/*
   *    Hypervisor filesystem for Linux on s390. z/VM implementation.
   *

   *    Copyright IBM Corp. 2006

   *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
   */
  
  #include <linux/types.h>
  #include <linux/errno.h>
  #include <linux/string.h>
  #include <linux/vmalloc.h>
  #include <asm/ebcdic.h>

  #include <asm/timex.h>

  #include "hypfs.h"
  
  #define NAME_LEN 8

  #define DBFS_D2FC_HDR_VERSION 0

  
  static char local_guest[] = "        ";
  static char all_guests[] = "*       ";
  static char *guest_query;
  
  struct diag2fc_data {
  	__u32 version;
  	__u32 flags;
  	__u64 used_cpu;
  	__u64 el_time;
  	__u64 mem_min_kb;
  	__u64 mem_max_kb;
  	__u64 mem_share_kb;
  	__u64 mem_used_kb;
  	__u32 pcpus;
  	__u32 lcpus;
  	__u32 vcpus;

  	__u32 ocpus;

  	__u32 cpu_max;
  	__u32 cpu_shares;
  	__u32 cpu_use_samp;
  	__u32 cpu_delay_samp;
  	__u32 page_wait_samp;
  	__u32 idle_samp;
  	__u32 other_samp;
  	__u32 total_samp;
  	char  guest_name[NAME_LEN];
  };
  
  struct diag2fc_parm_list {
  	char userid[NAME_LEN];
  	char aci_grp[NAME_LEN];
  	__u64 addr;
  	__u32 size;
  	__u32 fmt;
  };
  
  static int diag2fc(int size, char* query, void *addr)
  {
  	unsigned long residual_cnt;
  	unsigned long rc;
  	struct diag2fc_parm_list parm_list;
  
  	memcpy(parm_list.userid, query, NAME_LEN);
  	ASCEBC(parm_list.userid, NAME_LEN);
  	parm_list.addr = (unsigned long) addr ;
  	parm_list.size = size;
  	parm_list.fmt = 0x02;
  	memset(parm_list.aci_grp, 0x40, NAME_LEN);
  	rc = -1;
  
  	asm volatile(
  		"	diag    %0,%1,0x2fc
  "
  		"0:
  "
  		EX_TABLE(0b,0b)
  		: "=d" (residual_cnt), "+d" (rc) : "0" (&parm_list) : "memory");
  
  	if ((rc != 0 ) && (rc != -2))
  		return rc;
  	else
  		return -residual_cnt;
  }

  /*
   * Allocate buffer for "query" and store diag 2fc at "offset"
   */
  static void *diag2fc_store(char *query, unsigned int *count, int offset)

  {

  	void *data;

  	int size;

  
  	do {
  		size = diag2fc(0, query, NULL);
  		if (size < 0)
  			return ERR_PTR(-EACCES);

  		data = vmalloc(size + offset);

  		if (!data)
  			return ERR_PTR(-ENOMEM);

  		if (diag2fc(size, query, data + offset) == 0)

  			break;
  		vfree(data);
  	} while (1);

  	*count = (size / sizeof(struct diag2fc_data));

  
  	return data;
  }

  static void diag2fc_free(const void *data)

  {
  	vfree(data);
  }

  #define ATTRIBUTE(dir, name, member) \

  do { \
  	void *rc; \

  	rc = hypfs_create_u64(dir, name, member); \

  	if (IS_ERR(rc)) \
  		return PTR_ERR(rc); \
  } while(0)

  static int hpyfs_vm_create_guest(struct dentry *systems_dir,

  				 struct diag2fc_data *data)
  {
  	char guest_name[NAME_LEN + 1] = {};
  	struct dentry *guest_dir, *cpus_dir, *samples_dir, *mem_dir;
  	int dedicated_flag, capped_value;
  
  	capped_value = (data->flags & 0x00000006) >> 1;
  	dedicated_flag = (data->flags & 0x00000008) >> 3;
  
  	/* guest dir */
  	memcpy(guest_name, data->guest_name, NAME_LEN);
  	EBCASC(guest_name, NAME_LEN);

  	strim(guest_name);

  	guest_dir = hypfs_mkdir(systems_dir, guest_name);

  	if (IS_ERR(guest_dir))
  		return PTR_ERR(guest_dir);

  	ATTRIBUTE(guest_dir, "onlinetime_us", data->el_time);

  
  	/* logical cpu information */

  	cpus_dir = hypfs_mkdir(guest_dir, "cpus");

  	if (IS_ERR(cpus_dir))
  		return PTR_ERR(cpus_dir);

  	ATTRIBUTE(cpus_dir, "cputime_us", data->used_cpu);
  	ATTRIBUTE(cpus_dir, "capped", capped_value);
  	ATTRIBUTE(cpus_dir, "dedicated", dedicated_flag);
  	ATTRIBUTE(cpus_dir, "count", data->vcpus);

  	/*
  	 * Note: The "weight_min" attribute got the wrong name.
  	 * The value represents the number of non-stopped (operating)
  	 * CPUS.
  	 */
  	ATTRIBUTE(cpus_dir, "weight_min", data->ocpus);

  	ATTRIBUTE(cpus_dir, "weight_max", data->cpu_max);
  	ATTRIBUTE(cpus_dir, "weight_cur", data->cpu_shares);

  
  	/* memory information */

  	mem_dir = hypfs_mkdir(guest_dir, "mem");

  	if (IS_ERR(mem_dir))
  		return PTR_ERR(mem_dir);

  	ATTRIBUTE(mem_dir, "min_KiB", data->mem_min_kb);
  	ATTRIBUTE(mem_dir, "max_KiB", data->mem_max_kb);
  	ATTRIBUTE(mem_dir, "used_KiB", data->mem_used_kb);
  	ATTRIBUTE(mem_dir, "share_KiB", data->mem_share_kb);

  
  	/* samples */

  	samples_dir = hypfs_mkdir(guest_dir, "samples");

  	if (IS_ERR(samples_dir))
  		return PTR_ERR(samples_dir);

  	ATTRIBUTE(samples_dir, "cpu_using", data->cpu_use_samp);
  	ATTRIBUTE(samples_dir, "cpu_delay", data->cpu_delay_samp);
  	ATTRIBUTE(samples_dir, "mem_delay", data->page_wait_samp);
  	ATTRIBUTE(samples_dir, "idle", data->idle_samp);
  	ATTRIBUTE(samples_dir, "other", data->other_samp);
  	ATTRIBUTE(samples_dir, "total", data->total_samp);

  	return 0;
  }

  int hypfs_vm_create_files(struct dentry *root)

  {
  	struct dentry *dir, *file;
  	struct diag2fc_data *data;

  	unsigned int count = 0;
  	int rc, i;

  	data = diag2fc_store(guest_query, &count, 0);

  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	/* Hpervisor Info */

  	dir = hypfs_mkdir(root, "hyp");

  	if (IS_ERR(dir)) {
  		rc = PTR_ERR(dir);
  		goto failed;
  	}

  	file = hypfs_create_str(dir, "type", "z/VM Hypervisor");

  	if (IS_ERR(file)) {
  		rc = PTR_ERR(file);
  		goto failed;
  	}
  
  	/* physical cpus */

  	dir = hypfs_mkdir(root, "cpus");

  	if (IS_ERR(dir)) {
  		rc = PTR_ERR(dir);
  		goto failed;
  	}

  	file = hypfs_create_u64(dir, "count", data->lcpus);

  	if (IS_ERR(file)) {
  		rc = PTR_ERR(file);
  		goto failed;
  	}
  
  	/* guests */

  	dir = hypfs_mkdir(root, "systems");

  	if (IS_ERR(dir)) {
  		rc = PTR_ERR(dir);
  		goto failed;
  	}
  
  	for (i = 0; i < count; i++) {

  		rc = hpyfs_vm_create_guest(dir, &(data[i]));

  		if (rc)
  			goto failed;
  	}
  	diag2fc_free(data);
  	return 0;
  
  failed:
  	diag2fc_free(data);
  	return rc;
  }

  struct dbfs_d2fc_hdr {
  	u64	len;		/* Length of d2fc buffer without header */
  	u16	version;	/* Version of header */
  	char	tod_ext[16];	/* TOD clock for d2fc */
  	u64	count;		/* Number of VM guests in d2fc buffer */
  	char	reserved[30];
  } __attribute__ ((packed));
  
  struct dbfs_d2fc {
  	struct dbfs_d2fc_hdr	hdr;	/* 64 byte header */
  	char			buf[];	/* d2fc buffer */
  } __attribute__ ((packed));

  static int dbfs_diag2fc_create(void **data, void **data_free_ptr, size_t *size)

  {

  	struct dbfs_d2fc *d2fc;

  	unsigned int count;

  	d2fc = diag2fc_store(guest_query, &count, sizeof(d2fc->hdr));
  	if (IS_ERR(d2fc))
  		return PTR_ERR(d2fc);

  	get_tod_clock_ext(d2fc->hdr.tod_ext);

  	d2fc->hdr.len = count * sizeof(struct diag2fc_data);
  	d2fc->hdr.version = DBFS_D2FC_HDR_VERSION;
  	d2fc->hdr.count = count;
  	memset(&d2fc->hdr.reserved, 0, sizeof(d2fc->hdr.reserved));
  	*data = d2fc;
  	*data_free_ptr = d2fc;
  	*size = d2fc->hdr.len + sizeof(struct dbfs_d2fc_hdr);

  	return 0;
  }

  static struct hypfs_dbfs_file dbfs_file_2fc = {
  	.name		= "diag_2fc",
  	.data_create	= dbfs_diag2fc_create,
  	.data_free	= diag2fc_free,

  };

  int hypfs_vm_init(void)
  {

  	if (!MACHINE_IS_VM)
  		return 0;

  	if (diag2fc(0, all_guests, NULL) > 0)
  		guest_query = all_guests;
  	else if (diag2fc(0, local_guest, NULL) > 0)
  		guest_query = local_guest;
  	else
  		return -EACCES;

  	return hypfs_dbfs_create_file(&dbfs_file_2fc);

  }

  
  void hypfs_vm_exit(void)
  {
  	if (!MACHINE_IS_VM)
  		return;

  	hypfs_dbfs_remove_file(&dbfs_file_2fc);

  }