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kernel/linux-rt-4.4.41/arch/powerpc/platforms/powernv/opal-nvram.c 2 KB
5113f6f70   김현기   kernel add
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  /*
   * PowerNV nvram code.
   *
   * Copyright 2011 IBM Corp.
   *
   * 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.
   */
  
  #define DEBUG
  
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/of.h>
  
  #include <asm/opal.h>
  #include <asm/nvram.h>
  #include <asm/machdep.h>
  
  static unsigned int nvram_size;
  
  static ssize_t opal_nvram_size(void)
  {
  	return nvram_size;
  }
  
  static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
  {
  	s64 rc;
  	int off;
  
  	if (*index >= nvram_size)
  		return 0;
  	off = *index;
  	if ((off + count) > nvram_size)
  		count = nvram_size - off;
  	rc = opal_read_nvram(__pa(buf), count, off);
  	if (rc != OPAL_SUCCESS)
  		return -EIO;
  	*index += count;
  	return count;
  }
  
  static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
  {
  	s64 rc = OPAL_BUSY;
  	int off;
  
  	if (*index >= nvram_size)
  		return 0;
  	off = *index;
  	if ((off + count) > nvram_size)
  		count = nvram_size - off;
  
  	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  		rc = opal_write_nvram(__pa(buf), count, off);
  		if (rc == OPAL_BUSY_EVENT)
  			opal_poll_events(NULL);
  	}
  	*index += count;
  	return count;
  }
  
  static int __init opal_nvram_init_log_partitions(void)
  {
  	/* Scan nvram for partitions */
  	nvram_scan_partitions();
  	nvram_init_oops_partition(0);
  	return 0;
  }
  machine_arch_initcall(powernv, opal_nvram_init_log_partitions);
  
  void __init opal_nvram_init(void)
  {
  	struct device_node *np;
  	const __be32 *nbytes_p;
  
  	np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram");
  	if (np == NULL)
  		return;
  
  	nbytes_p = of_get_property(np, "#bytes", NULL);
  	if (!nbytes_p) {
  		of_node_put(np);
  		return;
  	}
  	nvram_size = be32_to_cpup(nbytes_p);
  
  	pr_info("OPAL nvram setup, %u bytes
  ", nvram_size);
  	of_node_put(np);
  
  	ppc_md.nvram_read = opal_nvram_read;
  	ppc_md.nvram_write = opal_nvram_write;
  	ppc_md.nvram_size = opal_nvram_size;
  }