mlxsw: core: Add API for QSFP module temperature thresholds reading

Add new API to read QSFP module's temperature thresholds - warning and
critical.

New internal API reads the temperature thresholds from the modules,
which are equipped with the thermal sensor. These thresholds will be
exposed via hwmon subsystem.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/Makefile

 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_MLXSW_CORE)	+= mlxsw_core.o
 mlxsw_core-objs			:= core.o core_acl_flex_keys.o \
-				   core_acl_flex_actions.o
+				   core_acl_flex_actions.o core_env.o
 mlxsw_core-$(CONFIG_MLXSW_CORE_HWMON) += core_hwmon.o
 mlxsw_core-$(CONFIG_MLXSW_CORE_THERMAL) += core_thermal.o
 obj-$(CONFIG_MLXSW_PCI)		+= mlxsw_pci.o

drivers/net/ethernet/mellanox/mlxsw/core_env.c

+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/* Copyright (c) 2018 Mellanox Technologies. All rights reserved */
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+
+#include "core.h"
+#include "core_env.h"
+#include "item.h"
+#include "reg.h"
+
+static int mlxsw_env_validate_cable_ident(struct mlxsw_core *core, int id,
+					  bool *qsfp)
+{
+	char eeprom_tmp[MLXSW_REG_MCIA_EEPROM_SIZE];
+	char mcia_pl[MLXSW_REG_MCIA_LEN];
+	u8 ident;
+	int err;
+
+	mlxsw_reg_mcia_pack(mcia_pl, id, 0, MLXSW_REG_MCIA_PAGE0_LO_OFF, 0, 1,
+			    MLXSW_REG_MCIA_I2C_ADDR_LOW);
+	err = mlxsw_reg_query(core, MLXSW_REG(mcia), mcia_pl);
+	if (err)
+		return err;
+	mlxsw_reg_mcia_eeprom_memcpy_from(mcia_pl, eeprom_tmp);
+	ident = eeprom_tmp[0];
+	switch (ident) {
+	case MLXSW_REG_MCIA_EEPROM_MODULE_INFO_ID_SFP:
+		*qsfp = false;
+		break;
+	case MLXSW_REG_MCIA_EEPROM_MODULE_INFO_ID_QSFP: /* fall-through */
+	case MLXSW_REG_MCIA_EEPROM_MODULE_INFO_ID_QSFP_PLUS: /* fall-through */
+	case MLXSW_REG_MCIA_EEPROM_MODULE_INFO_ID_QSFP28: /* fall-through */
+	case MLXSW_REG_MCIA_EEPROM_MODULE_INFO_ID_QSFP_DD:
+		*qsfp = true;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int mlxsw_env_module_temp_thresholds_get(struct mlxsw_core *core, int module,
+					 int off, int *temp)
+{
+	char eeprom_tmp[MLXSW_REG_MCIA_EEPROM_SIZE];
+	union {
+		u8 buf[MLXSW_REG_MCIA_TH_ITEM_SIZE];
+		u16 temp;
+	} temp_thresh;
+	char mcia_pl[MLXSW_REG_MCIA_LEN] = {0};
+	char mtbr_pl[MLXSW_REG_MTBR_LEN] = {0};
+	u16 module_temp;
+	bool qsfp;
+	int err;
+
+	mlxsw_reg_mtbr_pack(mtbr_pl, MLXSW_REG_MTBR_BASE_MODULE_INDEX + module,
+			    1);
+	err = mlxsw_reg_query(core, MLXSW_REG(mtbr), mtbr_pl);
+	if (err)
+		return err;
+
+	/* Don't read temperature thresholds for module with no valid info. */
+	mlxsw_reg_mtbr_temp_unpack(mtbr_pl, 0, &module_temp, NULL);
+	switch (module_temp) {
+	case MLXSW_REG_MTBR_BAD_SENS_INFO: /* fall-through */
+	case MLXSW_REG_MTBR_NO_CONN: /* fall-through */
+	case MLXSW_REG_MTBR_NO_TEMP_SENS: /* fall-through */
+	case MLXSW_REG_MTBR_INDEX_NA:
+		*temp = 0;
+		return 0;
+	default:
+		/* Do not consider thresholds for zero temperature. */
+		if (!MLXSW_REG_MTMP_TEMP_TO_MC(module_temp)) {
+			*temp = 0;
+			return 0;
+		}
+		break;
+	}
+
+	/* Read Free Side Device Temperature Thresholds from page 03h
+	 * (MSB at lower byte address).
+	 * Bytes:
+	 * 128-129 - Temp High Alarm (SFP_TEMP_HIGH_ALARM);
+	 * 130-131 - Temp Low Alarm (SFP_TEMP_LOW_ALARM);
+	 * 132-133 - Temp High Warning (SFP_TEMP_HIGH_WARN);
+	 * 134-135 - Temp Low Warning (SFP_TEMP_LOW_WARN);
+	 */
+
+	/* Validate module identifier value. */
+	err = mlxsw_env_validate_cable_ident(core, module, &qsfp);
+	if (err)
+		return err;
+
+	if (qsfp)
+		mlxsw_reg_mcia_pack(mcia_pl, module, 0,
+				    MLXSW_REG_MCIA_TH_PAGE_NUM,
+				    MLXSW_REG_MCIA_TH_PAGE_OFF + off,
+				    MLXSW_REG_MCIA_TH_ITEM_SIZE,
+				    MLXSW_REG_MCIA_I2C_ADDR_LOW);
+	else
+		mlxsw_reg_mcia_pack(mcia_pl, module, 0,
+				    MLXSW_REG_MCIA_PAGE0_LO,
+				    off, MLXSW_REG_MCIA_TH_ITEM_SIZE,
+				    MLXSW_REG_MCIA_I2C_ADDR_HIGH);
+
+	err = mlxsw_reg_query(core, MLXSW_REG(mcia), mcia_pl);
+	if (err)
+		return err;
+
+	mlxsw_reg_mcia_eeprom_memcpy_from(mcia_pl, eeprom_tmp);
+	memcpy(temp_thresh.buf, eeprom_tmp, MLXSW_REG_MCIA_TH_ITEM_SIZE);
+	*temp = temp_thresh.temp * 1000;
+
+	return 0;
+}

drivers/net/ethernet/mellanox/mlxsw/core_env.h

+/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 */
+/* Copyright (c) 2018 Mellanox Technologies. All rights reserved */
+
+#ifndef _MLXSW_CORE_ENV_H
+#define _MLXSW_CORE_ENV_H
+
+int mlxsw_env_module_temp_thresholds_get(struct mlxsw_core *core, int module,
+					 int off, int *temp);
+
+#endif