133 lines
3 KiB
C
133 lines
3 KiB
C
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/*
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* linux/arch/arm/plat-omap/sram.c
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*
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* OMAP SRAM detection and management
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*
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* Copyright (C) 2005 Nokia Corporation
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* Written by Tony Lindgren <tony@atomide.com>
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*
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* Copyright (C) 2009-2012 Texas Instruments
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* Added OMAP4/5 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#undef DEBUG
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <asm/fncpy.h>
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#include <asm/tlb.h>
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#include <asm/cacheflush.h>
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#include <asm/set_memory.h>
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#include <asm/mach/map.h>
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#include <plat/sram.h>
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#define ROUND_DOWN(value,boundary) ((value) & (~((boundary)-1)))
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static void __iomem *omap_sram_base;
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static unsigned long omap_sram_skip;
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static unsigned long omap_sram_size;
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static void __iomem *omap_sram_ceil;
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/*
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* Memory allocator for SRAM: calculates the new ceiling address
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* for pushing a function using the fncpy API.
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*
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* Note that fncpy requires the returned address to be aligned
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* to an 8-byte boundary.
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*/
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static void *omap_sram_push_address(unsigned long size)
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{
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unsigned long available, new_ceil = (unsigned long)omap_sram_ceil;
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available = omap_sram_ceil - (omap_sram_base + omap_sram_skip);
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if (size > available) {
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pr_err("Not enough space in SRAM\n");
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return NULL;
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}
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new_ceil -= size;
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new_ceil = ROUND_DOWN(new_ceil, FNCPY_ALIGN);
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omap_sram_ceil = IOMEM(new_ceil);
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return (void *)omap_sram_ceil;
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}
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void *omap_sram_push(void *funcp, unsigned long size)
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{
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void *sram;
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unsigned long base;
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int pages;
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void *dst = NULL;
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sram = omap_sram_push_address(size);
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if (!sram)
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return NULL;
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base = (unsigned long)sram & PAGE_MASK;
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pages = PAGE_ALIGN(size) / PAGE_SIZE;
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set_memory_rw(base, pages);
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dst = fncpy(sram, funcp, size);
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set_memory_ro(base, pages);
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set_memory_x(base, pages);
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return dst;
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}
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/*
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* The SRAM context is lost during off-idle and stack
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* needs to be reset.
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*/
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void omap_sram_reset(void)
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{
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omap_sram_ceil = omap_sram_base + omap_sram_size;
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}
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/*
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* Note that we cannot use ioremap for SRAM, as clock init needs SRAM early.
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*/
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void __init omap_map_sram(unsigned long start, unsigned long size,
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unsigned long skip, int cached)
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{
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unsigned long base;
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int pages;
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if (size == 0)
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return;
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start = ROUND_DOWN(start, PAGE_SIZE);
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omap_sram_size = size;
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omap_sram_skip = skip;
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omap_sram_base = __arm_ioremap_exec(start, size, cached);
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if (!omap_sram_base) {
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pr_err("SRAM: Could not map\n");
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return;
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}
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omap_sram_reset();
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/*
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* Looks like we need to preserve some bootloader code at the
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* beginning of SRAM for jumping to flash for reboot to work...
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*/
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memset_io(omap_sram_base + omap_sram_skip, 0,
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omap_sram_size - omap_sram_skip);
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base = (unsigned long)omap_sram_base;
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pages = PAGE_ALIGN(omap_sram_size) / PAGE_SIZE;
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set_memory_ro(base, pages);
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set_memory_x(base, pages);
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}
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