MIPS: SEAD3: Parse memsize in DT shim

Parse the memsize argument provided by the bootloader in the DT shim
code, allowing the user to override it on the command line. This places
all of the DT manipulation code into sead3-dtshim.c.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14058/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/mti-sead3/sead3-dtshim.c

@@ -22,6 +22,73 @@
 
 static unsigned char fdt_buf[16 << 10] __initdata;
 
+static int append_memory(void *fdt)
+{
+	unsigned long phys_memsize, memsize;
+	__be32 mem_array[2];
+	int err, mem_off;
+	char *var;
+
+	/* find memory size from the bootloader environment */
+	var = fw_getenv("memsize");
+	if (var) {
+		err = kstrtoul(var, 0, &phys_memsize);
+		if (err) {
+			pr_err("Failed to read memsize env variable '%s'\n",
+			       var);
+			return -EINVAL;
+		}
+	} else {
+		pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
+		phys_memsize = 32 << 20;
+	}
+
+	/* default to using all available RAM */
+	memsize = phys_memsize;
+
+	/* allow the user to override the usable memory */
+	var = strstr(arcs_cmdline, "memsize=");
+	if (var)
+		memsize = memparse(var + strlen("memsize="), NULL);
+
+	/* if the user says there's more RAM than we thought, believe them */
+	phys_memsize = max_t(unsigned long, phys_memsize, memsize);
+
+	/* find or add a memory node */
+	mem_off = fdt_path_offset(fdt, "/memory");
+	if (mem_off == -FDT_ERR_NOTFOUND)
+		mem_off = fdt_add_subnode(fdt, 0, "memory");
+	if (mem_off < 0) {
+		pr_err("Unable to find or add memory DT node: %d\n", mem_off);
+		return mem_off;
+	}
+
+	err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
+	if (err) {
+		pr_err("Unable to set memory node device_type: %d\n", err);
+		return err;
+	}
+
+	mem_array[0] = 0;
+	mem_array[1] = cpu_to_be32(phys_memsize);
+	err = fdt_setprop(fdt, mem_off, "reg", mem_array, sizeof(mem_array));
+	if (err) {
+		pr_err("Unable to set memory regs property: %d\n", err);
+		return err;
+	}
+
+	mem_array[0] = 0;
+	mem_array[1] = cpu_to_be32(memsize);
+	err = fdt_setprop(fdt, mem_off, "linux,usable-memory",
+			  mem_array, sizeof(mem_array));
+	if (err) {
+		pr_err("Unable to set linux,usable-memory property: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
 static int remove_gic(void *fdt)
 {
 	const unsigned int cpu_ehci_int = 2;
@@ -205,6 +272,10 @@ void __init *sead3_dt_shim(void *fdt)
 	if (err)
 		panic("Unable to open FDT: %d", err);
 
+	err = append_memory(fdt_buf);
+	if (err)
+		panic("Unable to patch FDT: %d", err);
+
 	err = remove_gic(fdt_buf);
 	if (err)
 		panic("Unable to patch FDT: %d", err);

arch/mips/mti-sead3/sead3-setup.c

@@ -11,7 +11,6 @@
 #include <linux/of_fdt.h>
 
 #include <asm/prom.h>
-#include <asm/fw/fw.h>
 
 #include <asm/mach-sead3/sead3-dtshim.h>
 #include <asm/mips-boards/generic.h>
@@ -21,68 +20,6 @@ const char *get_system_type(void)
 	return "MIPS SEAD3";
 }
 
-static uint32_t get_memsize_from_cmdline(void)
-{
-	int memsize = 0;
-	char *p = arcs_cmdline;
-	char *s = "memsize=";
-
-	p = strstr(p, s);
-	if (p) {
-		p += strlen(s);
-		memsize = memparse(p, NULL);
-	}
-
-	return memsize;
-}
-
-static uint32_t get_memsize_from_env(void)
-{
-	int memsize = 0;
-	char *p;
-
-	p = fw_getenv("memsize");
-	if (p)
-		memsize = memparse(p, NULL);
-
-	return memsize;
-}
-
-static uint32_t get_memsize(void)
-{
-	uint32_t memsize;
-
-	memsize = get_memsize_from_cmdline();
-	if (memsize)
-		return memsize;
-
-	return get_memsize_from_env();
-}
-
-static void __init parse_memsize_param(void)
-{
-	int offset;
-	const uint64_t *prop_value;
-	int prop_len;
-	uint32_t memsize = get_memsize();
-
-	if (!memsize)
-		return;
-
-	offset = fdt_path_offset(__dtb_start, "/memory");
-	if (offset > 0) {
-		uint64_t new_value;
-		/*
-		 * reg contains 2 32-bits BE values, offset and size. We just
-		 * want to replace the size value without affecting the offset
-		 */
-		prop_value = fdt_getprop(__dtb_start, offset, "reg", &prop_len);
-		new_value = be64_to_cpu(*prop_value);
-		new_value =  (new_value & ~0xffffffffllu) | memsize;
-		fdt_setprop_inplace_u64(__dtb_start, offset, "reg", new_value);
-	}
-}
-
 void __init *plat_get_fdt(void)
 {
 	return (void *)__dtb_start;
@@ -92,9 +29,6 @@ void __init plat_mem_setup(void)
 {
 	void *fdt = plat_get_fdt();
 
-	/* allow command line/bootloader env to override memory size in DT */
-	parse_memsize_param();
-
 	fdt = sead3_dt_shim(fdt);
 	__dt_setup_arch(fdt);
 }