Commit e81a8c7d authored by Paul Burton's avatar Paul Burton Committed by Ralf Baechle
Browse files

MIPS: Malta: Setup RAM regions via DT 



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: default avatarPaul 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: default avatarRalf Baechle <ralf@linux-mips.org>
parent ea050714

arch/mips/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -450,6 +450,8 @@ config MIPS_MALTA 
	select SYS_SUPPORTS_ZBOOT

	select USE_OF

	select ZONE_DMA32 if 64BIT

	select BUILTIN_DTB

	select LIBFDT

	help

	  This enables support for the MIPS Technologies Malta evaluation

	  board.

arch/mips/boot/dts/mti/malta.dts

+4 −0
Original line number Diff line number Diff line 
/dts-v1/;



/memreserve/ 0x00000000 0x00001000;	/* YAMON exception vectors */

/memreserve/ 0x00001000 0x000ef000;	/* YAMON */

/memreserve/ 0x000f0000 0x00010000;	/* PIIX4 ISA memory */



/ {

	#address-cells = <1>;

	#size-cells = <1>;

arch/mips/include/asm/mach-malta/malta-dtshim.h

0 → 100644
+29 −0
Original line number Diff line number Diff line 
/*

 * 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.

 */



#ifndef __MIPS_MALTA_DTSHIM_H__

#define __MIPS_MALTA_DTSHIM_H__



#include <linux/init.h>



#ifdef CONFIG_MIPS_MALTA



extern void __init *malta_dt_shim(void *fdt);



#else /* !CONFIG_MIPS_MALTA */



static inline void *malta_dt_shim(void *fdt)

{

	return fdt;

}



#endif /* !CONFIG_MIPS_MALTA */



#endif /* __MIPS_MALTA_DTSHIM_H__ */

arch/mips/mti-malta/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#

obj-y				+= malta-display.o

obj-y				+= malta-dt.o

obj-y				+= malta-dtshim.o

obj-y				+= malta-init.o

obj-y				+= malta-int.o

obj-y				+= malta-memory.o
@@ -17,3 +18,5 @@ obj-y += malta-time.o 


obj-$(CONFIG_MIPS_CMP)		+= malta-amon.o

obj-$(CONFIG_MIPS_MALTA_PM)	+= malta-pm.o



CFLAGS_malta-dtshim.o = -I$(src)/../../../scripts/dtc/libfdt

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

0 → 100644
+162 −0
Original line number Diff line number Diff line 
/*

 * 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;

}

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