sfc: Distinguish critical and non-critical over-temperature conditions

Set both the 'maximum' and critical temperature limits for LM87
hardware monitors on Falcon boards.  Do not shut down a port until the
critical temperature is reached, but warn as soon as the 'maximum'
temperature is reached.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 80 insertions, 29 deletions

diff --git a/drivers/net/sfc/falcon_boards.c b/drivers/net/sfc/falcon_boards.c
index cfc29d76758..86180ee02ec 100644
--- a/drivers/net/sfc/falcon_boards.c
+++ b/drivers/net/sfc/falcon_boards.c
@@ -30,17 +30,28 @@
 #define FALCON_BOARD_SFN4112F 0x52
 
 /* Board temperature is about 15°C above ambient when air flow is
- * limited. */
+ * limited.  The maximum acceptable ambient temperature varies
+ * depending on the PHY specifications but the critical temperature
+ * above which we should shut down to avoid damage is 80°C. */
 #define FALCON_BOARD_TEMP_BIAS  15
+#define FALCON_BOARD_TEMP_CRIT  (80 + FALCON_BOARD_TEMP_BIAS)
 
 /* SFC4000 datasheet says: 'The maximum permitted junction temperature
  * is 125°C; the thermal design of the environment for the SFC4000
  * should aim to keep this well below 100°C.' */
+#define FALCON_JUNC_TEMP_MIN    0
 #define FALCON_JUNC_TEMP_MAX    90
+#define FALCON_JUNC_TEMP_CRIT   125
 
 /*****************************************************************************
  * Support for LM87 sensor chip used on several boards
  */
+#define LM87_REG_TEMP_HW_INT_LOCK       0x13
+#define LM87_REG_TEMP_HW_EXT_LOCK       0x14
+#define LM87_REG_TEMP_HW_INT            0x17
+#define LM87_REG_TEMP_HW_EXT            0x18
+#define LM87_REG_TEMP_EXT1              0x26
+#define LM87_REG_TEMP_INT               0x27
 #define LM87_REG_ALARMS1                0x41
 #define LM87_REG_ALARMS2                0x42
 #define LM87_IN_LIMITS(nr, _min, _max)                  \
@@ -57,6 +68,27 @@
 
 #if defined(CONFIG_SENSORS_LM87) || defined(CONFIG_SENSORS_LM87_MODULE)
 
+static int efx_poke_lm87(struct i2c_client *client, const u8 *reg_values)
+{
+        while (*reg_values) {
+                u8 reg = *reg_values++;
+                u8 value = *reg_values++;
+                int rc = i2c_smbus_write_byte_data(client, reg, value);
+                if (rc)
+                        return rc;
+        }
+        return 0;
+}
+
+static const u8 falcon_lm87_common_regs[] = {
+        LM87_REG_TEMP_HW_INT_LOCK, FALCON_BOARD_TEMP_CRIT,
+        LM87_REG_TEMP_HW_INT, FALCON_BOARD_TEMP_CRIT,
+        LM87_TEMP_EXT1_LIMITS(FALCON_JUNC_TEMP_MIN, FALCON_JUNC_TEMP_MAX),
+        LM87_REG_TEMP_HW_EXT_LOCK, FALCON_JUNC_TEMP_CRIT,
+        LM87_REG_TEMP_HW_EXT, FALCON_JUNC_TEMP_CRIT,
+        0
+};
+
 static int efx_init_lm87(struct efx_nic *efx, struct i2c_board_info *info,
                          const u8 *reg_values)
 {
@@ -67,13 +99,12 @@ static int efx_init_lm87(struct efx_nic *efx, struct i2c_board_info *info,
         if (!client)
                 return -EIO;
 
-        while (*reg_values) {
-                u8 reg = *reg_values++;
-                u8 value = *reg_values++;
-                rc = i2c_smbus_write_byte_data(client, reg, value);
-                if (rc)
-                        goto err;
-        }
+        rc = efx_poke_lm87(client, reg_values);
+        if (rc)
+                goto err;
+        rc = efx_poke_lm87(client, falcon_lm87_common_regs);
+        if (rc)
+                goto err;
 
         board->hwmon_client = client;
         return 0;
@@ -91,36 +122,56 @@ static void efx_fini_lm87(struct efx_nic *efx)
 static int efx_check_lm87(struct efx_nic *efx, unsigned mask)
 {
         struct i2c_client *client = falcon_board(efx)->hwmon_client;
-        s32 alarms1, alarms2;
+        bool temp_crit, elec_fault, is_failure;
+        u16 alarms;
+        s32 reg;
 
         /* If link is up then do not monitor temperature */
         if (EFX_WORKAROUND_7884(efx) && efx->link_state.up)
                 return 0;
 
-        alarms1 = i2c_smbus_read_byte_data(client, LM87_REG_ALARMS1);
-        alarms2 = i2c_smbus_read_byte_data(client, LM87_REG_ALARMS2);
-        if (alarms1 < 0)
-                return alarms1;
-        if (alarms2 < 0)
-                return alarms2;
-        alarms1 &= mask;
-        alarms2 &= mask >> 8;
-        if (alarms1 || alarms2) {
+        reg = i2c_smbus_read_byte_data(client, LM87_REG_ALARMS1);
+        if (reg < 0)
+                return reg;
+        alarms = reg;
+        reg = i2c_smbus_read_byte_data(client, LM87_REG_ALARMS2);
+        if (reg < 0)
+                return reg;
+        alarms |= reg << 8;
+        alarms &= mask;
+
+        temp_crit = false;
+        if (alarms & LM87_ALARM_TEMP_INT) {
+                reg = i2c_smbus_read_byte_data(client, LM87_REG_TEMP_INT);
+                if (reg < 0)
+                        return reg;
+                if (reg > FALCON_BOARD_TEMP_CRIT)
+                        temp_crit = true;
+        }
+        if (alarms & LM87_ALARM_TEMP_EXT1) {
+                reg = i2c_smbus_read_byte_data(client, LM87_REG_TEMP_EXT1);
+                if (reg < 0)
+                        return reg;
+                if (reg > FALCON_JUNC_TEMP_CRIT)
+                        temp_crit = true;
+        }
+        elec_fault = alarms & ~(LM87_ALARM_TEMP_INT | LM87_ALARM_TEMP_EXT1);
+        is_failure = temp_crit || elec_fault;
+
+        if (alarms)
                 netif_err(efx, hw, efx->net_dev,
-                          "LM87 detected a hardware failure (status %02x:%02x)"
-                          "%s%s%s\n",
-                          alarms1, alarms2,
-                          (alarms1 & LM87_ALARM_TEMP_INT) ?
+                          "LM87 detected a hardware %s (status %02x:%02x)"
+                          "%s%s%s%s\n",
+                          is_failure ? "failure" : "problem",
+                          alarms & 0xff, alarms >> 8,
+                          (alarms & LM87_ALARM_TEMP_INT) ?
                           "; board is overheating" : "",
-                          (alarms1 & LM87_ALARM_TEMP_EXT1) ?
+                          (alarms & LM87_ALARM_TEMP_EXT1) ?
                           "; controller is overheating" : "",
-                          (alarms1 & ~(LM87_ALARM_TEMP_INT | LM87_ALARM_TEMP_EXT1)
-                           || alarms2) ?
-                          "; electrical fault" : "");
-                return -ERANGE;
-        }
+                          temp_crit ? "; reached critical temperature" : "",
+                          elec_fault ? "; electrical fault" : "");
 
-        return 0;
+        return is_failure ? -ERANGE : 0;
 }
 
 #else /* !CONFIG_SENSORS_LM87 */