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Diffstat (limited to 'kernel/arch/mips/mti-malta/malta-dtshim.c')
-rw-r--r--kernel/arch/mips/mti-malta/malta-dtshim.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/kernel/arch/mips/mti-malta/malta-dtshim.c b/kernel/arch/mips/mti-malta/malta-dtshim.c
new file mode 100644
index 000000000..f7133efc5
--- /dev/null
+++ b/kernel/arch/mips/mti-malta/malta-dtshim.c
@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Paul Burton <paul.burton@imgtec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/libfdt.h>
+#include <linux/of_fdt.h>
+#include <linux/sizes.h>
+#include <asm/bootinfo.h>
+#include <asm/fw/fw.h>
+#include <asm/page.h>
+
+static unsigned char fdt_buf[16 << 10] __initdata;
+
+/* determined physical memory size, not overridden by command line args */
+extern unsigned long physical_memsize;
+
+#define MAX_MEM_ARRAY_ENTRIES 1
+
+static unsigned __init gen_fdt_mem_array(__be32 *mem_array, unsigned long size)
+{
+ unsigned long size_preio;
+ unsigned entries;
+
+ entries = 1;
+ mem_array[0] = cpu_to_be32(PHYS_OFFSET);
+ if (config_enabled(CONFIG_EVA)) {
+ /*
+ * The current Malta EVA configuration is "special" in that it
+ * always makes use of addresses in the upper half of the 32 bit
+ * physical address map, which gives it a contiguous region of
+ * DDR but limits it to 2GB.
+ */
+ mem_array[1] = cpu_to_be32(size);
+ } else {
+ size_preio = min_t(unsigned long, size, SZ_256M);
+ mem_array[1] = cpu_to_be32(size_preio);
+ }
+
+ BUG_ON(entries > MAX_MEM_ARRAY_ENTRIES);
+ return entries;
+}
+
+static void __init append_memory(void *fdt, int root_off)
+{
+ __be32 mem_array[2 * MAX_MEM_ARRAY_ENTRIES];
+ unsigned long memsize;
+ unsigned mem_entries;
+ int i, err, mem_off;
+ char *var, param_name[10], *var_names[] = {
+ "ememsize", "memsize",
+ };
+
+ /* if a memory node already exists, leave it alone */
+ mem_off = fdt_path_offset(fdt, "/memory");
+ if (mem_off >= 0)
+ return;
+
+ /* find memory size from the bootloader environment */
+ for (i = 0; i < ARRAY_SIZE(var_names); i++) {
+ var = fw_getenv(var_names[i]);
+ if (!var)
+ continue;
+
+ err = kstrtoul(var, 0, &physical_memsize);
+ if (!err)
+ break;
+
+ pr_warn("Failed to read the '%s' env variable '%s'\n",
+ var_names[i], var);
+ }
+
+ if (!physical_memsize) {
+ pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
+ physical_memsize = 32 << 20;
+ }
+
+ if (config_enabled(CONFIG_CPU_BIG_ENDIAN)) {
+ /*
+ * SOC-it swaps, or perhaps doesn't swap, when DMA'ing
+ * the last word of physical memory.
+ */
+ physical_memsize -= PAGE_SIZE;
+ }
+
+ /* default to using all available RAM */
+ memsize = physical_memsize;
+
+ /* allow the user to override the usable memory */
+ for (i = 0; i < ARRAY_SIZE(var_names); i++) {
+ snprintf(param_name, sizeof(param_name), "%s=", var_names[i]);
+ var = strstr(arcs_cmdline, param_name);
+ if (!var)
+ continue;
+
+ memsize = memparse(var + strlen(param_name), NULL);
+ }
+
+ /* if the user says there's more RAM than we thought, believe them */
+ physical_memsize = max_t(unsigned long, physical_memsize, memsize);
+
+ /* append memory to the DT */
+ mem_off = fdt_add_subnode(fdt, root_off, "memory");
+ if (mem_off < 0)
+ panic("Unable to add memory node to DT: %d", mem_off);
+
+ err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
+ if (err)
+ panic("Unable to set memory node device_type: %d", err);
+
+ mem_entries = gen_fdt_mem_array(mem_array, physical_memsize);
+ err = fdt_setprop(fdt, mem_off, "reg", mem_array,
+ mem_entries * 2 * sizeof(mem_array[0]));
+ if (err)
+ panic("Unable to set memory regs property: %d", err);
+
+ mem_entries = gen_fdt_mem_array(mem_array, memsize);
+ err = fdt_setprop(fdt, mem_off, "linux,usable-memory", mem_array,
+ mem_entries * 2 * sizeof(mem_array[0]));
+ if (err)
+ panic("Unable to set linux,usable-memory property: %d", err);
+}
+
+void __init *malta_dt_shim(void *fdt)
+{
+ int root_off, len, err;
+ const char *compat;
+
+ if (fdt_check_header(fdt))
+ panic("Corrupt DT");
+
+ err = fdt_open_into(fdt, fdt_buf, sizeof(fdt_buf));
+ if (err)
+ panic("Unable to open FDT: %d", err);
+
+ root_off = fdt_path_offset(fdt_buf, "/");
+ if (root_off < 0)
+ panic("No / node in DT");
+
+ compat = fdt_getprop(fdt_buf, root_off, "compatible", &len);
+ if (!compat)
+ panic("No root compatible property in DT: %d", len);
+
+ /* if this isn't Malta, leave the DT alone */
+ if (strncmp(compat, "mti,malta", len))
+ return fdt;
+
+ append_memory(fdt_buf, root_off);
+
+ err = fdt_pack(fdt_buf);
+ if (err)
+ panic("Unable to pack FDT: %d\n", err);
+
+ return fdt_buf;
+}