[PATCH V9 0/8] Introduce ACPI world to ITS irqchip

[PATCH V9 0/8] Introduce ACPI world to ITS irqchip

[Tomasz Nowicki]

The series builds the PCI/MSI domain stack based on initial IORT driver
which is added in first place. As a reference please see IORT spec:
http://infocenter.arm.com/help/topic/com.arm.doc.den0049b/DEN0049B_IO_Remapping_Table.pdf

Tested on Cavium ThunderX server and Qualcomm Technologies server platform QDF2XXX.
The patches can be found here:
https://github.com/semihalf-nowicki-tomasz/linux.git (its-acpi-v9)

v8 -> v9
- rebased against v4.8-rc4
- move root IORT pointer validation to one place iort_scan_node()
- function names & Kconfig option name improvements
- remove annoying dev_err() appearances for non-IORT users
- for debug purpose print full ITS resource range

v7 -> v8
- rebased against v4.8-rc1
- move IORT support under new drivers/acpi/arm64 directory
- memory leak fix for iort_match_node_callback()
- iort_node_map_rid() algorithm improvements
- fix RID match check in iort_id_map()
- fix typos and white spaces

v6 -> v7
- rebased against irq/irqchip-4.8
- improvements for IORT ID mapping
- call IORT init call from acpi_init() instead of arch_initcall()
- split IORT driver in to two parts: core and ITS/MSI

v5 -> v6
- added locking mechanism for IORT list with domain token
- IORT function name improvements
- extended IORT RID mapping helper
- reworked IORT to be more SMMU friendly
- IORT functions which map RID and find corresponding domain are not
  PCI specific any more (struct pci_dev -> struct device)
- bug fixes

v4 -> v5
- rebased against v4.7-rc1
- drop generic layer and call IORT functions directly
- improve resource abstraction and string formatting

v3 -> v4
- rebased against v4.5
- add ACPI support for IRQ domain handling on a per-device basis
- reorder domain setup step
- improve error handling
- code style improvements

v2 -> v3
- rebased on top of 4.4
- fixes and improvements for redistributor init via GICC structures
- fixes as per kbuild reports

v1 -> v2
- rebased on top of 4.4-rc4
- use pci_msi_domain_get_msi_rid for requester ID to device ID translation

Tomasz Nowicki (8):
  ACPI: I/O Remapping Table (IORT) initial support
  ACPI: Add new IORT functions to support MSI domain handling
  PCI/MSI: Setup MSI domain on a per-device basis using IORT ACPI table
  irqchip/gicv3-its: Cleanup for ITS domain initialization
  irqchip/gicv3-its: Refactor ITS DT init code to prepare for ACPI
  irqchip/gicv3-its: Probe ITS in the ACPI way
  irqchip/gicv3-its: Factor out PCI-MSI part that might be reused for
    ACPI
  irqchip/gicv3-its: Use MADT ITS subtable to do PCI/MSI domain
    initialization

 drivers/acpi/Kconfig                     |   4 +
 drivers/acpi/Makefile                    |   2 +
 drivers/acpi/arm64/Kconfig               |   6 +
 drivers/acpi/arm64/Makefile              |   1 +
 drivers/acpi/arm64/iort.c                | 378 +++++++++++++++++++++++++++++++
 drivers/acpi/bus.c                       |   2 +
 drivers/irqchip/Kconfig                  |   1 +
 drivers/irqchip/irq-gic-v3-its-pci-msi.c |  88 +++++--
 drivers/irqchip/irq-gic-v3-its.c         | 171 ++++++++++----
 drivers/irqchip/irq-gic-v3.c             |   7 +-
 drivers/pci/msi.c                        |  11 +-
 include/linux/iort.h                     |  41 ++++
 include/linux/irqchip/arm-gic-v3.h       |   4 +-
 13 files changed, 646 insertions(+), 70 deletions(-)
 create mode 100644 drivers/acpi/arm64/Kconfig
 create mode 100644 drivers/acpi/arm64/Makefile
 create mode 100644 drivers/acpi/arm64/iort.c
 create mode 100644 include/linux/iort.h

-- 
1.9.1

[PATCH V9 1/8] ACPI: I/O Remapping Table (IORT) initial support

[Tomasz Nowicki]

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.
http://infocenter.arm.com/help/topic/com.arm.doc.den0049b/DEN0049B_IO_Remapping_Table.pdf

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

IORT support is placed under drivers/acpi/arm64/ new directory due to its
ARM64 specific nature. The code there is considered only for ARM64.
The long term plan is to keep all ARM64 specific tables support
in this place e.g. GTDT table.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 drivers/acpi/Kconfig        |   4 +
 drivers/acpi/Makefile       |   2 +
 drivers/acpi/arm64/Kconfig  |   6 ++
 drivers/acpi/arm64/Makefile |   1 +
 drivers/acpi/arm64/iort.c   | 221 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/bus.c          |   2 +
 include/linux/iort.h        |  30 ++++++
 7 files changed, 266 insertions(+)
 create mode 100644 drivers/acpi/arm64/Kconfig
 create mode 100644 drivers/acpi/arm64/Makefile
 create mode 100644 drivers/acpi/arm64/iort.c
 create mode 100644 include/linux/iort.h

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 445ce28..d5c0614 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -521,4 +521,8 @@ config ACPI_CONFIGFS
 	  userspace. The configurable ACPI groups will be visible under
 	  /config/acpi, assuming configfs is mounted under /config.
 
+if ARM64
+source "drivers/acpi/arm64/Kconfig"
+endif
+
 endif	# ACPI
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 5ae9d85..e5ada78 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -105,3 +105,5 @@ obj-$(CONFIG_ACPI_CONFIGFS)	+= acpi_configfs.o
 
 video-objs			+= acpi_video.o video_detect.o
 obj-y				+= dptf/
+
+obj-$(CONFIG_ARM64)		+= arm64/
diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig
new file mode 100644
index 0000000..4616da4
--- /dev/null
+++ b/drivers/acpi/arm64/Kconfig
@@ -0,0 +1,6 @@
+#
+# ACPI Configuration for ARM64
+#
+
+config ACPI_IORT
+	bool
diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
new file mode 100644
index 0000000..72331f2
--- /dev/null
+++ b/drivers/acpi/arm64/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_ACPI_IORT) 	+= iort.o
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
new file mode 100644
index 0000000..82d5e7d
--- /dev/null
+++ b/drivers/acpi/arm64/iort.c
@@ -0,0 +1,221 @@
+/*
+ * 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/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;
+
+	if (!iort_table)
+		return NULL;
+
+	/* 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");
+		} else {
+			int match;
+
+			match = !strcmp(ncomp->device_name, buffer.pointer);
+			acpi_os_free(buffer.pointer);
+
+			if (match)
+				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)
+{
+	/* 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;
+
+	/* Parse the ID mapping tree to find specified node type */
+	while (node) {
+		struct acpi_iort_id_mapping *map;
+		int i;
+
+		if (node->type == type) {
+			if (rid_out)
+				*rid_out = rid;
+			return node;
+		}
+
+		if (!node->mapping_offset || !node->mapping_count)
+			goto fail_map;
+
+		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);
+			goto fail_map;
+		}
+
+		/* Do the RID translation */
+		for (i = 0; i < node->mapping_count; i++, map++) {
+			if (!iort_id_map(map, node->type, rid, &rid))
+				break;
+		}
+
+		if (i == node->mapping_count)
+			goto fail_map;
+
+		node = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
+				    map->output_reference);
+	}
+
+fail_map:
+	/* Map input RID to output RID unchanged on mapping failure*/
+	if (rid_out)
+		*rid_out = rid_in;
+
+	return NULL;
+}
+
+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 acpi_iort_init(void)
+{
+	acpi_status status;
+
+	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/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 85b7d07..7ddfbf2 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -36,6 +36,7 @@
 #ifdef CONFIG_X86
 #include <asm/mpspec.h>
 #endif
+#include <linux/iort.h>
 #include <linux/pci.h>
 #include <acpi/apei.h>
 #include <linux/dmi.h>
@@ -1186,6 +1187,7 @@ static int __init acpi_init(void)
 	}
 
 	pci_mmcfg_late_init();
+	acpi_iort_init();
 	acpi_scan_init();
 	acpi_ec_init();
 	acpi_debugfs_init();
diff --git a/include/linux/iort.h b/include/linux/iort.h
new file mode 100644
index 0000000..f4d5d45
--- /dev/null
+++ b/include/linux/iort.h
@@ -0,0 +1,30 @@
+/*
+ * 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>
+
+#ifdef CONFIG_ACPI_IORT
+void acpi_iort_init(void);
+#else
+static inline void acpi_iort_init(void) { }
+#endif
+
+#endif /* __IORT_H__ */
-- 
1.9.1

[PATCH V9 2/8] ACPI: Add new IORT functions to support MSI domain handling

[Tomasz Nowicki]

For ITS, MSI functionality consists on building domain stack and
during that process we need to reference to domain stack components
e.g. before we create new DOMAIN_BUS_PCI_MSI domain we need to specify
its DOMAIN_BUS_NEXUS parent domain. In order to manage that process
properly, maintain list which elements contain domain token
(unique for MSI domain stack) and ITS ID: iort_register_domain_token()
and iort_deregister_domain_token(). Then retrieve domain token
any time later with ITS ID being key off: iort_find_domain_token().
With domain token and domain type we are able to find corresponding
IRQ domain.

Since IORT is prepared to describe MSI domain on a per-device basis,
use existing IORT helpers and implement two calls:
1. iort_msi_map_rid() to map MSI RID for a device
2. iort_get_device_domain() to find domain token for a device

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
---
 drivers/acpi/arm64/iort.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/iort.h      |  11 ++++
 2 files changed, 168 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 82d5e7d..f38253c 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -22,12 +22,91 @@
 #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);
+static DEFINE_SPINLOCK(iort_msi_chip_lock);
+
+/**
+ * iort_register_domain_token() - register domain token and related ITS ID
+ * to the list from where we can get it back later on.
+ * @trans_id: ITS ID.
+ * @fw_node: Domain token.
+ *
+ * Returns: 0 on success, -ENOMEM if no 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;
+
+	spin_lock(&iort_msi_chip_lock);
+	list_add(&its_msi_chip->list, &iort_msi_chip_list);
+	spin_unlock(&iort_msi_chip_lock);
+
+	return 0;
+}
+
+/**
+ * iort_deregister_domain_token() - Deregister domain token based on ITS ID
+ * @trans_id: ITS ID.
+ *
+ * Returns: none.
+ */
+void iort_deregister_domain_token(int trans_id)
+{
+	struct iort_its_msi_chip *its_msi_chip, *t;
+
+	spin_lock(&iort_msi_chip_lock);
+	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;
+		}
+	}
+	spin_unlock(&iort_msi_chip_lock);
+}
+
+/**
+ * iort_find_domain_token() - Find domain token based on given ITS ID
+ * @trans_id: ITS ID.
+ *
+ * Returns: domain token when find on the list, NULL otherwise
+ */
+struct fwnode_handle *iort_find_domain_token(int trans_id)
+{
+	struct fwnode_handle *fw_node = NULL;
+	struct iort_its_msi_chip *its_msi_chip;
+
+	spin_lock(&iort_msi_chip_lock);
+	list_for_each_entry(its_msi_chip, &iort_msi_chip_list, list) {
+		if (its_msi_chip->translation_id == trans_id) {
+			fw_node = its_msi_chip->fw_node;
+			break;
+		}
+	}
+	spin_unlock(&iort_msi_chip_lock);
+
+	return fw_node;
+}
+
 static struct acpi_iort_node *
 iort_scan_node(enum acpi_iort_node_type type,
 	       iort_find_node_callback callback, void *context)
@@ -209,6 +288,84 @@ iort_find_dev_node(struct device *dev)
 			      iort_match_node_callback, &pbus->dev);
 }
 
+/**
+ * iort_msi_map_rid() - Map a MSI requester ID for a device
+ * @dev: The device for which the mapping is to be done.
+ * @req_id: The device requester ID.
+ *
+ * Returns: mapped MSI RID on success, input requester ID otherwise
+ */
+u32 iort_msi_map_rid(struct device *dev, u32 req_id)
+{
+	struct acpi_iort_node *node;
+	u32 dev_id;
+
+	node = iort_find_dev_node(dev);
+	if (!node)
+		return req_id;
+
+	iort_node_map_rid(node, req_id, &dev_id, ACPI_IORT_NODE_ITS_GROUP);
+	return dev_id;
+}
+
+/**
+ * iort_dev_find_its_id() - Find the ITS identifier for a device
+ * @dev: The device.
+ * @idx: Index of the ITS identifier list.
+ * @its_id: ITS identifier.
+ *
+ * Returns: 0 on success, appropriate error value otherwise
+ */
+static int
+iort_dev_find_its_id(struct device *dev, u32 req_id, unsigned int idx,
+		     int *its_id)
+{
+	struct acpi_iort_its_group *its;
+	struct acpi_iort_node *node;
+
+	node = iort_find_dev_node(dev);
+	if (!node)
+		return -ENXIO;
+
+	node = iort_node_map_rid(node, req_id, NULL, ACPI_IORT_NODE_ITS_GROUP);
+	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(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_get_device_domain() - Find MSI domain related to a device
+ * @dev: The device.
+ * @req_id: Requester ID for the device.
+ *
+ * Returns: the MSI domain for this device, NULL otherwise
+ */
+struct irq_domain *
+iort_get_device_domain(struct device *dev, u32 req_id)
+{
+	static struct fwnode_handle *handle;
+	int its_id;
+
+	if (iort_dev_find_its_id(dev, req_id, 0, &its_id))
+		return NULL;
+
+	handle = iort_find_domain_token(its_id);
+	if (!handle)
+		return NULL;
+
+	return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
+}
+
 void __init acpi_iort_init(void)
 {
 	acpi_status status;
diff --git a/include/linux/iort.h b/include/linux/iort.h
index f4d5d45..74ab47f 100644
--- a/include/linux/iort.h
+++ b/include/linux/iort.h
@@ -20,11 +20,22 @@
 #define __IORT_H__
 
 #include <linux/acpi.h>
+#include <linux/fwnode.h>
+#include <linux/irqdomain.h>
 
+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_find_domain_token(int trans_id);
 #ifdef CONFIG_ACPI_IORT
 void acpi_iort_init(void);
+u32 iort_msi_map_rid(struct device *dev, u32 req_id);
+struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
 #else
 static inline void acpi_iort_init(void) { }
+static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id)
+{ return req_id; }
+static inline struct irq_domain *
+iort_get_device_domain(struct device *dev, u32 req_id) { return NULL; }
 #endif
 
 #endif /* __IORT_H__ */
-- 
1.9.1

[PATCH V9 3/8] PCI/MSI: Setup MSI domain on a per-device basis using IORT ACPI table

[Tomasz Nowicki]

It is possible to provide information about which MSI controller to
use on a per-device basis for DT. This patch supply this with ACPI support.

Currently, IORT is the only one ACPI table which can provide such mapping.
In order to plug IORT into MSI infrastructure we are adding ACPI
equivalents for finding PCI device domain and its RID translation
(pci_msi_domain_get_msi_rid and pci_msi_domain_get_msi_rid calls).

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/msi.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 98f1222..37f253a 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -19,6 +19,7 @@
 #include <linux/smp.h>
 #include <linux/errno.h>
 #include <linux/io.h>
+#include <linux/iort.h>
 #include <linux/slab.h>
 #include <linux/irqdomain.h>
 #include <linux/of_irq.h>
@@ -1502,8 +1503,8 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
 	pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
 
 	of_node = irq_domain_get_of_node(domain);
-	if (of_node)
-		rid = of_msi_map_rid(&pdev->dev, of_node, rid);
+	rid = of_node ? of_msi_map_rid(&pdev->dev, of_node, rid) :
+			iort_msi_map_rid(&pdev->dev, rid);
 
 	return rid;
 }
@@ -1519,9 +1520,13 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
  */
 struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
 {
+	struct irq_domain *dom;
 	u32 rid = 0;
 
 	pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
-	return of_msi_map_get_device_domain(&pdev->dev, rid);
+	dom = of_msi_map_get_device_domain(&pdev->dev, rid);
+	if (!dom)
+		dom = iort_get_device_domain(&pdev->dev, rid);
+	return dom;
 }
 #endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
-- 
1.9.1

[PATCH V9 4/8] irqchip/gicv3-its: Cleanup for ITS domain initialization

[Tomasz Nowicki]

There is no point to initialize ITS without having msi-controller
property in corresponding DT node. However, its_probe is checking
msi-controller presence at the end, so we can save our time and do that
check prior to its_probe call. Also, for the code clarity purpose,
we put domain initialization to separate function.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
---
 drivers/irqchip/irq-gic-v3-its.c | 57 ++++++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 23 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 36b9c28..943442d 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1614,13 +1614,37 @@ static void its_enable_quirks(struct its_node *its)
 	gic_enable_quirks(iidr, its_quirks, its);
 }
 
+static int its_init_domain(struct device_node *node, struct its_node *its,
+			   struct irq_domain *parent)
+{
+	struct irq_domain *inner_domain;
+	struct msi_domain_info *info;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	inner_domain = irq_domain_add_tree(node, &its_domain_ops, its);
+	if (!inner_domain) {
+		kfree(info);
+		return -ENOMEM;
+	}
+
+	inner_domain->parent = parent;
+	inner_domain->bus_token = DOMAIN_BUS_NEXUS;
+	info->ops = &its_msi_domain_ops;
+	info->data = its;
+	inner_domain->host_data = info;
+
+	return 0;
+}
+
 static int __init its_probe(struct device_node *node,
 			    struct irq_domain *parent)
 {
 	struct resource res;
 	struct its_node *its;
 	void __iomem *its_base;
-	struct irq_domain *inner_domain;
 	u32 val;
 	u64 baser, tmp;
 	int err;
@@ -1712,28 +1736,9 @@ static int __init its_probe(struct device_node *node,
 	writeq_relaxed(0, its->base + GITS_CWRITER);
 	writel_relaxed(GITS_CTLR_ENABLE, its->base + GITS_CTLR);
 
-	if (of_property_read_bool(node, "msi-controller")) {
-		struct msi_domain_info *info;
-
-		info = kzalloc(sizeof(*info), GFP_KERNEL);
-		if (!info) {
-			err = -ENOMEM;
-			goto out_free_tables;
-		}
-
-		inner_domain = irq_domain_add_tree(node, &its_domain_ops, its);
-		if (!inner_domain) {
-			err = -ENOMEM;
-			kfree(info);
-			goto out_free_tables;
-		}
-
-		inner_domain->parent = parent;
-		inner_domain->bus_token = DOMAIN_BUS_NEXUS;
-		info->ops = &its_msi_domain_ops;
-		info->data = its;
-		inner_domain->host_data = info;
-	}
+	err = its_init_domain(node, its, parent);
+	if (err)
+		goto out_free_tables;
 
 	spin_lock(&its_lock);
 	list_add(&its->entry, &its_nodes);
@@ -1784,6 +1789,12 @@ int __init its_init(struct device_node *node, struct rdists *rdists,
 
 	for (np = of_find_matching_node(node, its_device_id); np;
 	     np = of_find_matching_node(np, its_device_id)) {
+		if (!of_property_read_bool(np, "msi-controller")) {
+			pr_warn("%s: no msi-controller property, ITS ignored\n",
+				np->full_name);
+			continue;
+		}
+
 		its_probe(np, parent_domain);
 	}
 
-- 
1.9.1

[PATCH V9 5/8] irqchip/gicv3-its: Refactor ITS DT init code to prepare for ACPI

[Tomasz Nowicki]

In order to add ACPI support we need to isolate ACPI&DT common code and
move DT logic to corresponding functions. To achieve this we are using
firmware agnostic handle which can be unpacked to either DT or ACPI node.

No functional changes other than a very minor one:
1. Terminate its_init call with -ENODEV for non-DT case which allows
to remove hack from its-gic-v3.c.
2. Fix ITS base register address type (from 'unsigned long' to 'phys_addr_t'),
as a bonus we get nice string formatting.
3. Since there is only one of ITS parent domain convert it to static global
variable and drop the parameter from its_probe_one. Users can refer to it
in more convenient way then.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
---
 drivers/irqchip/irq-gic-v3-its.c   | 65 ++++++++++++++++++++++----------------
 drivers/irqchip/irq-gic-v3.c       |  7 ++--
 include/linux/irqchip/arm-gic-v3.h |  4 +--
 3 files changed, 42 insertions(+), 34 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 943442d..c7518c7 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -75,7 +75,7 @@ struct its_node {
 	raw_spinlock_t		lock;
 	struct list_head	entry;
 	void __iomem		*base;
-	unsigned long		phys_base;
+	phys_addr_t		phys_base;
 	struct its_cmd_block	*cmd_base;
 	struct its_cmd_block	*cmd_write;
 	struct its_baser	tables[GITS_BASER_NR_REGS];
@@ -115,6 +115,7 @@ struct its_device {
 static LIST_HEAD(its_nodes);
 static DEFINE_SPINLOCK(its_lock);
 static struct rdists *gic_rdists;
+static struct irq_domain *its_parent;
 
 #define gic_data_rdist()		(raw_cpu_ptr(gic_rdists->rdist))
 #define gic_data_rdist_rd_base()	(gic_data_rdist()->rd_base)
@@ -1614,8 +1615,7 @@ static void its_enable_quirks(struct its_node *its)
 	gic_enable_quirks(iidr, its_quirks, its);
 }
 
-static int its_init_domain(struct device_node *node, struct its_node *its,
-			   struct irq_domain *parent)
+static int its_init_domain(struct fwnode_handle *handle, struct its_node *its)
 {
 	struct irq_domain *inner_domain;
 	struct msi_domain_info *info;
@@ -1624,13 +1624,13 @@ static int its_init_domain(struct device_node *node, struct its_node *its,
 	if (!info)
 		return -ENOMEM;
 
-	inner_domain = irq_domain_add_tree(node, &its_domain_ops, its);
+	inner_domain = irq_domain_create_tree(handle, &its_domain_ops, its);
 	if (!inner_domain) {
 		kfree(info);
 		return -ENOMEM;
 	}
 
-	inner_domain->parent = parent;
+	inner_domain->parent = its_parent;
 	inner_domain->bus_token = DOMAIN_BUS_NEXUS;
 	info->ops = &its_msi_domain_ops;
 	info->data = its;
@@ -1639,43 +1639,35 @@ static int its_init_domain(struct device_node *node, struct its_node *its,
 	return 0;
 }
 
-static int __init its_probe(struct device_node *node,
-			    struct irq_domain *parent)
+static int __init its_probe_one(struct resource *res,
+				struct fwnode_handle *handle, int numa_node)
 {
-	struct resource res;
 	struct its_node *its;
 	void __iomem *its_base;
 	u32 val;
 	u64 baser, tmp;
 	int err;
 
-	err = of_address_to_resource(node, 0, &res);
-	if (err) {
-		pr_warn("%s: no regs?\n", node->full_name);
-		return -ENXIO;
-	}
-
-	its_base = ioremap(res.start, resource_size(&res));
+	its_base = ioremap(res->start, resource_size(res));
 	if (!its_base) {
-		pr_warn("%s: unable to map registers\n", node->full_name);
+		pr_warn("ITS@%pa: Unable to map ITS registers\n", &res->start);
 		return -ENOMEM;
 	}
 
 	val = readl_relaxed(its_base + GITS_PIDR2) & GIC_PIDR2_ARCH_MASK;
 	if (val != 0x30 && val != 0x40) {
-		pr_warn("%s: no ITS detected, giving up\n", node->full_name);
+		pr_warn("ITS@%pa: No ITS detected, giving up\n", &res->start);
 		err = -ENODEV;
 		goto out_unmap;
 	}
 
 	err = its_force_quiescent(its_base);
 	if (err) {
-		pr_warn("%s: failed to quiesce, giving up\n",
-			node->full_name);
+		pr_warn("ITS@%pa: Failed to quiesce, giving up\n", &res->start);
 		goto out_unmap;
 	}
 
-	pr_info("ITS: %s\n", node->full_name);
+	pr_info("ITS %pR\n", res);
 
 	its = kzalloc(sizeof(*its), GFP_KERNEL);
 	if (!its) {
@@ -1687,9 +1679,9 @@ static int __init its_probe(struct device_node *node,
 	INIT_LIST_HEAD(&its->entry);
 	INIT_LIST_HEAD(&its->its_device_list);
 	its->base = its_base;
-	its->phys_base = res.start;
+	its->phys_base = res->start;
 	its->ite_size = ((readl_relaxed(its_base + GITS_TYPER) >> 4) & 0xf) + 1;
-	its->numa_node = of_node_to_nid(node);
+	its->numa_node = numa_node;
 
 	its->cmd_base = kzalloc(ITS_CMD_QUEUE_SZ, GFP_KERNEL);
 	if (!its->cmd_base) {
@@ -1736,7 +1728,7 @@ static int __init its_probe(struct device_node *node,
 	writeq_relaxed(0, its->base + GITS_CWRITER);
 	writel_relaxed(GITS_CTLR_ENABLE, its->base + GITS_CTLR);
 
-	err = its_init_domain(node, its, parent);
+	err = its_init_domain(handle, its);
 	if (err)
 		goto out_free_tables;
 
@@ -1754,7 +1746,7 @@ out_free_its:
 	kfree(its);
 out_unmap:
 	iounmap(its_base);
-	pr_err("ITS: failed probing %s (%d)\n", node->full_name, err);
+	pr_err("ITS@%pa: failed probing (%d)\n", &res->start, err);
 	return err;
 }
 
@@ -1782,10 +1774,10 @@ static struct of_device_id its_device_id[] = {
 	{},
 };
 
-int __init its_init(struct device_node *node, struct rdists *rdists,
-	     struct irq_domain *parent_domain)
+static int __init its_of_probe(struct device_node *node)
 {
 	struct device_node *np;
+	struct resource res;
 
 	for (np = of_find_matching_node(node, its_device_id); np;
 	     np = of_find_matching_node(np, its_device_id)) {
@@ -1795,8 +1787,27 @@ int __init its_init(struct device_node *node, struct rdists *rdists,
 			continue;
 		}
 
-		its_probe(np, parent_domain);
+		if (of_address_to_resource(np, 0, &res)) {
+			pr_warn("%s: no regs?\n", np->full_name);
+			continue;
+		}
+
+		its_probe_one(&res, &np->fwnode, of_node_to_nid(np));
 	}
+	return 0;
+}
+
+int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
+		    struct irq_domain *parent_domain)
+{
+	struct device_node *of_node;
+
+	its_parent = parent_domain;
+	of_node = to_of_node(handle);
+	if (of_node)
+		its_of_probe(of_node);
+	else
+		return -ENODEV;
 
 	if (list_empty(&its_nodes)) {
 		pr_warn("ITS: No ITS available, not enabling LPIs\n");
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index ede5672..1efc02a 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -910,7 +910,6 @@ static int __init gic_init_bases(void __iomem *dist_base,
 				 u64 redist_stride,
 				 struct fwnode_handle *handle)
 {
-	struct device_node *node;
 	u32 typer;
 	int gic_irqs;
 	int err;
@@ -951,10 +950,8 @@ static int __init gic_init_bases(void __iomem *dist_base,
 
 	set_handle_irq(gic_handle_irq);
 
-	node = to_of_node(handle);
-	if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis() &&
-	    node) /* Temp hack to prevent ITS init for ACPI */
-		its_init(node, &gic_data.rdists, gic_data.domain);
+	if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis())
+		its_init(handle, &gic_data.rdists, gic_data.domain);
 
 	gic_smp_init();
 	gic_dist_init();
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index 99ac022..8361c8d 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -430,9 +430,9 @@ struct rdists {
 };
 
 struct irq_domain;
-struct device_node;
+struct fwnode_handle;
 int its_cpu_init(void);
-int its_init(struct device_node *node, struct rdists *rdists,
+int its_init(struct fwnode_handle *handle, struct rdists *rdists,
 	     struct irq_domain *domain);
 
 static inline bool gic_enable_sre(void)
-- 
1.9.1

[PATCH V9 6/8] irqchip/gicv3-its: Probe ITS in the ACPI way

[Tomasz Nowicki]

ITS is prepared for being initialized different than DT,
therefore we can initialize it in ACPI way. We collect register base
address from MADT table and pass mandatory info to firmware-agnostic
ITS init call.

Use here IORT lib to register ITS domain which then can be found and
used on to build another PCI MSI domain in hierarchical stack domain.

NOTE: Waiting for proper ITS and NUMA node relation description in IORT
table, we pass around NUMA_NO_NODE to the its_probe_one init call.
This means that Cavium ThunderX erratum 23144 (pass1.1 only)
is not supported for ACPI boot method yet.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
---
 drivers/irqchip/Kconfig          |  1 +
 drivers/irqchip/irq-gic-v3-its.c | 61 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 7f87289..9aeea1d 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -39,6 +39,7 @@ config ARM_GIC_V3_ITS
 	bool
 	depends on PCI
 	depends on PCI_MSI
+	select ACPI_IORT if ACPI
 
 config ARM_NVIC
 	bool
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index c7518c7..7c0089f 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -15,10 +15,13 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/acpi.h>
 #include <linux/bitmap.h>
 #include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/iort.h>
 #include <linux/log2.h>
 #include <linux/mm.h>
 #include <linux/msi.h>
@@ -1438,6 +1441,11 @@ static int its_irq_gic_domain_alloc(struct irq_domain *domain,
 		fwspec.param[0] = GIC_IRQ_TYPE_LPI;
 		fwspec.param[1] = hwirq;
 		fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+	} else if (is_fwnode_irqchip(domain->parent->fwnode)) {
+		fwspec.fwnode = domain->parent->fwnode;
+		fwspec.param_count = 2;
+		fwspec.param[0] = hwirq;
+		fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
 	} else {
 		return -EINVAL;
 	}
@@ -1797,6 +1805,57 @@ static int __init its_of_probe(struct device_node *node)
 	return 0;
 }
 
+#ifdef CONFIG_ACPI
+
+#define ACPI_GICV3_ITS_MEM_SIZE (SZ_128K)
+
+static int __init gic_acpi_parse_madt_its(struct acpi_subtable_header *header,
+					  const unsigned long end)
+{
+	struct acpi_madt_generic_translator *its_entry;
+	struct fwnode_handle *dom_handle;
+	struct resource res;
+	int err;
+
+	its_entry = (struct acpi_madt_generic_translator *)header;
+	memset(&res, 0, sizeof(res));
+	res.start = its_entry->base_address;
+	res.end = its_entry->base_address + ACPI_GICV3_ITS_MEM_SIZE - 1;
+	res.flags = IORESOURCE_MEM;
+
+	dom_handle = irq_domain_alloc_fwnode((void *)its_entry->base_address);
+	if (!dom_handle) {
+		pr_err("ITS@%pa: Unable to allocate GICv3 ITS domain token\n",
+		       &res.start);
+		return -ENOMEM;
+	}
+
+	err = iort_register_domain_token(its_entry->translation_id, dom_handle);
+	if (err) {
+		pr_err("ITS@%pa: Unable to register GICv3 ITS domain token (ITS ID %d) to IORT\n",
+		       &res.start, its_entry->translation_id);
+		goto dom_err;
+	}
+
+	err = its_probe_one(&res, dom_handle, NUMA_NO_NODE);
+	if (!err)
+		return 0;
+
+	iort_deregister_domain_token(its_entry->translation_id);
+dom_err:
+	irq_domain_free_fwnode(dom_handle);
+	return err;
+}
+
+static void __init its_acpi_probe(void)
+{
+	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
+			      gic_acpi_parse_madt_its, 0);
+}
+#else
+static void __init its_acpi_probe(void) { }
+#endif
+
 int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
 		    struct irq_domain *parent_domain)
 {
@@ -1807,7 +1866,7 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
 	if (of_node)
 		its_of_probe(of_node);
 	else
-		return -ENODEV;
+		its_acpi_probe();
 
 	if (list_empty(&its_nodes)) {
 		pr_warn("ITS: No ITS available, not enabling LPIs\n");
-- 
1.9.1

[PATCH V9 7/8] irqchip/gicv3-its: Factor out PCI-MSI part that might be reused for ACPI

[Tomasz Nowicki]

Firmware agnostic code lands in common functions which do necessary
domain initialization based on unique domain handler. DT specific
code goes to DT specific init call.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-gic-v3-its-pci-msi.c | 44 +++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 15 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its-pci-msi.c b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
index aee60ed..d2c2496 100644
--- a/drivers/irqchip/irq-gic-v3-its-pci-msi.c
+++ b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
@@ -106,34 +106,48 @@ static struct of_device_id its_device_id[] = {
 	{},
 };
 
-static int __init its_pci_msi_init(void)
+static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
+				       const char *name)
 {
-	struct device_node *np;
 	struct irq_domain *parent;
 
+	parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
+	if (!parent || !msi_get_domain_info(parent)) {
+		pr_err("%s: Unable to locate ITS domain\n", name);
+		return -ENXIO;
+	}
+
+	if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
+				       parent)) {
+		pr_err("%s: Unable to create PCI domain\n", name);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int __init its_pci_of_msi_init(void)
+{
+	struct device_node *np;
+
 	for (np = of_find_matching_node(NULL, its_device_id); np;
 	     np = of_find_matching_node(np, its_device_id)) {
 		if (!of_property_read_bool(np, "msi-controller"))
 			continue;
 
-		parent = irq_find_matching_host(np, DOMAIN_BUS_NEXUS);
-		if (!parent || !msi_get_domain_info(parent)) {
-			pr_err("%s: unable to locate ITS domain\n",
-			       np->full_name);
+		if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
 			continue;
-		}
-
-		if (!pci_msi_create_irq_domain(of_node_to_fwnode(np),
-					       &its_pci_msi_domain_info,
-					       parent)) {
-			pr_err("%s: unable to create PCI domain\n",
-			       np->full_name);
-			continue;
-		}
 
 		pr_info("PCI/MSI: %s domain created\n", np->full_name);
 	}
 
 	return 0;
 }
+
+static int __init its_pci_msi_init(void)
+{
+	its_pci_of_msi_init();
+
+	return 0;
+}
 early_initcall(its_pci_msi_init);
-- 
1.9.1

[PATCH V9 8/8] irqchip/gicv3-its: Use MADT ITS subtable to do PCI/MSI domain initialization

[Tomasz Nowicki]

Let ACPI build ITS PCI MSI domain. ACPI code is responsible for retrieving
inner domain token and passing it on to its_pci_msi_init_one generic
init call.

IORT maintains list of registered domain tokens and allows to find
corresponding domain based on MADT ITS subtable ID info.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
---
 drivers/irqchip/irq-gic-v3-its-pci-msi.c | 44 ++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its-pci-msi.c b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
index d2c2496..ae7221c 100644
--- a/drivers/irqchip/irq-gic-v3-its-pci-msi.c
+++ b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
@@ -15,6 +15,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/iort.h>
 #include <linux/msi.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
@@ -144,9 +145,52 @@ static int __init its_pci_of_msi_init(void)
 	return 0;
 }
 
+#ifdef CONFIG_ACPI
+
+static int __init
+its_pci_msi_parse_madt(struct acpi_subtable_header *header,
+		       const unsigned long end)
+{
+	struct acpi_madt_generic_translator *its_entry;
+	struct fwnode_handle *dom_handle;
+	const char *node_name;
+	int err = -ENXIO;
+
+	its_entry = (struct acpi_madt_generic_translator *)header;
+	node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
+			      (long)its_entry->base_address);
+	dom_handle = iort_find_domain_token(its_entry->translation_id);
+	if (!dom_handle) {
+		pr_err("%s: Unable to locate ITS domain handle\n", node_name);
+		goto out;
+	}
+
+	err = its_pci_msi_init_one(dom_handle, node_name);
+	if (!err)
+		pr_info("PCI/MSI: %s domain created\n", node_name);
+
+out:
+	kfree(node_name);
+	return err;
+}
+
+static int __init its_pci_acpi_msi_init(void)
+{
+	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
+			      its_pci_msi_parse_madt, 0);
+	return 0;
+}
+#else
+static int __init its_pci_acpi_msi_init(void)
+{
+	return 0;
+}
+#endif
+
 static int __init its_pci_msi_init(void)
 {
 	its_pci_of_msi_init();
+	its_pci_acpi_msi_init();
 
 	return 0;
 }
-- 
1.9.1

Re: [PATCH V9 1/8] ACPI: I/O Remapping Table (IORT) initial support

[Rafael J. Wysocki]

On Mon, Sep 5, 2016 at 10:05 PM, Tomasz Nowicki <tn@semihalf.com> wrote:
> 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.
> http://infocenter.arm.com/help/topic/com.arm.doc.den0049b/DEN0049B_IO_Remapping_Table.pdf
>
> 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
>
> IORT support is placed under drivers/acpi/arm64/ new directory due to its
> ARM64 specific nature. The code there is considered only for ARM64.
> The long term plan is to keep all ARM64 specific tables support
> in this place e.g. GTDT table.
>
> Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
> Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Some cosmetic stuff below.

> ---
>  drivers/acpi/Kconfig        |   4 +
>  drivers/acpi/Makefile       |   2 +
>  drivers/acpi/arm64/Kconfig  |   6 ++
>  drivers/acpi/arm64/Makefile |   1 +
>  drivers/acpi/arm64/iort.c   | 221 ++++++++++++++++++++++++++++++++++++++++++++
>  drivers/acpi/bus.c          |   2 +
>  include/linux/iort.h        |  30 ++++++
>  7 files changed, 266 insertions(+)
>  create mode 100644 drivers/acpi/arm64/Kconfig
>  create mode 100644 drivers/acpi/arm64/Makefile
>  create mode 100644 drivers/acpi/arm64/iort.c
>  create mode 100644 include/linux/iort.h
>
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 445ce28..d5c0614 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -521,4 +521,8 @@ config ACPI_CONFIGFS
>           userspace. The configurable ACPI groups will be visible under
>           /config/acpi, assuming configfs is mounted under /config.
>
> +if ARM64
> +source "drivers/acpi/arm64/Kconfig"
> +endif
> +
>  endif  # ACPI
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 5ae9d85..e5ada78 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -105,3 +105,5 @@ obj-$(CONFIG_ACPI_CONFIGFS) += acpi_configfs.o
>
>  video-objs                     += acpi_video.o video_detect.o
>  obj-y                          += dptf/
> +
> +obj-$(CONFIG_ARM64)            += arm64/
> diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig
> new file mode 100644
> index 0000000..4616da4
> --- /dev/null
> +++ b/drivers/acpi/arm64/Kconfig
> @@ -0,0 +1,6 @@
> +#
> +# ACPI Configuration for ARM64
> +#
> +
> +config ACPI_IORT
> +       bool
> diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
> new file mode 100644
> index 0000000..72331f2
> --- /dev/null
> +++ b/drivers/acpi/arm64/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_ACPI_IORT)        += iort.o
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> new file mode 100644
> index 0000000..82d5e7d
> --- /dev/null
> +++ b/drivers/acpi/arm64/iort.c
> @@ -0,0 +1,221 @@
> +/*
> + * 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/iort.h>

Do we need a separate header file for this?

> +#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,

Please do not break function headers like this.  Specifically, the
return type and the name should be located in the same line.

> +              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;
> +
> +       /* 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;

It's better to write this as

if (iort_node->type == type && 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");

I'd switch the branches so that the one to be executed on success goes first.

Also consider using acpi_status variables for things like this.

        status = acpi_get_name(adev->handle, ACPI_FULL_PATHNAME, &buffer);
        if (ACPI_SUCCESS(status)) {

is much easier to follow than what you are doing here.

> +               } else {
> +                       int match;
> +
> +                       match = !strcmp(ncomp->device_name, buffer.pointer);
> +                       acpi_os_free(buffer.pointer);
> +
> +                       if (match)
> +                               return AE_OK;
> +               }
> +
> +               break;
> +       }
> +       case ACPI_IORT_NODE_PCI_ROOT_COMPLEX: {

What is the brace for?

> +               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)
> +{
> +       /* 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;
> +
> +       /* Parse the ID mapping tree to find specified node type */
> +       while (node) {
> +               struct acpi_iort_id_mapping *map;
> +               int i;
> +
> +               if (node->type == type) {
> +                       if (rid_out)
> +                               *rid_out = rid;
> +                       return node;
> +               }
> +
> +               if (!node->mapping_offset || !node->mapping_count)
> +                       goto fail_map;
> +
> +               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);
> +                       goto fail_map;
> +               }
> +
> +               /* Do the RID translation */
> +               for (i = 0; i < node->mapping_count; i++, map++) {
> +                       if (!iort_id_map(map, node->type, rid, &rid))
> +                               break;
> +               }
> +
> +               if (i == node->mapping_count)
> +                       goto fail_map;
> +
> +               node = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
> +                                   map->output_reference);
> +       }
> +
> +fail_map:
> +       /* Map input RID to output RID unchanged on mapping failure*/
> +       if (rid_out)
> +               *rid_out = rid_in;
> +
> +       return NULL;
> +}
> +
> +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 acpi_iort_init(void)
> +{
> +       acpi_status status;
> +
> +       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/drivers/acpi/bus.c b/drivers/acpi/bus.c
> index 85b7d07..7ddfbf2 100644
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -36,6 +36,7 @@
>  #ifdef CONFIG_X86
>  #include <asm/mpspec.h>
>  #endif
> +#include <linux/iort.h>
>  #include <linux/pci.h>
>  #include <acpi/apei.h>
>  #include <linux/dmi.h>
> @@ -1186,6 +1187,7 @@ static int __init acpi_init(void)
>         }
>
>         pci_mmcfg_late_init();
> +       acpi_iort_init();
>         acpi_scan_init();
>         acpi_ec_init();
>         acpi_debugfs_init();
> diff --git a/include/linux/iort.h b/include/linux/iort.h
> new file mode 100644
> index 0000000..f4d5d45
> --- /dev/null
> +++ b/include/linux/iort.h

If the new file header is necessary, it should be called acpi_iort.h IMO.

> @@ -0,0 +1,30 @@
> +/*
> + * 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>
> +
> +#ifdef CONFIG_ACPI_IORT
> +void acpi_iort_init(void);
> +#else
> +static inline void acpi_iort_init(void) { }
> +#endif

But I'm not really sure what would be wrong with putting this into acpi.h TBH.

> +
> +#endif /* __IORT_H__ */
> --
> 1.9.1
>

Thanks,
Rafael

Re: [PATCH V9 1/8] ACPI: I/O Remapping Table (IORT) initial support

[Tomasz Nowicki]

Hi Rafael,

On 05.09.2016 22:29, Rafael J. Wysocki wrote:
> On Mon, Sep 5, 2016 at 10:05 PM, Tomasz Nowicki <tn@semihalf.com> wrote:
>> 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.
>> http://infocenter.arm.com/help/topic/com.arm.doc.den0049b/DEN0049B_IO_Remapping_Table.pdf
>>
>> 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
>>
>> IORT support is placed under drivers/acpi/arm64/ new directory due to its
>> ARM64 specific nature. The code there is considered only for ARM64.
>> The long term plan is to keep all ARM64 specific tables support
>> in this place e.g. GTDT table.
>>
>> Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
>> Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
>> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>
> Some cosmetic stuff below.
>

[...]

>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
>> new file mode 100644
>> index 0000000..82d5e7d
>> --- /dev/null
>> +++ b/drivers/acpi/arm64/iort.c
>> @@ -0,0 +1,221 @@
>> +/*
>> + * 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/iort.h>
>
> Do we need a separate header file for this?

IMO yes. It's well isolated functionality and more will be added in 
patch 2 and IOMMU support by Lorenzo. Also, it's the same convention as 
for DMAR support.

>
>> +#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,
>
> Please do not break function headers like this.  Specifically, the
> return type and the name should be located in the same line.

OK

>
>> +              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;
>> +
>> +       /* 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;
>
> It's better to write this as
>
> if (iort_node->type == type && ACPI_SUCCESS(callback(iort_node, context))
>         return iort_node;

OK

>
>> +               }
>> +
>> +               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");
>
> I'd switch the branches so that the one to be executed on success goes first.
>
> Also consider using acpi_status variables for things like this.
>
>         status = acpi_get_name(adev->handle, ACPI_FULL_PATHNAME, &buffer);
>         if (ACPI_SUCCESS(status)) {
>
> is much easier to follow than what you are doing here.

Agree, actually I rewrite this function as follow:

static acpi_status iort_match_node_callback(struct acpi_iort_node *node,
					    void *context)
{
	struct device *dev = context;
	acpi_status status = AE_NOT_FOUND;

	switch (node->type) {
	case ACPI_IORT_NODE_NAMED_COMPONENT: {
		struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
		struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
		struct acpi_iort_named_component *ncomp;

		if (!adev)
			break;

		status = acpi_get_name(adev->handle, ACPI_FULL_PATHNAME, &buf);
		if (ACPI_FAILURE(status)) {
			dev_warn(dev, "Can't get device full path name\n");
			break;
		}

		ncomp = (struct acpi_iort_named_component *)node->node_data;
		if (!strcmp(ncomp->device_name, buf.pointer))
			status = AE_OK;

		acpi_os_free(buf.pointer);
		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))
			status = AE_OK;

		break;
	}
	}

	return status;
}

>
>> +               } else {
>> +                       int match;
>> +
>> +                       match = !strcmp(ncomp->device_name, buffer.pointer);
>> +                       acpi_os_free(buffer.pointer);
>> +
>> +                       if (match)
>> +                               return AE_OK;
>> +               }
>> +
>> +               break;
>> +       }
>> +       case ACPI_IORT_NODE_PCI_ROOT_COMPLEX: {
>
> What is the brace for?

To create namespace for below local variables. The same for 
ACPI_IORT_NODE_NAMED_COMPONENT case.

>
>> +               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;
>> +}
>> +

[...]

>> diff --git a/include/linux/iort.h b/include/linux/iort.h
>> new file mode 100644
>> index 0000000..f4d5d45
>> --- /dev/null
>> +++ b/include/linux/iort.h
>
> If the new file header is necessary, it should be called acpi_iort.h IMO.

OK

Thanks,
Tomasz

Re: [PATCH V9 1/8] ACPI: I/O Remapping Table (IORT) initial support

[Rafael J. Wysocki]

On Tue, Sep 6, 2016 at 9:24 AM, Tomasz Nowicki <tn@semihalf.com> wrote:
> Hi Rafael,
>
>
> On 05.09.2016 22:29, Rafael J. Wysocki wrote:
>>
>> On Mon, Sep 5, 2016 at 10:05 PM, Tomasz Nowicki <tn@semihalf.com> wrote:
>>>

[cut]

> static acpi_status iort_match_node_callback(struct acpi_iort_node *node,
>                                             void *context)
> {
>         struct device *dev = context;
>         acpi_status status = AE_NOT_FOUND;
>
>         switch (node->type) {
>         case ACPI_IORT_NODE_NAMED_COMPONENT: {
>                 struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
>                 struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
>                 struct acpi_iort_named_component *ncomp;
>
>                 if (!adev)
>                         break;
>
>                 status = acpi_get_name(adev->handle, ACPI_FULL_PATHNAME,
> &buf);
>                 if (ACPI_FAILURE(status)) {
>                         dev_warn(dev, "Can't get device full path name\n");
>                         break;
>                 }
>
>                 ncomp = (struct acpi_iort_named_component *)node->node_data;
>                 if (!strcmp(ncomp->device_name, buf.pointer))
>                         status = AE_OK;
>
>                 acpi_os_free(buf.pointer);
>                 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))
>                         status = AE_OK;
>
>                 break;
>         }
>         }
>
>         return status;
> }
>
>>
>>> +               } else {
>>> +                       int match;
>>> +
>>> +                       match = !strcmp(ncomp->device_name,
>>> buffer.pointer);
>>> +                       acpi_os_free(buffer.pointer);
>>> +
>>> +                       if (match)
>>> +                               return AE_OK;
>>> +               }
>>> +
>>> +               break;
>>> +       }
>>> +       case ACPI_IORT_NODE_PCI_ROOT_COMPLEX: {
>>
>>
>> What is the brace for?
>
>
> To create namespace for below local variables. The same for
> ACPI_IORT_NODE_NAMED_COMPONENT case.

This looks weird, though.  At least nest it in a usual way.

And what would be wrong with using if () {} else if () {} instead?

There are two cases only here anyway.

Thanks,
Rafael