tg3: Enable support for timesync gpio output

The PTP_CAPABLE tg3 devices have a gpio output that is toggled when the
free running counter matches a watchdog value. This patch adds support
to set the watchdog and enable this feature.

Since the output is controlled via bits in the EAV_REF_CLCK_CTL
register, we have to read-modify-write it when we stop/resume.

Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Nithin Nayak Sujir <nsujir@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 58 insertions, 3 deletions

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 935170757786..f077c8f5baa1 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -6093,10 +6093,12 @@ static u64 tg3_refclk_read(struct tg3 *tp)
 /* tp->lock must be held */
 static void tg3_refclk_write(struct tg3 *tp, u64 newval)
 {
-        tw32(TG3_EAV_REF_CLCK_CTL, TG3_EAV_REF_CLCK_CTL_STOP);
+        u32 clock_ctl = tr32(TG3_EAV_REF_CLCK_CTL);
+
+        tw32(TG3_EAV_REF_CLCK_CTL, clock_ctl | TG3_EAV_REF_CLCK_CTL_STOP);
         tw32(TG3_EAV_REF_CLCK_LSB, newval & 0xffffffff);
         tw32(TG3_EAV_REF_CLCK_MSB, newval >> 32);
-        tw32_f(TG3_EAV_REF_CLCK_CTL, TG3_EAV_REF_CLCK_CTL_RESUME);
+        tw32_f(TG3_EAV_REF_CLCK_CTL, clock_ctl | TG3_EAV_REF_CLCK_CTL_RESUME);
 }
 
 static inline void tg3_full_lock(struct tg3 *tp, int irq_sync);
@@ -6212,6 +6214,59 @@ static int tg3_ptp_settime(struct ptp_clock_info *ptp,
 static int tg3_ptp_enable(struct ptp_clock_info *ptp,
                           struct ptp_clock_request *rq, int on)
 {
+        struct tg3 *tp = container_of(ptp, struct tg3, ptp_info);
+        u32 clock_ctl;
+        int rval = 0;
+
+        switch (rq->type) {
+        case PTP_CLK_REQ_PEROUT:
+                if (rq->perout.index != 0)
+                        return -EINVAL;
+
+                tg3_full_lock(tp, 0);
+                clock_ctl = tr32(TG3_EAV_REF_CLCK_CTL);
+                clock_ctl &= ~TG3_EAV_CTL_TSYNC_GPIO_MASK;
+
+                if (on) {
+                        u64 nsec;
+
+                        nsec = rq->perout.start.sec * 1000000000ULL +
+                               rq->perout.start.nsec;
+
+                        if (rq->perout.period.sec || rq->perout.period.nsec) {
+                                netdev_warn(tp->dev,
+                                            "Device supports only a one-shot timesync output, period must be 0\n");
+                                rval = -EINVAL;
+                                goto err_out;
+                        }
+
+                        if (nsec & (1ULL << 63)) {
+                                netdev_warn(tp->dev,
+                                            "Start value (nsec) is over limit. Maximum size of start is only 63 bits\n");
+                                rval = -EINVAL;
+                                goto err_out;
+                        }
+
+                        tw32(TG3_EAV_WATCHDOG0_LSB, (nsec & 0xffffffff));
+                        tw32(TG3_EAV_WATCHDOG0_MSB,
+                             TG3_EAV_WATCHDOG0_EN |
+                             ((nsec >> 32) & TG3_EAV_WATCHDOG_MSB_MASK));
+
+                        tw32(TG3_EAV_REF_CLCK_CTL,
+                             clock_ctl | TG3_EAV_CTL_TSYNC_WDOG0);
+                } else {
+                        tw32(TG3_EAV_WATCHDOG0_MSB, 0);
+                        tw32(TG3_EAV_REF_CLCK_CTL, clock_ctl);
+                }
+
+err_out:
+                tg3_full_unlock(tp);
+                return rval;
+
+        default:
+                break;
+        }
+
         return -EOPNOTSUPP;
 }
 
@@ -6221,7 +6276,7 @@ static const struct ptp_clock_info tg3_ptp_caps = {
         .max_adj        = 250000000,
         .n_alarm        = 0,
         .n_ext_ts       = 0,
-        .n_per_out      = 0,
+        .n_per_out      = 1,
         .pps            = 0,
         .adjfreq        = tg3_ptp_adjfreq,
         .adjtime        = tg3_ptp_adjtime,