powerpc/kexec: Use of_property_read_reg()

Replace open-coded parsing of "reg" property with
of_property_read_reg().

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
[mpe: Rename end to size, add comment to the bail out case]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240702210344.722364-1-robh@kernel.org

diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
index 413c76de283dc5cf99798ce3fa5a2b595c6afeba..9738adabeb1feeaea9212c729e1f9a813552bc01 100644 (file)
--- a/arch/powerpc/kexec/file_load_64.c
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -18,6 +18,7 @@
 #include <linux/of_fdt.h>
 #include <linux/libfdt.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/memblock.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
@@ -376,11 +377,10 @@ static int kdump_setup_usable_lmb(struct drmem_lmb *lmb, const __be32 **usm,
 static int add_usable_mem_property(void *fdt, struct device_node *dn,
                                   struct umem_info *um_info)
 {
-       int n_mem_addr_cells, n_mem_size_cells, node;
+       int node;
        char path[NODE_PATH_LEN];
-       int i, len, ranges, ret;
-       const __be32 *prop;
-       u64 base, end;
+       int i, ret;
+       u64 base, size;
 
        of_node_get(dn);
 
@@ -399,41 +399,30 @@ static int add_usable_mem_property(void *fdt, struct device_node *dn,
                goto out;
        }
 
-       /* Get the address & size cells */
-       n_mem_addr_cells = of_n_addr_cells(dn);
-       n_mem_size_cells = of_n_size_cells(dn);
-       kexec_dprintk("address cells: %d, size cells: %d\n", n_mem_addr_cells,
-                     n_mem_size_cells);
-
        um_info->idx  = 0;
        if (!check_realloc_usable_mem(um_info, 2)) {
                ret = -ENOMEM;
                goto out;
        }
 
-       prop = of_get_property(dn, "reg", &len);
-       if (!prop || len <= 0) {
-               ret = 0;
-               goto out;
-       }
-
        /*
         * "reg" property represents sequence of (addr,size) tuples
         * each representing a memory range.
         */
-       ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
-
-       for (i = 0; i < ranges; i++) {
-               base = of_read_number(prop, n_mem_addr_cells);
-               prop += n_mem_addr_cells;
-               end = base + of_read_number(prop, n_mem_size_cells) - 1;
-               prop += n_mem_size_cells;
+       for (i = 0; ; i++) {
+               ret = of_property_read_reg(dn, i, &base, &size);
+               if (ret)
+                       break;
 
-               ret = add_usable_mem(um_info, base, end);
+               ret = add_usable_mem(um_info, base, base + size - 1);
                if (ret)
                        goto out;
        }
 
+       // No reg or empty reg? Skip this node.
+       if (i == 0)
+               goto out;
+
        /*
         * No kdump kernel usable memory found in this memory node.
         * Write (0,0) tuple in linux,usable-memory property for