pbl: provide externally visible fdt_find_mem

of_find_mem can be used for generic DT images for other architectures as
well. To support this, move the definition, so it can be used by others
in the future.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

2 files changed, 71 insertions, 0 deletions

diff --git a/pbl/Makefile b/pbl/Makefile
index c5a08c1354..9faa56ac91 100644
--- a/pbl/Makefile
+++ b/pbl/Makefile
@@ -4,4 +4,5 @@
 pbl-y += misc.o
 pbl-y += string.o
 pbl-y += decomp.o
+pbl-$(CONFIG_LIBFDT) += fdt.o
 pbl-$(CONFIG_PBL_CONSOLE) += console.o
diff --git a/pbl/fdt.c b/pbl/fdt.c
new file mode 100644
index 0000000000..b4a40a514b
--- /dev/null
+++ b/pbl/fdt.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/libfdt.h>
+#include <pbl.h>
+#include <printk.h>
+
+void fdt_find_mem(const void *fdt, unsigned long *membase, unsigned long *memsize)
+{
+	const __be32 *nap, *nsp, *reg;
+	uint32_t na, ns;
+	uint64_t memsize64, membase64;
+	int node, size, i;
+
+	/* Make sure FDT blob is sane */
+	if (fdt_check_header(fdt) != 0) {
+		pr_err("Invalid device tree blob\n");
+		goto err;
+	}
+
+	/* Find the #address-cells and #size-cells properties */
+	node = fdt_path_offset(fdt, "/");
+	if (node < 0) {
+		pr_err("Cannot find root node\n");
+		goto err;
+	}
+
+	nap = fdt_getprop(fdt, node, "#address-cells", &size);
+	if (!nap || (size != 4)) {
+		pr_err("Cannot find #address-cells property");
+		goto err;
+	}
+	na = fdt32_to_cpu(*nap);
+
+	nsp = fdt_getprop(fdt, node, "#size-cells", &size);
+	if (!nsp || (size != 4)) {
+		pr_err("Cannot find #size-cells property");
+		goto err;
+	}
+	ns = fdt32_to_cpu(*nap);
+
+	/* Find the memory range */
+	node = fdt_node_offset_by_prop_value(fdt, -1, "device_type",
+					     "memory", sizeof("memory"));
+	if (node < 0) {
+		pr_err("Cannot find memory node\n");
+		goto err;
+	}
+
+	reg = fdt_getprop(fdt, node, "reg", &size);
+	if (size < (na + ns) * sizeof(u32)) {
+		pr_err("cannot get memory range\n");
+		goto err;
+	}
+
+	membase64 = 0;
+	for (i = 0; i < na; i++)
+		membase64 = (membase64 << 32) | fdt32_to_cpu(*reg++);
+
+	/* get the memsize and truncate it to under 4G on 32 bit machines */
+	memsize64 = 0;
+	for (i = 0; i < ns; i++)
+		memsize64 = (memsize64 << 32) | fdt32_to_cpu(*reg++);
+
+	*membase = membase64;
+	*memsize = memsize64;
+
+	return;
+err:
+	pr_err("No memory, cannot continue\n");
+	while (1);
+}