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
33 static void __iomem *omap_sram_base;
34 static unsigned long omap_sram_skip;
35 static unsigned long omap_sram_size;
36 static 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 */
omap_sram_push_address(unsigned long size)45 void *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 */
omap_sram_reset(void)67 void 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 */
omap_map_sram(unsigned long start,unsigned long size,unsigned long skip,int cached)75 void __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