1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/arm/plat-omap/sram.c
4 *
5 * OMAP SRAM detection and management
6 *
7 * Copyright (C) 2005 Nokia Corporation
8 * Written by Tony Lindgren <tony@atomide.com>
9 *
10 * Copyright (C) 2009-2012 Texas Instruments
11 * Added OMAP4/5 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
12 */
13 #undef DEBUG
14
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/io.h>
19
20 #include <asm/fncpy.h>
21 #include <asm/tlb.h>
22 #include <asm/cacheflush.h>
23 #include <asm/set_memory.h>
24
25 #include <asm/mach/map.h>
26
27 #include <plat/sram.h>
28
29 #define ROUND_DOWN(value,boundary) ((value) & (~((boundary)-1)))
30
31 static void __iomem *omap_sram_base;
32 static unsigned long omap_sram_skip;
33 static unsigned long omap_sram_size;
34 static void __iomem *omap_sram_ceil;
35
36 /*
37 * Memory allocator for SRAM: calculates the new ceiling address
38 * for pushing a function using the fncpy API.
39 *
40 * Note that fncpy requires the returned address to be aligned
41 * to an 8-byte boundary.
42 */
omap_sram_push_address(unsigned long size)43 static void *omap_sram_push_address(unsigned long size)
44 {
45 unsigned long available, new_ceil = (unsigned long)omap_sram_ceil;
46
47 available = omap_sram_ceil - (omap_sram_base + omap_sram_skip);
48
49 if (size > available) {
50 pr_err("Not enough space in SRAM\n");
51 return NULL;
52 }
53
54 new_ceil -= size;
55 new_ceil = ROUND_DOWN(new_ceil, FNCPY_ALIGN);
56 omap_sram_ceil = IOMEM(new_ceil);
57
58 return (void *)omap_sram_ceil;
59 }
60
omap_sram_push(void * funcp,unsigned long size)61 void *omap_sram_push(void *funcp, unsigned long size)
62 {
63 void *sram;
64 unsigned long base;
65 int pages;
66 void *dst = NULL;
67
68 sram = omap_sram_push_address(size);
69 if (!sram)
70 return NULL;
71
72 base = (unsigned long)sram & PAGE_MASK;
73 pages = PAGE_ALIGN(size) / PAGE_SIZE;
74
75 set_memory_rw(base, pages);
76
77 dst = fncpy(sram, funcp, size);
78
79 set_memory_ro(base, pages);
80 set_memory_x(base, pages);
81
82 return dst;
83 }
84
85 /*
86 * The SRAM context is lost during off-idle and stack
87 * needs to be reset.
88 */
omap_sram_reset(void)89 void omap_sram_reset(void)
90 {
91 omap_sram_ceil = omap_sram_base + omap_sram_size;
92 }
93
94 /*
95 * Note that we cannot use ioremap for SRAM, as clock init needs SRAM early.
96 */
omap_map_sram(unsigned long start,unsigned long size,unsigned long skip,int cached)97 void __init omap_map_sram(unsigned long start, unsigned long size,
98 unsigned long skip, int cached)
99 {
100 unsigned long base;
101 int pages;
102
103 if (size == 0)
104 return;
105
106 start = ROUND_DOWN(start, PAGE_SIZE);
107 omap_sram_size = size;
108 omap_sram_skip = skip;
109 omap_sram_base = __arm_ioremap_exec(start, size, cached);
110 if (!omap_sram_base) {
111 pr_err("SRAM: Could not map\n");
112 return;
113 }
114
115 omap_sram_reset();
116
117 /*
118 * Looks like we need to preserve some bootloader code at the
119 * beginning of SRAM for jumping to flash for reboot to work...
120 */
121 memset_io(omap_sram_base + omap_sram_skip, 0,
122 omap_sram_size - omap_sram_skip);
123
124 base = (unsigned long)omap_sram_base;
125 pages = PAGE_ALIGN(omap_sram_size) / PAGE_SIZE;
126
127 set_memory_ro(base, pages);
128 set_memory_x(base, pages);
129 }
130