diff options
Diffstat (limited to 'arch/mips/mti-malta/malta-dtshim.c')
| -rw-r--r-- | arch/mips/mti-malta/malta-dtshim.c | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/arch/mips/mti-malta/malta-dtshim.c b/arch/mips/mti-malta/malta-dtshim.c new file mode 100644 index 000000000000..f7133efc5843 --- /dev/null +++ b/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; +} |