isci: Changes in COMSAS timings enabling ISCI to detect buggy disc drives.

This patch extends timings in COMSAS signaling, so ISCI can detect disc
drives having issues to send COMSAS in correct time frame.
Signed-off-by: Andrzej Jakowski <andrzej.jakowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/scsi/isci/phy.c

@@ -668,6 +668,19 @@ static const char *phy_event_name(u32 event_code)
 		phy_to_host(iphy)->id, iphy->phy_index, \
 		phy_state_name(state), phy_event_name(code), code)
 
+
+void scu_link_layer_set_txcomsas_timeout(struct isci_phy *iphy, u32 timeout)
+{
+	u32 val;
+
+	/* Extend timeout */
+	val = readl(&iphy->link_layer_registers->transmit_comsas_signal);
+	val &= ~SCU_SAS_LLTXCOMSAS_GEN_VAL(NEGTIME, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_MASK);
+	val |= SCU_SAS_LLTXCOMSAS_GEN_VAL(NEGTIME, timeout);
+
+	writel(val, &iphy->link_layer_registers->transmit_comsas_signal);
+}
+
 enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 {
 	enum sci_phy_states state = iphy->sm.current_state_id;
@@ -683,6 +696,13 @@ enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 			sci_phy_start_sata_link_training(iphy);
 			iphy->is_in_link_training = true;
 			break;
+		case SCU_EVENT_RECEIVED_IDENTIFY_TIMEOUT:
+		       /* Extend timeout value */
+		       scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_EXTENDED);
+
+		       /* Start the oob/sn state machine over again */
+		       sci_change_state(&iphy->sm, SCI_PHY_STARTING);
+		       break;
 		default:
 			phy_event_dbg(iphy, state, event_code);
 			return SCI_FAILURE;
@@ -717,9 +737,19 @@ enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 			sci_phy_start_sata_link_training(iphy);
 			break;
 		case SCU_EVENT_LINK_FAILURE:
+			/* Change the timeout value to default */
+			scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_DEFAULT);
+
 			/* Link failure change state back to the starting state */
 			sci_change_state(&iphy->sm, SCI_PHY_STARTING);
 			break;
+		case SCU_EVENT_RECEIVED_IDENTIFY_TIMEOUT:
+		       /* Extend the timeout value */
+		       scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_EXTENDED);
+
+		       /* Start the oob/sn state machine over again */
+		       sci_change_state(&iphy->sm, SCI_PHY_STARTING);
+		       break;
 		default:
 			phy_event_warn(iphy, state, event_code);
 			return SCI_FAILURE;
@@ -740,7 +770,14 @@ enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 			sci_phy_start_sata_link_training(iphy);
 			break;
 		case SCU_EVENT_RECEIVED_IDENTIFY_TIMEOUT:
+			/* Extend the timeout value */
+			scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_EXTENDED);
+
+			/* Start the oob/sn state machine over again */
+			sci_change_state(&iphy->sm, SCI_PHY_STARTING);
+			break;
 		case SCU_EVENT_LINK_FAILURE:
+			scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_DEFAULT);
 		case SCU_EVENT_HARD_RESET_RECEIVED:
 			/* Start the oob/sn state machine over again */
 			sci_change_state(&iphy->sm, SCI_PHY_STARTING);
@@ -753,6 +790,9 @@ enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 	case SCI_PHY_SUB_AWAIT_SAS_POWER:
 		switch (scu_get_event_code(event_code)) {
 		case SCU_EVENT_LINK_FAILURE:
+			/* Change the timeout value to default */
+			scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_DEFAULT);
+
 			/* Link failure change state back to the starting state */
 			sci_change_state(&iphy->sm, SCI_PHY_STARTING);
 			break;
@@ -764,6 +804,9 @@ enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 	case SCI_PHY_SUB_AWAIT_SATA_POWER:
 		switch (scu_get_event_code(event_code)) {
 		case SCU_EVENT_LINK_FAILURE:
+			/* Change the timeout value to default */
+			scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_DEFAULT);
+
 			/* Link failure change state back to the starting state */
 			sci_change_state(&iphy->sm, SCI_PHY_STARTING);
 			break;
@@ -788,6 +831,9 @@ enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 	case SCI_PHY_SUB_AWAIT_SATA_PHY_EN:
 		switch (scu_get_event_code(event_code)) {
 		case SCU_EVENT_LINK_FAILURE:
+			/* Change the timeout value to default */
+			scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_DEFAULT);
+
 			/* Link failure change state back to the starting state */
 			sci_change_state(&iphy->sm, SCI_PHY_STARTING);
 			break;
@@ -836,6 +882,9 @@ enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 						       SCI_PHY_SUB_AWAIT_SIG_FIS_UF);
 			break;
 		case SCU_EVENT_LINK_FAILURE:
+			/* Change the timeout value to default */
+			scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_DEFAULT);
+
 			/* Link failure change state back to the starting state */
 			sci_change_state(&iphy->sm, SCI_PHY_STARTING);
 			break;
@@ -859,6 +908,9 @@ enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 			break;
 
 		case SCU_EVENT_LINK_FAILURE:
+			/* Change the timeout value to default */
+			scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_DEFAULT);
+
 			/* Link failure change state back to the starting state */
 			sci_change_state(&iphy->sm, SCI_PHY_STARTING);
 			break;
@@ -871,6 +923,9 @@ enum sci_status sci_phy_event_handler(struct isci_phy *iphy, u32 event_code)
 	case SCI_PHY_READY:
 		switch (scu_get_event_code(event_code)) {
 		case SCU_EVENT_LINK_FAILURE:
+			/* Set default timeout */
+			scu_link_layer_set_txcomsas_timeout(iphy, SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_DEFAULT);
+
 			/* Link failure change state back to the starting state */
 			sci_change_state(&iphy->sm, SCI_PHY_STARTING);
 			break;

drivers/scsi/isci/registers.h

@@ -1239,6 +1239,14 @@ struct scu_transport_layer_registers {
 #define SCU_SAS_LLCTL_GEN_BIT(name) \
 	SCU_GEN_BIT(SCU_SAS_LINK_LAYER_CONTROL_ ## name)
 
+#define SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_DEFAULT                     (0xF0)
+#define SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_EXTENDED                    (0x1FF)
+#define SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_SHIFT                       (0)
+#define SCU_SAS_LINK_LAYER_TXCOMSAS_NEGTIME_MASK                        (0x3FF)
+
+#define SCU_SAS_LLTXCOMSAS_GEN_VAL(name, value) \
+	SCU_GEN_VALUE(SCU_SAS_LINK_LAYER_TXCOMSAS_ ## name, value)
+
 
 /* #define SCU_FRXHECR_DCNT_OFFSET      0x00B0 */
 #define SCU_PSZGCR_OFFSET           0x00E4