powerpc/mm: Fix memory_block_size_bytes() for non-pseries

Just compiling pseries in the kernel causes it to override
memory_block_size_bytes() regardless of what is the runtime
platform.

This cleans up the implementation of that function, fixing
a bug or two while at it, so that it's harmless (and potentially
useful) for other platforms. Without this, bugs in that code
would trigger a WARN_ON() in drivers/base/memory.c when
booting some different platforms.

If/when we have another platform supporting memory hotplug we
might want to either move that out to a generic place or
make it a ppc_md. callback.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 19 insertions, 11 deletions

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 33867ec4a234..9d6a8effeda2 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -12,6 +12,8 @@
 #include <linux/of.h>
 #include <linux/memblock.h>
 #include <linux/vmalloc.h>
+#include <linux/memory.h>
+
 #include <asm/firmware.h>
 #include <asm/machdep.h>
 #include <asm/pSeries_reconfig.h>
@@ -20,24 +22,25 @@
 static unsigned long get_memblock_size(void)
 {
         struct device_node *np;
-        unsigned int memblock_size = 0;
+        unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
+        struct resource r;
 
         np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
         if (np) {
-                const unsigned long *size;
+                const __be64 *size;
 
                 size = of_get_property(np, "ibm,lmb-size", NULL);
-                memblock_size = size ? *size : 0;
-
+                if (size)
+                        memblock_size = be64_to_cpup(size);
                 of_node_put(np);
-        } else {
+        } else  if (machine_is(pseries)) {
+                /* This fallback really only applies to pseries */
                 unsigned int memzero_size = 0;
-                const unsigned int *regs;
 
                 np = of_find_node_by_path("/memory@0");
                 if (np) {
-                        regs = of_get_property(np, "reg", NULL);
-                        memzero_size = regs ? regs[3] : 0;
+                        if (!of_address_to_resource(np, 0, &r))
+                                memzero_size = resource_size(&r);
                         of_node_put(np);
                 }
 
@@ -50,16 +53,21 @@ static unsigned long get_memblock_size(void)
                         sprintf(buf, "/memory@%x", memzero_size);
                         np = of_find_node_by_path(buf);
                         if (np) {
-                                regs = of_get_property(np, "reg", NULL);
-                                memblock_size = regs ? regs[3] : 0;
+                                if (!of_address_to_resource(np, 0, &r))
+                                        memblock_size = resource_size(&r);
                                 of_node_put(np);
                         }
                 }
         }
-
         return memblock_size;
 }
 
+/* WARNING: This is going to override the generic definition whenever
+ * pseries is built-in regardless of what platform is active at boot
+ * time. This is fine for now as this is the only "option" and it
+ * should work everywhere. If not, we'll have to turn this into a
+ * ppc_md. callback
+ */
 unsigned long memory_block_size_bytes(void)
 {
         return get_memblock_size();