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 detect IORT table presence and save its
root pointer obtained through acpi_get_table(). The pointer validity
depends on acpi_gbl_permanent_mmap because if acpi_gbl_permanent_mmap
is not set while using IORT nodes we would dereference unmapped pointers.
For the aforementioned reason call iort_table_detect() from acpi_init()
which guarantees acpi_gbl_permanent_mmap to be set at that point.
Add generic helpers which are helpful for scanning and retrieving
information from IORT table content. List of the most important helpers:
- iort_find_dev_node() finds IORT node for a given device
- iort_node_map_rid() maps device RID and returns IORT node which provides
final translation
Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
---
drivers/acpi/Kconfig | 3 +
drivers/acpi/Makefile | 1 +
drivers/acpi/bus.c | 2 +
drivers/acpi/iort.c | 220 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/iort.h | 30 +++++++
5 files changed, 256 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/bus.c b/drivers/acpi/bus.c
index 31e8da6..176c17d 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -33,6 +33,7 @@
#ifdef CONFIG_X86
#include <asm/mpspec.h>
#endif
+#include <linux/iort.h>
#include <linux/pci.h>
#include <acpi/apei.h>
#include <linux/dmi.h>
@@ -1118,6 +1119,7 @@ static int __init acpi_init(void)
}
pci_mmcfg_late_init();
+ iort_table_detect();
acpi_scan_init();
acpi_ec_init();
acpi_debugfs_init();
diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c
new file mode 100644
index 0000000..e342bac
--- /dev/null
+++ b/drivers/acpi/iort.c
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2016, Semihalf
+ * Author: Tomasz Nowicki <tn@xxxxxxxxxxxx>
+ *
+ * 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/iort.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+
+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 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;
+
+ /* Get the first IORT node */
+ iort = (struct acpi_table_iort *)iort_table;
+ 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 (WARN_TAINT(iort_node >= iort_end, TAINT_FIRMWARE_WORKAROUND,
+ "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_match_node_callback(struct acpi_iort_node *node, void *context)
+{
+ struct device *dev = context;
+
+ switch (node->type) {
+ case ACPI_IORT_NODE_NAMED_COMPONENT: {
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
+ struct acpi_iort_named_component *ncomp;
+
+ if (!adev)
+ break;
+
+ ncomp = (struct acpi_iort_named_component *)node->node_data;
+
+ if (ACPI_FAILURE(acpi_get_name(adev->handle,
+ ACPI_FULL_PATHNAME, &buffer))) {
+ dev_warn(dev, "Can't get device full path name\n");
+ break;
+ }
+
+ if (!strcmp(ncomp->device_name, (char *)buffer.pointer))
+ return AE_OK;
+
+ break;
+ }
+ case ACPI_IORT_NODE_PCI_ROOT_COMPLEX: {
+ struct acpi_iort_root_complex *pci_rc;
+ struct pci_bus *bus;
+
+ 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 int
+iort_id_map(struct acpi_iort_id_mapping *map, u8 type, u32 rid_in, u32 *rid_out)
+{
+ if (!rid_out)
+ return -EINVAL;
+
+ /* Single mapping does not care for input id */
+ if (map->flags & ACPI_IORT_ID_SINGLE_MAPPING) {
+ if (type == ACPI_IORT_NODE_NAMED_COMPONENT ||
+ type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
+ *rid_out = map->output_base;
+ return 0;
+ }
+
+ pr_warn(FW_BUG "[map %p] SINGLE MAPPING flag not allowed for node type %d, skipping ID map\n",
+ map, type);
+ return -ENXIO;
+ }
+
+ if (rid_in < map->input_base ||
+ (rid_in > map->input_base + map->id_count))
+ return -ENXIO;
+
+ *rid_out = map->output_base + (rid_in - map->input_base);
+ return 0;
+}
+
+static struct acpi_iort_node *
+iort_node_map_rid(struct acpi_iort_node *node, u32 rid_in,
+ u32 *rid_out, u8 type)
+{
+ u32 rid = rid_in;
+ int found = 0;
+
+ /* Climb up ID mapping tree to find specified node type */
+ while (node && node->type != type) {
+ struct acpi_iort_id_mapping *map;
+ int i;
+
+ if (!node->mapping_offset || !node->mapping_count) {
+ node = NULL;
+ break;
+ }
+
+ map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
+ node->mapping_offset);
+
+ /* Firmware bug! */
+ if (!map->output_reference) {
+ pr_err(FW_BUG "[node %p type %d] ID map has NULL parent reference\n",
+ node, node->type);
+ node = NULL;
+ break;
+ }
+
+ /* Do the RID translation */
+ for (i = 0; i < node->mapping_count; i++, map++) {
+ if(!iort_id_map(map, node->type, rid, &rid)) {
+ found = 1;
+ break;
+ }
+ }
+
+ if (!found) {
+ node = NULL;
+ break;
+ }
+
+ node = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
+ map->output_reference);
+ }
+
+ /* Take input RID as output RID in case of any error */
+ if (rid_out)
+ *rid_out = node ? rid : rid_in;
+ return node;
+}
+
+static struct acpi_iort_node *
+iort_find_dev_node(struct device *dev)
+{
+ struct pci_bus *pbus;
+
+ if (!dev_is_pci(dev))
+ return iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
+ iort_match_node_callback, dev);
+
+ /* Find a PCI root bus */
+ pbus = to_pci_dev(dev)->bus;
+ while (!pci_is_root_bus(pbus))
+ pbus = pbus->parent;
+
+ return iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
+ iort_match_node_callback, &pbus->dev);
+}
+
+void __init iort_table_detect(void)
+{
+ acpi_status status;
+
+ if (acpi_disabled)
+ return;
+
+ status = acpi_get_table(ACPI_SIG_IORT, 0, &iort_table);
+ if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+ const char *msg = acpi_format_exception(status);
+ pr_err("Failed to get table, %s\n", msg);
+ }
+}
diff --git a/include/linux/iort.h b/include/linux/iort.h
new file mode 100644
index 0000000..cde6809
--- /dev/null
+++ b/include/linux/iort.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2016, Semihalf
+ * Author: Tomasz Nowicki <tn@xxxxxxxxxxxx>
+ *
+ * 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>
+
+#ifdef CONFIG_IORT_TABLE
+void iort_table_detect(void);
+#else
+static inline void iort_table_detect(void) { }
+#endif
+
+#endif /* __IORT_H__ */
--
1.9.1
--
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