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
 31static void __iomem *omap_sram_base;
 32static unsigned long omap_sram_skip;
 33static unsigned long omap_sram_size;
 34static 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 */
 43static 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
 61void *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 */
 89void 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 */
 97void __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}