From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753399AbcFOLD5 (ORCPT ); Wed, 15 Jun 2016 07:03:57 -0400 Received: from foss.arm.com ([217.140.101.70]:36608 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750882AbcFOLDx (ORCPT ); Wed, 15 Jun 2016 07:03:53 -0400 Date: Wed, 15 Jun 2016 12:04:27 +0100 From: Lorenzo Pieralisi To: Tomasz Nowicki Cc: marc.zyngier@arm.com, tglx@linutronix.de, jason@lakedaemon.net, rjw@rjwysocki.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 Subject: Re: [PATCH V6 1/7] ACPI: I/O Remapping Table (IORT) initial support Message-ID: <20160615110427.GD30560@red-moon> References: <1465828873-23498-1-git-send-email-tn@semihalf.com> <1465828873-23498-2-git-send-email-tn@semihalf.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1465828873-23498-2-git-send-email-tn@semihalf.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 13, 2016 at 04:41:07PM +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: > - register ITS MSI chip along with ITS translation ID and domain token > - deregister ITS MSI chip based on ITS translation ID > - find registered domain token based on ITS translation ID > - map MSI RID for a device > - find domain token for a device > > Signed-off-by: Tomasz Nowicki > --- > drivers/acpi/Kconfig | 3 + > drivers/acpi/Makefile | 1 + > drivers/acpi/iort.c | 386 ++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/iort.h | 38 +++++ > 4 files changed, 428 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 f98c328..111dd50 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 632e81f..0390f27 100644 > --- a/drivers/acpi/Makefile > +++ b/drivers/acpi/Makefile > @@ -83,6 +83,7 @@ obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o > obj-$(CONFIG_ACPI_BGRT) += bgrt.o > obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o > obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o > +obj-$(CONFIG_IORT_TABLE) += iort.o > > # processor has its own "processor." module_param namespace > processor-y := processor_driver.o > diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c > new file mode 100644 > index 0000000..5bccbc8 > --- /dev/null > +++ b/drivers/acpi/iort.c > @@ -0,0 +1,386 @@ > +/* > + * 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 > +#include > +#include > + > +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; A question to be sorted out: We assume we can rely on the iort_table pointer, obtained through acpi_get_table(), since we assume acpi_glb_permanent_mmap is set (?), correct ? x86 DMAR code seems to rely on that (without even checking acpi_gbl_permanent_mmap) and this has consequences on when we can really start parsing IORT entries through this patch (because if acpi_gbl_permanent_mmap is not set while using IORT nodes we would dereference unmapped pointers). @Rafael: can you confirm that's the right approach ? > +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. > + * @translation_id: ITS ID. > + * @token: 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 > + * @translation_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 > + * @translation_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; > +} You are lumping irq_domain/MSI/ITS code and basic IORT (core) support in one patch, I would split them in two. > +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 struct acpi_iort_node * > +iort_node_map_rid(struct acpi_iort_node *node, u32 rid_in, > + u32 *rid_out, u8 type) > +{ > + > + if (!node) > + goto out; Mmmm..can you explain to me what's the logic here ? > + /* Go upstream */ > + while (node->type != type) { > + struct acpi_iort_id_mapping *id; > + int i, found = 0; > + > + /* Exit when no mapping array */ > + if (!node->mapping_offset || !node->mapping_count) > + return NULL; > + > + id = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node, > + node->mapping_offset); > + > + for (i = 0, found = 0; i < node->mapping_count; i++, id++) { > + /* > + * Single mapping is not translation rule, > + * lets move on for this case > + */ > + if (id->flags & ACPI_IORT_ID_SINGLE_MAPPING) { > + if (node->type != ACPI_IORT_NODE_SMMU) { This is wrong (ie node can be an SMMU v3 and an ITS group). > + rid_in = id->output_base; > + found = 1; > + break; > + } > + > + pr_warn(FW_BUG "[node %p type %d] SINGLE MAPPING flag not allowed for SMMU node, skipping ID map\n", > + node, node->type); > + continue; > + } > + > + if (rid_in < id->input_base || > + (rid_in > id->input_base + id->id_count)) > + continue; > + > + rid_in = id->output_base + (rid_in - id->input_base); > + found = 1; > + break; > + } > + This inner loop is getting too complicated (and this function with it) to my taste. Is it reasonable to factor it out in a separate function ? > + if (!found) > + return NULL; > + > + /* Firmware bug! */ > + if (!id->output_reference) { > + pr_err(FW_BUG "[node %p type %d] ID map has NULL parent reference\n", > + node, node->type); > + return NULL; > + } > + > + node = ACPI_ADD_PTR(struct acpi_iort_node, iort_table, > + id->output_reference); > + } > + > +out: > + if (rid_out) > + *rid_out = rid_in; > + return node; > +} > + > +static struct acpi_iort_node * > +iort_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); > +} > + > +/** > + * 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; > + > + if (!iort_table) > + return req_id; > + > + node = iort_find_dev_node(dev); > + if (!node) { > + dev_err(dev, "can't find related IORT node\n"); > + return req_id; > + } > + > + if (!iort_node_map_rid(node, req_id, &dev_id, > + ACPI_IORT_NODE_ITS_GROUP)) > + return req_id; > + > + 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) { > + dev_err(dev, "can't find related IORT node\n"); > + return -ENXIO; > + } > + > + node = iort_node_map_rid(node, req_id, NULL, ACPI_IORT_NODE_ITS_GROUP); > + if (!node) { > + dev_err(dev, "can't find related ITS node\n"); > + 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_table) > + return NULL; > + > + if (iort_dev_find_its_id(dev, req_id, 0, &its_id)) ^ This is supposed to be an index in the ITS identifiers list and it is always 0 (I *guess* that's because _any_ identifier in that group would do but I want to undestand why), please explain :) One reason more why I think you should split this patch in two so that it becomes easier for Marc to review the ITS specific bits: - IORT core - ITS/MSI IORT handling > + return NULL; > + > + handle = iort_find_domain_token(its_id); > + if (!handle) > + return NULL; > + > + return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI); > +} > + > +static int __init iort_table_detect(void) > +{ > + acpi_status status; > + > + if (acpi_disabled) > + return -ENODEV; > + > + status = acpi_get_table(ACPI_SIG_IORT, 0, &iort_table); > + if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) { > + const char *msg = acpi_format_exception(status); > + pr_err("Failed to get table, %s\n", msg); > + return -EINVAL; > + } > + > + return 0; > +} > +arch_initcall(iort_table_detect); To prevent calling it from an initcall we can call it from arch code (but careful about the iort_table pointer validity, see above). We should settle the iort_table pointer validity first, everything else depends on it. Lorenzo > diff --git a/include/linux/iort.h b/include/linux/iort.h > new file mode 100644 > index 0000000..1bcf2fc > --- /dev/null > +++ b/include/linux/iort.h > @@ -0,0 +1,38 @@ > +/* > + * 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 > + > +struct fwnode_handle; > +int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node); > +void iort_deregister_domain_token(int trans_id); > +struct fwnode_handle *iort_find_domain_token(int trans_id); > +#ifdef CONFIG_IORT_TABLE > +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 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 >