1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/arch/arm/plat-omap/sram.c
5 * OMAP SRAM detection and management
7 * Copyright (C) 2005 Nokia Corporation
10 * Copyright (C) 2009-2012 Texas Instruments
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
20 #include <asm/fncpy.h>
22 #include <asm/cacheflush.h>
23 #include <asm/set_memory.h>
25 #include <asm/mach/map.h>
27 #include <plat/sram.h>
29 #define ROUND_DOWN(value,boundary) ((value) & (~((boundary)-1)))
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;
37 * Memory allocator for SRAM: calculates the new ceiling address
38 * for pushing a function using the fncpy API.
40 * Note that fncpy requires the returned address to be aligned
41 * to an 8-byte boundary.
43 static void *omap_sram_push_address(unsigned long size)
45 unsigned long available, new_ceil = (unsigned long)omap_sram_ceil;
47 available = omap_sram_ceil - (omap_sram_base + omap_sram_skip);
49 if (size > available) {
50 pr_err("Not enough space in SRAM\n");
55 new_ceil = ROUND_DOWN(new_ceil, FNCPY_ALIGN);
56 omap_sram_ceil = IOMEM(new_ceil);
58 return (void *)omap_sram_ceil;
61 void *omap_sram_push(void *funcp, unsigned long size)
68 sram = omap_sram_push_address(size);
72 base = (unsigned long)sram & PAGE_MASK;
73 pages = PAGE_ALIGN(size) / PAGE_SIZE;
75 set_memory_rw(base, pages);
77 dst = fncpy(sram, funcp, size);
79 set_memory_ro(base, pages);
80 set_memory_x(base, pages);
86 * The SRAM context is lost during off-idle and stack
89 void omap_sram_reset(void)
91 omap_sram_ceil = omap_sram_base + omap_sram_size;
95 * Note that we cannot use ioremap for SRAM, as clock init needs SRAM early.
97 void __init omap_map_sram(unsigned long start, unsigned long size,
98 unsigned long skip, int cached)
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");
118 * Looks like we need to preserve some bootloader code at the
119 * beginning of SRAM for jumping to flash for reboot to work...
121 memset_io(omap_sram_base + omap_sram_skip, 0,
122 omap_sram_size - omap_sram_skip);
124 base = (unsigned long)omap_sram_base;
125 pages = PAGE_ALIGN(omap_sram_size) / PAGE_SIZE;
127 set_memory_ro(base, pages);
128 set_memory_x(base, pages);