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1// SPDX-License-Identifier: GPL-2.02/* Copyright (C) IBM Corporation 2023 */3 4#include <linux/device.h>5#include <linux/fsi.h>6#include <linux/i2c.h>7#include <linux/module.h>8#include <linux/mod_devicetable.h>9#include <linux/mutex.h>10 11#include "fsi-master-i2cr.h"12 13#define CREATE_TRACE_POINTS14#include <trace/events/fsi_master_i2cr.h>15 16#define I2CR_ADDRESS_CFAM(a) ((a) >> 2)17#define I2CR_INITIAL_PARITY true18 19#define I2CR_STATUS_CMD 0x6000220#define I2CR_STATUS_ERR BIT_ULL(61)21#define I2CR_ERROR_CMD 0x6000422#define I2CR_LOG_CMD 0x6000823 24static const u8 i2cr_cfam[] = {25 0xc0, 0x02, 0x0d, 0xa6,26 0x80, 0x01, 0x10, 0x02,27 0x80, 0x01, 0x10, 0x02,28 0x80, 0x01, 0x10, 0x02,29 0x80, 0x01, 0x80, 0x52,30 0x80, 0x01, 0x10, 0x02,31 0x80, 0x01, 0x10, 0x02,32 0x80, 0x01, 0x10, 0x02,33 0x80, 0x01, 0x10, 0x02,34 0x80, 0x01, 0x22, 0x2d,35 0x00, 0x00, 0x00, 0x00,36 0xde, 0xad, 0xc0, 0xde37};38 39static bool i2cr_check_parity32(u32 v, bool parity)40{41 u32 i;42 43 for (i = 0; i < 32; ++i) {44 if (v & (1u << i))45 parity = !parity;46 }47 48 return parity;49}50 51static bool i2cr_check_parity64(u64 v)52{53 u32 i;54 bool parity = I2CR_INITIAL_PARITY;55 56 for (i = 0; i < 64; ++i) {57 if (v & (1llu << i))58 parity = !parity;59 }60 61 return parity;62}63 64static u32 i2cr_get_command(u32 address, bool parity)65{66 address <<= 1;67 68 if (i2cr_check_parity32(address, parity))69 address |= 1;70 71 return address;72}73 74static int i2cr_transfer(struct i2c_client *client, u32 command, u64 *data)75{76 struct i2c_msg msgs[2];77 int ret;78 79 msgs[0].addr = client->addr;80 msgs[0].flags = 0;81 msgs[0].len = sizeof(command);82 msgs[0].buf = (__u8 *)&command;83 msgs[1].addr = client->addr;84 msgs[1].flags = I2C_M_RD;85 msgs[1].len = sizeof(*data);86 msgs[1].buf = (__u8 *)data;87 88 ret = i2c_transfer(client->adapter, msgs, 2);89 if (ret == 2)90 return 0;91 92 trace_i2cr_i2c_error(client, command, ret);93 94 if (ret < 0)95 return ret;96 97 return -EIO;98}99 100static int i2cr_check_status(struct i2c_client *client)101{102 u64 status;103 int ret;104 105 ret = i2cr_transfer(client, I2CR_STATUS_CMD, &status);106 if (ret)107 return ret;108 109 if (status & I2CR_STATUS_ERR) {110 u32 buf[3] = { 0, 0, 0 };111 u64 error;112 u64 log;113 114 i2cr_transfer(client, I2CR_ERROR_CMD, &error);115 i2cr_transfer(client, I2CR_LOG_CMD, &log);116 117 trace_i2cr_status_error(client, status, error, log);118 119 buf[0] = I2CR_STATUS_CMD;120 i2c_master_send(client, (const char *)buf, sizeof(buf));121 122 buf[0] = I2CR_ERROR_CMD;123 i2c_master_send(client, (const char *)buf, sizeof(buf));124 125 buf[0] = I2CR_LOG_CMD;126 i2c_master_send(client, (const char *)buf, sizeof(buf));127 128 dev_err(&client->dev, "status:%016llx error:%016llx log:%016llx\n", status, error,129 log);130 return -EREMOTEIO;131 }132 133 trace_i2cr_status(client, status);134 return 0;135}136 137int fsi_master_i2cr_read(struct fsi_master_i2cr *i2cr, u32 addr, u64 *data)138{139 u32 command = i2cr_get_command(addr, I2CR_INITIAL_PARITY);140 int ret;141 142 mutex_lock(&i2cr->lock);143 144 ret = i2cr_transfer(i2cr->client, command, data);145 if (ret)146 goto unlock;147 148 ret = i2cr_check_status(i2cr->client);149 if (ret)150 goto unlock;151 152 trace_i2cr_read(i2cr->client, command, data);153 154unlock:155 mutex_unlock(&i2cr->lock);156 return ret;157}158EXPORT_SYMBOL_GPL(fsi_master_i2cr_read);159 160int fsi_master_i2cr_write(struct fsi_master_i2cr *i2cr, u32 addr, u64 data)161{162 u32 buf[3] = { 0 };163 int ret;164 165 buf[0] = i2cr_get_command(addr, i2cr_check_parity64(data));166 memcpy(&buf[1], &data, sizeof(data));167 168 mutex_lock(&i2cr->lock);169 170 ret = i2c_master_send(i2cr->client, (const char *)buf, sizeof(buf));171 if (ret == sizeof(buf)) {172 ret = i2cr_check_status(i2cr->client);173 if (!ret)174 trace_i2cr_write(i2cr->client, buf[0], data);175 } else {176 trace_i2cr_i2c_error(i2cr->client, buf[0], ret);177 178 if (ret >= 0)179 ret = -EIO;180 }181 182 mutex_unlock(&i2cr->lock);183 return ret;184}185EXPORT_SYMBOL_GPL(fsi_master_i2cr_write);186 187static int i2cr_read(struct fsi_master *master, int link, uint8_t id, uint32_t addr, void *val,188 size_t size)189{190 struct fsi_master_i2cr *i2cr = container_of(master, struct fsi_master_i2cr, master);191 u64 data;192 size_t i;193 int ret;194 195 if (link || id || (addr & 0xffff0000) || !(size == 1 || size == 2 || size == 4))196 return -EINVAL;197 198 /*199 * The I2CR doesn't have CFAM or FSI slave address space - only the200 * engines. In order for this to work with the FSI core, we need to201 * emulate at minimum the CFAM config table so that the appropriate202 * engines are discovered.203 */204 if (addr < 0xc00) {205 if (addr > sizeof(i2cr_cfam) - 4)206 addr = (addr & 0x3) + (sizeof(i2cr_cfam) - 4);207 208 memcpy(val, &i2cr_cfam[addr], size);209 return 0;210 }211 212 ret = fsi_master_i2cr_read(i2cr, I2CR_ADDRESS_CFAM(addr), &data);213 if (ret)214 return ret;215 216 /*217 * FSI core expects up to 4 bytes BE back, while I2CR replied with LE218 * bytes on the wire.219 */220 for (i = 0; i < size; ++i)221 ((u8 *)val)[i] = ((u8 *)&data)[7 - i];222 223 return 0;224}225 226static int i2cr_write(struct fsi_master *master, int link, uint8_t id, uint32_t addr,227 const void *val, size_t size)228{229 struct fsi_master_i2cr *i2cr = container_of(master, struct fsi_master_i2cr, master);230 u64 data = 0;231 size_t i;232 233 if (link || id || (addr & 0xffff0000) || !(size == 1 || size == 2 || size == 4))234 return -EINVAL;235 236 /* I2CR writes to CFAM or FSI slave address are a successful no-op. */237 if (addr < 0xc00)238 return 0;239 240 /*241 * FSI core passes up to 4 bytes BE, while the I2CR expects LE bytes on242 * the wire.243 */244 for (i = 0; i < size; ++i)245 ((u8 *)&data)[7 - i] = ((u8 *)val)[i];246 247 return fsi_master_i2cr_write(i2cr, I2CR_ADDRESS_CFAM(addr), data);248}249 250static void i2cr_release(struct device *dev)251{252 struct fsi_master_i2cr *i2cr = to_fsi_master_i2cr(to_fsi_master(dev));253 254 of_node_put(dev->of_node);255 256 kfree(i2cr);257}258 259static int i2cr_probe(struct i2c_client *client)260{261 struct fsi_master_i2cr *i2cr;262 int ret;263 264 i2cr = kzalloc(sizeof(*i2cr), GFP_KERNEL);265 if (!i2cr)266 return -ENOMEM;267 268 /* Only one I2CR on any given I2C bus (fixed I2C device address) */269 i2cr->master.idx = client->adapter->nr;270 dev_set_name(&i2cr->master.dev, "i2cr%d", i2cr->master.idx);271 i2cr->master.dev.parent = &client->dev;272 i2cr->master.dev.of_node = of_node_get(dev_of_node(&client->dev));273 i2cr->master.dev.release = i2cr_release;274 275 i2cr->master.n_links = 1;276 i2cr->master.read = i2cr_read;277 i2cr->master.write = i2cr_write;278 279 mutex_init(&i2cr->lock);280 i2cr->client = client;281 282 ret = fsi_master_register(&i2cr->master);283 if (ret)284 return ret;285 286 i2c_set_clientdata(client, i2cr);287 return 0;288}289 290static void i2cr_remove(struct i2c_client *client)291{292 struct fsi_master_i2cr *i2cr = i2c_get_clientdata(client);293 294 fsi_master_unregister(&i2cr->master);295}296 297static const struct of_device_id i2cr_ids[] = {298 { .compatible = "ibm,i2cr-fsi-master" },299 { }300};301MODULE_DEVICE_TABLE(of, i2cr_ids);302 303static struct i2c_driver i2cr_driver = {304 .probe = i2cr_probe,305 .remove = i2cr_remove,306 .driver = {307 .name = "fsi-master-i2cr",308 .of_match_table = i2cr_ids,309 },310};311 312module_i2c_driver(i2cr_driver)313 314MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");315MODULE_DESCRIPTION("IBM I2C Responder virtual FSI master driver");316MODULE_LICENSE("GPL");317