From 24a7fffb2533bb44d4ec84bb824732a9c4882f15 Mon Sep 17 00:00:00 2001 From: Nikhil Gupta Date: Fri, 20 Jan 2023 02:10:34 +0530 Subject: [PATCH] ptp_qoriq: fix latency in ptp_qoriq_adjtime() operation 1588 driver loses about 1us in adjtime operation at PTP slave This is because adjtime operation uses a slow non-atomic tmr_cnt_read() followed by tmr_cnt_write() operation. In the above sequence, since the timer counter operation keeps incrementing, it leads to latency. The tmr_offset register (which is added to TMR_CNT_H/L register giving the current time) must be programmed with the delta nanoseconds. Signed-off-by: Nikhil Gupta Reviewed-by: Vladimir Oltean Tested-by: Vladimir Oltean Link: https://lore.kernel.org/r/20230119204034.7969-1-nikhil.gupta@nxp.com Signed-off-by: Jakub Kicinski --- drivers/ptp/ptp_qoriq.c | 50 +++++++++++++++++++++++++++++++++++++------ include/linux/fsl/ptp_qoriq.h | 1 + 2 files changed, 44 insertions(+), 7 deletions(-) diff --git a/drivers/ptp/ptp_qoriq.c b/drivers/ptp/ptp_qoriq.c index 08f4cf0..6153016 100644 --- a/drivers/ptp/ptp_qoriq.c +++ b/drivers/ptp/ptp_qoriq.c @@ -48,6 +48,29 @@ static void tmr_cnt_write(struct ptp_qoriq *ptp_qoriq, u64 ns) ptp_qoriq->write(®s->ctrl_regs->tmr_cnt_h, hi); } +static u64 tmr_offset_read(struct ptp_qoriq *ptp_qoriq) +{ + struct ptp_qoriq_registers *regs = &ptp_qoriq->regs; + u32 lo, hi; + u64 ns; + + lo = ptp_qoriq->read(®s->ctrl_regs->tmroff_l); + hi = ptp_qoriq->read(®s->ctrl_regs->tmroff_h); + ns = ((u64) hi) << 32; + ns |= lo; + return ns; +} + +static void tmr_offset_write(struct ptp_qoriq *ptp_qoriq, u64 delta_ns) +{ + struct ptp_qoriq_registers *regs = &ptp_qoriq->regs; + u32 lo = delta_ns & 0xffffffff; + u32 hi = delta_ns >> 32; + + ptp_qoriq->write(®s->ctrl_regs->tmroff_l, lo); + ptp_qoriq->write(®s->ctrl_regs->tmroff_h, hi); +} + /* Caller must hold ptp_qoriq->lock. */ static void set_alarm(struct ptp_qoriq *ptp_qoriq) { @@ -55,7 +78,9 @@ static void set_alarm(struct ptp_qoriq *ptp_qoriq) u64 ns; u32 lo, hi; - ns = tmr_cnt_read(ptp_qoriq) + 1500000000ULL; + ns = tmr_cnt_read(ptp_qoriq) + tmr_offset_read(ptp_qoriq) + + 1500000000ULL; + ns = div_u64(ns, 1000000000UL) * 1000000000ULL; ns -= ptp_qoriq->tclk_period; hi = ns >> 32; @@ -207,15 +232,24 @@ EXPORT_SYMBOL_GPL(ptp_qoriq_adjfine); int ptp_qoriq_adjtime(struct ptp_clock_info *ptp, s64 delta) { - s64 now; - unsigned long flags; struct ptp_qoriq *ptp_qoriq = container_of(ptp, struct ptp_qoriq, caps); + s64 now, curr_delta; + unsigned long flags; spin_lock_irqsave(&ptp_qoriq->lock, flags); - now = tmr_cnt_read(ptp_qoriq); - now += delta; - tmr_cnt_write(ptp_qoriq, now); + /* On LS1021A, eTSEC2 and eTSEC3 do not take into account the TMR_OFF + * adjustment + */ + if (ptp_qoriq->etsec) { + now = tmr_cnt_read(ptp_qoriq); + now += delta; + tmr_cnt_write(ptp_qoriq, now); + } else { + curr_delta = tmr_offset_read(ptp_qoriq); + curr_delta += delta; + tmr_offset_write(ptp_qoriq, curr_delta); + } set_fipers(ptp_qoriq); spin_unlock_irqrestore(&ptp_qoriq->lock, flags); @@ -232,7 +266,7 @@ int ptp_qoriq_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts) spin_lock_irqsave(&ptp_qoriq->lock, flags); - ns = tmr_cnt_read(ptp_qoriq); + ns = tmr_cnt_read(ptp_qoriq) + tmr_offset_read(ptp_qoriq); spin_unlock_irqrestore(&ptp_qoriq->lock, flags); @@ -253,6 +287,7 @@ int ptp_qoriq_settime(struct ptp_clock_info *ptp, spin_lock_irqsave(&ptp_qoriq->lock, flags); + tmr_offset_write(ptp_qoriq, 0); tmr_cnt_write(ptp_qoriq, ns); set_fipers(ptp_qoriq); @@ -488,6 +523,7 @@ int ptp_qoriq_init(struct ptp_qoriq *ptp_qoriq, void __iomem *base, /* The eTSEC uses differnt memory map with DPAA/ENETC */ if (of_device_is_compatible(node, "fsl,etsec-ptp")) { + ptp_qoriq->etsec = true; ptp_qoriq->regs.ctrl_regs = base + ETSEC_CTRL_REGS_OFFSET; ptp_qoriq->regs.alarm_regs = base + ETSEC_ALARM_REGS_OFFSET; ptp_qoriq->regs.fiper_regs = base + ETSEC_FIPER_REGS_OFFSET; diff --git a/include/linux/fsl/ptp_qoriq.h b/include/linux/fsl/ptp_qoriq.h index 01acebe..b301bf7 100644 --- a/include/linux/fsl/ptp_qoriq.h +++ b/include/linux/fsl/ptp_qoriq.h @@ -149,6 +149,7 @@ struct ptp_qoriq { struct device *dev; bool extts_fifo_support; bool fiper3_support; + bool etsec; int irq; int phc_index; u32 tclk_period; /* nanoseconds */ -- 2.7.4