1 /**

     2     Network Driver for Beckhoff CCAT communication controller

     3     Copyright (C) 2015  Beckhoff Automation GmbH & Co. KG

     4     Author: Patrick Bruenn <p.bruenn@beckhoff.com>

     5 

     6     This program is free software; you can redistribute it and/or modify

     7     it under the terms of the GNU General Public License as published by

     8     the Free Software Foundation; either version 2 of the License, or

     9     (at your option) any later version.

    10 

    11     This program is distributed in the hope that it will be useful,

    12     but WITHOUT ANY WARRANTY; without even the implied warranty of

    13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    14     GNU General Public License for more details.

    15 

    16     You should have received a copy of the GNU General Public License along

    17     with this program; if not, write to the Free Software Foundation, Inc.,

    18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

    19 */

    20 

    21 #include "module.h"

    22 #include <asm/io.h>

    23 #include <linux/fs.h>

    24 #include <linux/module.h>

    25 #include <linux/uaccess.h>

    26 

    27 #define CCAT_SRAM_DEVICES_MAX 4

    28 

    29 static ssize_t __sram_read(struct cdev_buffer *buffer, char __user * buf,

    30 			   size_t len, loff_t * off)

    31 {

    32 	memcpy_fromio(buffer->data, buffer->ccdev->ioaddr + *off, len);

    33 	if (copy_to_user(buf, buffer->data, len))

    34 		return -EFAULT;

    35 

    36 	*off += len;

    37 	return len;

    38 }

    39 

    40 static ssize_t ccat_sram_read(struct file *const f, char __user * buf,

    41 			      size_t len, loff_t * off)

    42 {

    43 	struct cdev_buffer *buffer = f->private_data;

    44 	const size_t iosize = buffer->ccdev->iosize;

    45 

    46 	if (*off >= iosize) {

    47 		return 0;

    48 	}

    49 

    50 	len = min(len, (size_t) (iosize - *off));

    51 

    52 	return __sram_read(buffer, buf, len, off);

    53 }

    54 

    55 static ssize_t ccat_sram_write(struct file *const f, const char __user * buf,

    56 			       size_t len, loff_t * off)

    57 {

    58 	struct cdev_buffer *const buffer = f->private_data;

    59 

    60 	if (*off + len > buffer->ccdev->iosize) {

    61 		return 0;

    62 	}

    63 

    64 	if (copy_from_user(buffer->data, buf, len)) {

    65 		return -EFAULT;

    66 	}

    67 

    68 	memcpy_toio(buffer->ccdev->ioaddr + *off, buffer->data, len);

    69 

    70 	*off += len;

    71 	return len;

    72 }

    73 

    74 static struct ccat_cdev dev_table[CCAT_SRAM_DEVICES_MAX];

    75 static struct ccat_class cdev_class = {

    76 	.instances = {0},

    77 	.count = CCAT_SRAM_DEVICES_MAX,

    78 	.devices = dev_table,

    79 	.name = "ccat_sram",

    80 	.fops = {

    81 		 .owner = THIS_MODULE,

    82 		 .open = ccat_cdev_open,

    83 		 .release = ccat_cdev_release,

    84 		 .read = ccat_sram_read,

    85 		 .write = ccat_sram_write,

    86 		 },

    87 };

    88 

    89 static int ccat_sram_probe(struct ccat_function *func)

    90 {

    91 	static const u8 NO_SRAM_CONNECTED = 0;

    92 	const u8 type = func->info.sram_width & 0x3;

    93 	const size_t iosize = (1 << func->info.sram_size);

    94 

    95 	pr_info("%s: 0x%04x rev: 0x%04x\n", __FUNCTION__, func->info.type,

    96 		func->info.rev);

    97 	if (type == NO_SRAM_CONNECTED) {

    98 		return -ENODEV;

    99 	}

   100 	return ccat_cdev_probe(func, &cdev_class, iosize);

   101 }

   102 

   103 const struct ccat_driver sram_driver = {

   104 	.type = CCATINFO_SRAM,

   105 	.probe = ccat_sram_probe,

   106 	.remove = ccat_cdev_remove,

   107 	.cdev_class = &cdev_class,

   108 };