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

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  [PATCH V8 1/8] ACPI: I/O Remapping Table (IORT) initial support Tomasz Nowicki <tn@semihalf.com> - 2016-08-11 12:10 +0200
    Re: [PATCH V8 1/8] ACPI: I/O Remapping Table (IORT) initial support Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-08-12 18:40 +0200
      Re: [PATCH V8 1/8] ACPI: I/O Remapping Table (IORT) initial support Tomasz Nowicki <tn@semihalf.com> - 2016-08-18 08:40 +0200
    Re: [PATCH V8 1/8] ACPI: I/O Remapping Table (IORT) initial support Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-08-18 13:20 +0200

#1460354 — [PATCH V8 1/8] ACPI: I/O Remapping Table (IORT) initial support

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>
---
 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-$(CONFIG_ARM64)		+= arm64/
diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig
new file mode 100644
index 0000000..fc818dc
--- /dev/null
+++ b/drivers/acpi/arm64/Kconfig
@@ -0,0 +1,6 @@
+#
+# ACPI Configuration for ARM64
+#
+
+config IORT_TABLE
+	bool
diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
new file mode 100644
index 0000000..d01be6f
--- /dev/null
+++ b/drivers/acpi/arm64/Makefile
@@ -0,0 +1 @@
+obj-$(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@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;
+
+	/* 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@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_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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#1461312

Hi Tomasz,

On Thu, Aug 11, 2016 at 12:06:31PM +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.
> 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.

We still need to get Rafael ACK on this, keeping in mind that the
eg code parsing DMAR table relies on the same assumption.

[...]

> 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"
> +

Just curious: Why do you need a space ?

> +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
> +	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@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;

See above.

[...]

> +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();

That's another bit we have to make sure Rafael is ok with, given
that IORT is ARM64 specific (but we stub it out if it is not
configured).

Having said that:

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

>  	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@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_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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#1464938

On 12.08.2016 18:33, Lorenzo Pieralisi wrote:
> Hi Tomasz,
>
> On Thu, Aug 11, 2016 at 12:06:31PM +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.
>> 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.
>
> We still need to get Rafael ACK on this, keeping in mind that the
> eg code parsing DMAR table relies on the same assumption.

Exactly.

Rafael, can you please have a look ?

>
> [...]
>
>> 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"
>> +
>
> Just curious: Why do you need a space ?

No good reason, it will disappear for next version.

>
>> +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
>> +	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@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;
>
> See above.
>
> [...]
>
>> +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();
>
> That's another bit we have to make sure Rafael is ok with, given
> that IORT is ARM64 specific (but we stub it out if it is not
> configured).
>
> Having said that:
>
> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Thanks for your time.

Tomasz

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#1465185

On Thu, Aug 18, 2016 at 06:55:50PM +0800, Dennis Chen wrote:

[...]

> > +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;
> >
> Here, the same as I comments on Lorenzo's patch. If IORT is missed in
> the firmware, then iort_table will be NULL, result in kernel panic in
> the codes followed.

The pointer is checked in the functions that are visible to
other compilation units before calling this function:

iort_msi_map_rid()
iort_get_device_domain()

I missed to check it when I added iort_node_match() and
iort_iommu_configure() though, which makes me think that it is probably
better to move the iort_table pointer check to iort_scan_node() so that
it is done in one single place instead of adding it to all given
external interfaces.

Lorenzo

> 
> Thanks,
> Dennis
> > +	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@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_IORT_TABLE
> > +void iort_table_detect(void);
> > +#else
> > +static inline void iort_table_detect(void) { }
> > +#endif
> > +
> > +#endif /* __IORT_H__ */
> > -- 
> > 1.9.1
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 

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