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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mb862xx-i2c.c (3550B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Coral-P(A)/Lime I2C adapter driver
      4 *
      5 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
      6 */
      7
      8#include <linux/fb.h>
      9#include <linux/i2c.h>
     10#include <linux/io.h>
     11#include <linux/delay.h>
     12#include <linux/export.h>
     13
     14#include "mb862xxfb.h"
     15#include "mb862xx_reg.h"
     16
     17static int mb862xx_i2c_wait_event(struct i2c_adapter *adap)
     18{
     19	struct mb862xxfb_par *par = adap->algo_data;
     20	u32 reg;
     21
     22	do {
     23		udelay(10);
     24		reg = inreg(i2c, GC_I2C_BCR);
     25		if (reg & (I2C_INT | I2C_BER))
     26			break;
     27	} while (1);
     28
     29	return (reg & I2C_BER) ? 0 : 1;
     30}
     31
     32static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr)
     33{
     34	struct mb862xxfb_par *par = adap->algo_data;
     35
     36	outreg(i2c, GC_I2C_DAR, addr);
     37	outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE);
     38	outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START);
     39	if (!mb862xx_i2c_wait_event(adap))
     40		return -EIO;
     41	par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
     42	return par->i2c_rs;
     43}
     44
     45static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte)
     46{
     47	struct mb862xxfb_par *par = adap->algo_data;
     48
     49	outreg(i2c, GC_I2C_DAR, byte);
     50	outreg(i2c, GC_I2C_BCR, I2C_START);
     51	if (!mb862xx_i2c_wait_event(adap))
     52		return -EIO;
     53	return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
     54}
     55
     56static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last)
     57{
     58	struct mb862xxfb_par *par = adap->algo_data;
     59
     60	outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK));
     61	if (!mb862xx_i2c_wait_event(adap))
     62		return 0;
     63	*byte = inreg(i2c, GC_I2C_DAR);
     64	return 1;
     65}
     66
     67static void mb862xx_i2c_stop(struct i2c_adapter *adap)
     68{
     69	struct mb862xxfb_par *par = adap->algo_data;
     70
     71	outreg(i2c, GC_I2C_BCR, I2C_STOP);
     72	outreg(i2c, GC_I2C_CCR, I2C_DISABLE);
     73	par->i2c_rs = 0;
     74}
     75
     76static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m)
     77{
     78	int i, ret = 0;
     79	int last = m->len - 1;
     80
     81	for (i = 0; i < m->len; i++) {
     82		if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) {
     83			ret = -EIO;
     84			break;
     85		}
     86	}
     87	return ret;
     88}
     89
     90static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m)
     91{
     92	int i, ret = 0;
     93
     94	for (i = 0; i < m->len; i++) {
     95		if (!mb862xx_i2c_write_byte(adap, m->buf[i])) {
     96			ret = -EIO;
     97			break;
     98		}
     99	}
    100	return ret;
    101}
    102
    103static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
    104			int num)
    105{
    106	struct mb862xxfb_par *par = adap->algo_data;
    107	struct i2c_msg *m;
    108	int addr;
    109	int i = 0, err = 0;
    110
    111	dev_dbg(par->dev, "%s: %d msgs\n", __func__, num);
    112
    113	for (i = 0; i < num; i++) {
    114		m = &msgs[i];
    115		if (!m->len) {
    116			dev_dbg(par->dev, "%s: null msgs\n", __func__);
    117			continue;
    118		}
    119		addr = m->addr;
    120		if (m->flags & I2C_M_RD)
    121			addr |= 1;
    122
    123		err = mb862xx_i2c_do_address(adap, addr);
    124		if (err < 0)
    125			break;
    126		if (m->flags & I2C_M_RD)
    127			err = mb862xx_i2c_read(adap, m);
    128		else
    129			err = mb862xx_i2c_write(adap, m);
    130	}
    131
    132	if (i)
    133		mb862xx_i2c_stop(adap);
    134
    135	return (err < 0) ? err : i;
    136}
    137
    138static u32 mb862xx_func(struct i2c_adapter *adap)
    139{
    140	return I2C_FUNC_SMBUS_BYTE_DATA;
    141}
    142
    143static const struct i2c_algorithm mb862xx_algo = {
    144	.master_xfer	= mb862xx_xfer,
    145	.functionality	= mb862xx_func,
    146};
    147
    148static struct i2c_adapter mb862xx_i2c_adapter = {
    149	.name		= "MB862xx I2C adapter",
    150	.algo		= &mb862xx_algo,
    151	.owner		= THIS_MODULE,
    152};
    153
    154int mb862xx_i2c_init(struct mb862xxfb_par *par)
    155{
    156	mb862xx_i2c_adapter.algo_data = par;
    157	par->adap = &mb862xx_i2c_adapter;
    158
    159	return i2c_add_adapter(par->adap);
    160}
    161
    162void mb862xx_i2c_exit(struct mb862xxfb_par *par)
    163{
    164	if (par->adap) {
    165		i2c_del_adapter(par->adap);
    166		par->adap = NULL;
    167	}
    168}