1/*
2 * linux/arch/arm/plat-omap/sram.c
3 *
4 * OMAP SRAM detection and management
5 *
6 * Copyright (C) 2005 Nokia Corporation
7 * Written by Tony Lindgren <tony@atomide.com>
8 *
9 * Copyright (C) 2009-2012 Texas Instruments
10 * Added OMAP4/5 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
15 */
16#undef DEBUG
17
18#include <linux/module.h>
19#include <linux/kernel.h>
20#include <linux/init.h>
21#include <linux/io.h>
22
23#include <asm/fncpy.h>
24#include <asm/tlb.h>
25#include <asm/cacheflush.h>
26
27#include <asm/mach/map.h>
28
29#include <plat/sram.h>
30
31#define ROUND_DOWN(value,boundary)	((value) & (~((boundary)-1)))
32
33static void __iomem *omap_sram_base;
34static unsigned long omap_sram_skip;
35static unsigned long omap_sram_size;
36static void __iomem *omap_sram_ceil;
37
38/*
39 * Memory allocator for SRAM: calculates the new ceiling address
40 * for pushing a function using the fncpy API.
41 *
42 * Note that fncpy requires the returned address to be aligned
43 * to an 8-byte boundary.
44 */
45void *omap_sram_push_address(unsigned long size)
46{
47	unsigned long available, new_ceil = (unsigned long)omap_sram_ceil;
48
49	available = omap_sram_ceil - (omap_sram_base + omap_sram_skip);
50
51	if (size > available) {
52		pr_err("Not enough space in SRAM\n");
53		return NULL;
54	}
55
56	new_ceil -= size;
57	new_ceil = ROUND_DOWN(new_ceil, FNCPY_ALIGN);
58	omap_sram_ceil = IOMEM(new_ceil);
59
60	return (void *)omap_sram_ceil;
61}
62
63/*
64 * The SRAM context is lost during off-idle and stack
65 * needs to be reset.
66 */
67void omap_sram_reset(void)
68{
69	omap_sram_ceil = omap_sram_base + omap_sram_size;
70}
71
72/*
73 * Note that we cannot use ioremap for SRAM, as clock init needs SRAM early.
74 */
75void __init omap_map_sram(unsigned long start, unsigned long size,
76				 unsigned long skip, int cached)
77{
78	if (size == 0)
79		return;
80
81	start = ROUND_DOWN(start, PAGE_SIZE);
82	omap_sram_size = size;
83	omap_sram_skip = skip;
84	omap_sram_base = __arm_ioremap_exec(start, size, cached);
85	if (!omap_sram_base) {
86		pr_err("SRAM: Could not map\n");
87		return;
88	}
89
90	omap_sram_reset();
91
92	/*
93	 * Looks like we need to preserve some bootloader code at the
94	 * beginning of SRAM for jumping to flash for reboot to work...
95	 */
96	memset_io(omap_sram_base + omap_sram_skip, 0,
97		  omap_sram_size - omap_sram_skip);
98}
99