// SPDX-License-Identifier: GPL-2.0

  /*
   * Linux Guest Relocation (LGR) detection
   *
   * Copyright IBM Corp. 2012
   * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
   */

  #include <linux/init.h>
  #include <linux/export.h>

  #include <linux/timer.h>
  #include <linux/slab.h>

  #include <asm/facility.h>

  #include <asm/sysinfo.h>
  #include <asm/ebcdic.h>

  #include <asm/debug.h>
  #include <asm/ipl.h>
  
  #define LGR_TIMER_INTERVAL_SECS (30 * 60)
  #define VM_LEVEL_MAX 2 /* Maximum is 8, but we only record two levels */
  
  /*
   * LGR info: Contains stfle and stsi data
   */
  struct lgr_info {
  	/* Bit field with facility information: 4 DWORDs are stored */
  	u64 stfle_fac_list[4];
  	/* Level of system (1 = CEC, 2 = LPAR, 3 = z/VM */
  	u32 level;
  	/* Level 1: CEC info (stsi 1.1.1) */
  	char manufacturer[16];
  	char type[4];
  	char sequence[16];
  	char plant[4];
  	char model[16];
  	/* Level 2: LPAR info (stsi 2.2.2) */
  	u16 lpar_number;
  	char name[8];
  	/* Level 3: VM info (stsi 3.2.2) */
  	u8 vm_count;
  	struct {
  		char name[8];
  		char cpi[16];
  	} vm[VM_LEVEL_MAX];
  } __packed __aligned(8);
  
  /*
   * LGR globals
   */

  static char lgr_page[PAGE_SIZE] __aligned(PAGE_SIZE);

  static struct lgr_info lgr_info_last;
  static struct lgr_info lgr_info_cur;
  static struct debug_info *lgr_dbf;
  
  /*

   * Copy buffer and then convert it to ASCII
   */
  static void cpascii(char *dst, char *src, int size)
  {
  	memcpy(dst, src, size);
  	EBCASC(dst, size);
  }
  
  /*
   * Fill LGR info with 1.1.1 stsi data
   */
  static void lgr_stsi_1_1_1(struct lgr_info *lgr_info)
  {

  	struct sysinfo_1_1_1 *si = (void *) lgr_page;

  	if (stsi(si, 1, 1, 1))

  		return;
  	cpascii(lgr_info->manufacturer, si->manufacturer,
  		sizeof(si->manufacturer));
  	cpascii(lgr_info->type, si->type, sizeof(si->type));
  	cpascii(lgr_info->model, si->model, sizeof(si->model));
  	cpascii(lgr_info->sequence, si->sequence, sizeof(si->sequence));
  	cpascii(lgr_info->plant, si->plant, sizeof(si->plant));
  }
  
  /*
   * Fill LGR info with 2.2.2 stsi data
   */
  static void lgr_stsi_2_2_2(struct lgr_info *lgr_info)
  {

  	struct sysinfo_2_2_2 *si = (void *) lgr_page;

  	if (stsi(si, 2, 2, 2))

  		return;
  	cpascii(lgr_info->name, si->name, sizeof(si->name));
  	memcpy(&lgr_info->lpar_number, &si->lpar_number,
  	       sizeof(lgr_info->lpar_number));
  }
  
  /*
   * Fill LGR info with 3.2.2 stsi data
   */
  static void lgr_stsi_3_2_2(struct lgr_info *lgr_info)
  {

  	struct sysinfo_3_2_2 *si = (void *) lgr_page;

  	int i;

  	if (stsi(si, 3, 2, 2))

  		return;
  	for (i = 0; i < min_t(u8, si->count, VM_LEVEL_MAX); i++) {
  		cpascii(lgr_info->vm[i].name, si->vm[i].name,
  			sizeof(si->vm[i].name));
  		cpascii(lgr_info->vm[i].cpi, si->vm[i].cpi,
  			sizeof(si->vm[i].cpi));
  	}
  	lgr_info->vm_count = si->count;
  }
  
  /*
   * Fill LGR info with current data
   */
  static void lgr_info_get(struct lgr_info *lgr_info)
  {

  	int level;

  	memset(lgr_info, 0, sizeof(*lgr_info));
  	stfle(lgr_info->stfle_fac_list, ARRAY_SIZE(lgr_info->stfle_fac_list));

  	level = stsi(NULL, 0, 0, 0);
  	lgr_info->level = level;
  	if (level >= 1)

  		lgr_stsi_1_1_1(lgr_info);

  	if (level >= 2)

  		lgr_stsi_2_2_2(lgr_info);

  	if (level >= 3)

  		lgr_stsi_3_2_2(lgr_info);
  }
  
  /*
   * Check if LGR info has changed and if yes log new LGR info to s390dbf
   */
  void lgr_info_log(void)
  {
  	static DEFINE_SPINLOCK(lgr_info_lock);
  	unsigned long flags;
  
  	if (!spin_trylock_irqsave(&lgr_info_lock, flags))
  		return;
  	lgr_info_get(&lgr_info_cur);
  	if (memcmp(&lgr_info_last, &lgr_info_cur, sizeof(lgr_info_cur)) != 0) {
  		debug_event(lgr_dbf, 1, &lgr_info_cur, sizeof(lgr_info_cur));
  		lgr_info_last = lgr_info_cur;
  	}
  	spin_unlock_irqrestore(&lgr_info_lock, flags);
  }
  EXPORT_SYMBOL_GPL(lgr_info_log);
  
  static void lgr_timer_set(void);
  
  /*
   * LGR timer callback
   */

  static void lgr_timer_fn(struct timer_list *unused)

  {
  	lgr_info_log();
  	lgr_timer_set();
  }

  static struct timer_list lgr_timer;

  
  /*
   * Setup next LGR timer
   */
  static void lgr_timer_set(void)
  {

  	mod_timer(&lgr_timer, jiffies + msecs_to_jiffies(LGR_TIMER_INTERVAL_SECS * MSEC_PER_SEC));

  }
  
  /*
   * Initialize LGR: Add s390dbf, write initial lgr_info and setup timer
   */
  static int __init lgr_init(void)
  {

  	lgr_dbf = debug_register("lgr", 1, 1, sizeof(struct lgr_info));

  	if (!lgr_dbf)

  		return -ENOMEM;

  	debug_register_view(lgr_dbf, &debug_hex_ascii_view);
  	lgr_info_get(&lgr_info_last);
  	debug_event(lgr_dbf, 1, &lgr_info_last, sizeof(lgr_info_last));

  	timer_setup(&lgr_timer, lgr_timer_fn, TIMER_DEFERRABLE);

  	lgr_timer_set();
  	return 0;
  }

  device_initcall(lgr_init);