Re: [Linaro-acpi] [PATCH V8 1/8] ACPI: I/O Remapping Table (IORT) initial support

[Fu Wei]

Hi Tomasz,

On 11 August 2016 at 18:06, Tomasz Nowicki <tn@xxxxxxxxxxxx> 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@xxxxxxxxxxxx>
> Reviewed-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> ---
>  drivers/acpi/Kconfig        |   5 +
>  drivers/acpi/Makefile       |   2 +
>  drivers/acpi/arm64/Kconfig  |   6 ++
>  drivers/acpi/arm64/Makefile |   1 +
>  drivers/acpi/arm64/iort.c   | 218 ++++++++++++++++++++++++++++++++++++++++++++
>  drivers/acpi/bus.c          |   2 +
>  include/linux/iort.h        |  30 ++++++
>  7 files changed, 264 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..6cef2d1 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -521,4 +521,9 @@ 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..fc818dc
> --- /dev/null
> +++ b/drivers/acpi/arm64/Kconfig
> @@ -0,0 +1,6 @@
> +#
> +# ACPI Configuration for ARM64
> +#
> +
> +config IORT_TABLE

Sorry for nit-picking, but is that better to use ACPI_IORT
or maybe ARM64__IORT ??

> +       bool
> diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
> new file mode 100644
> index 0000000..d01be6f
> --- /dev/null
> +++ b/drivers/acpi/arm64/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_IORT_TABLE)       += iort.o
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> new file mode 100644
> index 0000000..f89056e
> --- /dev/null
> +++ b/drivers/acpi/arm64/iort.c
> @@ -0,0 +1,218 @@
> +/*
> + * Copyright (C) 2016, Semihalf
> + *     Author: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * This file implements early detection/parsing of I/O mapping
> + * reported to OS through firmware via I/O Remapping Table (IORT)
> + * IORT document number: ARM DEN 0049A
> + */
> +
> +#define pr_fmt(fmt)    "ACPI: IORT: " fmt
> +
> +#include <linux/iort.h>
> +#include <linux/kernel.h>
> +#include <linux/pci.h>
> +
> +typedef acpi_status (*iort_find_node_callback)
> +       (struct acpi_iort_node *node, void *context);
> +
> +/* Root pointer to the mapped IORT table */
> +static struct acpi_table_header *iort_table;
> +
> +static struct acpi_iort_node *
> +iort_scan_node(enum acpi_iort_node_type type,
> +              iort_find_node_callback callback, void *context)
> +{
> +       struct acpi_iort_node *iort_node, *iort_end;
> +       struct acpi_table_iort *iort;
> +       int i;
> +
> +       /* Get the first IORT node */
> +       iort = (struct acpi_table_iort *)iort_table;
> +       iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
> +                                iort->node_offset);
> +       iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
> +                               iort_table->length);
> +
> +       for (i = 0; i < iort->node_count; i++) {
> +               if (WARN_TAINT(iort_node >= iort_end, TAINT_FIRMWARE_WORKAROUND,
> +                              "IORT node pointer overflows, bad table!\n"))
> +                       return NULL;
> +
> +               if (iort_node->type == type) {
> +                       if (ACPI_SUCCESS(callback(iort_node, context)))
> +                               return iort_node;
> +               }
> +
> +               iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
> +                                        iort_node->length);
> +       }
> +
> +       return NULL;
> +}
> +
> +static acpi_status
> +iort_match_node_callback(struct acpi_iort_node *node, void *context)
> +{
> +       struct device *dev = context;
> +
> +       switch (node->type) {
> +       case ACPI_IORT_NODE_NAMED_COMPONENT: {
> +               struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +               struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
> +               struct acpi_iort_named_component *ncomp;
> +
> +               if (!adev)
> +                       break;
> +
> +               ncomp = (struct acpi_iort_named_component *)node->node_data;
> +
> +               if (ACPI_FAILURE(acpi_get_name(adev->handle,
> +                                              ACPI_FULL_PATHNAME, &buffer))) {
> +                       dev_warn(dev, "Can't get device full path name\n");
> +               } 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 iort_table_detect(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..55a84da 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();
> +       iort_table_detect();
>         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..cde6809
> --- /dev/null
> +++ b/include/linux/iort.h
> @@ -0,0 +1,30 @@
> +/*
> + * Copyright (C) 2016, Semihalf
> + *     Author: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
> + * Place - Suite 330, Boston, MA 02111-1307 USA.
> + */
> +
> +#ifndef __IORT_H__
> +#define __IORT_H__
> +
> +#include <linux/acpi.h>
> +
> +#ifdef CONFIG_IORT_TABLE
> +void iort_table_detect(void);
> +#else
> +static inline void iort_table_detect(void) { }
> +#endif
> +
> +#endif /* __IORT_H__ */
> --
> 1.9.1
>
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-- 
Best regards,

Fu Wei
Software Engineer
Red Hat