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ptp: ocp: Have FPGA fold in ns adjustment for adjtime.

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The current implementation of adjtime uses gettime/settime to
perform nanosecond adjustments.  This introduces addtional phase
errors due to delays.

Instead, use the FPGA's ability to just apply the nanosecond
adjustment to the clock directly.

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jonathan Lemon 2021-09-14 19:16:34 -07:00 committed by David S. Miller
parent a62a56d04e
commit 6d59d4fa17
1 changed files with 25 additions and 15 deletions
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40
drivers/ptp/ptp_ocp.c
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@ -594,9 +594,6 @@ ptp_ocp_settime(struct ptp_clock_info *ptp_info, const struct timespec64 *ts)
struct ptp_ocp *bp = container_of(ptp_info, struct ptp_ocp, ptp_info);
unsigned long flags;
if (ioread32(&bp->reg->status) & OCP_STATUS_IN_SYNC)
return 0;
spin_lock_irqsave(&bp->lock, flags);
__ptp_ocp_settime_locked(bp, ts);
spin_unlock_irqrestore(&bp->lock, flags);
@ -604,26 +601,39 @@ ptp_ocp_settime(struct ptp_clock_info *ptp_info, const struct timespec64 *ts)
return 0;
}
static void
__ptp_ocp_adjtime_locked(struct ptp_ocp *bp, u64 adj_val)
{
u32 select, ctrl;
select = ioread32(&bp->reg->select);
iowrite32(OCP_SELECT_CLK_REG, &bp->reg->select);
iowrite32(adj_val, &bp->reg->offset_ns);
iowrite32(adj_val & 0x7f, &bp->reg->offset_window_ns);
ctrl = OCP_CTRL_ADJUST_OFFSET | OCP_CTRL_ENABLE;
iowrite32(ctrl, &bp->reg->ctrl);
/* restore clock selection */
iowrite32(select >> 16, &bp->reg->select);
}
static int
ptp_ocp_adjtime(struct ptp_clock_info *ptp_info, s64 delta_ns)
{
struct ptp_ocp *bp = container_of(ptp_info, struct ptp_ocp, ptp_info);
struct timespec64 ts;
unsigned long flags;
int err;
u32 adj_ns, sign;
if (ioread32(&bp->reg->status) & OCP_STATUS_IN_SYNC)
return 0;
sign = delta_ns < 0 ? BIT(31) : 0;
adj_ns = sign ? -delta_ns : delta_ns;
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);
}
__ptp_ocp_adjtime_locked(bp, sign | adj_ns);
spin_unlock_irqrestore(&bp->lock, flags);
return err;
return 0;
}
static int
@ -636,7 +646,7 @@ ptp_ocp_null_adjfine(struct ptp_clock_info *ptp_info, long scaled_ppm)
}
static int
ptp_ocp_adjphase(struct ptp_clock_info *ptp_info, s32 phase_ns)
ptp_ocp_null_adjphase(struct ptp_clock_info *ptp_info, s32 phase_ns)
{
return -EOPNOTSUPP;
}
@ -699,7 +709,7 @@ static const struct ptp_clock_info ptp_ocp_clock_info = {
.settime64 = ptp_ocp_settime,
.adjtime = ptp_ocp_adjtime,
.adjfine = ptp_ocp_null_adjfine,
.adjphase = ptp_ocp_adjphase,
.adjphase = ptp_ocp_null_adjphase,
.enable = ptp_ocp_enable,
.pps = true,
.n_ext_ts = 4,