[RFC PATCH 01/24] ARM: GICv3 ITS: parse and store ITS subnodes from hardware DT

[Andre Przywara <andre.przywara@arm.com>]

Parse the DT GIC subnodes to find every ITS MSI controller the hardware
offers. Store that information in a list to both propagate all of them
later to Dom0, but also to be able to iterate over all ITSes.
This introduces an ITS Kconfig option.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 xen/arch/arm/Kconfig          |  5 ++++
 xen/arch/arm/Makefile         |  1 +
 xen/arch/arm/gic-its.c        | 67 +++++++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/gic-v3.c         |  6 ++++
 xen/include/asm-arm/gic-its.h | 57 ++++++++++++++++++++++++++++++++++++
 5 files changed, 136 insertions(+)
 create mode 100644 xen/arch/arm/gic-its.c
 create mode 100644 xen/include/asm-arm/gic-its.h

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 797c91f..9fe3b8e 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -45,6 +45,11 @@ config ACPI
 config HAS_GICV3
 	bool
 
+config HAS_ITS
+        bool "GICv3 ITS MSI controller support"
+        depends on ARM_64
+        depends on HAS_GICV3
+
 config ALTERNATIVE
 	bool
 
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 64fdf41..c2c4daa 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -18,6 +18,7 @@ obj-$(EARLY_PRINTK) += early_printk.o
 obj-y += gic.o
 obj-y += gic-v2.o
 obj-$(CONFIG_HAS_GICV3) += gic-v3.o
+obj-$(CONFIG_HAS_ITS) += gic-its.o
 obj-y += guestcopy.o
 obj-y += hvm.o
 obj-y += io.o
diff --git a/xen/arch/arm/gic-its.c b/xen/arch/arm/gic-its.c
new file mode 100644
index 0000000..0f42a77
--- /dev/null
+++ b/xen/arch/arm/gic-its.c
@@ -0,0 +1,67 @@
+/*
+ * xen/arch/arm/gic-its.c
+ *
+ * ARM Generic Interrupt Controller ITS support
+ *
+ * Copyright (C) 2016 - ARM Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#include <xen/config.h>
+#include <xen/lib.h>
+#include <xen/device_tree.h>
+#include <xen/libfdt/libfdt.h>
+#include <asm/gic.h>
+#include <asm/gic_v3_defs.h>
+#include <asm/gic-its.h>
+
+void gicv3_its_dt_init(const struct dt_device_node *node)
+{
+    const struct dt_device_node *its = NULL;
+    struct host_its *its_data;
+
+    /*
+     * Check for ITS MSI subnodes. If any, add the ITS register
+     * frames to the ITS list.
+     */
+    dt_for_each_child_node(node, its)
+    {
+        paddr_t addr, size;
+
+        if ( !dt_device_is_compatible(its, "arm,gic-v3-its") )
+            continue;
+
+        if ( dt_device_get_address(its, 0, &addr, &size) )
+            panic("GICv3: Cannot find a valid ITS frame address");
+
+        its_data = xzalloc(struct host_its);
+        if ( !its_data )
+            panic("GICv3: Cannot allocate memory for ITS frame");
+
+        its_data->addr = addr;
+        its_data->size = size;
+        its_data->dt_node = its;
+
+        printk("GICv3: Found ITS @0x%lx\n", addr);
+
+        list_add_tail(&its_data->entry, &host_its_list);
+    }
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index b8be395..238da84 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -43,9 +43,12 @@
 #include <asm/device.h>
 #include <asm/gic.h>
 #include <asm/gic_v3_defs.h>
+#include <asm/gic-its.h>
 #include <asm/cpufeature.h>
 #include <asm/acpi.h>
 
+LIST_HEAD(host_its_list);
+
 /* Global state */
 static struct {
     void __iomem *map_dbase;  /* Mapped address of distributor registers */
@@ -1229,6 +1232,9 @@ static void __init gicv3_dt_init(void)
 
     dt_device_get_address(node, 1 + gicv3.rdist_count + 2,
                           &vbase, &vsize);
+
+    /* Check for ITS child nodes and build the host ITS list accordingly. */
+    gicv3_its_dt_init(node);
 }
 
 static int gicv3_iomem_deny_access(const struct domain *d)
diff --git a/xen/include/asm-arm/gic-its.h b/xen/include/asm-arm/gic-its.h
new file mode 100644
index 0000000..2f5c51c
--- /dev/null
+++ b/xen/include/asm-arm/gic-its.h
@@ -0,0 +1,57 @@
+/*
+ * ARM GICv3 ITS support
+ *
+ * Andre Przywara <andre.przywara@arm.com>
+ * Copyright (c) 2016 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#ifndef __ASM_ARM_ITS_H__
+#define __ASM_ARM_ITS_H__
+
+#ifndef __ASSEMBLY__
+#include <xen/device_tree.h>
+
+/* data structure for each hardware ITS */
+struct host_its {
+    struct list_head entry;
+    const struct dt_device_node *dt_node;
+    paddr_t addr;
+    paddr_t size;
+};
+
+extern struct list_head host_its_list;
+
+#ifdef CONFIG_HAS_ITS
+
+/* Parse the host DT and pick up all host ITSes. */
+void gicv3_its_dt_init(const struct dt_device_node *node);
+
+#else
+
+static inline void gicv3_its_dt_init(const struct dt_device_node *node)
+{
+}
+
+#endif /* CONFIG_HAS_ITS */
+
+#endif /* __ASSEMBLY__ */
+#endif
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
2.9.0


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