Patch "ptp: ocp: Add ptp_ocp_adjtime_coarse for large adjustments" has been added to the 5.16-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ptp: ocp: Add ptp_ocp_adjtime_coarse for large adjustments

to the 5.16-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ptp-ocp-add-ptp_ocp_adjtime_coarse-for-large-adjustm.patch
and it can be found in the queue-5.16 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit ff38defe5e96242ec919416054973ec803a864dd
Author: Jonathan Lemon <jonathan.lemon@xxxxxxxxx>
Date:   Mon Feb 28 12:39:57 2022 -0800

    ptp: ocp: Add ptp_ocp_adjtime_coarse for large adjustments
    
    [ Upstream commit 90f8f4c0e3cebd541deaa45cf0e470bb9810dd4f ]
    
    In ("ptp: ocp: Have FPGA fold in ns adjustment for adjtime."), the
    ns adjustment was written to the FPGA register, so the clock could
    accurately perform adjustments.
    
    However, the adjtime() call passes in a s64, while the clock adjustment
    registers use a s32.  When trying to perform adjustments with a large
    value (37 sec), things fail.
    
    Examine the incoming delta, and if larger than 1 sec, use the original
    (coarse) adjustment method.  If smaller than 1 sec, then allow the
    FPGA to fold in the changes over a 1 second window.
    
    Fixes: 6d59d4fa1789 ("ptp: ocp: Have FPGA fold in ns adjustment for adjtime.")
    Signed-off-by: Jonathan Lemon <jonathan.lemon@xxxxxxxxx>
    Acked-by: Richard Cochran <richardcochran@xxxxxxxxx>
    Link: https://lore.kernel.org/r/20220228203957.367371-1-jonathan.lemon@xxxxxxxxx
    Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index 0f1b5a7d2a89..17ad5f0d13b2 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -607,7 +607,7 @@ ptp_ocp_settime(struct ptp_clock_info *ptp_info, const struct timespec64 *ts)
 }
 
 static void
-__ptp_ocp_adjtime_locked(struct ptp_ocp *bp, u64 adj_val)
+__ptp_ocp_adjtime_locked(struct ptp_ocp *bp, u32 adj_val)
 {
 	u32 select, ctrl;
 
@@ -615,7 +615,7 @@ __ptp_ocp_adjtime_locked(struct ptp_ocp *bp, u64 adj_val)
 	iowrite32(OCP_SELECT_CLK_REG, &bp->reg->select);
 
 	iowrite32(adj_val, &bp->reg->offset_ns);
-	iowrite32(adj_val & 0x7f, &bp->reg->offset_window_ns);
+	iowrite32(NSEC_PER_SEC, &bp->reg->offset_window_ns);
 
 	ctrl = OCP_CTRL_ADJUST_OFFSET | OCP_CTRL_ENABLE;
 	iowrite32(ctrl, &bp->reg->ctrl);
@@ -624,6 +624,22 @@ __ptp_ocp_adjtime_locked(struct ptp_ocp *bp, u64 adj_val)
 	iowrite32(select >> 16, &bp->reg->select);
 }
 
+static void
+ptp_ocp_adjtime_coarse(struct ptp_ocp *bp, u64 delta_ns)
+{
+	struct timespec64 ts;
+	unsigned long flags;
+	int err;
+
+	spin_lock_irqsave(&bp->lock, flags);
+	err = __ptp_ocp_gettime_locked(bp, &ts, NULL);
+	if (likely(!err)) {
+		timespec64_add_ns(&ts, delta_ns);
+		__ptp_ocp_settime_locked(bp, &ts);
+	}
+	spin_unlock_irqrestore(&bp->lock, flags);
+}
+
 static int
 ptp_ocp_adjtime(struct ptp_clock_info *ptp_info, s64 delta_ns)
 {
@@ -631,6 +647,11 @@ ptp_ocp_adjtime(struct ptp_clock_info *ptp_info, s64 delta_ns)
 	unsigned long flags;
 	u32 adj_ns, sign;
 
+	if (delta_ns > NSEC_PER_SEC || -delta_ns > NSEC_PER_SEC) {
+		ptp_ocp_adjtime_coarse(bp, delta_ns);
+		return 0;
+	}
+
 	sign = delta_ns < 0 ? BIT(31) : 0;
 	adj_ns = sign ? -delta_ns : delta_ns;