[PATCH V6 1/7] ACPI: I/O Remapping Table (IORT) initial support
Marc Zyngier
marc.zyngier at arm.com
Wed Jun 15 01:31:27 PDT 2016
On Mon, 13 Jun 2016 16:41:07 +0200
Tomasz Nowicki <tn at 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.
>
> 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 <tn at semihalf.com>
> ---
> 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 <tn at semihalf.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * This file implements early detection/parsing of I/O mapping
> + * reported to OS through firmware via I/O Remapping Table (IORT)
> + * IORT document number: ARM DEN 0049A
> + */
> +
> +#define pr_fmt(fmt) "ACPI: IORT: " fmt
> +
> +#include <linux/export.h>
> +#include <linux/iort.h>
> +#include <linux/irqdomain.h>
> +#include <linux/kernel.h>
> +#include <linux/pci.h>
> +
> +struct iort_its_msi_chip {
> + struct list_head list;
> + struct fwnode_handle *fw_node;
> + u32 translation_id;
> +};
> +
> +typedef acpi_status (*iort_find_node_callback)
> + (struct acpi_iort_node *node, void *context);
> +
> +/* Root pointer to the mapped IORT table */
> +static struct acpi_table_header *iort_table;
> +
> +static LIST_HEAD(iort_msi_chip_list);
> +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;
> +}
> +
> +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;
> +
> + /* 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) {
> + rid_in = id->output_base;
> + found = 1;
> + break;
> + }
> +
> + pr_warn(FW_BUG "[node %p type %d] SINGLE MAPPING flag not allowed for SMMU node, skipping ID map\n",
> + node, node->type);
> + continue;
> + }
> +
> + if (rid_in < id->input_base ||
> + (rid_in > id->input_base + id->id_count))
> + continue;
> +
> + rid_in = id->output_base + (rid_in - id->input_base);
> + found = 1;
> + break;
> + }
> +
> + if (!found)
> + return NULL;
Why this special case? It would make more sense to use the normal
epilogue, and update rid_out. Unless not finding a translation for a
given rid is illegal?
> +
> + /* 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;
And once you've fixed the special case in iort_node_map_rid, you can
unconditionally return dev_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))
> + return NULL;
> +
> + handle = iort_find_domain_token(its_id);
> + if (!handle)
> + return NULL;
Can this actually happen? I can't see how, unless you have a race
between iort_dev_find_its_id and iort_find_domain_token. And given that
both these functions are only called from here, maybe you're better off
having a single function:
struct fwnode_handle *iort_dev_find_its_domain_token(struct device *dev,
u32 rid);
which returns the atomic lookup of the ITS handle. Or is there any
constraints preventing us from holding the lock?
> +
> + 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);
Instead of an initcall, can't this be directly called from whatever
ACPI init we already have?
> 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 <tn at semihalf.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
> + * Place - Suite 330, Boston, MA 02111-1307 USA.
> + */
> +
> +#ifndef __IORT_H__
> +#define __IORT_H__
> +
> +#include <linux/acpi.h>
> +
> +struct fwnode_handle;
> +int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node);
> +void iort_deregister_domain_token(int trans_id);
> +struct fwnode_handle *iort_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__ */
Other than the above, this is finally starting to look like something
I can work with, provided that you address these small comments. I'd
also expect the ACPI folks (Rafael, Lorenzo) to chime in and comment on
this.
Thanks,
M.
--
Jazz is not dead. It just smells funny.
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