[Xen-devel] [PATCH 2/4] xen: arm: parse modules from DT during early boot.

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

The bootloader should populate /chosen/modules/module@<N>/ for each
module it wishes to pass to the hypervisor. The content of these nodes
is described in docs/misc/arm/device-tree/booting.txt

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
v6: Match based on compatibility instead of path
v5: Moved later in the series
v4: Use /chosen/modules/module@N
    Identify module type by compatible property not number.
v3: Use a reg = < > property for the module address/length.
v2: Reserve the zeroeth module for Xen itself (not used yet)
    Use a more idiomatic DT layout
    Document said layout
---
 docs/misc/arm/device-tree/booting.txt |   25 +++++++++++++++
 xen/common/device_tree.c              |   54 ++++++++++++++++++++++++++++++++-
 2 files changed, 78 insertions(+), 1 deletions(-)
 create mode 100644 docs/misc/arm/device-tree/booting.txt

diff --git a/docs/misc/arm/device-tree/booting.txt 
b/docs/misc/arm/device-tree/booting.txt
new file mode 100644
index 0000000..94cd3f1
--- /dev/null
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -0,0 +1,25 @@
+Xen is passed the dom0 kernel and initrd via a reference in the /chosen
+node of the device tree.
+
+Each node has the form /chosen/modules/module@<N> and contains the following
+properties:
+
+- compatible
+
+       Must be:
+
+               "xen,<type>", "xen,multiboot-module"
+
+       where <type> must be one of:
+
+       - "linux-zimage" -- the dom0 kernel
+       - "linux-initrd" -- the dom0 ramdisk
+
+- reg
+
+       Specifies the physical address of the module in RAM and the
+       length of the module.
+
+- bootargs (optional)
+
+       Command line associated with this module
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index f10ba1b..c92f8ca 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -341,6 +341,48 @@ static void __init process_gic_node(const void *fdt, int 
node,
     early_info.gic.gic_vcpu_addr = start;
 }
 
+static void __init process_multiboot_node(const void *fdt, int node,
+                                          const char *name,
+                                          u32 address_cells, u32 size_cells)
+{
+    const struct fdt_property *prop;
+    const u32 *cell;
+    int nr;
+    struct dt_mb_module *mod;
+    int len;
+
+    if ( fdt_node_check_compatible(fdt, node, "xen,linux-zimage") == 0 )
+        nr = 1;
+    else if ( fdt_node_check_compatible(fdt, node, "xen,linux-initrd") == 0)
+        nr = 2;
+    else
+        early_panic("%s not a known xen multiboot type\n", name);
+
+    mod = &early_info.modules.module[nr];
+
+    prop = fdt_get_property(fdt, node, "reg", NULL);
+    if ( !prop )
+        early_panic("node %s missing `reg' property\n", name);
+
+    cell = (const u32 *)prop->data;
+    device_tree_get_reg(&cell, address_cells, size_cells,
+                        &mod->start, &mod->size);
+
+    prop = fdt_get_property(fdt, node, "bootargs", &len);
+    if ( prop )
+    {
+        if ( len > sizeof(mod->cmdline) )
+            early_panic("module %d command line too long\n", nr);
+
+        safe_strcpy(mod->cmdline, prop->data);
+    }
+    else
+        mod->cmdline[0] = 0;
+
+    if ( nr > early_info.modules.nr_mods )
+        early_info.modules.nr_mods = nr;
+}
+
 static int __init early_scan_node(const void *fdt,
                                   int node, const char *name, int depth,
                                   u32 address_cells, u32 size_cells,
@@ -352,6 +394,8 @@ static int __init early_scan_node(const void *fdt,
         process_cpu_node(fdt, node, name, address_cells, size_cells);
     else if ( device_tree_node_compatible(fdt, node, "arm,cortex-a15-gic") )
         process_gic_node(fdt, node, name, address_cells, size_cells);
+    else if ( device_tree_node_compatible(fdt, node, "xen,multiboot-module" ) )
+        process_multiboot_node(fdt, node, name, address_cells, size_cells);
 
     return 0;
 }
@@ -359,12 +403,20 @@ static int __init early_scan_node(const void *fdt,
 static void __init early_print_info(void)
 {
     struct dt_mem_info *mi = &early_info.mem;
+    struct dt_module_info *mods = &early_info.modules;
     int i;
 
     for ( i = 0; i < mi->nr_banks; i++ )
-        early_printk("RAM: %016llx - %016llx\n",
+        early_printk("RAM: %"PRIpaddr" - %"PRIpaddr"\n",
                      mi->bank[i].start,
                      mi->bank[i].start + mi->bank[i].size - 1);
+    early_printk("\n");
+    for ( i = 1 ; i < mods->nr_mods + 1; i++ )
+        early_printk("MODULE[%d]: %"PRIpaddr" - %"PRIpaddr" %s\n",
+                     i,
+                     mods->module[i].start,
+                     mods->module[i].start + mods->module[i].size,
+                     mods->module[i].cmdline);
 }
 
 /**
-- 
1.7.9.1


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