/* Copyright © 2010 - 2013 UNISYS CORPORATION
 * All rights reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 */

/** @file *********************************************************************
 *
 *  Handle procfs-specific tasks.
 *  Note that this file does not know about any module-specific things, nor
 *  does it know anything about what information to reveal as part of the proc
 *  entries.  The 2 functions that take care of displaying device and
 *  driver specific information are passed as parameters to
 *  visor_easyproc_InitDriver().
 *
 *      void show_device_info(struct seq_file *seq, void *p);
 *      void show_driver_info(struct seq_file *seq);
 *
 *  The second parameter to show_device_info is actually a pointer to the
 *  device-specific info to show.  It is the context that was originally
 *  passed to visor_easyproc_InitDevice().
 *
 ******************************************************************************
 */

#include <linux/proc_fs.h>

#include "uniklog.h"
#include "timskmod.h"
#include "easyproc.h"

#define MYDRVNAME "easyproc"


/*
 *   /proc/<ProcId>                              ProcDir
 *   /proc/<ProcId>/driver                       ProcDriverDir
 *   /proc/<ProcId>/driver/diag                  ProcDriverDiagFile
 *   /proc/<ProcId>/device                       ProcDeviceDir
 *   /proc/<ProcId>/device/0                     procDevicexDir
 *   /proc/<ProcId>/device/0/diag                procDevicexDiagFile
 */


static ssize_t proc_write_device(struct file *file, const char __user *buffer,
				 size_t count, loff_t *ppos);
static ssize_t proc_write_driver(struct file *file, const char __user *buffer,
				 size_t count, loff_t *ppos);

static struct proc_dir_entry *
	createProcDir(char *name, struct proc_dir_entry *parent)
{
	struct proc_dir_entry *p = proc_mkdir_mode(name, S_IFDIR, parent);
	if (p == NULL)
		ERRDRV("failed to create /proc directory %s", name);
	return p;
}

static int seq_show_driver(struct seq_file *seq, void *offset);
static int proc_open_driver(struct inode *inode, struct file *file)
{
	return single_open(file, seq_show_driver, PDE_DATA(inode));
}
static const struct file_operations proc_fops_driver = {
	.open = proc_open_driver,
	.read = seq_read,
	.write = proc_write_driver,
	.llseek = seq_lseek,
	.release = single_release,
};

static int seq_show_device(struct seq_file *seq, void *offset);
static int seq_show_device_property(struct seq_file *seq, void *offset);
static int proc_open_device(struct inode *inode, struct file *file)
{
	return single_open(file, seq_show_device, PDE_DATA(inode));
}
static const struct file_operations proc_fops_device = {
	.open = proc_open_device,
	.read = seq_read,
	.write = proc_write_device,
	.llseek = seq_lseek,
	.release = single_release,
};
static int proc_open_device_property(struct inode *inode, struct file *file)
{
	return single_open(file, seq_show_device_property, PDE_DATA(inode));
}
static const struct file_operations proc_fops_device_property = {
	.open = proc_open_device_property,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};


void visor_easyproc_InitDriver(struct easyproc_driver_info *pdriver,
			       char *procId,
			       void (*show_driver_info)(struct seq_file *),
			       void (*show_device_info)(struct seq_file *,
							void *))
{
	memset(pdriver, 0, sizeof(struct easyproc_driver_info));
	pdriver->ProcId = procId;
	if (pdriver->ProcId == NULL)
		ERRDRV("ProcId cannot be NULL (trouble ahead)!");
	pdriver->Show_driver_info = show_driver_info;
	pdriver->Show_device_info = show_device_info;
	if (pdriver->ProcDir == NULL)
		pdriver->ProcDir = createProcDir(pdriver->ProcId, NULL);
	if ((pdriver->ProcDir != NULL) && (pdriver->ProcDriverDir == NULL))
		pdriver->ProcDriverDir = createProcDir("driver",
						       pdriver->ProcDir);
	if ((pdriver->ProcDir != NULL) && (pdriver->ProcDeviceDir == NULL))
		pdriver->ProcDeviceDir = createProcDir("device",
						       pdriver->ProcDir);
	if ((pdriver->ProcDriverDir != NULL) &&
	    (pdriver->ProcDriverDiagFile == NULL)) {
		pdriver->ProcDriverDiagFile =
			proc_create_data("diag", 0,
					 pdriver->ProcDriverDir,
					 &proc_fops_driver, pdriver);
		if (pdriver->ProcDriverDiagFile == NULL)
			ERRDRV("failed to register /proc/%s/driver/diag entry",
			       pdriver->ProcId);
	}
}
EXPORT_SYMBOL_GPL(visor_easyproc_InitDriver);


void visor_easyproc_InitDriverEx(struct easyproc_driver_info *pdriver,
				 char *procId,
				 void (*show_driver_info)(struct seq_file *),
				 void (*show_device_info)(struct seq_file *,
							  void *),
				 void (*write_driver_info)(char *buf,
							   size_t count,
							   loff_t *ppos),
				 void (*write_device_info)(char *buf,
							   size_t count,
							   loff_t *ppos,
							   void *p))
{
	visor_easyproc_InitDriver(pdriver, procId,
				  show_driver_info, show_device_info);
	pdriver->Write_driver_info = write_driver_info;
	pdriver->Write_device_info = write_device_info;
}
EXPORT_SYMBOL_GPL(visor_easyproc_InitDriverEx);


void visor_easyproc_DeInitDriver(struct easyproc_driver_info *pdriver)
{
	if (pdriver->ProcDriverDiagFile != NULL) {
		remove_proc_entry("diag", pdriver->ProcDriverDir);
		pdriver->ProcDriverDiagFile = NULL;
	}
	if (pdriver->ProcDriverDir != NULL) {
		remove_proc_entry("driver", pdriver->ProcDir);
		pdriver->ProcDriverDir = NULL;
	}
	if (pdriver->ProcDeviceDir != NULL) {
		remove_proc_entry("device", pdriver->ProcDir);
		pdriver->ProcDeviceDir = NULL;
	}
	if (pdriver->ProcDir != NULL) {
		remove_proc_entry(pdriver->ProcId, NULL);
		pdriver->ProcDir = NULL;
	}
	pdriver->ProcId = NULL;
	pdriver->Show_driver_info = NULL;
	pdriver->Show_device_info = NULL;
	pdriver->Write_driver_info = NULL;
	pdriver->Write_device_info = NULL;
}
EXPORT_SYMBOL_GPL(visor_easyproc_DeInitDriver);


void visor_easyproc_InitDevice(struct easyproc_driver_info *pdriver,
			       struct easyproc_device_info *p, int devno,
			       void *devdata)
{
	if ((pdriver->ProcDeviceDir != NULL) && (p->procDevicexDir == NULL)) {
		char s[29];
		sprintf(s, "%d", devno);
		p->procDevicexDir = createProcDir(s, pdriver->ProcDeviceDir);
		p->devno = devno;
	}
	p->devdata = devdata;
	p->pdriver = pdriver;
	p->devno = devno;
	if ((p->procDevicexDir != NULL) && (p->procDevicexDiagFile == NULL)) {
		p->procDevicexDiagFile =
			proc_create_data("diag", 0, p->procDevicexDir,
					 &proc_fops_device, p);
		if (p->procDevicexDiagFile == NULL)
			ERRDEVX(devno, "failed to register /proc/%s/device/%d/diag entry",
				pdriver->ProcId, devno
			       );
	}
	memset(&(p->device_property_info[0]), 0,
	       sizeof(p->device_property_info));
}
EXPORT_SYMBOL_GPL(visor_easyproc_InitDevice);


void visor_easyproc_CreateDeviceProperty(struct easyproc_device_info *p,
					 void (*show_property_info)
					 (struct seq_file *, void *),
					 char *property_name)
{
	size_t i;
	struct easyproc_device_property_info *px = NULL;

	if (p->procDevicexDir == NULL) {
		ERRDRV("state error");
		return;
	}
	for (i = 0; i < ARRAY_SIZE(p->device_property_info); i++) {
		if (p->device_property_info[i].procEntry == NULL) {
			px = &(p->device_property_info[i]);
			break;
		}
	}
	if (!px) {
		ERRDEVX(p->devno, "too many device properties");
		return;
	}
	px->devdata = p->devdata;
	px->pdriver = p->pdriver;
	px->procEntry = proc_create_data(property_name, 0, p->procDevicexDir,
					 &proc_fops_device_property, px);
	if (strlen(property_name)+1 > sizeof(px->property_name)) {
		ERRDEVX(p->devno, "device property name %s too long",
			property_name);
		return;
	}
	strcpy(px->property_name, property_name);
	if (px->procEntry == NULL) {
		ERRDEVX(p->devno, "failed to register /proc/%s/device/%d/%s entry",
			p->pdriver->ProcId, p->devno, property_name
		       );
		return;
	}
	px->show_device_property_info = show_property_info;
}
EXPORT_SYMBOL_GPL(visor_easyproc_CreateDeviceProperty);


void visor_easyproc_DeInitDevice(struct easyproc_driver_info *pdriver,
				 struct easyproc_device_info *p, int devno)
{
	size_t i;
	for (i = 0; i < ARRAY_SIZE(p->device_property_info); i++) {
		if (p->device_property_info[i].procEntry != NULL) {
			struct easyproc_device_property_info *px =
				&(p->device_property_info[i]);
			remove_proc_entry(px->property_name, p->procDevicexDir);
			px->procEntry = NULL;
		}
	}
	if (p->procDevicexDiagFile != NULL) {
		remove_proc_entry("diag", p->procDevicexDir);
		p->procDevicexDiagFile = NULL;
	}
	if (p->procDevicexDir != NULL) {
		char s[29];
		sprintf(s, "%d", devno);
		remove_proc_entry(s, pdriver->ProcDeviceDir);
		p->procDevicexDir = NULL;
	}
	p->devdata = NULL;
	p->pdriver = NULL;
}
EXPORT_SYMBOL_GPL(visor_easyproc_DeInitDevice);


static int seq_show_driver(struct seq_file *seq, void *offset)
{
	struct easyproc_driver_info *p =
		(struct easyproc_driver_info *)(seq->private);
	if (!p)
		return 0;
	(*(p->Show_driver_info))(seq);
	return 0;
}


static int seq_show_device(struct seq_file *seq, void *offset)
{
	struct easyproc_device_info *p =
		(struct easyproc_device_info *)(seq->private);
	if ((!p) || (!(p->pdriver)))
		return 0;
	(*(p->pdriver->Show_device_info))(seq, p->devdata);
	return 0;
}


static int seq_show_device_property(struct seq_file *seq, void *offset)
{
	struct easyproc_device_property_info *p =
		(struct easyproc_device_property_info *)(seq->private);
	if ((!p) || (!(p->show_device_property_info)))
		return 0;
	(*(p->show_device_property_info))(seq, p->devdata);
	return 0;
}


static ssize_t proc_write_driver(struct file *file, const char __user *buffer,
				 size_t count, loff_t *ppos)
{
	struct seq_file *seq = (struct seq_file *)file->private_data;
	struct easyproc_driver_info *p = NULL;
	char local_buf[256];
	if (seq == NULL)
		return 0;
	p = (struct easyproc_driver_info *)(seq->private);
	if ((!p) || (!(p->Write_driver_info)))
		return 0;
	if (count >= sizeof(local_buf))
		return -ENOMEM;
	if (copy_from_user(local_buf, buffer, count))
		return -EFAULT;
	local_buf[count] = '\0';  /* be friendly */
	(*(p->Write_driver_info))(local_buf, count, ppos);
	return count;
}


static ssize_t proc_write_device(struct file *file, const char __user *buffer,
				 size_t count, loff_t *ppos)
{
	struct seq_file *seq = (struct seq_file *)file->private_data;
	struct easyproc_device_info *p = NULL;
	char local_buf[256];
	if (seq == NULL)
		return 0;
	p = (struct easyproc_device_info *)(seq->private);
	if ((!p) || (!(p->pdriver)) || (!(p->pdriver->Write_device_info)))
		return 0;
	if (count >= sizeof(local_buf))
		return -ENOMEM;
	if (copy_from_user(local_buf, buffer, count))
		return -EFAULT;
	local_buf[count] = '\0';  /* be friendly */
	(*(p->pdriver->Write_device_info))(local_buf, count, ppos, p->devdata);
	return count;
}