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![Paul Burton](/assets/img/avatar_default.png)
Move memory configuration to be performed via device tree for the Malta board. This moves more Malta specific code to malta-dtshim.c, leaving the rest of the mti-malta code a little more board-agnostic. This will be useful to share more code between boards, with the device tree providing the board specifics as intended. Since we can't rely upon Malta boards running a bootloader capable of handling devictrees & filling in the required information, a piece of shim code (malta_dt_shim) is added to consume the (e)memsize variables provided as part of the bootloader environment (or on the kernel command line) then generate the DT memory node using the provided values. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: devicetree@vger.kernel.org Cc: Kumar Gala <galak@codeaurora.org> Cc: linux-kernel@vger.kernel.org Cc: Ian Campbell <ijc+devicetree@hellion.org.uk> Cc: Rob Herring <robh+dt@kernel.org> Cc: James Hogan <james.hogan@imgtec.com> Cc: Pawel Moll <pawel.moll@arm.com> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Mark Rutland <mark.rutland@arm.com> Patchwork: https://patchwork.linux-mips.org/patch/11222/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
162 lines
4.3 KiB
C
162 lines
4.3 KiB
C
/*
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* Copyright (C) 2015 Imagination Technologies
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* Author: Paul Burton <paul.burton@imgtec.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/bug.h>
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#include <linux/kernel.h>
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#include <linux/libfdt.h>
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#include <linux/of_fdt.h>
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#include <linux/sizes.h>
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#include <asm/bootinfo.h>
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#include <asm/fw/fw.h>
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#include <asm/page.h>
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static unsigned char fdt_buf[16 << 10] __initdata;
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/* determined physical memory size, not overridden by command line args */
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extern unsigned long physical_memsize;
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#define MAX_MEM_ARRAY_ENTRIES 1
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static unsigned __init gen_fdt_mem_array(__be32 *mem_array, unsigned long size)
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{
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unsigned long size_preio;
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unsigned entries;
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entries = 1;
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mem_array[0] = cpu_to_be32(PHYS_OFFSET);
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if (config_enabled(CONFIG_EVA)) {
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/*
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* The current Malta EVA configuration is "special" in that it
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* always makes use of addresses in the upper half of the 32 bit
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* physical address map, which gives it a contiguous region of
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* DDR but limits it to 2GB.
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*/
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mem_array[1] = cpu_to_be32(size);
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} else {
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size_preio = min_t(unsigned long, size, SZ_256M);
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mem_array[1] = cpu_to_be32(size_preio);
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}
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BUG_ON(entries > MAX_MEM_ARRAY_ENTRIES);
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return entries;
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}
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static void __init append_memory(void *fdt, int root_off)
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{
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__be32 mem_array[2 * MAX_MEM_ARRAY_ENTRIES];
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unsigned long memsize;
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unsigned mem_entries;
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int i, err, mem_off;
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char *var, param_name[10], *var_names[] = {
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"ememsize", "memsize",
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};
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/* if a memory node already exists, leave it alone */
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mem_off = fdt_path_offset(fdt, "/memory");
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if (mem_off >= 0)
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return;
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/* find memory size from the bootloader environment */
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for (i = 0; i < ARRAY_SIZE(var_names); i++) {
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var = fw_getenv(var_names[i]);
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if (!var)
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continue;
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err = kstrtoul(var, 0, &physical_memsize);
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if (!err)
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break;
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pr_warn("Failed to read the '%s' env variable '%s'\n",
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var_names[i], var);
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}
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if (!physical_memsize) {
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pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
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physical_memsize = 32 << 20;
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}
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if (config_enabled(CONFIG_CPU_BIG_ENDIAN)) {
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/*
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* SOC-it swaps, or perhaps doesn't swap, when DMA'ing
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* the last word of physical memory.
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*/
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physical_memsize -= PAGE_SIZE;
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}
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/* default to using all available RAM */
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memsize = physical_memsize;
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/* allow the user to override the usable memory */
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for (i = 0; i < ARRAY_SIZE(var_names); i++) {
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snprintf(param_name, sizeof(param_name), "%s=", var_names[i]);
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var = strstr(arcs_cmdline, param_name);
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if (!var)
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continue;
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memsize = memparse(var + strlen(param_name), NULL);
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}
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/* if the user says there's more RAM than we thought, believe them */
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physical_memsize = max_t(unsigned long, physical_memsize, memsize);
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/* append memory to the DT */
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mem_off = fdt_add_subnode(fdt, root_off, "memory");
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if (mem_off < 0)
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panic("Unable to add memory node to DT: %d", mem_off);
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err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
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if (err)
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panic("Unable to set memory node device_type: %d", err);
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mem_entries = gen_fdt_mem_array(mem_array, physical_memsize);
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err = fdt_setprop(fdt, mem_off, "reg", mem_array,
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mem_entries * 2 * sizeof(mem_array[0]));
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if (err)
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panic("Unable to set memory regs property: %d", err);
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mem_entries = gen_fdt_mem_array(mem_array, memsize);
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err = fdt_setprop(fdt, mem_off, "linux,usable-memory", mem_array,
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mem_entries * 2 * sizeof(mem_array[0]));
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if (err)
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panic("Unable to set linux,usable-memory property: %d", err);
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}
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void __init *malta_dt_shim(void *fdt)
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{
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int root_off, len, err;
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const char *compat;
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if (fdt_check_header(fdt))
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panic("Corrupt DT");
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err = fdt_open_into(fdt, fdt_buf, sizeof(fdt_buf));
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if (err)
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panic("Unable to open FDT: %d", err);
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root_off = fdt_path_offset(fdt_buf, "/");
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if (root_off < 0)
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panic("No / node in DT");
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compat = fdt_getprop(fdt_buf, root_off, "compatible", &len);
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if (!compat)
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panic("No root compatible property in DT: %d", len);
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/* if this isn't Malta, leave the DT alone */
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if (strncmp(compat, "mti,malta", len))
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return fdt;
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append_memory(fdt_buf, root_off);
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err = fdt_pack(fdt_buf);
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if (err)
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panic("Unable to pack FDT: %d\n", err);
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return fdt_buf;
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}
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