From 89bddcda7e4f4ff2586e736427405115c362bed4 Mon Sep 17 00:00:00 2001 From: Luwei Zhou Date: Fri, 10 Oct 2014 13:15:29 +0800 Subject: [PATCH] net: fec: ptp: Use hardware algorithm to adjust PTP counter. The FEC IP supports hardware adjustment for ptp timer. Refer to the description of ENET_ATCOR and ENET_ATINC registers in the spec about the hardware adjustment. This patch uses hardware support to adjust the ptp offset and frequency on the slave side. Signed-off-by: Luwei Zhou Signed-off-by: Frank Li Signed-off-by: Fugang Duan Signed-off-by: David S. Miller --- drivers/net/ethernet/freescale/fec.h | 3 ++ drivers/net/ethernet/freescale/fec_ptp.c | 65 ++++++++++++++++++++++++++------ 2 files changed, 56 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h index 1d5e1822bb2c..b0e60258d403 100644 --- a/drivers/net/ethernet/freescale/fec.h +++ b/drivers/net/ethernet/freescale/fec.h @@ -484,6 +484,9 @@ struct fec_enet_private { unsigned int itr_clk_rate; u32 rx_copybreak; + + /* ptp clock period in ns*/ + unsigned int ptp_inc; }; void fec_ptp_init(struct platform_device *pdev); diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c index 8016bdd1995f..f5ee460d5be9 100644 --- a/drivers/net/ethernet/freescale/fec_ptp.c +++ b/drivers/net/ethernet/freescale/fec_ptp.c @@ -145,32 +145,59 @@ void fec_ptp_start_cyclecounter(struct net_device *ndev) */ static int fec_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb) { - u64 diff; unsigned long flags; int neg_adj = 0; - u32 mult = FEC_CC_MULT; + u32 i, tmp; + u32 corr_inc, corr_period; + u32 corr_ns; + u64 lhs, rhs; struct fec_enet_private *fep = container_of(ptp, struct fec_enet_private, ptp_caps); + if (ppb == 0) + return 0; + if (ppb < 0) { ppb = -ppb; neg_adj = 1; } - diff = mult; - diff *= ppb; - diff = div_u64(diff, 1000000000ULL); + /* In theory, corr_inc/corr_period = ppb/NSEC_PER_SEC; + * Try to find the corr_inc between 1 to fep->ptp_inc to + * meet adjustment requirement. + */ + lhs = NSEC_PER_SEC; + rhs = (u64)ppb * (u64)fep->ptp_inc; + for (i = 1; i <= fep->ptp_inc; i++) { + if (lhs >= rhs) { + corr_inc = i; + corr_period = div_u64(lhs, rhs); + break; + } + lhs += NSEC_PER_SEC; + } + /* Not found? Set it to high value - double speed + * correct in every clock step. + */ + if (i > fep->ptp_inc) { + corr_inc = fep->ptp_inc; + corr_period = 1; + } + + if (neg_adj) + corr_ns = fep->ptp_inc - corr_inc; + else + corr_ns = fep->ptp_inc + corr_inc; spin_lock_irqsave(&fep->tmreg_lock, flags); - /* - * dummy read to set cycle_last in tc to now. - * So use adjusted mult to calculate when next call - * timercounter_read. - */ - timecounter_read(&fep->tc); - fep->cc.mult = neg_adj ? mult - diff : mult + diff; + tmp = readl(fep->hwp + FEC_ATIME_INC) & FEC_T_INC_MASK; + tmp |= corr_ns << FEC_T_INC_CORR_OFFSET; + writel(tmp, fep->hwp + FEC_ATIME_INC); + writel(corr_period, fep->hwp + FEC_ATIME_CORR); + /* dummy read to update the timer. */ + timecounter_read(&fep->tc); spin_unlock_irqrestore(&fep->tmreg_lock, flags); @@ -190,12 +217,19 @@ static int fec_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta) container_of(ptp, struct fec_enet_private, ptp_caps); unsigned long flags; u64 now; + u32 counter; spin_lock_irqsave(&fep->tmreg_lock, flags); now = timecounter_read(&fep->tc); now += delta; + /* Get the timer value based on adjusted timestamp. + * Update the counter with the masked value. + */ + counter = now & fep->cc.mask; + writel(counter, fep->hwp + FEC_ATIME); + /* reset the timecounter */ timecounter_init(&fep->tc, &fep->cc, now); @@ -246,6 +280,7 @@ static int fec_ptp_settime(struct ptp_clock_info *ptp, u64 ns; unsigned long flags; + u32 counter; mutex_lock(&fep->ptp_clk_mutex); /* Check the ptp clock */ @@ -256,8 +291,13 @@ static int fec_ptp_settime(struct ptp_clock_info *ptp, ns = ts->tv_sec * 1000000000ULL; ns += ts->tv_nsec; + /* Get the timer value based on timestamp. + * Update the counter with the masked value. + */ + counter = ns & fep->cc.mask; spin_lock_irqsave(&fep->tmreg_lock, flags); + writel(counter, fep->hwp + FEC_ATIME); timecounter_init(&fep->tc, &fep->cc, ns); spin_unlock_irqrestore(&fep->tmreg_lock, flags); mutex_unlock(&fep->ptp_clk_mutex); @@ -396,6 +436,7 @@ void fec_ptp_init(struct platform_device *pdev) fep->ptp_caps.enable = fec_ptp_enable; fep->cycle_speed = clk_get_rate(fep->clk_ptp); + fep->ptp_inc = NSEC_PER_SEC / fep->cycle_speed; spin_lock_init(&fep->tmreg_lock); -- 2.11.0