From 278d24047891a1bf4a98128eaa8ecafd019e58c2 Mon Sep 17 00:00:00 2001 From: Luwei Zhou Date: Fri, 10 Oct 2014 13:15:30 +0800 Subject: [PATCH] net: fec: ptp: Enable PPS output based on ptp clock FEC ptp timer has 4 channel compare/trigger function. It can be used to enable pps output. The pulse would be ouput high exactly on N second. The pulse ouput high on compare event mode is used to produce pulse per second. The pulse width would be one cycle based on ptp timer clock source.Since 31-bit ptp hardware timer is used, the timer will wrap more than 2 seconds. We need to reload the compare compare event about every 1 second. Signed-off-by: Luwei Zhou Signed-off-by: David S. Miller --- drivers/net/ethernet/freescale/fec.h | 7 + drivers/net/ethernet/freescale/fec_main.c | 2 + drivers/net/ethernet/freescale/fec_ptp.c | 197 +++++++++++++++++++++- 3 files changed, 205 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h index b0e60258d403..1e65917a9381 100644 --- a/drivers/net/ethernet/freescale/fec.h +++ b/drivers/net/ethernet/freescale/fec.h @@ -487,12 +487,19 @@ struct fec_enet_private { /* ptp clock period in ns*/ unsigned int ptp_inc; + + /* pps */ + int pps_channel; + unsigned int reload_period; + int pps_enable; + unsigned int next_counter; }; void fec_ptp_init(struct platform_device *pdev); void fec_ptp_start_cyclecounter(struct net_device *ndev); int fec_ptp_set(struct net_device *ndev, struct ifreq *ifr); int fec_ptp_get(struct net_device *ndev, struct ifreq *ifr); +uint fec_ptp_check_pps_event(struct fec_enet_private *fep); /****************************************************************************/ #endif /* FEC_H */ diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 7a8209e73199..e364d1fc7bdc 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -1622,6 +1622,8 @@ fec_enet_interrupt(int irq, void *dev_id) complete(&fep->mdio_done); } + fec_ptp_check_pps_event(fep); + return ret; } diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c index f5ee460d5be9..0fdcdc9ea028 100644 --- a/drivers/net/ethernet/freescale/fec_ptp.c +++ b/drivers/net/ethernet/freescale/fec_ptp.c @@ -61,6 +61,24 @@ #define FEC_T_INC_CORR_MASK 0x00007f00 #define FEC_T_INC_CORR_OFFSET 8 +#define FEC_T_CTRL_PINPER 0x00000080 +#define FEC_T_TF0_MASK 0x00000001 +#define FEC_T_TF0_OFFSET 0 +#define FEC_T_TF1_MASK 0x00000002 +#define FEC_T_TF1_OFFSET 1 +#define FEC_T_TF2_MASK 0x00000004 +#define FEC_T_TF2_OFFSET 2 +#define FEC_T_TF3_MASK 0x00000008 +#define FEC_T_TF3_OFFSET 3 +#define FEC_T_TDRE_MASK 0x00000001 +#define FEC_T_TDRE_OFFSET 0 +#define FEC_T_TMODE_MASK 0x0000003C +#define FEC_T_TMODE_OFFSET 2 +#define FEC_T_TIE_MASK 0x00000040 +#define FEC_T_TIE_OFFSET 6 +#define FEC_T_TF_MASK 0x00000080 +#define FEC_T_TF_OFFSET 7 + #define FEC_ATIME_CTRL 0x400 #define FEC_ATIME 0x404 #define FEC_ATIME_EVT_OFFSET 0x408 @@ -69,8 +87,143 @@ #define FEC_ATIME_INC 0x414 #define FEC_TS_TIMESTAMP 0x418 +#define FEC_TGSR 0x604 +#define FEC_TCSR(n) (0x608 + n * 0x08) +#define FEC_TCCR(n) (0x60C + n * 0x08) +#define MAX_TIMER_CHANNEL 3 +#define FEC_TMODE_TOGGLE 0x05 +#define FEC_HIGH_PULSE 0x0F + #define FEC_CC_MULT (1 << 31) #define FEC_COUNTER_PERIOD (1 << 31) +#define PPS_OUPUT_RELOAD_PERIOD NSEC_PER_SEC +#define FEC_CHANNLE_0 0 +#define DEFAULT_PPS_CHANNEL FEC_CHANNLE_0 + +/** + * fec_ptp_enable_pps + * @fep: the fec_enet_private structure handle + * @enable: enable the channel pps output + * + * This function enble the PPS ouput on the timer channel. + */ +static int fec_ptp_enable_pps(struct fec_enet_private *fep, uint enable) +{ + unsigned long flags; + u32 val, tempval; + int inc; + struct timespec ts; + u64 ns; + u32 remainder; + val = 0; + + if (!(fep->hwts_tx_en || fep->hwts_rx_en)) { + dev_err(&fep->pdev->dev, "No ptp stack is running\n"); + return -EINVAL; + } + + if (fep->pps_enable == enable) + return 0; + + fep->pps_channel = DEFAULT_PPS_CHANNEL; + fep->reload_period = PPS_OUPUT_RELOAD_PERIOD; + inc = fep->ptp_inc; + + spin_lock_irqsave(&fep->tmreg_lock, flags); + + if (enable) { + /* clear capture or output compare interrupt status if have. + */ + writel(FEC_T_TF_MASK, fep->hwp + FEC_TCSR(fep->pps_channel)); + + /* It is recommended to doulbe check the TMODE field in the + * TCSR register to be cleared before the first compare counter + * is written into TCCR register. Just add a double check. + */ + val = readl(fep->hwp + FEC_TCSR(fep->pps_channel)); + do { + val &= ~(FEC_T_TMODE_MASK); + writel(val, fep->hwp + FEC_TCSR(fep->pps_channel)); + val = readl(fep->hwp + FEC_TCSR(fep->pps_channel)); + } while (val & FEC_T_TMODE_MASK); + + /* Dummy read counter to update the counter */ + timecounter_read(&fep->tc); + /* We want to find the first compare event in the next + * second point. So we need to know what the ptp time + * is now and how many nanoseconds is ahead to get next second. + * The remaining nanosecond ahead before the next second would be + * NSEC_PER_SEC - ts.tv_nsec. Add the remaining nanoseconds + * to current timer would be next second. + */ + tempval = readl(fep->hwp + FEC_ATIME_CTRL); + tempval |= FEC_T_CTRL_CAPTURE; + writel(tempval, fep->hwp + FEC_ATIME_CTRL); + + tempval = readl(fep->hwp + FEC_ATIME); + /* Convert the ptp local counter to 1588 timestamp */ + ns = timecounter_cyc2time(&fep->tc, tempval); + ts.tv_sec = div_u64_rem(ns, 1000000000ULL, &remainder); + ts.tv_nsec = remainder; + + /* The tempval is less than 3 seconds, and so val is less than + * 4 seconds. No overflow for 32bit calculation. + */ + val = NSEC_PER_SEC - (u32)ts.tv_nsec + tempval; + + /* Need to consider the situation that the current time is + * very close to the second point, which means NSEC_PER_SEC + * - ts.tv_nsec is close to be zero(For example 20ns); Since the timer + * is still running when we calculate the first compare event, it is + * possible that the remaining nanoseonds run out before the compare + * counter is calculated and written into TCCR register. To avoid + * this possibility, we will set the compare event to be the next + * of next second. The current setting is 31-bit timer and wrap + * around over 2 seconds. So it is okay to set the next of next + * seond for the timer. + */ + val += NSEC_PER_SEC; + + /* We add (2 * NSEC_PER_SEC - (u32)ts.tv_nsec) to current + * ptp counter, which maybe cause 32-bit wrap. Since the + * (NSEC_PER_SEC - (u32)ts.tv_nsec) is less than 2 second. + * We can ensure the wrap will not cause issue. If the offset + * is bigger than fep->cc.mask would be a error. + */ + val &= fep->cc.mask; + writel(val, fep->hwp + FEC_TCCR(fep->pps_channel)); + + /* Calculate the second the compare event timestamp */ + fep->next_counter = (val + fep->reload_period) & fep->cc.mask; + + /* * Enable compare event when overflow */ + val = readl(fep->hwp + FEC_ATIME_CTRL); + val |= FEC_T_CTRL_PINPER; + writel(val, fep->hwp + FEC_ATIME_CTRL); + + /* Compare channel setting. */ + val = readl(fep->hwp + FEC_TCSR(fep->pps_channel)); + val |= (1 << FEC_T_TF_OFFSET | 1 << FEC_T_TIE_OFFSET); + val &= ~(1 << FEC_T_TDRE_OFFSET); + val &= ~(FEC_T_TMODE_MASK); + val |= (FEC_HIGH_PULSE << FEC_T_TMODE_OFFSET); + writel(val, fep->hwp + FEC_TCSR(fep->pps_channel)); + + /* Write the second compare event timestamp and calculate + * the third timestamp. Refer the TCCR register detail in the spec. + */ + writel(fep->next_counter, fep->hwp + FEC_TCCR(fep->pps_channel)); + fep->next_counter = (fep->next_counter + fep->reload_period) & fep->cc.mask; + } else { + writel(0, fep->hwp + FEC_TCSR(fep->pps_channel)); + } + + fep->pps_enable = enable; + spin_unlock_irqrestore(&fep->tmreg_lock, flags); + + return 0; +} + /** * fec_ptp_read - read raw cycle counter (to be used by time counter) * @cc: the cyclecounter structure @@ -314,6 +467,15 @@ static int fec_ptp_settime(struct ptp_clock_info *ptp, static int fec_ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *rq, int on) { + struct fec_enet_private *fep = + container_of(ptp, struct fec_enet_private, ptp_caps); + int ret = 0; + + if (rq->type == PTP_CLK_REQ_PPS) { + ret = fec_ptp_enable_pps(fep, on); + + return ret; + } return -EOPNOTSUPP; } @@ -428,7 +590,7 @@ void fec_ptp_init(struct platform_device *pdev) fep->ptp_caps.n_ext_ts = 0; fep->ptp_caps.n_per_out = 0; fep->ptp_caps.n_pins = 0; - fep->ptp_caps.pps = 0; + fep->ptp_caps.pps = 1; fep->ptp_caps.adjfreq = fec_ptp_adjfreq; fep->ptp_caps.adjtime = fec_ptp_adjtime; fep->ptp_caps.gettime = fec_ptp_gettime; @@ -452,3 +614,36 @@ void fec_ptp_init(struct platform_device *pdev) schedule_delayed_work(&fep->time_keep, HZ); } + +/** + * fec_ptp_check_pps_event + * @fep: the fec_enet_private structure handle + * + * This function check the pps event and reload the timer compare counter. + */ +uint fec_ptp_check_pps_event(struct fec_enet_private *fep) +{ + u32 val; + u8 channel = fep->pps_channel; + struct ptp_clock_event event; + + val = readl(fep->hwp + FEC_TCSR(channel)); + if (val & FEC_T_TF_MASK) { + /* Write the next next compare(not the next according the spec) + * value to the register + */ + writel(fep->next_counter, fep->hwp + FEC_TCCR(channel)); + do { + writel(val, fep->hwp + FEC_TCSR(channel)); + } while (readl(fep->hwp + FEC_TCSR(channel)) & FEC_T_TF_MASK); + + /* Update the counter; */ + fep->next_counter = (fep->next_counter + fep->reload_period) & fep->cc.mask; + + event.type = PTP_CLOCK_PPS; + ptp_clock_event(fep->ptp_clock, &event); + return 1; + } + + return 0; +}