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

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * mach-davinci/sram.c - DaVinci simple SRAM allocator
   4 *
   5 * Copyright (C) 2009 David Brownell
   6 */
   7#include <linux/module.h>
   8#include <linux/init.h>
   9#include <linux/io.h>
  10#include <linux/genalloc.h>
  11
  12#include <mach/common.h>
  13#include "sram.h"
  14
  15static struct gen_pool *sram_pool;
  16
  17struct gen_pool *sram_get_gen_pool(void)
  18{
  19        return sram_pool;
  20}
  21
  22void *sram_alloc(size_t len, dma_addr_t *dma)
  23{
  24        dma_addr_t dma_base = davinci_soc_info.sram_dma;
  25
  26        if (dma)
  27                *dma = 0;
  28        if (!sram_pool || (dma && !dma_base))
  29                return NULL;
  30
  31        return gen_pool_dma_alloc(sram_pool, len, dma);
  32
  33}
  34EXPORT_SYMBOL(sram_alloc);
  35
  36void sram_free(void *addr, size_t len)
  37{
  38        gen_pool_free(sram_pool, (unsigned long) addr, len);
  39}
  40EXPORT_SYMBOL(sram_free);
  41
  42
  43/*
  44 * REVISIT This supports CPU and DMA access to/from SRAM, but it
  45 * doesn't (yet?) support some other notable uses of SRAM:  as TCM
  46 * for data and/or instructions; and holding code needed to enter
  47 * and exit suspend states (while DRAM can't be used).
  48 */
  49static int __init sram_init(void)
  50{
  51        phys_addr_t phys = davinci_soc_info.sram_dma;
  52        unsigned len = davinci_soc_info.sram_len;
  53        int status = 0;
  54        void __iomem *addr;
  55
  56        if (len) {
  57                len = min_t(unsigned, len, SRAM_SIZE);
  58                sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1);
  59                if (!sram_pool)
  60                        status = -ENOMEM;
  61        }
  62
  63        if (sram_pool) {
  64                addr = ioremap(phys, len);
  65                if (!addr)
  66                        return -ENOMEM;
  67                status = gen_pool_add_virt(sram_pool, (unsigned long) addr,
  68                                           phys, len, -1);
  69                if (status < 0)
  70                        iounmap(addr);
  71        }
  72
  73        WARN_ON(status < 0);
  74        return status;
  75}
  76core_initcall(sram_init);
  77
  78