arch/arm/mach-imx/iram_alloc.c

   1 /*
   2  * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  17  * MA 02110-1301, USA.
  18  */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/io.h>
  22 #include <linux/module.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/genalloc.h>
  25 #include "linux/platform_data/imx-iram.h"
  26
  27 static unsigned long iram_phys_base;
  28 static void __iomem *iram_virt_base;
  29 static struct gen_pool *iram_pool;
  30
  31 static inline void __iomem *iram_phys_to_virt(unsigned long p)
  32 {
  33         return iram_virt_base + (p - iram_phys_base);
  34 }
  35
  36 void __iomem *iram_alloc(unsigned int size, unsigned long *dma_addr)
  37 {
  38         if (!iram_pool)
  39                 return NULL;
  40
  41         *dma_addr = gen_pool_alloc(iram_pool, size);
  42         pr_debug("iram alloc - %dB@0x%lX\n", size, *dma_addr);
  43         if (!*dma_addr)
  44                 return NULL;
  45         return iram_phys_to_virt(*dma_addr);
  46 }
  47 EXPORT_SYMBOL(iram_alloc);
  48
  49 void iram_free(unsigned long addr, unsigned int size)
  50 {
  51         if (!iram_pool)
  52                 return;
  53
  54         gen_pool_free(iram_pool, addr, size);
  55 }
  56 EXPORT_SYMBOL(iram_free);
  57
  58 int __init iram_init(unsigned long base, unsigned long size)
  59 {
  60         iram_phys_base = base;
  61
  62         iram_pool = gen_pool_create(PAGE_SHIFT, -1);
  63         if (!iram_pool)
  64                 return -ENOMEM;
  65
  66         gen_pool_add(iram_pool, base, size, -1);
  67         iram_virt_base = ioremap(iram_phys_base, size);
  68         if (!iram_virt_base)
  69                 return -EIO;
  70
  71         pr_debug("i.MX IRAM pool: %ld KB@0x%p\n", size / 1024, iram_virt_base);
  72         return 0;
  73 }