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kernel/linux-imx6_3.14.28/arch/m68k/atari/stram.c 3.58 KB
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  /*
   * Functions for ST-RAM allocations
   *
   * Copyright 1994-97 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file COPYING in the main directory of this archive
   * for more details.
   */
  
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/kdev_t.h>
  #include <linux/major.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/vmalloc.h>
  #include <linux/pagemap.h>
  #include <linux/bootmem.h>
  #include <linux/mount.h>
  #include <linux/blkdev.h>
  #include <linux/module.h>
  
  #include <asm/setup.h>
  #include <asm/machdep.h>
  #include <asm/page.h>
  #include <asm/pgtable.h>
  #include <asm/atarihw.h>
  #include <asm/atari_stram.h>
  #include <asm/io.h>
  
  
  /*
   * The ST-RAM allocator allocates memory from a pool of reserved ST-RAM of
   * configurable size, set aside on ST-RAM init.
   * As long as this pool is not exhausted, allocation of real ST-RAM can be
   * guaranteed.
   */
  
  /* set if kernel is in ST-RAM */
  static int kernel_in_stram;
  
  static struct resource stram_pool = {
  	.name = "ST-RAM Pool"
  };
  
  static unsigned long pool_size = 1024*1024;
  
  
  static int __init atari_stram_setup(char *arg)
  {
  	if (!MACH_IS_ATARI)
  		return 0;
  
  	pool_size = memparse(arg, NULL);
  	return 0;
  }
  
  early_param("stram_pool", atari_stram_setup);
  
  
  /*
   * This init function is called very early by atari/config.c
   * It initializes some internal variables needed for stram_alloc()
   */
  void __init atari_stram_init(void)
  {
  	int i;
  	void *stram_start;
  
  	/*
  	 * determine whether kernel code resides in ST-RAM
  	 * (then ST-RAM is the first memory block at virtual 0x0)
  	 */
  	stram_start = phys_to_virt(0);
  	kernel_in_stram = (stram_start == 0);
  
  	for (i = 0; i < m68k_num_memory; ++i) {
  		if (m68k_memory[i].addr == 0) {
  			return;
  		}
  	}
  
  	/* Should never come here! (There is always ST-Ram!) */
  	panic("atari_stram_init: no ST-RAM found!");
  }
  
  
  /*
   * This function is called from setup_arch() to reserve the pages needed for
   * ST-RAM management.
   */
  void __init atari_stram_reserve_pages(void *start_mem)
  {
  	/*
  	 * always reserve first page of ST-RAM, the first 2 KiB are
  	 * supervisor-only!
  	 */
  	if (!kernel_in_stram)
  		reserve_bootmem(0, PAGE_SIZE, BOOTMEM_DEFAULT);
  
  	stram_pool.start = (resource_size_t)alloc_bootmem_low_pages(pool_size);
  	stram_pool.end = stram_pool.start + pool_size - 1;
  	request_resource(&iomem_resource, &stram_pool);
  
  	pr_debug("atari_stram pool: size = %lu bytes, resource = %pR
  ",
  		 pool_size, &stram_pool);
  }
  
  
  void *atari_stram_alloc(unsigned long size, const char *owner)
  {
  	struct resource *res;
  	int error;
  
  	pr_debug("atari_stram_alloc: allocate %lu bytes
  ", size);
  
  	/* round up */
  	size = PAGE_ALIGN(size);
  
  	res = kzalloc(sizeof(struct resource), GFP_KERNEL);
  	if (!res)
  		return NULL;
  
  	res->name = owner;
  	error = allocate_resource(&stram_pool, res, size, 0, UINT_MAX,
  				  PAGE_SIZE, NULL, NULL);
  	if (error < 0) {
  		pr_err("atari_stram_alloc: allocate_resource() failed %d!
  ",
  		       error);
  		kfree(res);
  		return NULL;
  	}
  
  	pr_debug("atari_stram_alloc: returning %pR
  ", res);
  	return (void *)res->start;
  }
  EXPORT_SYMBOL(atari_stram_alloc);
  
  
  void atari_stram_free(void *addr)
  {
  	unsigned long start = (unsigned long)addr;
  	struct resource *res;
  	unsigned long size;
  
  	res = lookup_resource(&stram_pool, start);
  	if (!res) {
  		pr_err("atari_stram_free: trying to free nonexistent region "
  		       "at %p
  ", addr);
  		return;
  	}
  
  	size = resource_size(res);
  	pr_debug("atari_stram_free: free %lu bytes at %p
  ", size, addr);
  	release_resource(res);
  	kfree(res);
  }
  EXPORT_SYMBOL(atari_stram_free);