[PATCH v2] xen: arm: remove /xen-core-devices node from dom0 dtb

[Ian Campbell <ian.campbell@citrix.com>]

The intention of adding this node to contain the GIC, timer and memory nodes
(in 1c08d6004ea7) was to allow us to control the #address-cells and

However in the case of the memory node the #*-cells are always taken from the
root node (see ePAPR 3.1, "the following nodes shall be present at the root...
memory node"). This caused breakage on the arndale platform.

In addition it is not valid to just create sub-nodes like this. Unless they
declare themselves as a bus then they will not necessarily be enumerated
(although Linux currently does so in practice).

Therefore:
 - Move the memory node back to the top level.
 - Insert the timer and primary gic nodes in the same location as the host
   DTB, replacing the originals. Note that the nodes here may be marked as in
   use by Xen and therefore the check must be before we discard nodes used by
   Xen.
 - Drop any secondary gics.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
v2:
Discard secondary gics.
Left parameter as "parent" for now since that is used everywhere.
---
 xen/arch/arm/domain_build.c |  127 +++++++++++++++++++------------------------
 1 file changed, 55 insertions(+), 72 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index aa7e3d2..d79e038 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -48,24 +48,6 @@ custom_param("dom0_mem", parse_dom0_mem);
  */
 #define DOM0_FDT_EXTRA_SIZE (128 + sizeof(struct fdt_reserve_entry))
 
-/*
- * Number of cells used for addresses and sizes under the /xen/
- * node.
- *
- * We don't have a struct dt_device_node we can reference as a parent
- * to get these values, so use these constants instead.
- */
-#define XEN_FDT_NODE_ADDRESS_CELLS 2
-#define XEN_FDT_NODE_SIZE_CELLS 2
-#define XEN_FDT_NODE_REG_SIZE \
-    dt_cells_to_size(XEN_FDT_NODE_ADDRESS_CELLS + XEN_FDT_NODE_SIZE_CELLS)
-
-static void set_xen_range(__be32 **cellp, u64 address, u64 size)
-{
-    dt_set_cell(cellp, XEN_FDT_NODE_ADDRESS_CELLS, address);
-    dt_set_cell(cellp, XEN_FDT_NODE_SIZE_CELLS, size);
-}
-
 struct vcpu *__init alloc_dom0_vcpu0(void)
 {
     if ( opt_dom0_max_vcpus == 0 )
@@ -294,14 +276,16 @@ static int fdt_property_interrupts(void *fdt, gic_interrupt_t *intr,
 
 static int make_memory_node(const struct domain *d,
                             void *fdt,
+                            const struct dt_device_node *parent,
                             const struct kernel_info *kinfo)
 {
     int res, i;
-    int nr_cells = XEN_FDT_NODE_REG_SIZE*kinfo->mem.nr_banks;
+    int reg_size = dt_n_addr_cells(parent) + dt_n_size_cells(parent);
+    int nr_cells = reg_size*kinfo->mem.nr_banks;
     __be32 reg[nr_cells];
     __be32 *cells;
 
-    DPRINT("Create memory node\n");
+    DPRINT("Create memory node (reg size %d, nr cells %d)\n", reg_size, nr_cells);
 
     /* ePAPR 3.4 */
     res = fdt_begin_node(fdt, "memory");
@@ -321,10 +305,10 @@ static int make_memory_node(const struct domain *d,
         DPRINT("  Bank %d: %#"PRIx64"->%#"PRIx64"\n",
                 i, start, start + size);
 
-        set_xen_range(&cells, start, size);
+        dt_set_range(&cells, parent, start, size);
     }
 
-    res = fdt_property(fdt, "reg", reg, nr_cells);
+    res = fdt_property(fdt, "reg", reg, sizeof(reg));
     if ( res )
         return res;
 
@@ -531,7 +515,8 @@ static int make_cpus_node(const struct domain *d, void *fdt,
     return res;
 }
 
-static int make_gic_node(const struct domain *d, void *fdt)
+static int make_gic_node(const struct domain *d, void *fdt,
+                         const struct dt_device_node *parent)
 {
     const struct dt_device_node *gic = dt_interrupt_controller;
     const void *compatible = NULL;
@@ -539,6 +524,16 @@ static int make_gic_node(const struct domain *d, void *fdt)
     __be32 *new_cells, *tmp;
     int res = 0;
 
+    /*
+     * Xen currently supports only a single GIC. Discard any secondary
+     * GIC entries.
+     */
+    if ( parent != dt_interrupt_controller )
+    {
+        DPRINT("  Skipping (secondary GIC)\n");
+        return 0;
+    }
+
     DPRINT("Create gic node\n");
 
     compatible = dt_get_property(gic, "compatible", &len);
@@ -565,7 +560,8 @@ static int make_gic_node(const struct domain *d, void *fdt)
     if ( res )
         return res;
 
-    len = XEN_FDT_NODE_REG_SIZE * 2;
+    len = dt_cells_to_size(dt_n_addr_cells(parent) + dt_n_size_cells(parent));
+    len *= 2; /* GIC has two memory regions: Distributor + CPU interface */
     new_cells = xzalloc_bytes(len);
     if ( new_cells == NULL )
         return -FDT_ERR_XEN(ENOMEM);
@@ -573,11 +569,11 @@ static int make_gic_node(const struct domain *d, void *fdt)
     tmp = new_cells;
     DPRINT("  Set Distributor Base 0x%"PRIpaddr"-0x%"PRIpaddr"\n",
            d->arch.vgic.dbase, d->arch.vgic.dbase + PAGE_SIZE - 1);
-    set_xen_range(&tmp, d->arch.vgic.dbase, PAGE_SIZE);
+    dt_set_range(&tmp, parent, d->arch.vgic.dbase, PAGE_SIZE);
 
     DPRINT("  Set Cpu Base 0x%"PRIpaddr"-0x%"PRIpaddr"\n",
            d->arch.vgic.cbase, d->arch.vgic.cbase + (PAGE_SIZE * 2) - 1);
-    set_xen_range(&tmp, d->arch.vgic.cbase, PAGE_SIZE * 2);
+    dt_set_range(&tmp, parent, d->arch.vgic.cbase, PAGE_SIZE * 2);
 
     res = fdt_property(fdt, "reg", new_cells, len);
     xfree(new_cells);
@@ -602,7 +598,8 @@ static int make_gic_node(const struct domain *d, void *fdt)
     return res;
 }
 
-static int make_timer_node(const struct domain *d, void *fdt)
+static int make_timer_node(const struct domain *d, void *fdt,
+                           const struct dt_device_node *parent)
 {
     static const struct dt_device_match timer_ids[] __initconst =
     {
@@ -662,46 +659,6 @@ static int make_timer_node(const struct domain *d, void *fdt)
     return res;
 }
 
-static int make_xen_node(const struct domain *d, void *fdt,
-                         const struct dt_device_node *parent,
-                         const struct kernel_info *kinfo)
-{
-    int res;
-
-    res = fdt_begin_node(fdt, "xen-core-devices");
-    if ( res )
-        return res;
-
-    res = fdt_property_cell(fdt, "#address-cells",
-                            XEN_FDT_NODE_ADDRESS_CELLS);
-    if ( res )
-        return res;
-
-    res = fdt_property_cell(fdt, "#size-cells",
-                            XEN_FDT_NODE_SIZE_CELLS);
-    if ( res )
-        return res;
-
-    res = fdt_property(fdt, "ranges", NULL, 0);
-    if ( res )
-        return res;
-
-    res = make_memory_node(d, fdt, kinfo);
-    if ( res )
-        return res;
-
-    res = make_gic_node(d, fdt);
-    if ( res )
-        return res;
-
-    res = make_timer_node(d, fdt);
-    if ( res )
-        return res;
-
-    res = fdt_end_node(fdt);
-    return res;
-}
-
 /* Map the device in the domain */
 static int map_device(struct domain *d, const struct dt_device_node *dev)
 {
@@ -792,7 +749,15 @@ static int handle_node(struct domain *d, struct kernel_info *kinfo,
         DT_MATCH_COMPATIBLE("arm,psci"),
         DT_MATCH_PATH("/cpus"),
         DT_MATCH_TYPE("memory"),
+        { /* sentinel */ },
+    };
+    static const struct dt_device_match gic_matches[] __initconst =
+    {
         DT_MATCH_GIC,
+        { /* sentinel */ },
+    };
+    static const struct dt_device_match timer_matches[] __initconst =
+    {
         DT_MATCH_TIMER,
         { /* sentinel */ },
     };
@@ -806,11 +771,28 @@ static int handle_node(struct domain *d, struct kernel_info *kinfo,
     DPRINT("handle %s\n", path);
 
     /* Skip theses nodes and the sub-nodes */
-    if ( dt_match_node(skip_matches, np ) ||
-         platform_device_is_blacklisted(np) ||
-         dt_device_used_by(np) == DOMID_XEN )
+    if ( dt_match_node(skip_matches, np ) )
+    {
+        DPRINT("  Skip it (matched)\n");
+        return 0;
+    }
+    if ( platform_device_is_blacklisted(np) )
     {
-        DPRINT("  Skip it!\n");
+        DPRINT("  Skip it (blacklisted)\n");
+        return 0;
+    }
+
+    /* Replace these nodes with our own. Note that the original may be
+     * used_by DOMID_XEN so this check comes first. */
+    if ( dt_match_node(gic_matches, np ) )
+        return make_gic_node(d, kinfo->fdt, np);
+    if ( dt_match_node(timer_matches, np ) )
+        return make_timer_node(d, kinfo->fdt, np);
+
+    /* Skip nodes used by Xen */
+    if ( dt_device_used_by(np) == DOMID_XEN )
+    {
+        DPRINT("  Skip it (used by Xen)\n");
         return 0;
     }
 
@@ -868,9 +850,10 @@ static int handle_node(struct domain *d, struct kernel_info *kinfo,
         if ( res )
             return res;
 
-        res = make_xen_node(d, kinfo->fdt, np, kinfo);
+        res = make_memory_node(d, kinfo->fdt, np, kinfo);
         if ( res )
             return res;
+
     }
 
     res = fdt_end_node(kinfo->fdt);
-- 
1.7.10.4