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-fsi.c (17843B)


      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * FSI-attached I2C master algorithm
      4 *
      5 * Copyright 2018 IBM Corporation
      6 *
      7 * This program is free software; you can redistribute it and/or
      8 * modify it under the terms of the GNU General Public License
      9 * as published by the Free Software Foundation; either version
     10 * 2 of the License, or (at your option) any later version.
     11 */
     12
     13#include <linux/bitfield.h>
     14#include <linux/bitops.h>
     15#include <linux/delay.h>
     16#include <linux/device.h>
     17#include <linux/errno.h>
     18#include <linux/fsi.h>
     19#include <linux/i2c.h>
     20#include <linux/jiffies.h>
     21#include <linux/kernel.h>
     22#include <linux/list.h>
     23#include <linux/module.h>
     24#include <linux/mutex.h>
     25#include <linux/of.h>
     26#include <linux/slab.h>
     27
     28#define FSI_ENGID_I2C		0x7
     29
     30#define I2C_DEFAULT_CLK_DIV	6
     31
     32/* i2c registers */
     33#define I2C_FSI_FIFO		0x00
     34#define I2C_FSI_CMD		0x04
     35#define I2C_FSI_MODE		0x08
     36#define I2C_FSI_WATER_MARK	0x0C
     37#define I2C_FSI_INT_MASK	0x10
     38#define I2C_FSI_INT_COND	0x14
     39#define I2C_FSI_OR_INT_MASK	0x14
     40#define I2C_FSI_INTS		0x18
     41#define I2C_FSI_AND_INT_MASK	0x18
     42#define I2C_FSI_STAT		0x1C
     43#define I2C_FSI_RESET_I2C	0x1C
     44#define I2C_FSI_ESTAT		0x20
     45#define I2C_FSI_RESET_ERR	0x20
     46#define I2C_FSI_RESID_LEN	0x24
     47#define I2C_FSI_SET_SCL		0x24
     48#define I2C_FSI_PORT_BUSY	0x28
     49#define I2C_FSI_RESET_SCL	0x2C
     50#define I2C_FSI_SET_SDA		0x30
     51#define I2C_FSI_RESET_SDA	0x34
     52
     53/* cmd register */
     54#define I2C_CMD_WITH_START	BIT(31)
     55#define I2C_CMD_WITH_ADDR	BIT(30)
     56#define I2C_CMD_RD_CONT		BIT(29)
     57#define I2C_CMD_WITH_STOP	BIT(28)
     58#define I2C_CMD_FORCELAUNCH	BIT(27)
     59#define I2C_CMD_ADDR		GENMASK(23, 17)
     60#define I2C_CMD_READ		BIT(16)
     61#define I2C_CMD_LEN		GENMASK(15, 0)
     62
     63/* mode register */
     64#define I2C_MODE_CLKDIV		GENMASK(31, 16)
     65#define I2C_MODE_PORT		GENMASK(15, 10)
     66#define I2C_MODE_ENHANCED	BIT(3)
     67#define I2C_MODE_DIAG		BIT(2)
     68#define I2C_MODE_PACE_ALLOW	BIT(1)
     69#define I2C_MODE_WRAP		BIT(0)
     70
     71/* watermark register */
     72#define I2C_WATERMARK_HI	GENMASK(15, 12)
     73#define I2C_WATERMARK_LO	GENMASK(7, 4)
     74
     75#define I2C_FIFO_HI_LVL		4
     76#define I2C_FIFO_LO_LVL		4
     77
     78/* interrupt register */
     79#define I2C_INT_INV_CMD		BIT(15)
     80#define I2C_INT_PARITY		BIT(14)
     81#define I2C_INT_BE_OVERRUN	BIT(13)
     82#define I2C_INT_BE_ACCESS	BIT(12)
     83#define I2C_INT_LOST_ARB	BIT(11)
     84#define I2C_INT_NACK		BIT(10)
     85#define I2C_INT_DAT_REQ		BIT(9)
     86#define I2C_INT_CMD_COMP	BIT(8)
     87#define I2C_INT_STOP_ERR	BIT(7)
     88#define I2C_INT_BUSY		BIT(6)
     89#define I2C_INT_IDLE		BIT(5)
     90
     91/* status register */
     92#define I2C_STAT_INV_CMD	BIT(31)
     93#define I2C_STAT_PARITY		BIT(30)
     94#define I2C_STAT_BE_OVERRUN	BIT(29)
     95#define I2C_STAT_BE_ACCESS	BIT(28)
     96#define I2C_STAT_LOST_ARB	BIT(27)
     97#define I2C_STAT_NACK		BIT(26)
     98#define I2C_STAT_DAT_REQ	BIT(25)
     99#define I2C_STAT_CMD_COMP	BIT(24)
    100#define I2C_STAT_STOP_ERR	BIT(23)
    101#define I2C_STAT_MAX_PORT	GENMASK(22, 16)
    102#define I2C_STAT_ANY_INT	BIT(15)
    103#define I2C_STAT_SCL_IN		BIT(11)
    104#define I2C_STAT_SDA_IN		BIT(10)
    105#define I2C_STAT_PORT_BUSY	BIT(9)
    106#define I2C_STAT_SELF_BUSY	BIT(8)
    107#define I2C_STAT_FIFO_COUNT	GENMASK(7, 0)
    108
    109#define I2C_STAT_ERR		(I2C_STAT_INV_CMD |			\
    110				 I2C_STAT_PARITY |			\
    111				 I2C_STAT_BE_OVERRUN |			\
    112				 I2C_STAT_BE_ACCESS |			\
    113				 I2C_STAT_LOST_ARB |			\
    114				 I2C_STAT_NACK |			\
    115				 I2C_STAT_STOP_ERR)
    116#define I2C_STAT_ANY_RESP	(I2C_STAT_ERR |				\
    117				 I2C_STAT_DAT_REQ |			\
    118				 I2C_STAT_CMD_COMP)
    119
    120/* extended status register */
    121#define I2C_ESTAT_FIFO_SZ	GENMASK(31, 24)
    122#define I2C_ESTAT_SCL_IN_SY	BIT(15)
    123#define I2C_ESTAT_SDA_IN_SY	BIT(14)
    124#define I2C_ESTAT_S_SCL		BIT(13)
    125#define I2C_ESTAT_S_SDA		BIT(12)
    126#define I2C_ESTAT_M_SCL		BIT(11)
    127#define I2C_ESTAT_M_SDA		BIT(10)
    128#define I2C_ESTAT_HI_WATER	BIT(9)
    129#define I2C_ESTAT_LO_WATER	BIT(8)
    130#define I2C_ESTAT_PORT_BUSY	BIT(7)
    131#define I2C_ESTAT_SELF_BUSY	BIT(6)
    132#define I2C_ESTAT_VERSION	GENMASK(4, 0)
    133
    134/* port busy register */
    135#define I2C_PORT_BUSY_RESET	BIT(31)
    136
    137/* wait for command complete or data request */
    138#define I2C_CMD_SLEEP_MAX_US	500
    139#define I2C_CMD_SLEEP_MIN_US	50
    140
    141/* wait after reset; choose time from legacy driver */
    142#define I2C_RESET_SLEEP_MAX_US	2000
    143#define I2C_RESET_SLEEP_MIN_US	1000
    144
    145/* choose timeout length from legacy driver; it's well tested */
    146#define I2C_ABORT_TIMEOUT	msecs_to_jiffies(100)
    147
    148struct fsi_i2c_master {
    149	struct fsi_device	*fsi;
    150	u8			fifo_size;
    151	struct list_head	ports;
    152	struct mutex		lock;
    153};
    154
    155struct fsi_i2c_port {
    156	struct list_head	list;
    157	struct i2c_adapter	adapter;
    158	struct fsi_i2c_master	*master;
    159	u16			port;
    160	u16			xfrd;
    161};
    162
    163static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg,
    164			    u32 *data)
    165{
    166	int rc;
    167	__be32 data_be;
    168
    169	rc = fsi_device_read(fsi, reg, &data_be, sizeof(data_be));
    170	if (rc)
    171		return rc;
    172
    173	*data = be32_to_cpu(data_be);
    174
    175	return 0;
    176}
    177
    178static int fsi_i2c_write_reg(struct fsi_device *fsi, unsigned int reg,
    179			     u32 *data)
    180{
    181	__be32 data_be = cpu_to_be32p(data);
    182
    183	return fsi_device_write(fsi, reg, &data_be, sizeof(data_be));
    184}
    185
    186static int fsi_i2c_dev_init(struct fsi_i2c_master *i2c)
    187{
    188	int rc;
    189	u32 mode = I2C_MODE_ENHANCED, extended_status, watermark;
    190	u32 interrupt = 0;
    191
    192	/* since we use polling, disable interrupts */
    193	rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_INT_MASK, &interrupt);
    194	if (rc)
    195		return rc;
    196
    197	mode |= FIELD_PREP(I2C_MODE_CLKDIV, I2C_DEFAULT_CLK_DIV);
    198	rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode);
    199	if (rc)
    200		return rc;
    201
    202	rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_ESTAT, &extended_status);
    203	if (rc)
    204		return rc;
    205
    206	i2c->fifo_size = FIELD_GET(I2C_ESTAT_FIFO_SZ, extended_status);
    207	watermark = FIELD_PREP(I2C_WATERMARK_HI,
    208			       i2c->fifo_size - I2C_FIFO_HI_LVL);
    209	watermark |= FIELD_PREP(I2C_WATERMARK_LO, I2C_FIFO_LO_LVL);
    210
    211	return fsi_i2c_write_reg(i2c->fsi, I2C_FSI_WATER_MARK, &watermark);
    212}
    213
    214static int fsi_i2c_set_port(struct fsi_i2c_port *port)
    215{
    216	int rc;
    217	struct fsi_device *fsi = port->master->fsi;
    218	u32 mode, dummy = 0;
    219
    220	rc = fsi_i2c_read_reg(fsi, I2C_FSI_MODE, &mode);
    221	if (rc)
    222		return rc;
    223
    224	if (FIELD_GET(I2C_MODE_PORT, mode) == port->port)
    225		return 0;
    226
    227	mode = (mode & ~I2C_MODE_PORT) | FIELD_PREP(I2C_MODE_PORT, port->port);
    228	rc = fsi_i2c_write_reg(fsi, I2C_FSI_MODE, &mode);
    229	if (rc)
    230		return rc;
    231
    232	/* reset engine when port is changed */
    233	return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy);
    234}
    235
    236static int fsi_i2c_start(struct fsi_i2c_port *port, struct i2c_msg *msg,
    237			 bool stop)
    238{
    239	struct fsi_i2c_master *i2c = port->master;
    240	u32 cmd = I2C_CMD_WITH_START | I2C_CMD_WITH_ADDR;
    241
    242	port->xfrd = 0;
    243
    244	if (msg->flags & I2C_M_RD)
    245		cmd |= I2C_CMD_READ;
    246
    247	if (stop || msg->flags & I2C_M_STOP)
    248		cmd |= I2C_CMD_WITH_STOP;
    249
    250	cmd |= FIELD_PREP(I2C_CMD_ADDR, msg->addr);
    251	cmd |= FIELD_PREP(I2C_CMD_LEN, msg->len);
    252
    253	return fsi_i2c_write_reg(i2c->fsi, I2C_FSI_CMD, &cmd);
    254}
    255
    256static int fsi_i2c_get_op_bytes(int op_bytes)
    257{
    258	/* fsi is limited to max 4 byte aligned ops */
    259	if (op_bytes > 4)
    260		return 4;
    261	else if (op_bytes == 3)
    262		return 2;
    263	return op_bytes;
    264}
    265
    266static int fsi_i2c_write_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg,
    267			      u8 fifo_count)
    268{
    269	int write;
    270	int rc;
    271	struct fsi_i2c_master *i2c = port->master;
    272	int bytes_to_write = i2c->fifo_size - fifo_count;
    273	int bytes_remaining = msg->len - port->xfrd;
    274
    275	bytes_to_write = min(bytes_to_write, bytes_remaining);
    276
    277	while (bytes_to_write) {
    278		write = fsi_i2c_get_op_bytes(bytes_to_write);
    279
    280		rc = fsi_device_write(i2c->fsi, I2C_FSI_FIFO,
    281				      &msg->buf[port->xfrd], write);
    282		if (rc)
    283			return rc;
    284
    285		port->xfrd += write;
    286		bytes_to_write -= write;
    287	}
    288
    289	return 0;
    290}
    291
    292static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg,
    293			     u8 fifo_count)
    294{
    295	int read;
    296	int rc;
    297	struct fsi_i2c_master *i2c = port->master;
    298	int bytes_to_read;
    299	int xfr_remaining = msg->len - port->xfrd;
    300	u32 dummy;
    301
    302	bytes_to_read = min_t(int, fifo_count, xfr_remaining);
    303
    304	while (bytes_to_read) {
    305		read = fsi_i2c_get_op_bytes(bytes_to_read);
    306
    307		if (xfr_remaining) {
    308			rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO,
    309					     &msg->buf[port->xfrd], read);
    310			if (rc)
    311				return rc;
    312
    313			port->xfrd += read;
    314			xfr_remaining -= read;
    315		} else {
    316			/* no more buffer but data in fifo, need to clear it */
    317			rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO, &dummy,
    318					     read);
    319			if (rc)
    320				return rc;
    321		}
    322
    323		bytes_to_read -= read;
    324	}
    325
    326	return 0;
    327}
    328
    329static int fsi_i2c_get_scl(struct i2c_adapter *adap)
    330{
    331	u32 stat = 0;
    332	struct fsi_i2c_port *port = adap->algo_data;
    333	struct fsi_i2c_master *i2c = port->master;
    334
    335	fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat);
    336
    337	return !!(stat & I2C_STAT_SCL_IN);
    338}
    339
    340static void fsi_i2c_set_scl(struct i2c_adapter *adap, int val)
    341{
    342	u32 dummy = 0;
    343	struct fsi_i2c_port *port = adap->algo_data;
    344	struct fsi_i2c_master *i2c = port->master;
    345
    346	if (val)
    347		fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy);
    348	else
    349		fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy);
    350}
    351
    352static int fsi_i2c_get_sda(struct i2c_adapter *adap)
    353{
    354	u32 stat = 0;
    355	struct fsi_i2c_port *port = adap->algo_data;
    356	struct fsi_i2c_master *i2c = port->master;
    357
    358	fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat);
    359
    360	return !!(stat & I2C_STAT_SDA_IN);
    361}
    362
    363static void fsi_i2c_set_sda(struct i2c_adapter *adap, int val)
    364{
    365	u32 dummy = 0;
    366	struct fsi_i2c_port *port = adap->algo_data;
    367	struct fsi_i2c_master *i2c = port->master;
    368
    369	if (val)
    370		fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SDA, &dummy);
    371	else
    372		fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SDA, &dummy);
    373}
    374
    375static void fsi_i2c_prepare_recovery(struct i2c_adapter *adap)
    376{
    377	int rc;
    378	u32 mode;
    379	struct fsi_i2c_port *port = adap->algo_data;
    380	struct fsi_i2c_master *i2c = port->master;
    381
    382	rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode);
    383	if (rc)
    384		return;
    385
    386	mode |= I2C_MODE_DIAG;
    387	fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode);
    388}
    389
    390static void fsi_i2c_unprepare_recovery(struct i2c_adapter *adap)
    391{
    392	int rc;
    393	u32 mode;
    394	struct fsi_i2c_port *port = adap->algo_data;
    395	struct fsi_i2c_master *i2c = port->master;
    396
    397	rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode);
    398	if (rc)
    399		return;
    400
    401	mode &= ~I2C_MODE_DIAG;
    402	fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode);
    403}
    404
    405static int fsi_i2c_reset_bus(struct fsi_i2c_master *i2c,
    406			     struct fsi_i2c_port *port)
    407{
    408	int rc;
    409	u32 stat, dummy = 0;
    410
    411	/* force bus reset, ignore errors */
    412	i2c_recover_bus(&port->adapter);
    413
    414	/* reset errors */
    415	rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy);
    416	if (rc)
    417		return rc;
    418
    419	/* wait for command complete */
    420	usleep_range(I2C_RESET_SLEEP_MIN_US, I2C_RESET_SLEEP_MAX_US);
    421
    422	rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat);
    423	if (rc)
    424		return rc;
    425
    426	if (stat & I2C_STAT_CMD_COMP)
    427		return 0;
    428
    429	/* failed to get command complete; reset engine again */
    430	rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy);
    431	if (rc)
    432		return rc;
    433
    434	/* re-init engine again */
    435	return fsi_i2c_dev_init(i2c);
    436}
    437
    438static int fsi_i2c_reset_engine(struct fsi_i2c_master *i2c, u16 port)
    439{
    440	int rc;
    441	u32 mode, dummy = 0;
    442
    443	/* reset engine */
    444	rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy);
    445	if (rc)
    446		return rc;
    447
    448	/* re-init engine */
    449	rc = fsi_i2c_dev_init(i2c);
    450	if (rc)
    451		return rc;
    452
    453	rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode);
    454	if (rc)
    455		return rc;
    456
    457	/* set port; default after reset is 0 */
    458	if (port) {
    459		mode &= ~I2C_MODE_PORT;
    460		mode |= FIELD_PREP(I2C_MODE_PORT, port);
    461		rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode);
    462		if (rc)
    463			return rc;
    464	}
    465
    466	/* reset busy register; hw workaround */
    467	dummy = I2C_PORT_BUSY_RESET;
    468	rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_PORT_BUSY, &dummy);
    469	if (rc)
    470		return rc;
    471
    472	return 0;
    473}
    474
    475static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status)
    476{
    477	int rc;
    478	unsigned long start;
    479	u32 cmd = I2C_CMD_WITH_STOP;
    480	u32 stat;
    481	struct fsi_i2c_master *i2c = port->master;
    482	struct fsi_device *fsi = i2c->fsi;
    483
    484	rc = fsi_i2c_reset_engine(i2c, port->port);
    485	if (rc)
    486		return rc;
    487
    488	rc = fsi_i2c_read_reg(fsi, I2C_FSI_STAT, &stat);
    489	if (rc)
    490		return rc;
    491
    492	/* if sda is low, peform full bus reset */
    493	if (!(stat & I2C_STAT_SDA_IN)) {
    494		rc = fsi_i2c_reset_bus(i2c, port);
    495		if (rc)
    496			return rc;
    497	}
    498
    499	/* skip final stop command for these errors */
    500	if (status & (I2C_STAT_PARITY | I2C_STAT_LOST_ARB | I2C_STAT_STOP_ERR))
    501		return 0;
    502
    503	/* write stop command */
    504	rc = fsi_i2c_write_reg(fsi, I2C_FSI_CMD, &cmd);
    505	if (rc)
    506		return rc;
    507
    508	/* wait until we see command complete in the master */
    509	start = jiffies;
    510
    511	do {
    512		rc = fsi_i2c_read_reg(fsi, I2C_FSI_STAT, &status);
    513		if (rc)
    514			return rc;
    515
    516		if (status & I2C_STAT_CMD_COMP)
    517			return 0;
    518
    519		usleep_range(I2C_CMD_SLEEP_MIN_US, I2C_CMD_SLEEP_MAX_US);
    520	} while (time_after(start + I2C_ABORT_TIMEOUT, jiffies));
    521
    522	return -ETIMEDOUT;
    523}
    524
    525static int fsi_i2c_handle_status(struct fsi_i2c_port *port,
    526				 struct i2c_msg *msg, u32 status)
    527{
    528	int rc;
    529	u8 fifo_count;
    530
    531	if (status & I2C_STAT_ERR) {
    532		rc = fsi_i2c_abort(port, status);
    533		if (rc)
    534			return rc;
    535
    536		if (status & I2C_STAT_INV_CMD)
    537			return -EINVAL;
    538
    539		if (status & (I2C_STAT_PARITY | I2C_STAT_BE_OVERRUN |
    540		    I2C_STAT_BE_ACCESS))
    541			return -EPROTO;
    542
    543		if (status & I2C_STAT_NACK)
    544			return -ENXIO;
    545
    546		if (status & I2C_STAT_LOST_ARB)
    547			return -EAGAIN;
    548
    549		if (status & I2C_STAT_STOP_ERR)
    550			return -EBADMSG;
    551
    552		return -EIO;
    553	}
    554
    555	if (status & I2C_STAT_DAT_REQ) {
    556		fifo_count = FIELD_GET(I2C_STAT_FIFO_COUNT, status);
    557
    558		if (msg->flags & I2C_M_RD)
    559			return fsi_i2c_read_fifo(port, msg, fifo_count);
    560
    561		return fsi_i2c_write_fifo(port, msg, fifo_count);
    562	}
    563
    564	if (status & I2C_STAT_CMD_COMP) {
    565		if (port->xfrd < msg->len)
    566			return -ENODATA;
    567
    568		return msg->len;
    569	}
    570
    571	return 0;
    572}
    573
    574static int fsi_i2c_wait(struct fsi_i2c_port *port, struct i2c_msg *msg,
    575			unsigned long timeout)
    576{
    577	u32 status = 0;
    578	int rc;
    579	unsigned long start = jiffies;
    580
    581	do {
    582		rc = fsi_i2c_read_reg(port->master->fsi, I2C_FSI_STAT,
    583				      &status);
    584		if (rc)
    585			return rc;
    586
    587		if (status & I2C_STAT_ANY_RESP) {
    588			rc = fsi_i2c_handle_status(port, msg, status);
    589			if (rc < 0)
    590				return rc;
    591
    592			/* cmd complete and all data xfrd */
    593			if (rc == msg->len)
    594				return 0;
    595
    596			/* need to xfr more data, but maybe don't need wait */
    597			continue;
    598		}
    599
    600		usleep_range(I2C_CMD_SLEEP_MIN_US, I2C_CMD_SLEEP_MAX_US);
    601	} while (time_after(start + timeout, jiffies));
    602
    603	return -ETIMEDOUT;
    604}
    605
    606static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
    607			int num)
    608{
    609	int i, rc;
    610	unsigned long start_time;
    611	struct fsi_i2c_port *port = adap->algo_data;
    612	struct fsi_i2c_master *master = port->master;
    613	struct i2c_msg *msg;
    614
    615	mutex_lock(&master->lock);
    616
    617	rc = fsi_i2c_set_port(port);
    618	if (rc)
    619		goto unlock;
    620
    621	for (i = 0; i < num; i++) {
    622		msg = msgs + i;
    623		start_time = jiffies;
    624
    625		rc = fsi_i2c_start(port, msg, i == num - 1);
    626		if (rc)
    627			goto unlock;
    628
    629		rc = fsi_i2c_wait(port, msg,
    630				  adap->timeout - (jiffies - start_time));
    631		if (rc)
    632			goto unlock;
    633	}
    634
    635unlock:
    636	mutex_unlock(&master->lock);
    637	return rc ? : num;
    638}
    639
    640static u32 fsi_i2c_functionality(struct i2c_adapter *adap)
    641{
    642	return I2C_FUNC_I2C | I2C_FUNC_PROTOCOL_MANGLING |
    643		I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
    644}
    645
    646static struct i2c_bus_recovery_info fsi_i2c_bus_recovery_info = {
    647	.recover_bus = i2c_generic_scl_recovery,
    648	.get_scl = fsi_i2c_get_scl,
    649	.set_scl = fsi_i2c_set_scl,
    650	.get_sda = fsi_i2c_get_sda,
    651	.set_sda = fsi_i2c_set_sda,
    652	.prepare_recovery = fsi_i2c_prepare_recovery,
    653	.unprepare_recovery = fsi_i2c_unprepare_recovery,
    654};
    655
    656static const struct i2c_algorithm fsi_i2c_algorithm = {
    657	.master_xfer = fsi_i2c_xfer,
    658	.functionality = fsi_i2c_functionality,
    659};
    660
    661static struct device_node *fsi_i2c_find_port_of_node(struct device_node *fsi,
    662						     int port)
    663{
    664	struct device_node *np;
    665	u32 port_no;
    666	int rc;
    667
    668	for_each_child_of_node(fsi, np) {
    669		rc = of_property_read_u32(np, "reg", &port_no);
    670		if (!rc && port_no == port)
    671			return np;
    672	}
    673
    674	return NULL;
    675}
    676
    677static int fsi_i2c_probe(struct device *dev)
    678{
    679	struct fsi_i2c_master *i2c;
    680	struct fsi_i2c_port *port;
    681	struct device_node *np;
    682	u32 port_no, ports, stat;
    683	int rc;
    684
    685	i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
    686	if (!i2c)
    687		return -ENOMEM;
    688
    689	mutex_init(&i2c->lock);
    690	i2c->fsi = to_fsi_dev(dev);
    691	INIT_LIST_HEAD(&i2c->ports);
    692
    693	rc = fsi_i2c_dev_init(i2c);
    694	if (rc)
    695		return rc;
    696
    697	rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat);
    698	if (rc)
    699		return rc;
    700
    701	ports = FIELD_GET(I2C_STAT_MAX_PORT, stat) + 1;
    702	dev_dbg(dev, "I2C master has %d ports\n", ports);
    703
    704	for (port_no = 0; port_no < ports; port_no++) {
    705		np = fsi_i2c_find_port_of_node(dev->of_node, port_no);
    706		if (!of_device_is_available(np))
    707			continue;
    708
    709		port = kzalloc(sizeof(*port), GFP_KERNEL);
    710		if (!port) {
    711			of_node_put(np);
    712			break;
    713		}
    714
    715		port->master = i2c;
    716		port->port = port_no;
    717
    718		port->adapter.owner = THIS_MODULE;
    719		port->adapter.dev.of_node = np;
    720		port->adapter.dev.parent = dev;
    721		port->adapter.algo = &fsi_i2c_algorithm;
    722		port->adapter.bus_recovery_info = &fsi_i2c_bus_recovery_info;
    723		port->adapter.algo_data = port;
    724
    725		snprintf(port->adapter.name, sizeof(port->adapter.name),
    726			 "i2c_bus-%u", port_no);
    727
    728		rc = i2c_add_adapter(&port->adapter);
    729		if (rc < 0) {
    730			dev_err(dev, "Failed to register adapter: %d\n", rc);
    731			kfree(port);
    732			continue;
    733		}
    734
    735		list_add(&port->list, &i2c->ports);
    736	}
    737
    738	dev_set_drvdata(dev, i2c);
    739
    740	return 0;
    741}
    742
    743static int fsi_i2c_remove(struct device *dev)
    744{
    745	struct fsi_i2c_master *i2c = dev_get_drvdata(dev);
    746	struct fsi_i2c_port *port, *tmp;
    747
    748	list_for_each_entry_safe(port, tmp, &i2c->ports, list) {
    749		list_del(&port->list);
    750		i2c_del_adapter(&port->adapter);
    751		kfree(port);
    752	}
    753
    754	return 0;
    755}
    756
    757static const struct fsi_device_id fsi_i2c_ids[] = {
    758	{ FSI_ENGID_I2C, FSI_VERSION_ANY },
    759	{ }
    760};
    761
    762static struct fsi_driver fsi_i2c_driver = {
    763	.id_table = fsi_i2c_ids,
    764	.drv = {
    765		.name = "i2c-fsi",
    766		.bus = &fsi_bus_type,
    767		.probe = fsi_i2c_probe,
    768		.remove = fsi_i2c_remove,
    769	},
    770};
    771
    772module_fsi_driver(fsi_i2c_driver);
    773
    774MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>");
    775MODULE_DESCRIPTION("FSI attached I2C master");
    776MODULE_LICENSE("GPL");