From 51d58c0c7921d3c93c44099b90dc46720d095bde Mon Sep 17 00:00:00 2001
From: Jacob Keller <jacob.e.keller@intel.com>
Date: Wed, 12 Mar 2025 15:15:51 -0700
Subject: [PATCH] renesas: reject PTP_STRICT_FLAGS as unsupported
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The ravb_ptp_extts() function checks the flags coming from the
PTP_EXTTS_REQUEST ioctl, to ensure that future flags are not accepted on
accident.
This was updated to 'honor' the PTP_STRICT_FLAGS in commit 6138e687c7b6
("ptp: Introduce strict checking of external time stamp options.").
However, the driver does not *actually* validate the flags.
I originally fixed this driver to reject future flags in commit
592025a03b34 ("renesas: reject unsupported external timestamp flags"). It
is still unclear whether this hardware timestamps the rising, falling, or
both edges of the input signal.
Accepting requests with PTP_STRICT_FLAGS is a bug, as this could lead to
users mistakenly assuming a request with PTP_RISING_EDGE actually
timestamps the rising edge only.
Reject requests with PTP_STRICT_FLAGS (and hence all PTP_EXTTS_REQUEST2
requests) until someone with access to the datasheet or hardware knowledge
can confirm the timestamping behavior and update this driver.
Fixes: 6138e687c7b6 ("ptp: Introduce strict checking of external time stamp options.")
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250312-jk-net-fixes-supported-extts-flags-v2-2-ea930ba82459@intel.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
drivers/net/ethernet/renesas/ravb_ptp.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/renesas/ravb_ptp.c b/drivers/net/ethernet/renesas/ravb_ptp.c
index 6e4ef7af27bf3..b4365906669f3 100644
--- a/drivers/net/ethernet/renesas/ravb_ptp.c
+++ b/drivers/net/ethernet/renesas/ravb_ptp.c
@@ -179,8 +179,7 @@ static int ravb_ptp_extts(struct ptp_clock_info *ptp,
/* Reject requests with unsupported flags */
if (req->flags & ~(PTP_ENABLE_FEATURE |
PTP_RISING_EDGE |
- PTP_FALLING_EDGE |
- PTP_STRICT_FLAGS))
+ PTP_FALLING_EDGE))
return -EOPNOTSUPP;
if (req->index)