diff mbox series

[net-next,3/3] bnxt_en: Add a non-real time mode to access NIC clock

Message ID 1667780192-3700-4-git-send-email-michael.chan@broadcom.com (mailing list archive)
State Accepted
Commit 85036aee1938d65da4be6ae1bc7e5e7e30b567b9
Delegated to: Netdev Maintainers
Headers show
Series bnxt_en: Updates | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1 this patch: 1
netdev/cc_maintainers warning 1 maintainers not CCed: richardcochran@gmail.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1 this patch: 1
netdev/checkpatch warning WARNING: line length of 85 exceeds 80 columns WARNING: line length of 86 exceeds 80 columns WARNING: line length of 96 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Michael Chan Nov. 7, 2022, 12:16 a.m. UTC 
From: Pavan Chebbi <pavan.chebbi@broadcom.com>

When using a PHC that is shared between multiple hosts,
in order to achieve consistent timestamps across all hosts,
we need to isolate the PHC from any host making frequency
adjustments.

This patch adds a non-real time mode for this purpose.
The implementation is based on a free running NIC hardware timer
which is used as the timestamper time-base. Each host implements
individual adjustments to a local timecounter based on the NIC free
running timer.

Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     |  5 ++-
 drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c | 45 ++++++++++++++-----
 drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h |  7 ++-
 3 files changed, 42 insertions(+), 15 deletions(-)

Comments

Leon Romanovsky Nov. 7, 2022, 7:51 a.m. UTC | #1 
On Sun, Nov 06, 2022 at 07:16:32PM -0500, Michael Chan wrote:
> From: Pavan Chebbi <pavan.chebbi@broadcom.com>
> 
> When using a PHC that is shared between multiple hosts,
> in order to achieve consistent timestamps across all hosts,
> we need to isolate the PHC from any host making frequency
> adjustments.
> 
> This patch adds a non-real time mode for this purpose.
> The implementation is based on a free running NIC hardware timer
> which is used as the timestamper time-base. Each host implements
> individual adjustments to a local timecounter based on the NIC free
> running timer.
> 
> Cc: Richard Cochran <richardcochran@gmail.com>
> Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
> Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
> Signed-off-by: Michael Chan <michael.chan@broadcom.com>
> ---
>  drivers/net/ethernet/broadcom/bnxt/bnxt.c     |  5 ++-
>  drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c | 45 ++++++++++++++-----
>  drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h |  7 ++-
>  3 files changed, 42 insertions(+), 15 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index d18e55b16375..d9ad325f7840 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -6985,8 +6985,11 @@  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;
 
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
index 2132ce63193c..460cb20599f6 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
@@ -14,6 +14,7 @@ 
 #include <linux/net_tstamp.h>
 #include <linux/timekeeping.h>
 #include <linux/ptp_classify.h>
+#include <linux/clocksource.h>
 #include "bnxt_hsi.h"
 #include "bnxt.h"
 #include "bnxt_hwrm.h"
@@ -210,18 +211,37 @@  static int bnxt_ptp_adjfreq(struct ptp_clock_info *ptp_info, s32 ppb)
 						ptp_info);
 	struct hwrm_port_mac_cfg_input *req;
 	struct bnxt *bp = ptp->bp;
-	int rc;
+	int rc = 0;
 
-	rc = hwrm_req_init(bp, req, HWRM_PORT_MAC_CFG);
-	if (rc)
-		return rc;
+	if (!(ptp->bp->fw_cap & BNXT_FW_CAP_PTP_RTC)) {
+		int neg_adj = 0;
+		u32 diff;
+		u64 adj;
 
-	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 adjfreq failed. rc = %d\n", rc);
+		if (ppb < 0) {
+			neg_adj = 1;
+			ppb = -ppb;
+		}
+		adj = ptp->cmult;
+		adj *= ppb;
+		diff = div_u64(adj, 1000000000ULL);
+
+		spin_lock_bh(&ptp->ptp_lock);
+		timecounter_read(&ptp->tc);
+		ptp->cc.mult = neg_adj ? ptp->cmult - diff : ptp->cmult + diff;
+		spin_unlock_bh(&ptp->ptp_lock);
+	} else {
+		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(ptp->bp, req);
+		if (rc)
+			netdev_err(ptp->bp->dev,
+				   "ptp adjfreq failed. rc = %d\n", rc);
+	}
 	return rc;
 }
 
@@ -846,8 +866,9 @@  static void bnxt_ptp_timecounter_init(struct bnxt *bp, bool init_tc)
 		memset(&ptp->cc, 0, sizeof(ptp->cc));
 		ptp->cc.read = bnxt_cc_read;
 		ptp->cc.mask = CYCLECOUNTER_MASK(48);
-		ptp->cc.shift = 0;
-		ptp->cc.mult = 1;
+		ptp->cc.shift = BNXT_CYCLES_SHIFT;
+		ptp->cc.mult = clocksource_khz2mult(BNXT_DEVCLK_FREQ, ptp->cc.shift);
+		ptp->cmult = ptp->cc.mult;
 		ptp->next_overflow_check = jiffies + BNXT_PHC_OVERFLOW_PERIOD;
 	}
 	if (init_tc)
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
index 4ce0a14c1e23..34162e07a119 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
@@ -17,6 +17,8 @@ 
 #define BNXT_PTP_GRC_WIN_BASE	0x6000
 
 #define BNXT_MAX_PHC_DRIFT	31000000
+#define BNXT_CYCLES_SHIFT	23
+#define BNXT_DEVCLK_FREQ	1000000
 #define BNXT_LO_TIMER_MASK	0x0000ffffffffUL
 #define BNXT_HI_TIMER_MASK	0xffff00000000UL
 
@@ -88,8 +90,9 @@  struct bnxt_ptp_cfg {
 	u64			old_time;
 	unsigned long		next_period;
 	unsigned long		next_overflow_check;
-	/* 48-bit PHC overflows in 78 hours.  Check overflow every 19 hours. */
-	#define BNXT_PHC_OVERFLOW_PERIOD	(19 * 3600 * HZ)
+	u32			cmult;
+	/* a 23b shift cyclecounter will overflow in ~36 mins.  Check overflow every 18 mins. */
+	#define BNXT_PHC_OVERFLOW_PERIOD	(18 * 60 * HZ)
 
 	u16			tx_seqid;
 	u16			tx_hdr_off;