b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 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 | */ |
| 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 | |
| 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 | */ |
| 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 | */ |
| 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 | } |