powerpc: Allow ppc_md platform hook to override memory_block_size_bytes

The pseries platform code unconditionally overrides
memory_block_size_bytes regardless of the running platform.

Create a ppc_md hook that so each platform can choose to
do what it wants.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/machdep.h

@@ -98,6 +98,9 @@ struct machdep_calls {
 	void		(*iommu_save)(void);
 	void		(*iommu_restore)(void);
 #endif
+#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
+	unsigned long	(*memory_block_size)(void);
+#endif
 #endif /* CONFIG_PPC64 */
 
 	void		(*pci_dma_dev_setup)(struct pci_dev *dev);

arch/powerpc/kernel/setup_64.c

@@ -36,6 +36,7 @@
 #include <linux/lockdep.h>
 #include <linux/memblock.h>
 #include <linux/hugetlb.h>
+#include <linux/memory.h>
 
 #include <asm/io.h>
 #include <asm/kdump.h>
@@ -780,6 +781,15 @@ void __init setup_per_cpu_areas(void)
 }
 #endif
 
+#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
+unsigned long memory_block_size_bytes(void)
+{
+	if (ppc_md.memory_block_size)
+		return ppc_md.memory_block_size();
+
+	return MIN_MEMORY_BLOCK_SIZE;
+}
+#endif
 
 #if defined(CONFIG_PPC_INDIRECT_PIO) || defined(CONFIG_PPC_INDIRECT_MMIO)
 struct ppc_pci_io ppc_pci_io;

arch/powerpc/platforms/pseries/hotplug-memory.c

@@ -21,7 +21,7 @@
 #include <asm/prom.h>
 #include <asm/sparsemem.h>
 
-static unsigned long get_memblock_size(void)
+unsigned long pseries_memory_block_size(void)
 {
 	struct device_node *np;
 	unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
@@ -64,17 +64,6 @@ static unsigned long get_memblock_size(void)
 	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();
-}
-
 #ifdef CONFIG_MEMORY_HOTREMOVE
 static int pseries_remove_memory(u64 start, u64 size)
 {
@@ -105,7 +94,7 @@ static int pseries_remove_memblock(unsigned long base, unsigned int memblock_siz
 	if (!pfn_valid(start_pfn))
 		goto out;
 
-	block_sz = memory_block_size_bytes();
+	block_sz = pseries_memory_block_size();
 	sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
 	nid = memory_add_physaddr_to_nid(base);
 
@@ -201,7 +190,7 @@ static int pseries_update_drconf_memory(struct of_prop_reconfig *pr)
 	u32 *p;
 	int i, rc = -EINVAL;
 
-	memblock_size = get_memblock_size();
+	memblock_size = pseries_memory_block_size();
 	if (!memblock_size)
 		return -EINVAL;
 

arch/powerpc/platforms/pseries/pseries.h

@@ -64,4 +64,6 @@ extern int dlpar_detach_node(struct device_node *);
 struct pci_host_bridge;
 int pseries_root_bridge_prepare(struct pci_host_bridge *bridge);
 
+unsigned long pseries_memory_block_size(void);
+
 #endif /* _PSERIES_PSERIES_H */

arch/powerpc/platforms/pseries/setup.c

@@ -810,4 +810,7 @@ define_machine(pseries) {
 #ifdef CONFIG_KEXEC
 	.machine_kexec          = pSeries_machine_kexec,
 #endif
+#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
+	.memory_block_size	= pseries_memory_block_size,
+#endif
 };