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-acorn.c (1932B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  ARM IOC/IOMD i2c driver.
      4 *
      5 *  Copyright (C) 2000 Russell King
      6 *
      7 *  On Acorn machines, the following i2c devices are on the bus:
      8 *	- PCF8583 real time clock & static RAM
      9 */
     10#include <linux/module.h>
     11#include <linux/i2c.h>
     12#include <linux/i2c-algo-bit.h>
     13#include <linux/io.h>
     14
     15#include <mach/hardware.h>
     16#include <asm/hardware/ioc.h>
     17
     18#define FORCE_ONES	0xdc
     19#define SCL		0x02
     20#define SDA		0x01
     21
     22/*
     23 * We must preserve all non-i2c output bits in IOC_CONTROL.
     24 * Note also that we need to preserve the value of SCL and
     25 * SDA outputs as well (which may be different from the
     26 * values read back from IOC_CONTROL).
     27 */
     28static u_int force_ones;
     29
     30static void ioc_setscl(void *data, int state)
     31{
     32	u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
     33	u_int ones = force_ones;
     34
     35	if (state)
     36		ones |= SCL;
     37	else
     38		ones &= ~SCL;
     39
     40	force_ones = ones;
     41
     42 	ioc_writeb(ioc_control | ones, IOC_CONTROL);
     43}
     44
     45static void ioc_setsda(void *data, int state)
     46{
     47	u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
     48	u_int ones = force_ones;
     49
     50	if (state)
     51		ones |= SDA;
     52	else
     53		ones &= ~SDA;
     54
     55	force_ones = ones;
     56
     57 	ioc_writeb(ioc_control | ones, IOC_CONTROL);
     58}
     59
     60static int ioc_getscl(void *data)
     61{
     62	return (ioc_readb(IOC_CONTROL) & SCL) != 0;
     63}
     64
     65static int ioc_getsda(void *data)
     66{
     67	return (ioc_readb(IOC_CONTROL) & SDA) != 0;
     68}
     69
     70static struct i2c_algo_bit_data ioc_data = {
     71	.setsda		= ioc_setsda,
     72	.setscl		= ioc_setscl,
     73	.getsda		= ioc_getsda,
     74	.getscl		= ioc_getscl,
     75	.udelay		= 80,
     76	.timeout	= HZ,
     77};
     78
     79static struct i2c_adapter ioc_ops = {
     80	.nr			= 0,
     81	.name			= "ioc",
     82	.algo_data		= &ioc_data,
     83};
     84
     85static int __init i2c_ioc_init(void)
     86{
     87	force_ones = FORCE_ONES | SCL | SDA;
     88
     89	return i2c_bit_add_numbered_bus(&ioc_ops);
     90}
     91
     92module_init(i2c_ioc_init);
     93
     94MODULE_AUTHOR("Russell King <linux@armlinux.org.uk>");
     95MODULE_DESCRIPTION("ARM IOC/IOMD i2c driver");
     96MODULE_LICENSE("GPL v2");