FEC: Add time stamping code and a PTP hardware clock
This patch adds a driver for the FEC(MX6) that offers time
stamping and a PTP haderware clock. Because FEC\ENET(MX6)
hardware frequency adjustment is complex, we have implemented
this in software by changing the multiplication factor of the
timecounter.
Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c
new file mode 100644
index 0000000..5352140
--- /dev/null
+++ b/drivers/net/ethernet/freescale/fec_ptp.c
@@ -0,0 +1,385 @@
+/*
+ * Fast Ethernet Controller (ENET) PTP driver for MX6x.
+ *
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/ptrace.h>
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/phy.h>
+#include <linux/fec.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/of_net.h>
+
+#include "fec.h"
+
+/* FEC 1588 register bits */
+#define FEC_T_CTRL_SLAVE 0x00002000
+#define FEC_T_CTRL_CAPTURE 0x00000800
+#define FEC_T_CTRL_RESTART 0x00000200
+#define FEC_T_CTRL_PERIOD_RST 0x00000030
+#define FEC_T_CTRL_PERIOD_EN 0x00000010
+#define FEC_T_CTRL_ENABLE 0x00000001
+
+#define FEC_T_INC_MASK 0x0000007f
+#define FEC_T_INC_OFFSET 0
+#define FEC_T_INC_CORR_MASK 0x00007f00
+#define FEC_T_INC_CORR_OFFSET 8
+
+#define FEC_ATIME_CTRL 0x400
+#define FEC_ATIME 0x404
+#define FEC_ATIME_EVT_OFFSET 0x408
+#define FEC_ATIME_EVT_PERIOD 0x40c
+#define FEC_ATIME_CORR 0x410
+#define FEC_ATIME_INC 0x414
+#define FEC_TS_TIMESTAMP 0x418
+
+#define FEC_CC_MULT (1 << 31)
+/**
+ * fec_ptp_read - read raw cycle counter (to be used by time counter)
+ * @cc: the cyclecounter structure
+ *
+ * this function reads the cyclecounter registers and is called by the
+ * cyclecounter structure used to construct a ns counter from the
+ * arbitrary fixed point registers
+ */
+static cycle_t fec_ptp_read(const struct cyclecounter *cc)
+{
+ struct fec_enet_private *fep =
+ container_of(cc, struct fec_enet_private, cc);
+ u32 tempval;
+
+ tempval = readl(fep->hwp + FEC_ATIME_CTRL);
+ tempval |= FEC_T_CTRL_CAPTURE;
+ writel(tempval, fep->hwp + FEC_ATIME_CTRL);
+
+ return readl(fep->hwp + FEC_ATIME);
+}
+
+/**
+ * fec_ptp_start_cyclecounter - create the cycle counter from hw
+ * @ndev: network device
+ *
+ * this function initializes the timecounter and cyclecounter
+ * structures for use in generated a ns counter from the arbitrary
+ * fixed point cycles registers in the hardware.
+ */
+void fec_ptp_start_cyclecounter(struct net_device *ndev)
+{
+ struct fec_enet_private *fep = netdev_priv(ndev);
+ unsigned long flags;
+ int inc;
+
+ inc = 1000000000 / clk_get_rate(fep->clk_ptp);
+
+ /* grab the ptp lock */
+ spin_lock_irqsave(&fep->tmreg_lock, flags);
+
+ /* 1ns counter */
+ writel(inc << FEC_T_INC_OFFSET, fep->hwp + FEC_ATIME_INC);
+
+ /* use free running count */
+ writel(0, fep->hwp + FEC_ATIME_EVT_PERIOD);
+
+ writel(FEC_T_CTRL_ENABLE, fep->hwp + FEC_ATIME_CTRL);
+
+ memset(&fep->cc, 0, sizeof(fep->cc));
+ fep->cc.read = fec_ptp_read;
+ fep->cc.mask = CLOCKSOURCE_MASK(32);
+ fep->cc.shift = 31;
+ fep->cc.mult = FEC_CC_MULT;
+
+ /* reset the ns time counter */
+ timecounter_init(&fep->tc, &fep->cc, ktime_to_ns(ktime_get_real()));
+
+ spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+}
+
+/**
+ * fec_ptp_adjfreq - adjust ptp cycle frequency
+ * @ptp: the ptp clock structure
+ * @ppb: parts per billion adjustment from base
+ *
+ * Adjust the frequency of the ptp cycle counter by the
+ * indicated ppb from the base frequency.
+ *
+ * Because ENET hardware frequency adjust is complex,
+ * using software method to do that.
+ */
+static int fec_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
+{
+ u64 diff;
+ unsigned long flags;
+ int neg_adj = 0;
+
+ struct fec_enet_private *fep =
+ container_of(ptp, struct fec_enet_private, ptp_caps);
+
+ if (ppb < 0) {
+ ppb = -ppb;
+ neg_adj = 1;
+ }
+
+ 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 = FEC_CC_MULT;
+ diff = fep->cc.mult;
+ diff *= ppb;
+ diff = div_u64(diff, 1000000000ULL);
+
+ if (neg_adj)
+ fep->cc.mult -= diff;
+ else
+ fep->cc.mult += diff;
+
+ spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+
+ return 0;
+}
+
+/**
+ * fec_ptp_adjtime
+ * @ptp: the ptp clock structure
+ * @delta: offset to adjust the cycle counter by
+ *
+ * adjust the timer by resetting the timecounter structure.
+ */
+static int fec_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+ struct fec_enet_private *fep =
+ container_of(ptp, struct fec_enet_private, ptp_caps);
+ unsigned long flags;
+ u64 now;
+
+ spin_lock_irqsave(&fep->tmreg_lock, flags);
+
+ now = timecounter_read(&fep->tc);
+ now += delta;
+
+ /* reset the timecounter */
+ timecounter_init(&fep->tc, &fep->cc, now);
+
+ spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+
+ return 0;
+}
+
+/**
+ * fec_ptp_gettime
+ * @ptp: the ptp clock structure
+ * @ts: timespec structure to hold the current time value
+ *
+ * read the timecounter and return the correct value on ns,
+ * after converting it into a struct timespec.
+ */
+static int fec_ptp_gettime(struct ptp_clock_info *ptp, struct timespec *ts)
+{
+ struct fec_enet_private *adapter =
+ container_of(ptp, struct fec_enet_private, ptp_caps);
+ u64 ns;
+ u32 remainder;
+ unsigned long flags;
+
+ spin_lock_irqsave(&adapter->tmreg_lock, flags);
+ ns = timecounter_read(&adapter->tc);
+ spin_unlock_irqrestore(&adapter->tmreg_lock, flags);
+
+ ts->tv_sec = div_u64_rem(ns, 1000000000ULL, &remainder);
+ ts->tv_nsec = remainder;
+
+ return 0;
+}
+
+/**
+ * fec_ptp_settime
+ * @ptp: the ptp clock structure
+ * @ts: the timespec containing the new time for the cycle counter
+ *
+ * reset the timecounter to use a new base value instead of the kernel
+ * wall timer value.
+ */
+static int fec_ptp_settime(struct ptp_clock_info *ptp,
+ const struct timespec *ts)
+{
+ struct fec_enet_private *fep =
+ container_of(ptp, struct fec_enet_private, ptp_caps);
+
+ u64 ns;
+ unsigned long flags;
+
+ ns = ts->tv_sec * 1000000000ULL;
+ ns += ts->tv_nsec;
+
+ spin_lock_irqsave(&fep->tmreg_lock, flags);
+ timecounter_init(&fep->tc, &fep->cc, ns);
+ spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ return 0;
+}
+
+/**
+ * fec_ptp_enable
+ * @ptp: the ptp clock structure
+ * @rq: the requested feature to change
+ * @on: whether to enable or disable the feature
+ *
+ */
+static int fec_ptp_enable(struct ptp_clock_info *ptp,
+ struct ptp_clock_request *rq, int on)
+{
+ return -EOPNOTSUPP;
+}
+
+/**
+ * fec_ptp_hwtstamp_ioctl - control hardware time stamping
+ * @ndev: pointer to net_device
+ * @ifreq: ioctl data
+ * @cmd: particular ioctl requested
+ */
+int fec_ptp_ioctl(struct net_device *ndev, struct ifreq *ifr, int cmd)
+{
+ struct fec_enet_private *fep = netdev_priv(ndev);
+
+ struct hwtstamp_config config;
+
+ if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
+ return -EFAULT;
+
+ /* reserved for future extensions */
+ if (config.flags)
+ return -EINVAL;
+
+ switch (config.tx_type) {
+ case HWTSTAMP_TX_OFF:
+ fep->hwts_tx_en = 0;
+ break;
+ case HWTSTAMP_TX_ON:
+ fep->hwts_tx_en = 1;
+ break;
+ default:
+ return -ERANGE;
+ }
+
+ switch (config.rx_filter) {
+ case HWTSTAMP_FILTER_NONE:
+ if (fep->hwts_rx_en)
+ fep->hwts_rx_en = 0;
+ config.rx_filter = HWTSTAMP_FILTER_NONE;
+ break;
+
+ default:
+ /*
+ * register RXMTRL must be set in order to do V1 packets,
+ * therefore it is not possible to time stamp both V1 Sync and
+ * Delay_Req messages and hardware does not support
+ * timestamping all packets => return error
+ */
+ fep->hwts_rx_en = 1;
+ config.rx_filter = HWTSTAMP_FILTER_ALL;
+ break;
+ }
+
+ return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ?
+ -EFAULT : 0;
+}
+
+/**
+ * fec_time_keep - call timecounter_read every second to avoid timer overrun
+ * because ENET just support 32bit counter, will timeout in 4s
+ */
+static void fec_time_keep(unsigned long _data)
+{
+ struct fec_enet_private *fep = (struct fec_enet_private *)_data;
+ u64 ns;
+ unsigned long flags;
+
+ spin_lock_irqsave(&fep->tmreg_lock, flags);
+ ns = timecounter_read(&fep->tc);
+ spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+
+ mod_timer(&fep->time_keep, jiffies + HZ);
+}
+
+/**
+ * fec_ptp_init
+ * @ndev: The FEC network adapter
+ *
+ * This function performs the required steps for enabling ptp
+ * support. If ptp support has already been loaded it simply calls the
+ * cyclecounter init routine and exits.
+ */
+
+void fec_ptp_init(struct net_device *ndev, struct platform_device *pdev)
+{
+ struct fec_enet_private *fep = netdev_priv(ndev);
+
+ fep->ptp_caps.owner = THIS_MODULE;
+ snprintf(fep->ptp_caps.name, 16, "fec ptp");
+
+ fep->ptp_caps.max_adj = 250000000;
+ fep->ptp_caps.n_alarm = 0;
+ fep->ptp_caps.n_ext_ts = 0;
+ fep->ptp_caps.n_per_out = 0;
+ fep->ptp_caps.pps = 0;
+ fep->ptp_caps.adjfreq = fec_ptp_adjfreq;
+ fep->ptp_caps.adjtime = fec_ptp_adjtime;
+ fep->ptp_caps.gettime = fec_ptp_gettime;
+ fep->ptp_caps.settime = fec_ptp_settime;
+ fep->ptp_caps.enable = fec_ptp_enable;
+
+ spin_lock_init(&fep->tmreg_lock);
+
+ fec_ptp_start_cyclecounter(ndev);
+
+ init_timer(&fep->time_keep);
+ fep->time_keep.data = (unsigned long)fep;
+ fep->time_keep.function = fec_time_keep;
+ fep->time_keep.expires = jiffies + HZ;
+ add_timer(&fep->time_keep);
+
+ fep->ptp_clock = ptp_clock_register(&fep->ptp_caps, &pdev->dev);
+ if (IS_ERR(fep->ptp_clock)) {
+ fep->ptp_clock = NULL;
+ pr_err("ptp_clock_register failed\n");
+ } else {
+ pr_info("registered PHC device on %s\n", ndev->name);
+ }
+}