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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nsc_gpio.c (3597B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* linux/drivers/char/nsc_gpio.c
      3
      4   National Semiconductor common GPIO device-file/VFS methods.
      5   Allows a user space process to control the GPIO pins.
      6
      7   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
      8   Copyright (c) 2005      Jim Cromie <jim.cromie@gmail.com>
      9*/
     10
     11#include <linux/fs.h>
     12#include <linux/module.h>
     13#include <linux/errno.h>
     14#include <linux/kernel.h>
     15#include <linux/init.h>
     16#include <linux/nsc_gpio.h>
     17#include <linux/platform_device.h>
     18#include <linux/uaccess.h>
     19#include <asm/io.h>
     20
     21#define NAME "nsc_gpio"
     22
     23void nsc_gpio_dump(struct nsc_gpio_ops *amp, unsigned index)
     24{
     25	/* retrieve current config w/o changing it */
     26	u32 config = amp->gpio_config(index, ~0, 0);
     27
     28	/* user requested via 'v' command, so its INFO */
     29	dev_info(amp->dev, "io%02u: 0x%04x %s %s %s %s %s %s %s\tio:%d/%d\n",
     30		 index, config,
     31		 (config & 1) ? "OE" : "TS",      /* output-enabled/tristate */
     32		 (config & 2) ? "PP" : "OD",      /* push pull / open drain */
     33		 (config & 4) ? "PUE" : "PUD",    /* pull up enabled/disabled */
     34		 (config & 8) ? "LOCKED" : "",    /* locked / unlocked */
     35		 (config & 16) ? "LEVEL" : "EDGE",/* level/edge input */
     36		 (config & 32) ? "HI" : "LO",     /* trigger on rise/fall edge */
     37		 (config & 64) ? "DEBOUNCE" : "", /* debounce */
     38
     39		 amp->gpio_get(index), amp->gpio_current(index));
     40}
     41
     42ssize_t nsc_gpio_write(struct file *file, const char __user *data,
     43		       size_t len, loff_t *ppos)
     44{
     45	unsigned m = iminor(file_inode(file));
     46	struct nsc_gpio_ops *amp = file->private_data;
     47	struct device *dev = amp->dev;
     48	size_t i;
     49	int err = 0;
     50
     51	for (i = 0; i < len; ++i) {
     52		char c;
     53		if (get_user(c, data + i))
     54			return -EFAULT;
     55		switch (c) {
     56		case '0':
     57			amp->gpio_set(m, 0);
     58			break;
     59		case '1':
     60			amp->gpio_set(m, 1);
     61			break;
     62		case 'O':
     63			dev_dbg(dev, "GPIO%d output enabled\n", m);
     64			amp->gpio_config(m, ~1, 1);
     65			break;
     66		case 'o':
     67			dev_dbg(dev, "GPIO%d output disabled\n", m);
     68			amp->gpio_config(m, ~1, 0);
     69			break;
     70		case 'T':
     71			dev_dbg(dev, "GPIO%d output is push pull\n", m);
     72			amp->gpio_config(m, ~2, 2);
     73			break;
     74		case 't':
     75			dev_dbg(dev, "GPIO%d output is open drain\n", m);
     76			amp->gpio_config(m, ~2, 0);
     77			break;
     78		case 'P':
     79			dev_dbg(dev, "GPIO%d pull up enabled\n", m);
     80			amp->gpio_config(m, ~4, 4);
     81			break;
     82		case 'p':
     83			dev_dbg(dev, "GPIO%d pull up disabled\n", m);
     84			amp->gpio_config(m, ~4, 0);
     85			break;
     86		case 'v':
     87			/* View Current pin settings */
     88			amp->gpio_dump(amp, m);
     89			break;
     90		case '\n':
     91			/* end of settings string, do nothing */
     92			break;
     93		default:
     94			dev_err(dev, "io%2d bad setting: chr<0x%2x>\n",
     95				m, (int)c);
     96			err++;
     97		}
     98	}
     99	if (err)
    100		return -EINVAL;	/* full string handled, report error */
    101
    102	return len;
    103}
    104
    105ssize_t nsc_gpio_read(struct file *file, char __user * buf,
    106		      size_t len, loff_t * ppos)
    107{
    108	unsigned m = iminor(file_inode(file));
    109	int value;
    110	struct nsc_gpio_ops *amp = file->private_data;
    111
    112	value = amp->gpio_get(m);
    113	if (put_user(value ? '1' : '0', buf))
    114		return -EFAULT;
    115
    116	return 1;
    117}
    118
    119/* common file-ops routines for both scx200_gpio and pc87360_gpio */
    120EXPORT_SYMBOL(nsc_gpio_write);
    121EXPORT_SYMBOL(nsc_gpio_read);
    122EXPORT_SYMBOL(nsc_gpio_dump);
    123
    124static int __init nsc_gpio_init(void)
    125{
    126	printk(KERN_DEBUG NAME " initializing\n");
    127	return 0;
    128}
    129
    130static void __exit nsc_gpio_cleanup(void)
    131{
    132	printk(KERN_DEBUG NAME " cleanup\n");
    133}
    134
    135module_init(nsc_gpio_init);
    136module_exit(nsc_gpio_cleanup);
    137
    138MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
    139MODULE_DESCRIPTION("NatSemi GPIO Common Methods");
    140MODULE_LICENSE("GPL");