diff options
Diffstat (limited to 'drivers/i2c/i2c-smbus.c')
| -rw-r--r-- | drivers/i2c/i2c-smbus.c | 104 |
1 files changed, 103 insertions, 1 deletions
diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c index 809bcf8387d0..dc0108287ccf 100644 --- a/drivers/i2c/i2c-smbus.c +++ b/drivers/i2c/i2c-smbus.c @@ -3,10 +3,11 @@ * i2c-smbus.c - SMBus extensions to the I2C protocol * * Copyright (C) 2008 David Brownell - * Copyright (C) 2010 Jean Delvare <jdelvare@suse.de> + * Copyright (C) 2010-2019 Jean Delvare <jdelvare@suse.de> */ #include <linux/device.h> +#include <linux/dmi.h> #include <linux/i2c.h> #include <linux/i2c-smbus.h> #include <linux/interrupt.h> @@ -196,6 +197,107 @@ EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert); module_i2c_driver(smbalert_driver); +/* + * SPD is not part of SMBus but we include it here for convenience as the + * target systems are the same. + * Restrictions to automatic SPD instantiation: + * - Only works if all filled slots have the same memory type + * - Only works for DDR2, DDR3 and DDR4 for now + * - Only works on systems with 1 to 4 memory slots + */ +#if IS_ENABLED(CONFIG_DMI) +void i2c_register_spd(struct i2c_adapter *adap) +{ + int n, slot_count = 0, dimm_count = 0; + u16 handle; + u8 common_mem_type = 0x0, mem_type; + u64 mem_size; + const char *name; + + while ((handle = dmi_memdev_handle(slot_count)) != 0xffff) { + slot_count++; + + /* Skip empty slots */ + mem_size = dmi_memdev_size(handle); + if (!mem_size) + continue; + + /* Skip undefined memory type */ + mem_type = dmi_memdev_type(handle); + if (mem_type <= 0x02) /* Invalid, Other, Unknown */ + continue; + + if (!common_mem_type) { + /* First filled slot */ + common_mem_type = mem_type; + } else { + /* Check that all filled slots have the same type */ + if (mem_type != common_mem_type) { + dev_warn(&adap->dev, + "Different memory types mixed, not instantiating SPD\n"); + return; + } + } + dimm_count++; + } + + /* No useful DMI data, bail out */ + if (!dimm_count) + return; + + dev_info(&adap->dev, "%d/%d memory slots populated (from DMI)\n", + dimm_count, slot_count); + + if (slot_count > 4) { + dev_warn(&adap->dev, + "Systems with more than 4 memory slots not supported yet, not instantiating SPD\n"); + return; + } + + switch (common_mem_type) { + case 0x13: /* DDR2 */ + case 0x18: /* DDR3 */ + case 0x1C: /* LPDDR2 */ + case 0x1D: /* LPDDR3 */ + name = "spd"; + break; + case 0x1A: /* DDR4 */ + case 0x1E: /* LPDDR4 */ + name = "ee1004"; + break; + default: + dev_info(&adap->dev, + "Memory type 0x%02x not supported yet, not instantiating SPD\n", + common_mem_type); + return; + } + + /* + * We don't know in which slots the memory modules are. We could + * try to guess from the slot names, but that would be rather complex + * and unreliable, so better probe all possible addresses until we + * have found all memory modules. + */ + for (n = 0; n < slot_count && dimm_count; n++) { + struct i2c_board_info info; + unsigned short addr_list[2]; + + memset(&info, 0, sizeof(struct i2c_board_info)); + strlcpy(info.type, name, I2C_NAME_SIZE); + addr_list[0] = 0x50 + n; + addr_list[1] = I2C_CLIENT_END; + + if (!IS_ERR(i2c_new_scanned_device(adap, &info, addr_list, NULL))) { + dev_info(&adap->dev, + "Successfully instantiated SPD at 0x%hx\n", + addr_list[0]); + dimm_count--; + } + } +} +EXPORT_SYMBOL_GPL(i2c_register_spd); +#endif + MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); MODULE_DESCRIPTION("SMBus protocol extensions support"); MODULE_LICENSE("GPL"); |