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 #include <asm/set_memory.h>
27
28 #include <asm/mach/map.h>
29
30 #include <plat/sram.h>
31
32 #define ROUND_DOWN(value,boundary) ((value) & (~((boundary)-1)))
33
34 static void __iomem *omap_sram_base;
35 static unsigned long omap_sram_skip;
36 static unsigned long omap_sram_size;
37 static void __iomem *omap_sram_ceil;
38
39 /*
40 * Memory allocator for SRAM: calculates the new ceiling address
41 * for pushing a function using the fncpy API.
42 *
43 * Note that fncpy requires the returned address to be aligned
44 * to an 8-byte boundary.
45 */
omap_sram_push_address(unsigned long size)46 static void *omap_sram_push_address(unsigned long size)
47 {
48 unsigned long available, new_ceil = (unsigned long)omap_sram_ceil;
49
50 available = omap_sram_ceil - (omap_sram_base + omap_sram_skip);
51
52 if (size > available) {
53 pr_err("Not enough space in SRAM\n");
54 return NULL;
55 }
56
57 new_ceil -= size;
58 new_ceil = ROUND_DOWN(new_ceil, FNCPY_ALIGN);
59 omap_sram_ceil = IOMEM(new_ceil);
60
61 return (void *)omap_sram_ceil;
62 }
63
omap_sram_push(void * funcp,unsigned long size)64 void *omap_sram_push(void *funcp, unsigned long size)
65 {
66 void *sram;
67 unsigned long base;
68 int pages;
69 void *dst = NULL;
70
71 sram = omap_sram_push_address(size);
72 if (!sram)
73 return NULL;
74
75 base = (unsigned long)sram & PAGE_MASK;
76 pages = PAGE_ALIGN(size) / PAGE_SIZE;
77
78 set_memory_rw(base, pages);
79
80 dst = fncpy(sram, funcp, size);
81
82 set_memory_ro(base, pages);
83 set_memory_x(base, pages);
84
85 return dst;
86 }
87
88 /*
89 * The SRAM context is lost during off-idle and stack
90 * needs to be reset.
91 */
omap_sram_reset(void)92 void omap_sram_reset(void)
93 {
94 omap_sram_ceil = omap_sram_base + omap_sram_size;
95 }
96
97 /*
98 * Note that we cannot use ioremap for SRAM, as clock init needs SRAM early.
99 */
omap_map_sram(unsigned long start,unsigned long size,unsigned long skip,int cached)100 void __init omap_map_sram(unsigned long start, unsigned long size,
101 unsigned long skip, int cached)
102 {
103 unsigned long base;
104 int pages;
105
106 if (size == 0)
107 return;
108
109 start = ROUND_DOWN(start, PAGE_SIZE);
110 omap_sram_size = size;
111 omap_sram_skip = skip;
112 omap_sram_base = __arm_ioremap_exec(start, size, cached);
113 if (!omap_sram_base) {
114 pr_err("SRAM: Could not map\n");
115 return;
116 }
117
118 omap_sram_reset();
119
120 /*
121 * Looks like we need to preserve some bootloader code at the
122 * beginning of SRAM for jumping to flash for reboot to work...
123 */
124 memset_io(omap_sram_base + omap_sram_skip, 0,
125 omap_sram_size - omap_sram_skip);
126
127 base = (unsigned long)omap_sram_base;
128 pages = PAGE_ALIGN(omap_sram_size) / PAGE_SIZE;
129
130 set_memory_ro(base, pages);
131 set_memory_x(base, pages);
132 }
133
