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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i2c-via.c (3563B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3    i2c Support for Via Technologies 82C586B South Bridge
      4
      5    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
      6
      7*/
      8
      9#include <linux/kernel.h>
     10#include <linux/module.h>
     11#include <linux/pci.h>
     12#include <linux/ioport.h>
     13#include <linux/i2c.h>
     14#include <linux/i2c-algo-bit.h>
     15#include <linux/io.h>
     16
     17/* Power management registers */
     18#define PM_CFG_REVID	0x08	/* silicon revision code */
     19#define PM_CFG_IOBASE0	0x20
     20#define PM_CFG_IOBASE1	0x48
     21
     22#define I2C_DIR		(pm_io_base+0x40)
     23#define I2C_OUT		(pm_io_base+0x42)
     24#define I2C_IN		(pm_io_base+0x44)
     25#define I2C_SCL		0x02	/* clock bit in DIR/OUT/IN register */
     26#define I2C_SDA		0x04
     27
     28/* io-region reservation */
     29#define IOSPACE		0x06
     30
     31static struct pci_driver vt586b_driver;
     32static u16 pm_io_base;
     33
     34/*
     35   It does not appear from the datasheet that the GPIO pins are
     36   open drain. So a we set a low value by setting the direction to
     37   output and a high value by setting the direction to input and
     38   relying on the required I2C pullup. The data value is initialized
     39   to 0 in via_init() and never changed.
     40*/
     41static void bit_via_setscl(void *data, int state)
     42{
     43	outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
     44}
     45
     46static void bit_via_setsda(void *data, int state)
     47{
     48	outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
     49}
     50
     51static int bit_via_getscl(void *data)
     52{
     53	return (0 != (inb(I2C_IN) & I2C_SCL));
     54}
     55
     56static int bit_via_getsda(void *data)
     57{
     58	return (0 != (inb(I2C_IN) & I2C_SDA));
     59}
     60
     61
     62static struct i2c_algo_bit_data bit_data = {
     63	.setsda		= bit_via_setsda,
     64	.setscl		= bit_via_setscl,
     65	.getsda		= bit_via_getsda,
     66	.getscl		= bit_via_getscl,
     67	.udelay		= 5,
     68	.timeout	= HZ
     69};
     70
     71static struct i2c_adapter vt586b_adapter = {
     72	.owner		= THIS_MODULE,
     73	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
     74	.name		= "VIA i2c",
     75	.algo_data	= &bit_data,
     76};
     77
     78
     79static const struct pci_device_id vt586b_ids[] = {
     80	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
     81	{ 0, }
     82};
     83
     84MODULE_DEVICE_TABLE (pci, vt586b_ids);
     85
     86static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
     87{
     88	u16 base;
     89	u8 rev;
     90	int res;
     91
     92	if (pm_io_base) {
     93		dev_err(&dev->dev, "i2c-via: Will only support one host\n");
     94		return -ENODEV;
     95	}
     96
     97	pci_read_config_byte(dev, PM_CFG_REVID, &rev);
     98
     99	switch (rev) {
    100	case 0x00:
    101		base = PM_CFG_IOBASE0;
    102		break;
    103	case 0x01:
    104	case 0x10:
    105		base = PM_CFG_IOBASE1;
    106		break;
    107
    108	default:
    109		base = PM_CFG_IOBASE1;
    110		/* later revision */
    111	}
    112
    113	pci_read_config_word(dev, base, &pm_io_base);
    114	pm_io_base &= (0xff << 8);
    115
    116	if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
    117		dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
    118		return -ENODEV;
    119	}
    120
    121	outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
    122	outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
    123
    124	/* set up the sysfs linkage to our parent device */
    125	vt586b_adapter.dev.parent = &dev->dev;
    126
    127	res = i2c_bit_add_bus(&vt586b_adapter);
    128	if ( res < 0 ) {
    129		release_region(I2C_DIR, IOSPACE);
    130		pm_io_base = 0;
    131		return res;
    132	}
    133	return 0;
    134}
    135
    136static void vt586b_remove(struct pci_dev *dev)
    137{
    138	i2c_del_adapter(&vt586b_adapter);
    139	release_region(I2C_DIR, IOSPACE);
    140	pm_io_base = 0;
    141}
    142
    143
    144static struct pci_driver vt586b_driver = {
    145	.name		= "vt586b_smbus",
    146	.id_table	= vt586b_ids,
    147	.probe		= vt586b_probe,
    148	.remove		= vt586b_remove,
    149};
    150
    151module_pci_driver(vt586b_driver);
    152
    153MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
    154MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
    155MODULE_LICENSE("GPL");