stmmac: add the support for PTP hw clock driver

This patch implements PHC (ptp hardware clock) driver for stmmac
driver to support 1588 PTP.

V2: added support for FINE method, reduced loop delay and review spinlock.

Signed-off-by: Rayagond Kokatanur <rayagond@vayavyalabs.com>
Hacked-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 215 insertions, 0 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
new file mode 100644
index 000000000000..93d4beff92c7
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
@@ -0,0 +1,215 @@
+/*******************************************************************************
+  PTP 1588 clock using the STMMAC.
+
+  Copyright (C) 2013  Vayavya Labs Pvt Ltd
+
+  This program is free software; you can redistribute it and/or modify it
+  under the terms and conditions of the GNU General Public License,
+  version 2, as published by the Free Software Foundation.
+
+  This program is distributed in the hope it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+  more details.
+
+  You should have received a copy of the GNU General Public License along with
+  this program; if not, write to the Free Software Foundation, Inc.,
+  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+
+  The full GNU General Public License is included in this distribution in
+  the file called "COPYING".
+
+  Author: Rayagond Kokatanur <rayagond@vayavyalabs.com>
+*******************************************************************************/
+#include "stmmac.h"
+#include "stmmac_ptp.h"
+
+/**
+ * stmmac_adjust_freq
+ *
+ * @ptp: pointer to ptp_clock_info structure
+ * @ppb: desired period change in parts ber billion
+ *
+ * Description: this function will adjust the frequency of hardware clock.
+ */
+static int stmmac_adjust_freq(struct ptp_clock_info *ptp, s32 ppb)
+{
+	struct stmmac_priv *priv =
+	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
+	unsigned long flags;
+	u32 diff, addend;
+	int neg_adj = 0;
+	u64 adj;
+
+	if (ppb < 0) {
+		neg_adj = 1;
+		ppb = -ppb;
+	}
+
+	addend = priv->default_addend;
+	adj = addend;
+	adj *= ppb;
+	diff = div_u64(adj, 1000000000ULL);
+	addend = neg_adj ? (addend - diff) : (addend + diff);
+
+	spin_lock_irqsave(&priv->ptp_lock, flags);
+
+	priv->hw->ptp->config_addend(priv->ioaddr, addend);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+/**
+ * stmmac_adjust_time
+ *
+ * @ptp: pointer to ptp_clock_info structure
+ * @delta: desired change in nanoseconds
+ *
+ * Description: this function will shift/adjust the hardware clock time.
+ */
+static int stmmac_adjust_time(struct ptp_clock_info *ptp, s64 delta)
+{
+	struct stmmac_priv *priv =
+	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
+	unsigned long flags;
+	u32 sec, nsec;
+	u32 quotient, reminder;
+	int neg_adj = 0;
+
+	if (delta < 0) {
+		neg_adj = 1;
+		delta = -delta;
+	}
+
+	quotient = div_u64_rem(delta, 1000000000ULL, &reminder);
+	sec = quotient;
+	nsec = reminder;
+
+	spin_lock_irqsave(&priv->ptp_lock, flags);
+
+	priv->hw->ptp->adjust_systime(priv->ioaddr, sec, nsec, neg_adj);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+/**
+ * stmmac_get_time
+ *
+ * @ptp: pointer to ptp_clock_info structure
+ * @ts: pointer to hold time/result
+ *
+ * Description: this function will read the current time from the
+ * hardware clock and store it in @ts.
+ */
+static int stmmac_get_time(struct ptp_clock_info *ptp, struct timespec *ts)
+{
+	struct stmmac_priv *priv =
+	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
+	unsigned long flags;
+	u64 ns;
+	u32 reminder;
+
+	spin_lock_irqsave(&priv->ptp_lock, flags);
+
+	ns = priv->hw->ptp->get_systime(priv->ioaddr);
+
+	spin_unlock_irqrestore(&priv->ptp_lock, flags);
+
+	ts->tv_sec = div_u64_rem(ns, 1000000000ULL, &reminder);
+	ts->tv_nsec = reminder;
+
+	return 0;
+}
+
+/**
+ * stmmac_set_time
+ *
+ * @ptp: pointer to ptp_clock_info structure
+ * @ts: time value to set
+ *
+ * Description: this function will set the current time on the
+ * hardware clock.
+ */
+static int stmmac_set_time(struct ptp_clock_info *ptp,
+			   const struct timespec *ts)
+{
+	struct stmmac_priv *priv =
+	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->ptp_lock, flags);
+
+	priv->hw->ptp->init_systime(priv->ioaddr, ts->tv_sec, ts->tv_nsec);
+
+	spin_unlock_irqrestore(&priv->ptp_lock, flags);
+
+	return 0;
+}
+
+static int stmmac_enable(struct ptp_clock_info *ptp,
+			 struct ptp_clock_request *rq, int on)
+{
+	return -EOPNOTSUPP;
+}
+
+/* structure describing a PTP hardware clock */
+static struct ptp_clock_info stmmac_ptp_clock_ops = {
+	.owner = THIS_MODULE,
+	.name = "stmmac_ptp_clock",
+	.max_adj = 62500000,
+	.n_alarm = 0,
+	.n_ext_ts = 0,
+	.n_per_out = 0,
+	.pps = 0,
+	.adjfreq = stmmac_adjust_freq,
+	.adjtime = stmmac_adjust_time,
+	.gettime = stmmac_get_time,
+	.settime = stmmac_set_time,
+	.enable = stmmac_enable,
+};
+
+/**
+ * stmmac_ptp_register
+ *
+ * @ndev: net device pointer
+ *
+ * Description: this function will register the ptp clock driver
+ * to kernel. It also does some house keeping work.
+ */
+int stmmac_ptp_register(struct stmmac_priv *priv)
+{
+	spin_lock_init(&priv->ptp_lock);
+	priv->ptp_clock_ops = stmmac_ptp_clock_ops;
+
+	priv->ptp_clock = ptp_clock_register(&priv->ptp_clock_ops,
+					     priv->device);
+	if (IS_ERR(priv->ptp_clock)) {
+		priv->ptp_clock = NULL;
+		pr_err("ptp_clock_register() failed on %s\n", priv->dev->name);
+	} else
+		pr_debug("Added PTP HW clock successfully on %s\n",
+			 priv->dev->name);
+
+	return 0;
+}
+
+/**
+ * stmmac_ptp_unregister
+ *
+ * @ndev: net device pointer
+ *
+ * Description: this function will remove/unregister the ptp clock driver
+ * from the kernel.
+ */
+void stmmac_ptp_unregister(struct stmmac_priv *priv)
+{
+	if (priv->ptp_clock) {
+		ptp_clock_unregister(priv->ptp_clock);
+		pr_debug("Removed PTP HW clock successfully on %s\n",
+			 priv->dev->name);
+	}
+}