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@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;
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@xxxxxxx>
Thanks for your time.
Tomasz
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