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kernel/linux-imx6_3.14.28/arch/arm/mach-davinci/sram.c 1.8 KB
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  /*
   * mach-davinci/sram.c - DaVinci simple SRAM allocator
   *
   * Copyright (C) 2009 David Brownell
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   */
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/io.h>
  #include <linux/genalloc.h>
  
  #include <mach/common.h>
  #include <mach/sram.h>
  
  static struct gen_pool *sram_pool;
  
  struct gen_pool *sram_get_gen_pool(void)
  {
  	return sram_pool;
  }
  
  void *sram_alloc(size_t len, dma_addr_t *dma)
  {
  	dma_addr_t dma_base = davinci_soc_info.sram_dma;
  
  	if (dma)
  		*dma = 0;
  	if (!sram_pool || (dma && !dma_base))
  		return NULL;
  
  	return gen_pool_dma_alloc(sram_pool, len, dma);
  
  }
  EXPORT_SYMBOL(sram_alloc);
  
  void sram_free(void *addr, size_t len)
  {
  	gen_pool_free(sram_pool, (unsigned long) addr, len);
  }
  EXPORT_SYMBOL(sram_free);
  
  
  /*
   * REVISIT This supports CPU and DMA access to/from SRAM, but it
   * doesn't (yet?) support some other notable uses of SRAM:  as TCM
   * for data and/or instructions; and holding code needed to enter
   * and exit suspend states (while DRAM can't be used).
   */
  static int __init sram_init(void)
  {
  	phys_addr_t phys = davinci_soc_info.sram_dma;
  	unsigned len = davinci_soc_info.sram_len;
  	int status = 0;
  	void __iomem *addr;
  
  	if (len) {
  		len = min_t(unsigned, len, SRAM_SIZE);
  		sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1);
  		if (!sram_pool)
  			status = -ENOMEM;
  	}
  
  	if (sram_pool) {
  		addr = ioremap(phys, len);
  		if (!addr)
  			return -ENOMEM;
  		status = gen_pool_add_virt(sram_pool, (unsigned long) addr,
  					   phys, len, -1);
  		if (status < 0)
  			iounmap(addr);
  	}
  
  	WARN_ON(status < 0);
  	return status;
  }
  core_initcall(sram_init);