LXR linux/arch/arm/mach-davinci/sram.c

   1/*
   2 * mach-davinci/sram.c - DaVinci simple SRAM allocator
   3 *
   4 * Copyright (C) 2009 David Brownell
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 */
  11#include <linux/module.h>
  12#include <linux/init.h>
  13#include <linux/io.h>
  14#include <linux/genalloc.h>
  15
  16#include <mach/common.h>
  17#include <mach/sram.h>
  18
  19static struct gen_pool *sram_pool;
  20
  21struct gen_pool *sram_get_gen_pool(void)
  22{
  23        return sram_pool;
  24}
  25
  26void *sram_alloc(size_t len, dma_addr_t *dma)
  27{
  28        unsigned long vaddr;
  29        dma_addr_t dma_base = davinci_soc_info.sram_dma;
  30
  31        if (dma)
  32                *dma = 0;
  33        if (!sram_pool || (dma && !dma_base))
  34                return NULL;
  35
  36        vaddr = gen_pool_alloc(sram_pool, len);
  37        if (!vaddr)
  38                return NULL;
  39
  40        if (dma)
  41                *dma = gen_pool_virt_to_phys(sram_pool, vaddr);
  42        return (void *)vaddr;
  43
  44}
  45EXPORT_SYMBOL(sram_alloc);
  46
  47void sram_free(void *addr, size_t len)
  48{
  49        gen_pool_free(sram_pool, (unsigned long) addr, len);
  50}
  51EXPORT_SYMBOL(sram_free);
  52
  53
  54/*
  55 * REVISIT This supports CPU and DMA access to/from SRAM, but it
  56 * doesn't (yet?) support some other notable uses of SRAM:  as TCM
  57 * for data and/or instructions; and holding code needed to enter
  58 * and exit suspend states (while DRAM can't be used).
  59 */
  60static int __init sram_init(void)
  61{
  62        phys_addr_t phys = davinci_soc_info.sram_dma;
  63        unsigned len = davinci_soc_info.sram_len;
  64        int status = 0;
  65        void __iomem *addr;
  66
  67        if (len) {
  68                len = min_t(unsigned, len, SRAM_SIZE);
  69                sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1);
  70                if (!sram_pool)
  71                        status = -ENOMEM;
  72        }
  73
  74        if (sram_pool) {
  75                addr = ioremap(phys, len);
  76                if (!addr)
  77                        return -ENOMEM;
  78                status = gen_pool_add_virt(sram_pool, (unsigned long) addr,
  79                                           phys, len, -1);
  80                if (status < 0)
  81                        iounmap(addr);
  82        }
  83
  84        WARN_ON(status < 0);
  85        return status;
  86}
  87core_initcall(sram_init);
  88
  89