cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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scx200_gpio.c (3171B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* linux/drivers/char/scx200_gpio.c
      3
      4   National Semiconductor SCx200 GPIO driver.  Allows a user space
      5   process to play with the GPIO pins.
      6
      7   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> */
      8
      9#include <linux/device.h>
     10#include <linux/fs.h>
     11#include <linux/module.h>
     12#include <linux/errno.h>
     13#include <linux/kernel.h>
     14#include <linux/init.h>
     15#include <linux/platform_device.h>
     16#include <linux/uaccess.h>
     17#include <asm/io.h>
     18
     19#include <linux/types.h>
     20#include <linux/cdev.h>
     21
     22#include <linux/scx200_gpio.h>
     23#include <linux/nsc_gpio.h>
     24
     25#define DRVNAME "scx200_gpio"
     26
     27static struct platform_device *pdev;
     28
     29MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
     30MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver");
     31MODULE_LICENSE("GPL");
     32
     33static int major = 0;		/* default to dynamic major */
     34module_param(major, int, 0);
     35MODULE_PARM_DESC(major, "Major device number");
     36
     37#define MAX_PINS 32		/* 64 later, when known ok */
     38
     39struct nsc_gpio_ops scx200_gpio_ops = {
     40	.owner		= THIS_MODULE,
     41	.gpio_config	= scx200_gpio_configure,
     42	.gpio_dump	= nsc_gpio_dump,
     43	.gpio_get	= scx200_gpio_get,
     44	.gpio_set	= scx200_gpio_set,
     45	.gpio_change	= scx200_gpio_change,
     46	.gpio_current	= scx200_gpio_current
     47};
     48EXPORT_SYMBOL_GPL(scx200_gpio_ops);
     49
     50static int scx200_gpio_open(struct inode *inode, struct file *file)
     51{
     52	unsigned m = iminor(inode);
     53	file->private_data = &scx200_gpio_ops;
     54
     55	if (m >= MAX_PINS)
     56		return -EINVAL;
     57	return nonseekable_open(inode, file);
     58}
     59
     60static int scx200_gpio_release(struct inode *inode, struct file *file)
     61{
     62	return 0;
     63}
     64
     65static const struct file_operations scx200_gpio_fileops = {
     66	.owner   = THIS_MODULE,
     67	.write   = nsc_gpio_write,
     68	.read    = nsc_gpio_read,
     69	.open    = scx200_gpio_open,
     70	.release = scx200_gpio_release,
     71	.llseek  = no_llseek,
     72};
     73
     74static struct cdev scx200_gpio_cdev;  /* use 1 cdev for all pins */
     75
     76static int __init scx200_gpio_init(void)
     77{
     78	int rc;
     79	dev_t devid;
     80
     81	if (!scx200_gpio_present()) {
     82		printk(KERN_ERR DRVNAME ": no SCx200 gpio present\n");
     83		return -ENODEV;
     84	}
     85
     86	/* support dev_dbg() with pdev->dev */
     87	pdev = platform_device_alloc(DRVNAME, 0);
     88	if (!pdev)
     89		return -ENOMEM;
     90
     91	rc = platform_device_add(pdev);
     92	if (rc)
     93		goto undo_malloc;
     94
     95	/* nsc_gpio uses dev_dbg(), so needs this */
     96	scx200_gpio_ops.dev = &pdev->dev;
     97
     98	if (major) {
     99		devid = MKDEV(major, 0);
    100		rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio");
    101	} else {
    102		rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio");
    103		major = MAJOR(devid);
    104	}
    105	if (rc < 0) {
    106		dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc);
    107		goto undo_platform_device_add;
    108	}
    109
    110	cdev_init(&scx200_gpio_cdev, &scx200_gpio_fileops);
    111	cdev_add(&scx200_gpio_cdev, devid, MAX_PINS);
    112
    113	return 0; /* succeed */
    114
    115undo_platform_device_add:
    116	platform_device_del(pdev);
    117undo_malloc:
    118	platform_device_put(pdev);
    119
    120	return rc;
    121}
    122
    123static void __exit scx200_gpio_cleanup(void)
    124{
    125	cdev_del(&scx200_gpio_cdev);
    126	/* cdev_put(&scx200_gpio_cdev); */
    127
    128	unregister_chrdev_region(MKDEV(major, 0), MAX_PINS);
    129	platform_device_unregister(pdev);
    130}
    131
    132module_init(scx200_gpio_init);
    133module_exit(scx200_gpio_cleanup);