bnxt_en: reset PHC frequency in free-running mode

When using a PHC in shared between multiple hosts, the previous
frequency value may not be reset and could lead to host being unable to
compensate the offset with timecounter adjustments. To avoid such state
reset the hardware frequency of PHC to zero on init. Some refactoring is
needed to make code readable.

Fixes: 85036ae ("bnxt_en: Add a non-real time mode to access NIC clock")
Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Link: https://lore.kernel.org/r/20230310151356.678059-1-vadfed@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: vvfedorenko

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -6990,11 +6990,9 @@ static int bnxt_hwrm_func_qcfg(struct bnxt *bp)
 		if (flags & FUNC_QCFG_RESP_FLAGS_FW_DCBX_AGENT_ENABLED)
 			bp->fw_cap |= BNXT_FW_CAP_DCBX_AGENT;
 	}
-	if (BNXT_PF(bp) && (flags & FUNC_QCFG_RESP_FLAGS_MULTI_HOST)) {
+	if (BNXT_PF(bp) && (flags & FUNC_QCFG_RESP_FLAGS_MULTI_HOST))
 		bp->flags |= BNXT_FLAG_MULTI_HOST;
-		if (bp->fw_cap & BNXT_FW_CAP_PTP_RTC)
-			bp->fw_cap &= ~BNXT_FW_CAP_PTP_RTC;
-	}
+
 	if (flags & FUNC_QCFG_RESP_FLAGS_RING_MONITOR_ENABLED)
 		bp->fw_cap |= BNXT_FW_CAP_RING_MONITOR;
 

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -2000,6 +2000,8 @@ struct bnxt {
 	u32			fw_dbg_cap;
 
 #define BNXT_NEW_RM(bp)		((bp)->fw_cap & BNXT_FW_CAP_NEW_RM)
+#define BNXT_PTP_USE_RTC(bp)	(!BNXT_MH(bp) && \
+				 ((bp)->fw_cap & BNXT_FW_CAP_PTP_RTC))
 	u32			hwrm_spec_code;
 	u16			hwrm_cmd_seq;
 	u16                     hwrm_cmd_kong_seq;

drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c

@@ -63,7 +63,7 @@ static int bnxt_ptp_settime(struct ptp_clock_info *ptp_info,
 						ptp_info);
 	u64 ns = timespec64_to_ns(ts);
 
-	if (ptp->bp->fw_cap & BNXT_FW_CAP_PTP_RTC)
+	if (BNXT_PTP_USE_RTC(ptp->bp))
 		return bnxt_ptp_cfg_settime(ptp->bp, ns);
 
 	spin_lock_bh(&ptp->ptp_lock);
@@ -196,7 +196,7 @@ static int bnxt_ptp_adjtime(struct ptp_clock_info *ptp_info, s64 delta)
 	struct bnxt_ptp_cfg *ptp = container_of(ptp_info, struct bnxt_ptp_cfg,
 						ptp_info);
 
-	if (ptp->bp->fw_cap & BNXT_FW_CAP_PTP_RTC)
+	if (BNXT_PTP_USE_RTC(ptp->bp))
 		return bnxt_ptp_adjphc(ptp, delta);
 
 	spin_lock_bh(&ptp->ptp_lock);
@@ -205,34 +205,39 @@ static int bnxt_ptp_adjtime(struct ptp_clock_info *ptp_info, s64 delta)
 	return 0;
 }
 
+static int bnxt_ptp_adjfine_rtc(struct bnxt *bp, long scaled_ppm)
+{
+	s32 ppb = scaled_ppm_to_ppb(scaled_ppm);
+	struct hwrm_port_mac_cfg_input *req;
+	int rc;
+
+	rc = hwrm_req_init(bp, req, HWRM_PORT_MAC_CFG);
+	if (rc)
+		return rc;
+
+	req->ptp_freq_adj_ppb = cpu_to_le32(ppb);
+	req->enables = cpu_to_le32(PORT_MAC_CFG_REQ_ENABLES_PTP_FREQ_ADJ_PPB);
+	rc = hwrm_req_send(bp, req);
+	if (rc)
+		netdev_err(bp->dev,
+			   "ptp adjfine failed. rc = %d\n", rc);
+	return rc;
+}
+
 static int bnxt_ptp_adjfine(struct ptp_clock_info *ptp_info, long scaled_ppm)
 {
 	struct bnxt_ptp_cfg *ptp = container_of(ptp_info, struct bnxt_ptp_cfg,
 						ptp_info);
-	struct hwrm_port_mac_cfg_input *req;
 	struct bnxt *bp = ptp->bp;
-	int rc = 0;
 
-	if (!(ptp->bp->fw_cap & BNXT_FW_CAP_PTP_RTC)) {
-		spin_lock_bh(&ptp->ptp_lock);
-		timecounter_read(&ptp->tc);
-		ptp->cc.mult = adjust_by_scaled_ppm(ptp->cmult, scaled_ppm);
-		spin_unlock_bh(&ptp->ptp_lock);
-	} else {
-		s32 ppb = scaled_ppm_to_ppb(scaled_ppm);
-
-		rc = hwrm_req_init(bp, req, HWRM_PORT_MAC_CFG);
-		if (rc)
-			return rc;
+	if (BNXT_PTP_USE_RTC(bp))
+		return bnxt_ptp_adjfine_rtc(bp, scaled_ppm);
 
-		req->ptp_freq_adj_ppb = cpu_to_le32(ppb);
-		req->enables = cpu_to_le32(PORT_MAC_CFG_REQ_ENABLES_PTP_FREQ_ADJ_PPB);
-		rc = hwrm_req_send(ptp->bp, req);
-		if (rc)
-			netdev_err(ptp->bp->dev,
-				   "ptp adjfine failed. rc = %d\n", rc);
-	}
-	return rc;
+	spin_lock_bh(&ptp->ptp_lock);
+	timecounter_read(&ptp->tc);
+	ptp->cc.mult = adjust_by_scaled_ppm(ptp->cmult, scaled_ppm);
+	spin_unlock_bh(&ptp->ptp_lock);
+	return 0;
 }
 
 void bnxt_ptp_pps_event(struct bnxt *bp, u32 data1, u32 data2)
@@ -879,7 +884,7 @@ int bnxt_ptp_init_rtc(struct bnxt *bp, bool phc_cfg)
 	u64 ns;
 	int rc;
 
-	if (!bp->ptp_cfg || !(bp->fw_cap & BNXT_FW_CAP_PTP_RTC))
+	if (!bp->ptp_cfg || !BNXT_PTP_USE_RTC(bp))
 		return -ENODEV;
 
 	if (!phc_cfg) {
@@ -932,13 +937,14 @@ int bnxt_ptp_init(struct bnxt *bp, bool phc_cfg)
 	atomic_set(&ptp->tx_avail, BNXT_MAX_TX_TS);
 	spin_lock_init(&ptp->ptp_lock);
 
-	if (bp->fw_cap & BNXT_FW_CAP_PTP_RTC) {
+	if (BNXT_PTP_USE_RTC(bp)) {
 		bnxt_ptp_timecounter_init(bp, false);
 		rc = bnxt_ptp_init_rtc(bp, phc_cfg);
 		if (rc)
 			goto out;
 	} else {
 		bnxt_ptp_timecounter_init(bp, true);
+		bnxt_ptp_adjfine_rtc(bp, 0);
 	}
 
 	ptp->ptp_info = bnxt_ptp_caps;