[Xen-devel] [PATCH v5 03/30] ARM: GICv3 ITS: parse and store ITS subnodes from hardware DT

[Andre Przywara <andre.przywara@xxxxxxx>]

Parse the GIC subnodes in the device tree 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 (as an EXPERT option), use
XEN_CONFIG_EXPERT=y on the make command line to see and use the option.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
 xen/arch/arm/Kconfig             |  5 +++
 xen/arch/arm/Makefile            |  1 +
 xen/arch/arm/gic-v3-its.c        | 77 ++++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/gic-v3.c            | 10 +++---
 xen/include/asm-arm/gic_v3_its.h | 67 ++++++++++++++++++++++++++++++++++
 5 files changed, 156 insertions(+), 4 deletions(-)
 create mode 100644 xen/arch/arm/gic-v3-its.c
 create mode 100644 xen/include/asm-arm/gic_v3_its.h

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 43123e6..d46b98c 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
+        prompt "GICv3 ITS MSI controller support" if EXPERT = "y"
+        depends on HAS_GICV3
+
 endmenu
 
 menu "ARM errata workaround via the alternative framework"
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 0ce94a8..39c0a03 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-v3-its.o
 obj-y += guestcopy.o
 obj-y += hvm.o
 obj-y += io.o
diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
new file mode 100644
index 0000000..6b02349
--- /dev/null
+++ b/xen/arch/arm/gic-v3-its.c
@@ -0,0 +1,77 @@
+/*
+ * xen/arch/arm/gic-v3-its.c
+ *
+ * ARM GICv3 Interrupt Translation Service (ITS) support
+ *
+ * Copyright (C) 2016,2017 - 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; under version 2 of the License.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/lib.h>
+#include <asm/gic_v3_defs.h>
+#include <asm/gic_v3_its.h>
+
+/*
+ * No lock here, as this list gets only populated upon boot while scanning
+ * firmware tables for all host ITSes, and only gets iterated afterwards.
+ */
+LIST_HEAD(host_its_list);
+
+bool gicv3_its_host_has_its(void)
+{
+    return !list_empty(&host_its_list);
+}
+
+/* Scan the DT for any ITS nodes and create a list of host ITSes out of it. */
+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)
+    {
+        uint64_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 695f01f..b626298 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -42,6 +42,7 @@
 #include <asm/device.h>
 #include <asm/gic.h>
 #include <asm/gic_v3_defs.h>
+#include <asm/gic_v3_its.h>
 #include <asm/cpufeature.h>
 #include <asm/acpi.h>
 
@@ -1227,11 +1228,12 @@ static void __init gicv3_dt_init(void)
      */
     res = dt_device_get_address(node, 1 + gicv3.rdist_count,
                                 &cbase, &csize);
-    if ( res )
-        return;
+    if ( !res )
+        dt_device_get_address(node, 1 + gicv3.rdist_count + 2,
+                              &vbase, &vsize);
 
-    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_v3_its.h b/xen/include/asm-arm/gic_v3_its.h
new file mode 100644
index 0000000..765a655
--- /dev/null
+++ b/xen/include/asm-arm/gic_v3_its.h
@@ -0,0 +1,67 @@
+/*
+ * ARM GICv3 ITS support
+ *
+ * Andre Przywara <andre.przywara@xxxxxxx>
+ * Copyright (c) 2016,2017 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; under version 2 of the License.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ASM_ARM_ITS_H__
+#define __ASM_ARM_ITS_H__
+
+#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;
+};
+
+
+#ifdef CONFIG_HAS_ITS
+
+extern struct list_head host_its_list;
+
+/* Parse the host DT and pick up all host ITSes. */
+void gicv3_its_dt_init(const struct dt_device_node *node);
+
+bool gicv3_its_host_has_its(void);
+
+#else
+
+static LIST_HEAD(host_its_list);
+
+static inline void gicv3_its_dt_init(const struct dt_device_node *node)
+{
+}
+
+static inline bool gicv3_its_host_has_its(void)
+{
+    return false;
+}
+
+#endif /* CONFIG_HAS_ITS */
+
+#endif
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
2.8.2


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