powerpc/mm: Cleanup memory block size probing

Parse the device tree in early init to find the memory block size to be
used by the kernel. Consolidate the memory block size device tree parsing
to one helper and use that on both powernv and pseries. We still want to
use machine-specific callback because on all machine types other than
powernv and pseries we continue to return MIN_MEMORY_BLOCK_SIZE.

pseries_memory_block_size used to look for the second memory
block (memory@x) to determine the memory_block_size value. This patch
changed that to look at all memory blocks and make sure we can map them all
correctly using the computed memory block size value.

Add workaround to force 256MB memory block size if device driver managed
memory such as GPU memory is present. This helps to add GPU memory
that is not aligned to 1G.

Co-developed-by: Reza Arbab <arbab@linux.ibm.com>
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
Signed-off-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801044447.11275-1-aneesh.kumar@linux.ibm.com

1 files changed, 4 insertions, 56 deletions

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 9c62c2c3b3d0..1333d9ab7621 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -21,54 +21,6 @@
 #include <asm/drmem.h>
 #include "pseries.h"
 
-unsigned long pseries_memory_block_size(void)
-{
-	struct device_node *np;
-	u64 memblock_size = MIN_MEMORY_BLOCK_SIZE;
-	struct resource r;
-
-	np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
-	if (np) {
-		int len;
-		int size_cells;
-		const __be32 *prop;
-
-		size_cells = of_n_size_cells(np);
-
-		prop = of_get_property(np, "ibm,lmb-size", &len);
-		if (prop && len >= size_cells * sizeof(__be32))
-			memblock_size = of_read_number(prop, size_cells);
-		of_node_put(np);
-
-	} else  if (machine_is(pseries)) {
-		/* This fallback really only applies to pseries */
-		unsigned int memzero_size = 0;
-
-		np = of_find_node_by_path("/memory@0");
-		if (np) {
-			if (!of_address_to_resource(np, 0, &r))
-				memzero_size = resource_size(&r);
-			of_node_put(np);
-		}
-
-		if (memzero_size) {
-			/* We now know the size of memory@0, use this to find
-			 * the first memoryblock and get its size.
-			 */
-			char buf[64];
-
-			sprintf(buf, "/memory@%x", memzero_size);
-			np = of_find_node_by_path(buf);
-			if (np) {
-				if (!of_address_to_resource(np, 0, &r))
-					memblock_size = resource_size(&r);
-				of_node_put(np);
-			}
-		}
-	}
-	return memblock_size;
-}
-
 static void dlpar_free_property(struct property *prop)
 {
 	kfree(prop->name);
@@ -283,7 +235,7 @@ static int dlpar_offline_lmb(struct drmem_lmb *lmb)
 
 static int pseries_remove_memblock(unsigned long base, unsigned long memblock_size)
 {
-	unsigned long block_sz, start_pfn;
+	unsigned long start_pfn;
 	int sections_per_block;
 	int i;
 
@@ -294,8 +246,7 @@ static int pseries_remove_memblock(unsigned long base, unsigned long memblock_si
 	if (!pfn_valid(start_pfn))
 		goto out;
 
-	block_sz = pseries_memory_block_size();
-	sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
+	sections_per_block = memory_block_size / MIN_MEMORY_BLOCK_SIZE;
 
 	for (i = 0; i < sections_per_block; i++) {
 		__remove_memory(base, MIN_MEMORY_BLOCK_SIZE);
@@ -354,7 +305,6 @@ static int dlpar_add_lmb(struct drmem_lmb *);
 static int dlpar_remove_lmb(struct drmem_lmb *lmb)
 {
 	struct memory_block *mem_block;
-	unsigned long block_sz;
 	int rc;
 
 	if (!lmb_is_removable(lmb))
@@ -370,13 +320,11 @@ static int dlpar_remove_lmb(struct drmem_lmb *lmb)
 		return rc;
 	}
 
-	block_sz = pseries_memory_block_size();
-
-	__remove_memory(lmb->base_addr, block_sz);
+	__remove_memory(lmb->base_addr, memory_block_size);
 	put_device(&mem_block->dev);
 
 	/* Update memory regions for memory remove */
-	memblock_remove(lmb->base_addr, block_sz);
+	memblock_remove(lmb->base_addr, memory_block_size);
 
 	invalidate_lmb_associativity_index(lmb);
 	lmb->flags &= ~DRCONF_MEM_ASSIGNED;