Based on benh's proposal at
https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-September/101237.html,
this change provides support for reserving memory from the
reserved-ranges node at the root of the device tree.
We just call memblock_reserve on these ranges for now.
Signed-off-by: Jeremy Kerr <j...@ozlabs.org>
---
arch/powerpc/kernel/prom.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 8b6f7a9..1208c8f 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -559,6 +559,34 @@ void __init early_init_dt_setup_initrd_arch(unsigned long
start,
}
#endif
+static bool __init early_reserve_mem_dt(void)
+{
+ unsigned long i, len, dt_root;
+ const __be32 *prop;
+
+ dt_root = ((unsigned long)initial_boot_params) +
+ be32_to_cpu(initial_boot_params->off_dt_struct);
+
+ prop = of_get_flat_dt_prop(dt_root, "reserved-ranges", &len);
+
+ if (!prop)
+ return false;
+
+ /* Each reserved range is an (address,size) pair, 2 cells each */
+ for (i = 0; i < len / sizeof(*prop);
+ i += dt_root_addr_cells + dt_root_size_cells) {
+ u64 base, size;
+
+ base = of_read_number(prop + (i * 4), 2);
+ size = of_read_number(prop + (i * 4) + 2, 2);
+
+ if (size)
+ memblock_reserve(base, size);
+ }
+
+ return true;
+}
+
static void __init early_reserve_mem(void)
{
u64 base, size;
@@ -574,6 +602,14 @@ static void __init early_reserve_mem(void)
self_size = initial_boot_params->totalsize;
memblock_reserve(self_base, self_size);
+ /*
+ * Try looking for reserved-regions property in the DT first; if
+ * it's present, it'll contain all of the necessary reservation
+ * info
+ */
+ if (early_reserve_mem_dt())
+ return;
+
#ifdef CONFIG_BLK_DEV_INITRD
/* then reserve the initrd, if any */
if (initrd_start && (initrd_end > initrd_start))
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