#include <linux/string.h>
 #include <linux/memblock.h>
+#include <linux/delay.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
 
 #include <asm/page.h>
 #include <asm/prom.h>
 #include <asm/fadump.h>
 
 static struct fw_dump fw_dump;
+static struct fadump_mem_struct fdm;
+static const struct fadump_mem_struct *fdm_active;
+
+static DEFINE_MUTEX(fadump_mutex);
 
 /* Scan the Firmware Assisted dump configuration details. */
 int __init early_init_dt_scan_fw_dump(unsigned long node,
         * The 'ibm,kernel-dump' rtas node is present only if there is
         * dump data waiting for us.
         */
-       if (of_get_flat_dt_prop(node, "ibm,kernel-dump", NULL))
+       fdm_active = of_get_flat_dt_prop(node, "ibm,kernel-dump", NULL);
+       if (fdm_active)
                fw_dump.dump_active = 1;
 
        /* Get the sizes required to store dump data for the firmware provided
        return 1;
 }
 
+int is_fadump_active(void)
+{
+       return fw_dump.dump_active;
+}
+
+/* Print firmware assisted dump configurations for debugging purpose. */
+static void fadump_show_config(void)
+{
+       pr_debug("Support for firmware-assisted dump (fadump): %s\n",
+                       (fw_dump.fadump_supported ? "present" : "no support"));
+
+       if (!fw_dump.fadump_supported)
+               return;
+
+       pr_debug("Fadump enabled    : %s\n",
+                               (fw_dump.fadump_enabled ? "yes" : "no"));
+       pr_debug("Dump Active       : %s\n",
+                               (fw_dump.dump_active ? "yes" : "no"));
+       pr_debug("Dump section sizes:\n");
+       pr_debug("    CPU state data size: %lx\n", fw_dump.cpu_state_data_size);
+       pr_debug("    HPTE region size   : %lx\n", fw_dump.hpte_region_size);
+       pr_debug("Boot memory size  : %lx\n", fw_dump.boot_memory_size);
+}
+
+static unsigned long init_fadump_mem_struct(struct fadump_mem_struct *fdm,
+                               unsigned long addr)
+{
+       if (!fdm)
+               return 0;
+
+       memset(fdm, 0, sizeof(struct fadump_mem_struct));
+       addr = addr & PAGE_MASK;
+
+       fdm->header.dump_format_version = 0x00000001;
+       fdm->header.dump_num_sections = 3;
+       fdm->header.dump_status_flag = 0;
+       fdm->header.offset_first_dump_section =
+               (u32)offsetof(struct fadump_mem_struct, cpu_state_data);
+
+       /*
+        * Fields for disk dump option.
+        * We are not using disk dump option, hence set these fields to 0.
+        */
+       fdm->header.dd_block_size = 0;
+       fdm->header.dd_block_offset = 0;
+       fdm->header.dd_num_blocks = 0;
+       fdm->header.dd_offset_disk_path = 0;
+
+       /* set 0 to disable an automatic dump-reboot. */
+       fdm->header.max_time_auto = 0;
+
+       /* Kernel dump sections */
+       /* cpu state data section. */
+       fdm->cpu_state_data.request_flag = FADUMP_REQUEST_FLAG;
+       fdm->cpu_state_data.source_data_type = FADUMP_CPU_STATE_DATA;
+       fdm->cpu_state_data.source_address = 0;
+       fdm->cpu_state_data.source_len = fw_dump.cpu_state_data_size;
+       fdm->cpu_state_data.destination_address = addr;
+       addr += fw_dump.cpu_state_data_size;
+
+       /* hpte region section */
+       fdm->hpte_region.request_flag = FADUMP_REQUEST_FLAG;
+       fdm->hpte_region.source_data_type = FADUMP_HPTE_REGION;
+       fdm->hpte_region.source_address = 0;
+       fdm->hpte_region.source_len = fw_dump.hpte_region_size;
+       fdm->hpte_region.destination_address = addr;
+       addr += fw_dump.hpte_region_size;
+
+       /* RMA region section */
+       fdm->rmr_region.request_flag = FADUMP_REQUEST_FLAG;
+       fdm->rmr_region.source_data_type = FADUMP_REAL_MODE_REGION;
+       fdm->rmr_region.source_address = RMA_START;
+       fdm->rmr_region.source_len = fw_dump.boot_memory_size;
+       fdm->rmr_region.destination_address = addr;
+       addr += fw_dump.boot_memory_size;
+
+       return addr;
+}
+
 /**
  * fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM
  *
                fw_dump.fadump_enabled = 0;
                return 0;
        }
-       /* Initialize boot memory size */
-       fw_dump.boot_memory_size = fadump_calculate_reserve_size();
+       /*
+        * Initialize boot memory size
+        * If dump is active then we have already calculated the size during
+        * first kernel.
+        */
+       if (fdm_active)
+               fw_dump.boot_memory_size = fdm_active->rmr_region.source_len;
+       else
+               fw_dump.boot_memory_size = fadump_calculate_reserve_size();
 
        /*
         * Calculate the memory boundary.
        return 0;
 }
 early_param("fadump_reserve_mem", early_fadump_reserve_mem);
+
+static void register_fw_dump(struct fadump_mem_struct *fdm)
+{
+       int rc;
+       unsigned int wait_time;
+
+       pr_debug("Registering for firmware-assisted kernel dump...\n");
+
+       /* TODO: Add upper time limit for the delay */
+       do {
+               rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
+                       FADUMP_REGISTER, fdm,
+                       sizeof(struct fadump_mem_struct));
+
+               wait_time = rtas_busy_delay_time(rc);
+               if (wait_time)
+                       mdelay(wait_time);
+
+       } while (wait_time);
+
+       switch (rc) {
+       case -1:
+               printk(KERN_ERR "Failed to register firmware-assisted kernel"
+                       " dump. Hardware Error(%d).\n", rc);
+               break;
+       case -3:
+               printk(KERN_ERR "Failed to register firmware-assisted kernel"
+                       " dump. Parameter Error(%d).\n", rc);
+               break;
+       case -9:
+               printk(KERN_ERR "firmware-assisted kernel dump is already "
+                       " registered.");
+               fw_dump.dump_registered = 1;
+               break;
+       case 0:
+               printk(KERN_INFO "firmware-assisted kernel dump registration"
+                       " is successful\n");
+               fw_dump.dump_registered = 1;
+               break;
+       }
+}
+
+static void register_fadump(void)
+{
+       /*
+        * If no memory is reserved then we can not register for firmware-
+        * assisted dump.
+        */
+       if (!fw_dump.reserve_dump_area_size)
+               return;
+
+       /* register the future kernel dump with firmware. */
+       register_fw_dump(&fdm);
+}
+
+static int fadump_unregister_dump(struct fadump_mem_struct *fdm)
+{
+       int rc = 0;
+       unsigned int wait_time;
+
+       pr_debug("Un-register firmware-assisted dump\n");
+
+       /* TODO: Add upper time limit for the delay */
+       do {
+               rc = rtas_call(fw_dump.ibm_configure_kernel_dump, 3, 1, NULL,
+                       FADUMP_UNREGISTER, fdm,
+                       sizeof(struct fadump_mem_struct));
+
+               wait_time = rtas_busy_delay_time(rc);
+               if (wait_time)
+                       mdelay(wait_time);
+       } while (wait_time);
+
+       if (rc) {
+               printk(KERN_ERR "Failed to un-register firmware-assisted dump."
+                       " unexpected error(%d).\n", rc);
+               return rc;
+       }
+       fw_dump.dump_registered = 0;
+       return 0;
+}
+
+static ssize_t fadump_enabled_show(struct kobject *kobj,
+                                       struct kobj_attribute *attr,
+                                       char *buf)
+{
+       return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
+}
+
+static ssize_t fadump_register_show(struct kobject *kobj,
+                                       struct kobj_attribute *attr,
+                                       char *buf)
+{
+       return sprintf(buf, "%d\n", fw_dump.dump_registered);
+}
+
+static ssize_t fadump_register_store(struct kobject *kobj,
+                                       struct kobj_attribute *attr,
+                                       const char *buf, size_t count)
+{
+       int ret = 0;
+
+       if (!fw_dump.fadump_enabled || fdm_active)
+               return -EPERM;
+
+       mutex_lock(&fadump_mutex);
+
+       switch (buf[0]) {
+       case '0':
+               if (fw_dump.dump_registered == 0) {
+                       ret = -EINVAL;
+                       goto unlock_out;
+               }
+               /* Un-register Firmware-assisted dump */
+               fadump_unregister_dump(&fdm);
+               break;
+       case '1':
+               if (fw_dump.dump_registered == 1) {
+                       ret = -EINVAL;
+                       goto unlock_out;
+               }
+               /* Register Firmware-assisted dump */
+               register_fadump();
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+
+unlock_out:
+       mutex_unlock(&fadump_mutex);
+       return ret < 0 ? ret : count;
+}
+
+static int fadump_region_show(struct seq_file *m, void *private)
+{
+       const struct fadump_mem_struct *fdm_ptr;
+
+       if (!fw_dump.fadump_enabled)
+               return 0;
+
+       if (fdm_active)
+               fdm_ptr = fdm_active;
+       else
+               fdm_ptr = &fdm;
+
+       seq_printf(m,
+                       "CPU : [%#016llx-%#016llx] %#llx bytes, "
+                       "Dumped: %#llx\n",
+                       fdm_ptr->cpu_state_data.destination_address,
+                       fdm_ptr->cpu_state_data.destination_address +
+                       fdm_ptr->cpu_state_data.source_len - 1,
+                       fdm_ptr->cpu_state_data.source_len,
+                       fdm_ptr->cpu_state_data.bytes_dumped);
+       seq_printf(m,
+                       "HPTE: [%#016llx-%#016llx] %#llx bytes, "
+                       "Dumped: %#llx\n",
+                       fdm_ptr->hpte_region.destination_address,
+                       fdm_ptr->hpte_region.destination_address +
+                       fdm_ptr->hpte_region.source_len - 1,
+                       fdm_ptr->hpte_region.source_len,
+                       fdm_ptr->hpte_region.bytes_dumped);
+       seq_printf(m,
+                       "DUMP: [%#016llx-%#016llx] %#llx bytes, "
+                       "Dumped: %#llx\n",
+                       fdm_ptr->rmr_region.destination_address,
+                       fdm_ptr->rmr_region.destination_address +
+                       fdm_ptr->rmr_region.source_len - 1,
+                       fdm_ptr->rmr_region.source_len,
+                       fdm_ptr->rmr_region.bytes_dumped);
+
+       if (!fdm_active ||
+               (fw_dump.reserve_dump_area_start ==
+               fdm_ptr->cpu_state_data.destination_address))
+               return 0;
+
+       /* Dump is active. Show reserved memory region. */
+       seq_printf(m,
+                       "    : [%#016llx-%#016llx] %#llx bytes, "
+                       "Dumped: %#llx\n",
+                       (unsigned long long)fw_dump.reserve_dump_area_start,
+                       fdm_ptr->cpu_state_data.destination_address - 1,
+                       fdm_ptr->cpu_state_data.destination_address -
+                       fw_dump.reserve_dump_area_start,
+                       fdm_ptr->cpu_state_data.destination_address -
+                       fw_dump.reserve_dump_area_start);
+       return 0;
+}
+
+static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
+                                               0444, fadump_enabled_show,
+                                               NULL);
+static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
+                                               0644, fadump_register_show,
+                                               fadump_register_store);
+
+static int fadump_region_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, fadump_region_show, inode->i_private);
+}
+
+static const struct file_operations fadump_region_fops = {
+       .open    = fadump_region_open,
+       .read    = seq_read,
+       .llseek  = seq_lseek,
+       .release = single_release,
+};
+
+static void fadump_init_files(void)
+{
+       struct dentry *debugfs_file;
+       int rc = 0;
+
+       rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
+       if (rc)
+               printk(KERN_ERR "fadump: unable to create sysfs file"
+                       " fadump_enabled (%d)\n", rc);
+
+       rc = sysfs_create_file(kernel_kobj, &fadump_register_attr.attr);
+       if (rc)
+               printk(KERN_ERR "fadump: unable to create sysfs file"
+                       " fadump_registered (%d)\n", rc);
+
+       debugfs_file = debugfs_create_file("fadump_region", 0444,
+                                       powerpc_debugfs_root, NULL,
+                                       &fadump_region_fops);
+       if (!debugfs_file)
+               printk(KERN_ERR "fadump: unable to create debugfs file"
+                               " fadump_region\n");
+       return;
+}
+
+/*
+ * Prepare for firmware-assisted dump.
+ */
+int __init setup_fadump(void)
+{
+       if (!fw_dump.fadump_enabled)
+               return 0;
+
+       if (!fw_dump.fadump_supported) {
+               printk(KERN_ERR "Firmware-assisted dump is not supported on"
+                       " this hardware\n");
+               return 0;
+       }
+
+       fadump_show_config();
+       /* Initialize the kernel dump memory structure for FAD registration. */
+       if (fw_dump.reserve_dump_area_size)
+               init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
+       fadump_init_files();
+
+       return 1;
+}
+subsys_initcall(setup_fadump);