| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Jean Delvare | 519 | 39.80% | 2 | 8.33% |
| Heiner Kallweit | 461 | 35.35% | 11 | 45.83% |
| Armin Wolf | 240 | 18.40% | 3 | 12.50% |
| Guenter Roeck | 64 | 4.91% | 2 | 8.33% |
| Jonas Malaco | 10 | 0.77% | 1 | 4.17% |
| Wolfram Sang | 6 | 0.46% | 1 | 4.17% |
| Thomas Gleixner | 1 | 0.08% | 1 | 4.17% |
| Greg Kroah-Hartman | 1 | 0.08% | 1 | 4.17% |
| Uwe Kleine-König | 1 | 0.08% | 1 | 4.17% |
| Liu Shixin | 1 | 0.08% | 1 | 4.17% |
| Total | 1304 | 24 |
// SPDX-License-Identifier: GPL-2.0-or-later /* * ee1004 - driver for DDR4 SPD EEPROMs * * Copyright (C) 2017-2019 Jean Delvare * * Based on the at24 driver: * Copyright (C) 2005-2007 David Brownell * Copyright (C) 2008 Wolfram Sang, Pengutronix */ #include <linux/device.h> #include <linux/i2c.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/mod_devicetable.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/nvmem-provider.h> /* * DDR4 memory modules use special EEPROMs following the Jedec EE1004 * specification. These are 512-byte EEPROMs using a single I2C address * in the 0x50-0x57 range for data. One of two 256-byte page is selected * by writing a command to I2C address 0x36 or 0x37 on the same I2C bus. * * Therefore we need to request these 2 additional addresses, and serialize * access to all such EEPROMs with a single mutex. * * We assume it is safe to read up to 32 bytes at once from these EEPROMs. * We use SMBus access even if I2C is available, these EEPROMs are small * enough, and reading from them infrequent enough, that we favor simplicity * over performance. */ #define EE1004_MAX_BUSSES 8 #define EE1004_ADDR_SET_PAGE 0x36 #define EE1004_NUM_PAGES 2 #define EE1004_PAGE_SIZE 256 #define EE1004_PAGE_SHIFT 8 #define EE1004_EEPROM_SIZE (EE1004_PAGE_SIZE * EE1004_NUM_PAGES) /* * Mutex protects ee1004_set_page and ee1004_dev_count, and must be held * from page selection to end of read. */ static DEFINE_MUTEX(ee1004_bus_lock); static struct ee1004_bus_data { struct i2c_adapter *adap; struct i2c_client *set_page[EE1004_NUM_PAGES]; unsigned int dev_count; int current_page; } ee1004_bus_data[EE1004_MAX_BUSSES]; static const struct i2c_device_id ee1004_ids[] = { { "ee1004" }, { } }; MODULE_DEVICE_TABLE(i2c, ee1004_ids); /*-------------------------------------------------------------------------*/ static struct ee1004_bus_data *ee1004_get_bus_data(struct i2c_adapter *adap) { int i; for (i = 0; i < EE1004_MAX_BUSSES; i++) if (ee1004_bus_data[i].adap == adap) return ee1004_bus_data + i; /* If not existent yet, create new entry */ for (i = 0; i < EE1004_MAX_BUSSES; i++) if (!ee1004_bus_data[i].adap) { ee1004_bus_data[i].adap = adap; return ee1004_bus_data + i; } return NULL; } static int ee1004_get_current_page(struct ee1004_bus_data *bd) { int err; err = i2c_smbus_read_byte(bd->set_page[0]); if (err == -ENXIO) { /* Nack means page 1 is selected */ return 1; } if (err < 0) { /* Anything else is a real error, bail out */ return err; } /* Ack means page 0 is selected, returned value meaningless */ return 0; } static int ee1004_set_current_page(struct i2c_client *client, int page) { struct ee1004_bus_data *bd = i2c_get_clientdata(client); int ret; if (page == bd->current_page) return 0; /* Data is ignored */ ret = i2c_smbus_write_byte(bd->set_page[page], 0x00); /* * Don't give up just yet. Some memory modules will select the page * but not ack the command. Check which page is selected now. */ if (ret == -ENXIO && ee1004_get_current_page(bd) == page) ret = 0; if (ret < 0) { dev_err(&client->dev, "Failed to select page %d (%d)\n", page, ret); return ret; } dev_dbg(&client->dev, "Selected page %d\n", page); bd->current_page = page; return 0; } static ssize_t ee1004_eeprom_read(struct i2c_client *client, char *buf, unsigned int offset, size_t count) { int status, page; page = offset >> EE1004_PAGE_SHIFT; offset &= (1 << EE1004_PAGE_SHIFT) - 1; status = ee1004_set_current_page(client, page); if (status) return status; /* Can't cross page boundaries */ if (offset + count > EE1004_PAGE_SIZE) count = EE1004_PAGE_SIZE - offset; if (count > I2C_SMBUS_BLOCK_MAX) count = I2C_SMBUS_BLOCK_MAX; return i2c_smbus_read_i2c_block_data_or_emulated(client, offset, count, buf); } static int ee1004_read(void *priv, unsigned int off, void *val, size_t count) { struct i2c_client *client = priv; char *buf = val; int ret; if (unlikely(!count)) return count; if (off + count > EE1004_EEPROM_SIZE) return -EINVAL; /* * Read data from chip, protecting against concurrent access to * other EE1004 SPD EEPROMs on the same adapter. */ mutex_lock(&ee1004_bus_lock); while (count) { ret = ee1004_eeprom_read(client, buf, off, count); if (ret < 0) { mutex_unlock(&ee1004_bus_lock); return ret; } buf += ret; off += ret; count -= ret; } mutex_unlock(&ee1004_bus_lock); return 0; } static void ee1004_probe_temp_sensor(struct i2c_client *client) { struct i2c_board_info info = { .type = "jc42" }; unsigned short addr = 0x18 | (client->addr & 7); unsigned short addr_list[] = { addr, I2C_CLIENT_END }; u8 data[2]; int ret; /* byte 14, bit 7 is set if temp sensor is present */ ret = ee1004_eeprom_read(client, data, 14, 1); if (ret != 1) return; if (!(data[0] & BIT(7))) { /* * If the SPD data suggests that there is no temperature * sensor, it may still be there for SPD revision 1.0. * See SPD Annex L, Revision 1 and 2, for details. * Check DIMM type and SPD revision; if it is a DDR4 * with SPD revision 1.0, check the thermal sensor address * and instantiate the jc42 driver if a chip is found at * that address. * It is not necessary to check if there is a chip at the * temperature sensor address since i2c_new_scanned_device() * will do that and return silently if no chip is found. */ ret = ee1004_eeprom_read(client, data, 1, 2); if (ret != 2 || data[0] != 0x10 || data[1] != 0x0c) return; } i2c_new_scanned_device(client->adapter, &info, addr_list, NULL); } static void ee1004_cleanup(int idx, struct ee1004_bus_data *bd) { if (--bd->dev_count == 0) { while (--idx >= 0) i2c_unregister_device(bd->set_page[idx]); memset(bd, 0, sizeof(struct ee1004_bus_data)); } } static void ee1004_cleanup_bus_data(void *data) { struct ee1004_bus_data *bd = data; /* Remove page select clients if this is the last device */ mutex_lock(&ee1004_bus_lock); ee1004_cleanup(EE1004_NUM_PAGES, bd); mutex_unlock(&ee1004_bus_lock); } static int ee1004_init_bus_data(struct i2c_client *client) { struct ee1004_bus_data *bd; int err, cnr = 0; bd = ee1004_get_bus_data(client->adapter); if (!bd) return dev_err_probe(&client->dev, -ENOSPC, "Only %d busses supported", EE1004_MAX_BUSSES); i2c_set_clientdata(client, bd); if (++bd->dev_count == 1) { /* Use 2 dummy devices for page select command */ for (cnr = 0; cnr < EE1004_NUM_PAGES; cnr++) { struct i2c_client *cl; cl = i2c_new_dummy_device(client->adapter, EE1004_ADDR_SET_PAGE + cnr); if (IS_ERR(cl)) { err = PTR_ERR(cl); goto err_out; } bd->set_page[cnr] = cl; } /* Remember current page to avoid unneeded page select */ err = ee1004_get_current_page(bd); if (err < 0) goto err_out; dev_dbg(&client->dev, "Currently selected page: %d\n", err); bd->current_page = err; } return 0; err_out: ee1004_cleanup(cnr, bd); return err; } static int ee1004_probe(struct i2c_client *client) { struct nvmem_config config = { .dev = &client->dev, .name = dev_name(&client->dev), .id = NVMEM_DEVID_NONE, .owner = THIS_MODULE, .type = NVMEM_TYPE_EEPROM, .read_only = true, .root_only = false, .reg_read = ee1004_read, .size = EE1004_EEPROM_SIZE, .word_size = 1, .stride = 1, .priv = client, .compat = true, .base_dev = &client->dev, }; struct nvmem_device *ndev; int err; /* Make sure we can operate on this adapter */ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_I2C_BLOCK) && !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_BYTE_DATA)) return -EPFNOSUPPORT; mutex_lock(&ee1004_bus_lock); err = ee1004_init_bus_data(client); if (err < 0) { mutex_unlock(&ee1004_bus_lock); return err; } ee1004_probe_temp_sensor(client); mutex_unlock(&ee1004_bus_lock); err = devm_add_action_or_reset(&client->dev, ee1004_cleanup_bus_data, i2c_get_clientdata(client)); if (err < 0) return err; ndev = devm_nvmem_register(&client->dev, &config); if (IS_ERR(ndev)) return PTR_ERR(ndev); dev_info(&client->dev, "%u byte EE1004-compliant SPD EEPROM, read-only\n", EE1004_EEPROM_SIZE); return 0; } /*-------------------------------------------------------------------------*/ static struct i2c_driver ee1004_driver = { .driver = { .name = "ee1004", }, .probe = ee1004_probe, .id_table = ee1004_ids, }; module_i2c_driver(ee1004_driver); MODULE_DESCRIPTION("Driver for EE1004-compliant DDR4 SPD EEPROMs"); MODULE_AUTHOR("Jean Delvare"); MODULE_LICENSE("GPL");
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with Cregit http://github.com/cregit/cregit
Version 2.0-RC1