) 2016, Semihalf
+ * Author: Tomasz Nowicki <tn@semihalf.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * This file implements early detection/parsing of I/O mapping
+ * reported to OS through firmware via I/O Remapping Table (IORT)
+ * IORT document number: ARM DEN 0049A
+ */
+
+#define pr_fmt(fmt) "ACPI: IORT: " fmt
+
+#include <linux/export.h>
+#include <linux/iort.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+
+struct iort_its_msi_chip {
+ struct list_head list;
+ struct fwnode_handle *fw_node;
+ u32 translation_id;
+};
+
+typedef acpi_status (*iort_find_node_callback)
+ (struct acpi_iort_node *node, void *context);
+
+/* Root pointer to the mapped IORT table */
+static struct acpi_table_header *iort_table;
+
+static LIST_HEAD(iort_msi_chip_list);
+
+/**
+ * iort_register_domain_token() - register domain token and related ITS ID
+ * to the list from where we can get it back
+ * later on.
+ * @translation_id: ITS ID
+ * @token: domain token
+ *
+ * Returns: 0 on success, -ENOMEM if not memory when allocating list element.
+ */
+int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node)
+{
+ struct iort_its_msi_chip *its_msi_chip;
+
+ its_msi_chip = kzalloc(sizeof(*its_msi_chip), GFP_KERNEL);
+ if (!its_msi_chip)
+ return -ENOMEM;
+
+ its_msi_chip->fw_node = fw_node;
+ its_msi_chip->translation_id = trans_id;
+
+ list_add(&its_msi_chip->list, &iort_msi_chip_list);
+ return 0;
+}
+
+/**
+ * iort_unregister_domain_token() - unregister domain token based on ITS ID.
+ * @translation_id: ITS ID
+ *
+ * Returns: none.
+ */
+void iort_deregister_domain_token(int trans_id)
+{
+ struct iort_its_msi_chip *its_msi_chip, *t;
+
+ list_for_each_entry_safe(its_msi_chip, t, &iort_msi_chip_list, list) {
+ if (its_msi_chip->translation_id == trans_id) {
+ list_del(&its_msi_chip->list);
+ kfree(its_msi_chip);
+ break;
+ }
+ }
+}
+
+/**
+ * iort_find_its_domain_token() - find domain token based on given ITS ID.
+ * @translation_id: ITS ID
+ *
+ * Returns: domain token when find on the list, NULL otherwise.
+ */
+struct fwnode_handle *iort_its_find_domain_token(int trans_id)
+{
+ struct iort_its_msi_chip *its_msi_chip;
+
+ list_for_each_entry(its_msi_chip, &iort_msi_chip_list, list) {
+ if (its_msi_chip->translation_id == trans_id)
+ return its_msi_chip->fw_node;
+ }
+
+ return NULL;
+}
+
+static struct acpi_iort_node *
+iort_scan_node(enum acpi_iort_node_type type,
+ iort_find_node_callback callback, void *context)
+{
+ struct acpi_iort_node *iort_node, *iort_end;
+ struct acpi_table_iort *iort;
+ int i;
+
+ if (!iort_table)
+ return NULL;
+
+ /*
+ * iort_table and iort both point to the start of IORT table, but
+ * have different struct types
+ */
+ iort = (struct acpi_table_iort *)iort_table;
+
+ /* Get the first IORT node */
+ iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
+ iort->node_offset);
+ iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
+ iort_table->length);
+
+ for (i = 0; i < iort->node_count; i++) {
+ if (iort_node >= iort_end) {
+ pr_err("iort node pointer overflows, bad table\n");
+ return NULL;
+ }
+
+ if (iort_node->type == type) {
+ if (ACPI_SUCCESS(callback(iort_node, context)))
+ return iort_node;
+ }
+
+ iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
+ iort_node->length);
+ }
+
+ return NULL;
+}
+
+static acpi_status
+iort_find_dev_callback(struct acpi_iort_node *node, void *context)
+{
+ struct acpi_iort_root_complex *pci_rc;
+ struct device *dev = context;
+ struct pci_bus *bus;
+
+ switch (node->type) {
+ case ACPI_IORT_NODE_PCI_ROOT_COMPLEX:
+ bus = to_pci_bus(dev);
+ pci_rc = (struct acpi_iort_root_complex *)node->node_data;
+
+ /*
+ * It is assumed that PCI segment numbers maps one-to-one
+ * with root complexes. Each segment number can represent only
+ * one root complex.
+ */
+ if (pci_rc->pci_segment_number == pci_domain_nr(bus))
+ return AE_OK;
+
+ break;
+ }
+
+ return AE_NOT_FOUND;
+}
+
+static struct acpi_iort_node *
+iort_dev_map_rid(struct acpi_iort_node *node, u32 rid_in,
+ u32 *rid_out)
+{
+
+ if (!node)
+ goto out;
+
+ /* Go upstream */
+ while (node->type != ACPI_IORT_NODE_ITS_GROUP) {
+ struct acpi_iort_id_mapping *id;
+ int i, found = 0;
+
+ /* Exit when no mapping array */
+ if (!node->mapping_offset || !node->mapping_count)
+ return NULL;
+
+ id = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
+ node->mapping_offset);
+
+ for (i = 0, found = 0; i < node->mapping_count; i++, id++) {
+ /*
+ * Single mapping is not translation rule,
+ * lets move on for this case
+ */
+ if (id->flags & ACPI_IORT_ID_SINGLE_MAPPING) {
+ if (node->type != ACPI_IORT_NODE_SMMU) {
+ rid_in = id->output_base;
+ found = 1;
+ break;
+ }
+
+ pr_warn(FW_BUG "[node %p type %d] SINGLE MAPPING flag not allowed for SMMU node, skipping ID map\n",
+ node, node->type);
+ continue;
+ }
+
+ if (rid_in < id->input_base ||
+ (rid_in > id->input_base + id->id_count))
+ continue;
+
+ rid_in = id->output_base + (rid_in - id->input_base);
+ found = 1;
+ break;
+ }
+
+ if (!found)
+ return NULL;
+
+ /* Firmware bug! */
+ if (!id->output_reference) {
+ pr_err(FW_BUG "[node %p type %d] ID map has NULL parent reference\n",
+ node, node->type);
+ return NULL;
+ }
+
+ node = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
+ id->output_reference);
+ }
+
+out:
+ if (rid_out)
+ *rid_out = rid_in;
+ return node;
+}
+
+static struct acpi_iort_node *
+iort_its_find_node_and_map_rid(struct pci_dev *pdev, u32 req_id, u32 *dev_id)
+{
+ struct pci_bus *pbus = pdev->bus;
+ struct acpi_iort_node *node;
+
+ /* Find a PCI root bus */
+ while (!pci_is_root_bus(pbus))
+ pbus = pbus->parent;
+
+
+ node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
+ iort_find_dev_callback, &pbus->dev);
+ if (!node) {
+ dev_err(&pdev->dev, "can't find related IORT node\n");
+ return NULL;
+ }
+
+ return iort_dev_map_rid(node, req_id, dev_id);
+}
+
+/**
+ * iort_pci_domain_get_msi_rid() - find MSI RID based on PCI device ID
+ * @pdev: The PCI device
+ * @req_id: The PCI device requester ID
+ *
+ * Returns: MSI RID on success, input requester ID otherwise
+ */
+u32 iort_pci_get_msi_rid(struct pci_dev *pdev, u32 req_id)
+{
+ u32 dev_id;
+
+ if (!iort_its_find_node_and_map_rid(pdev, req_id, &dev_id))
+ return req_id;
+
+ return dev_id;
+}
+
+/**
+ * iort_pci_find_its_id() - find the ITS identifier based on specified device.
+ * @pdev: The PCI device
+ * @idx: Index of the ITS identifier list
+ * @its_id: ITS identifier
+ *
+ * Returns: 0 on success, appropriate error value otherwise
+ */
+static int
+iort_pci_find_its_id(struct pci_dev *pdev, u32 req_id, unsigned int idx,
+ int *its_id)
+{
+ struct acpi_iort_its_group *its;
+ struct acpi_iort_node *node;
+
+ node = iort_its_find_node_and_map_rid(pdev, req_id, NULL);
+ if (!node)
+ return -ENXIO;
+
+ /* Move to ITS specific data */
+ its = (struct acpi_iort_its_group *)node->node_data;
+ if (idx > its->its_count) {
+ dev_err(&pdev->dev, "requested ITS ID index [%d] is greater than available[%d]\n",
+ idx, its->its_count);
+ return -ENXIO;
+ }
+
+ *its_id = its->identifiers[idx];
+ return 0;
+}
+
+/**
+ * iort_pci_get_msi_domain_handle() - find registered domain token related to
+ * PCI device
+ * @pdev: The PCI device
+ * @req_id: The PCI device requester ID
+ *
+ * Returns: the MSI domain for this device, NULL otherwise
+ */
+struct irq_domain *
+iort_pci_get_domain(struct pci_dev *pdev, u32 req_id)
+{
+ static struct fwnode_handle *handle;
+ int its_id;
+
+ if (iort_pci_find_its_id(pdev, req_id, 0, &its_id))
+ return NULL;
+
+ handle = iort_its_find_domain_token(its_id);
+ if (!handle)
+ return NULL;
+
+ return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
+}
+
+static int __init iort_table_detect(void)
+{
+ acpi_status status;
+
+ if (acpi_disabled)
+ return -ENODEV;
+
+ status = acpi_get_table(ACPI_SIG_IORT, 0, &iort_table);
+ if (ACPI_FAILURE(status)) {
+ const char *msg = acpi_format_exception(status);
+ pr_err("Failed to get table, %s\n", msg);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+arch_initcall(iort_table_detect);
diff --git a/include/linux/iort.h b/include/linux/iort.h
new file mode 100644
index 0000000..490ff4d
--- /dev/null
+++ b/include/linux/iort.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2016, Semihalf
+ * Author: Tomasz Nowicki <tn@semihalf.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#ifndef __IORT_H__
+#define __IORT_H__
+
+#include <linux/acpi.h>
+
+struct fwnode_handle;
+int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node);
+void iort_deregister_domain_token(int trans_id);
+struct fwnode_handle *iort_its_find_domain_token(int trans_id);
+#ifdef CONFIG_IORT_TABLE
+u32 iort_pci_get_msi_rid(struct pci_dev *pdev, u32 req_id);
+struct irq_domain *iort_pci_get_domain(struct pci_dev *pdev, u32 req_id);
+#else
+static inline u32 iort_pci_get_msi_rid(struct pci_dev *pdev, u32 req_id)
+{ return req_id; }
+static inline struct irq_domain *
+iort_pci_get_domain(struct pci_dev *pdev, u32 req_id) { return NULL; }
+#endif
+
+#endif /* __IORT_H__ */
--
1.9.1