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[net-next,v4,8/9] net: stmmac: Configure only the relevant bits for timestamping setup

Message ID 20241112170658.2388529-9-maxime.chevallier@bootlin.com (mailing list archive)
State Accepted
Commit 62935443214eef45604dd58f0534eb28d235eb83
Delegated to: Netdev Maintainers
Headers show
Series Support external snapshots on dwmac1000 | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 11 of 11 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
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: 4 this patch: 4
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 23 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-11-13--03-00 (tests: 786)

Commit Message

Maxime Chevallier Nov. 12, 2024, 5:06 p.m. UTC 
The PTP_TCR (Timestamp Control Register) is used to configure several
features related to packet timestamping.

On one hand, it configures the 1588 packet processing, to indicate what
types of frames should be timestamped (all, only 1588v1 or 1588v2, using
L2 or L4 timestamping, on IPv4 or IPv6, etc.). This is congfigured
usually through the ioctl / ndo dedicated for such setup. This
configuration is done by setting some fields in that register, that seem
to behave the same way on all dwmac variants, including DWMAC1000.

On the other hand, and only on DWMAC1000 apparently, some fields in that
register are used to configure external snapshots (bits 24/25).
On DWMAC4 and others, these fields are reserved and external
snapshots are configured through a dedicated register that simply
doesn't seem to exist on DWMAC1000.

This configuration is done in the dwmac1000-specific ptp_clock_info ops
(cf dwmac1000_ptp_enable()).

So to avoid the timestamping configuration interfering with the external
snapshots, this commit makes sure that the config_hw_tstamping only
configures the relevant bits in PTP_TCR, so that the DWMAC1000
timestamping can correctly rely on these otherwise reserved fields.

Reviewed-by: Daniel Machon <daniel.machon@microchip.com>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 .../net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c
index a94829ef8cfb..0f59aa982604 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c
@@ -18,9 +18,22 @@ 
 #include "dwmac4.h"
 #include "stmmac.h"
 
+#define STMMAC_HWTS_CFG_MASK	(PTP_TCR_TSENA | PTP_TCR_TSCFUPDT | \
+				 PTP_TCR_TSINIT | PTP_TCR_TSUPDT | \
+				 PTP_TCR_TSCTRLSSR | PTP_TCR_SNAPTYPSEL_1 | \
+				 PTP_TCR_TSIPV4ENA | PTP_TCR_TSIPV6ENA | \
+				 PTP_TCR_TSEVNTENA | PTP_TCR_TSMSTRENA | \
+				 PTP_TCR_TSVER2ENA | PTP_TCR_TSIPENA | \
+				 PTP_TCR_TSTRIG | PTP_TCR_TSENALL)
+
 static void config_hw_tstamping(void __iomem *ioaddr, u32 data)
 {
-	writel(data, ioaddr + PTP_TCR);
+	u32 regval = readl(ioaddr + PTP_TCR);
+
+	regval &= ~STMMAC_HWTS_CFG_MASK;
+	regval |= data;
+
+	writel(regval, ioaddr + PTP_TCR);
 }
 
 static void config_sub_second_increment(void __iomem *ioaddr,