staging/rdma/hfi1: Support external device configuration requests from 8051

This patch implements support for turning on and off the clock data
recovery mechanisms implemented in QSFP cable on request by the DC 8051
on a per-lane basis.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/staging/rdma/hfi1/chip.c

@@ -6085,13 +6085,19 @@ static void hreq_response(struct hfi1_devdata *dd, u8 return_code, u16 rsp_data)
 }
 
 /*
- * Handle requests from the 8051.
+ * Handle host requests from the 8051.
+ *
+ * This is a work-queue function outside of the interrupt.
  */
-static void handle_8051_request(struct hfi1_devdata *dd)
+void handle_8051_request(struct work_struct *work)
 {
+	struct hfi1_pportdata *ppd = container_of(work, struct hfi1_pportdata,
+							dc_host_req_work);
+	struct hfi1_devdata *dd = ppd->dd;
 	u64 reg;
-	u16 data;
-	u8 type;
+	u16 data = 0;
+	u8 type, i, lanes, *cache = ppd->qsfp_info.cache;
+	u8 cdr_ctrl_byte = cache[QSFP_CDR_CTRL_BYTE_OFFS];
 
 	reg = read_csr(dd, DC_DC8051_CFG_EXT_DEV_1);
 	if ((reg & DC_DC8051_CFG_EXT_DEV_1_REQ_NEW_SMASK) == 0)
@@ -6112,12 +6118,46 @@ static void handle_8051_request(struct hfi1_devdata *dd)
 	case HREQ_READ_CONFIG:
 	case HREQ_SET_TX_EQ_ABS:
 	case HREQ_SET_TX_EQ_REL:
-	case HREQ_ENABLE:
 		dd_dev_info(dd, "8051 request: request 0x%x not supported\n",
 			type);
 		hreq_response(dd, HREQ_NOT_SUPPORTED, 0);
 		break;
 
+	case HREQ_ENABLE:
+		lanes = data & 0xF;
+		for (i = 0; lanes; lanes >>= 1, i++) {
+			if (!(lanes & 1))
+				continue;
+			if (data & 0x200) {
+				/* enable TX CDR */
+				if (cache[QSFP_MOD_PWR_OFFS] & 0x8 &&
+				    cache[QSFP_CDR_INFO_OFFS] & 0x80)
+					cdr_ctrl_byte |= (1 << (i + 4));
+			} else {
+				/* disable TX CDR */
+				if (cache[QSFP_MOD_PWR_OFFS] & 0x8 &&
+				    cache[QSFP_CDR_INFO_OFFS] & 0x80)
+					cdr_ctrl_byte &= ~(1 << (i + 4));
+			}
+
+			if (data & 0x800) {
+				/* enable RX CDR */
+				if (cache[QSFP_MOD_PWR_OFFS] & 0x4 &&
+				    cache[QSFP_CDR_INFO_OFFS] & 0x40)
+					cdr_ctrl_byte |= (1 << i);
+			} else {
+				/* disable RX CDR */
+				if (cache[QSFP_MOD_PWR_OFFS] & 0x4 &&
+				    cache[QSFP_CDR_INFO_OFFS] & 0x40)
+					cdr_ctrl_byte &= ~(1 << i);
+			}
+		}
+		qsfp_write(ppd, ppd->dd->hfi1_id, QSFP_CDR_CTRL_BYTE_OFFS,
+			   &cdr_ctrl_byte, 1);
+		hreq_response(dd, HREQ_SUCCESS, data);
+		refresh_qsfp_cache(ppd, &ppd->qsfp_info);
+		break;
+
 	case HREQ_CONFIG_DONE:
 		hreq_response(dd, HREQ_SUCCESS, 0);
 		break;
@@ -7373,7 +7413,7 @@ static void handle_8051_interrupt(struct hfi1_devdata *dd, u32 unused, u64 reg)
 			host_msg &= ~(u64)LINKUP_ACHIEVED;
 		}
 		if (host_msg & EXT_DEVICE_CFG_REQ) {
-			handle_8051_request(dd);
+			queue_work(ppd->hfi1_wq, &ppd->dc_host_req_work);
 			host_msg &= ~(u64)EXT_DEVICE_CFG_REQ;
 		}
 		if (host_msg & VERIFY_CAP_FRAME) {

drivers/staging/rdma/hfi1/chip.h

@@ -647,6 +647,7 @@ void handle_verify_cap(struct work_struct *work);
 void handle_freeze(struct work_struct *work);
 void handle_link_up(struct work_struct *work);
 void handle_link_down(struct work_struct *work);
+void handle_8051_request(struct work_struct *work);
 void handle_link_downgrade(struct work_struct *work);
 void handle_link_bounce(struct work_struct *work);
 void handle_sma_message(struct work_struct *work);

drivers/staging/rdma/hfi1/hfi.h

@@ -589,6 +589,7 @@ struct hfi1_pportdata {
 	struct work_struct link_vc_work;
 	struct work_struct link_up_work;
 	struct work_struct link_down_work;
+	struct work_struct dc_host_req_work;
 	struct work_struct sma_message_work;
 	struct work_struct freeze_work;
 	struct work_struct link_downgrade_work;

drivers/staging/rdma/hfi1/init.c

@@ -495,6 +495,7 @@ void hfi1_init_pportdata(struct pci_dev *pdev, struct hfi1_pportdata *ppd,
 	INIT_WORK(&ppd->link_vc_work, handle_verify_cap);
 	INIT_WORK(&ppd->link_up_work, handle_link_up);
 	INIT_WORK(&ppd->link_down_work, handle_link_down);
+	INIT_WORK(&ppd->dc_host_req_work, handle_8051_request);
 	INIT_WORK(&ppd->freeze_work, handle_freeze);
 	INIT_WORK(&ppd->link_downgrade_work, handle_link_downgrade);
 	INIT_WORK(&ppd->sma_message_work, handle_sma_message);