From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH V7 1/8] ACPI: I/O Remapping Table (IORT) initial support Date: Tue, 21 Jun 2016 18:36:56 +0100 Message-ID: <20160621173656.GA31875@red-moon> References: <1466420541-20101-1-git-send-email-tn@semihalf.com> <1466420541-20101-2-git-send-email-tn@semihalf.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from foss.arm.com ([217.140.101.70]:42573 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751209AbcFURgY (ORCPT ); Tue, 21 Jun 2016 13:36:24 -0400 Content-Disposition: inline In-Reply-To: <1466420541-20101-2-git-send-email-tn@semihalf.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Tomasz Nowicki , rjw@rjwysocki.net Cc: marc.zyngier@arm.com, tglx@linutronix.de, jason@lakedaemon.net, bhelgaas@google.com, robert.richter@caviumnetworks.com, shijie.huang@arm.com, Suravee.Suthikulpanit@amd.com, hanjun.guo@linaro.org, al.stone@linaro.org, mw@semihalf.com, graeme.gregory@linaro.org, Catalin.Marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ddaney.cavm@gmail.com, okaya@codeaurora.org, andrea.gallo@linaro.org, linux-pci@vger.kernel.org Hi Rafael, On Mon, Jun 20, 2016 at 01:02:14PM +0200, Tomasz Nowicki 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. > > 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. This moot point has become a blocker for this patchset and we need your feedback please. I noticed that x86 code (drivers/iommu/dmar.c) makes the same assumption (ie a table pointer, dmar_tbl, retrieved through acpi_get_table_with_size() can be stashed in a global variable and reused in functions like dmar_acpi_dev_scope_init() and dmar_ir_support() without going through the ACPI API to retrieve it again. Is this a valid assumption ? This patch relies on it, since otherwise it would become quite unwieldy (and unnecessary) to create a cache of IORT nodes entries, so if we can retrieve the table pointer through acpi_get_table_size() in iort_table_detect() and stash it for further use that would make things much simpler (as they are in the current patch). I think that's the whole point behind acpi_gbl_permanent_mmap, if that's set the corresponding tables pointers can be considered permanently mapped, we really need to know if that's a reliable assumption to make progress. Thanks, Lorenzo > 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 > --- > 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 > #endif > +#include > #include > #include > #include > @@ -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 > + * > + * 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 > +#include > +#include > + > +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 > + * > + * 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 > + > +#ifdef CONFIG_IORT_TABLE > +void iort_table_detect(void); > +#else > +static inline void iort_table_detect(void) { } > +#endif > + > +#endif /* __IORT_H__ */ > -- > 1.9.1 > From mboxrd@z Thu Jan 1 00:00:00 1970 From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi) Date: Tue, 21 Jun 2016 18:36:56 +0100 Subject: [PATCH V7 1/8] ACPI: I/O Remapping Table (IORT) initial support In-Reply-To: <1466420541-20101-2-git-send-email-tn@semihalf.com> References: <1466420541-20101-1-git-send-email-tn@semihalf.com> <1466420541-20101-2-git-send-email-tn@semihalf.com> Message-ID: <20160621173656.GA31875@red-moon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Rafael, On Mon, Jun 20, 2016 at 01:02:14PM +0200, Tomasz Nowicki 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. > > 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. This moot point has become a blocker for this patchset and we need your feedback please. I noticed that x86 code (drivers/iommu/dmar.c) makes the same assumption (ie a table pointer, dmar_tbl, retrieved through acpi_get_table_with_size() can be stashed in a global variable and reused in functions like dmar_acpi_dev_scope_init() and dmar_ir_support() without going through the ACPI API to retrieve it again. Is this a valid assumption ? This patch relies on it, since otherwise it would become quite unwieldy (and unnecessary) to create a cache of IORT nodes entries, so if we can retrieve the table pointer through acpi_get_table_size() in iort_table_detect() and stash it for further use that would make things much simpler (as they are in the current patch). I think that's the whole point behind acpi_gbl_permanent_mmap, if that's set the corresponding tables pointers can be considered permanently mapped, we really need to know if that's a reliable assumption to make progress. Thanks, Lorenzo > 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 > --- > 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 > #endif > +#include > #include > #include > #include > @@ -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 > + * > + * 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 > +#include > +#include > + > +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 > + * > + * 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 > + > +#ifdef CONFIG_IORT_TABLE > +void iort_table_detect(void); > +#else > +static inline void iort_table_detect(void) { } > +#endif > + > +#endif /* __IORT_H__ */ > -- > 1.9.1 >