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From:   Aleksey Makarov <aleksey.makarov@cavium.com>
To:     netdev@vger.kernel.org
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        "Goutham, Sunil" <Sunil.Goutham@cavium.com>,
        Radoslaw Biernacki <rad@semihalf.com>,
        Aleksey Makarov <aleksey.makarov@cavium.com>,
        Robert Richter <rric@kernel.org>
Subject: [PATCH net-next 1/2] net: add support for Cavium PTP coprocessor
Date:   Tue,  7 Nov 2017 22:07:01 +0300
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From: Radoslaw Biernacki <rad@semihalf.com>

This patch adds support for the Precision Time Protocol
Clocks and Timestamping hardware found on Cavium ThunderX
processors.

Signed-off-by: Radoslaw Biernacki <rad@semihalf.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@cavium.com>
---
 drivers/net/ethernet/cavium/Kconfig             |  13 +
 drivers/net/ethernet/cavium/Makefile            |   1 +
 drivers/net/ethernet/cavium/common/Makefile     |   1 +
 drivers/net/ethernet/cavium/common/cavium_ptp.c | 353 ++++++++++++++++++++++++
 drivers/net/ethernet/cavium/common/cavium_ptp.h |  78 ++++++
 5 files changed, 446 insertions(+)
 create mode 100644 drivers/net/ethernet/cavium/common/Makefile
 create mode 100644 drivers/net/ethernet/cavium/common/cavium_ptp.c
 create mode 100644 drivers/net/ethernet/cavium/common/cavium_ptp.h

diff --git a/drivers/net/ethernet/cavium/Kconfig b/drivers/net/ethernet/cavium/Kconfig
index dcbce6cac63e..634c79a8c812 100644
--- a/drivers/net/ethernet/cavium/Kconfig
+++ b/drivers/net/ethernet/cavium/Kconfig
@@ -50,6 +50,19 @@ config	THUNDER_NIC_RGX
 	  This driver supports configuring XCV block of RGX interface
 	  present on CN81XX chip.
 
+config CAVIUM_PTP
+	tristate "Cavium PTP coprocessor as PTP clock"
+	depends on 64BIT
+	depends on PTP_1588_CLOCK
+	select CAVIUM_RST
+	default y
+	---help---
+	  This driver adds support for the Precision Time Protocol Clocks and
+	  Timestamping coprocessor (PTP) found on Cavium processors.
+	  PTP provides timestamping mechanism that is suitable for use in IEEE 1588
+	  Precision Time Protocol or other purposes.  Timestamps can be used in
+	  BGX, TNS, GTI, and NIC blocks.
+
 config LIQUIDIO
 	tristate "Cavium LiquidIO support"
 	depends on 64BIT
diff --git a/drivers/net/ethernet/cavium/Makefile b/drivers/net/ethernet/cavium/Makefile
index 872da9f7c31a..946bba84e81d 100644
--- a/drivers/net/ethernet/cavium/Makefile
+++ b/drivers/net/ethernet/cavium/Makefile
@@ -1,6 +1,7 @@
 #
 # Makefile for the Cavium ethernet device drivers.
 #
+obj-$(CONFIG_NET_VENDOR_CAVIUM) += common/
 obj-$(CONFIG_NET_VENDOR_CAVIUM) += thunder/
 obj-$(CONFIG_NET_VENDOR_CAVIUM) += liquidio/
 obj-$(CONFIG_NET_VENDOR_CAVIUM) += octeon/
diff --git a/drivers/net/ethernet/cavium/common/Makefile b/drivers/net/ethernet/cavium/common/Makefile
new file mode 100644
index 000000000000..dd8561b8060b
--- /dev/null
+++ b/drivers/net/ethernet/cavium/common/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_CAVIUM_PTP) += cavium_ptp.o
diff --git a/drivers/net/ethernet/cavium/common/cavium_ptp.c b/drivers/net/ethernet/cavium/common/cavium_ptp.c
new file mode 100644
index 000000000000..6c6f162bedbf
--- /dev/null
+++ b/drivers/net/ethernet/cavium/common/cavium_ptp.c
@@ -0,0 +1,353 @@
+/*
+ * cavium_ptp.c - PTP 1588 clock on Cavium hardware
+ *
+ * Copyright (c) 2003-2015, 2017 Cavium, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License.
+ *
+ * This file may also be available under a different license from Cavium.
+ * Contact Cavium, Inc. for more information
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/timecounter.h>
+#include <linux/pci.h>
+
+#include "cavium_ptp.h"
+
+#define DRV_NAME	"Cavium PTP Driver"
+
+#define PCI_DEVICE_ID_CAVIUM_PTP	0xA00C
+#define PCI_DEVICE_ID_CAVIUM_RST	0xA00E
+
+#define PCI_PTP_BAR_NO	0
+#define PCI_RST_BAR_NO	0
+
+#define PTP_CLOCK_CFG		0xF00ULL
+#define  PTP_CLOCK_CFG_PTP_EN	BIT(0)
+#define PTP_CLOCK_LO		0xF08ULL
+#define PTP_CLOCK_HI		0xF10ULL
+#define PTP_CLOCK_COMP		0xF18ULL
+
+#define RST_BOOT	0x1600ULL
+#define CLOCK_BASE_RATE	50000000ULL
+
+static u64 ptp_cavium_clock_get(void)
+{
+	struct pci_dev *pdev;
+	void __iomem *base;
+	u64 ret = CLOCK_BASE_RATE * 16;
+
+	pdev = pci_get_device(PCI_VENDOR_ID_CAVIUM,
+			      PCI_DEVICE_ID_CAVIUM_RST, NULL);
+	if (!pdev)
+		goto error;
+
+	base = pci_ioremap_bar(pdev, PCI_RST_BAR_NO);
+	if (!base)
+		goto error_put_pdev;
+
+	ret = CLOCK_BASE_RATE * ((readq_relaxed(base + RST_BOOT) >> 33) & 0x3f);
+
+	iounmap(base);
+
+error_put_pdev:
+	pci_dev_put(pdev);
+
+error:
+	return ret;
+}
+
+/* The Cavium PTP can *only* be found in SoCs containing the ThunderX
+ * ARM64 CPU implementation.  All accesses to the device registers on this
+ * platform are implicitly strongly ordered with respect to memory
+ * accesses. So writeq_relaxed() and readq_relaxed() are safe to use with
+ * no memory barriers in this driver.  The readq()/writeq() functions add
+ * explicit ordering operation which in this case are redundant, and only
+ * add overhead.
+ */
+
+static u64 cavium_ptp_reg_read(struct cavium_ptp *clock, u64 offset)
+{
+	return readq_relaxed(clock->reg_base + offset);
+}
+
+static void cavium_ptp_reg_write(struct cavium_ptp *clock, u64 offset, u64 val)
+{
+	writeq_relaxed(val, clock->reg_base + offset);
+}
+
+struct cavium_ptp *cavium_ptp_get(void)
+{
+	struct cavium_ptp *ptp;
+	struct pci_dev *pdev;
+
+	pdev = pci_get_device(PCI_VENDOR_ID_CAVIUM,
+			      PCI_DEVICE_ID_CAVIUM_PTP, NULL);
+	if (!pdev)
+		return ERR_PTR(-ENODEV);
+
+	ptp = pci_get_drvdata(pdev);
+	if (!ptp) {
+		pci_dev_put(pdev);
+		ptp = ERR_PTR(-EPROBE_DEFER);
+	}
+
+	return ptp;
+}
+EXPORT_SYMBOL(cavium_ptp_get);
+
+void cavium_ptp_put(struct cavium_ptp *ptp)
+{
+	pci_dev_put(ptp->pdev);
+}
+EXPORT_SYMBOL(cavium_ptp_put);
+
+/**
+ * cavium_ptp_adjfreq() - Adjust ptp frequency
+ * @ptp: PTP clock info
+ * @ppb: how much to adjust by, in parts-per-billion
+ */
+static int cavium_ptp_adjfreq(struct ptp_clock_info *ptp_info, s32 ppb)
+{
+	struct cavium_ptp *clock =
+		container_of(ptp_info, struct cavium_ptp, ptp_info);
+	unsigned long flags;
+	u64 comp;
+	u64 adj;
+	bool neg_adj = false;
+
+	if (ppb < 0) {
+		neg_adj = true;
+		ppb = -ppb;
+	}
+
+	/* The hardware adds the clock compensation value to the PTP clock
+	 * on every coprocessor clock cycle. Typical convention is that it
+	 * represent number of nanosecond betwen each cycle. In this
+	 * convention compensation value is in 64 bit fixed-point
+	 * representation where upper 32 bits are number of nanoseconds
+	 * and lower is fractions of nanosecond.
+	 * The ppb represent the ratio in "parts per bilion" by which the
+	 * compensation value should be corrected.
+	 * To calculate new compenstation value we use 64bit fixed point
+	 * arithmetic on following formula comp = tbase + tbase * ppb / 1G
+	 * where tbase is the basic compensation value calculated initialy
+	 * in cavium_ptp_init() -> tbase = 1/Hz. Then we use endian
+	 * independent structure definition to write data to PTP register.
+	 */
+	comp = ((u64)1000000000ull << 32) / clock->clock_rate;
+	adj = comp * ppb;
+	adj = div_u64(adj, 1000000000ull);
+	comp = neg_adj ? comp - adj : comp + adj;
+
+	spin_lock_irqsave(&clock->spin_lock, flags);
+	cavium_ptp_reg_write(clock, PTP_CLOCK_COMP, comp);
+	spin_unlock_irqrestore(&clock->spin_lock, flags);
+
+	return 0;
+}
+
+/**
+ * cavium_ptp_adjtime() - Adjust ptp time
+ * @ptp:   PTP clock info
+ * @delta: how much to adjust by, in nanosecs
+ */
+static int cavium_ptp_adjtime(struct ptp_clock_info *ptp_info, s64 delta)
+{
+	struct cavium_ptp *clock =
+		container_of(ptp_info, struct cavium_ptp, ptp_info);
+	unsigned long flags;
+
+	spin_lock_irqsave(&clock->spin_lock, flags);
+	timecounter_adjtime(&clock->time_counter, delta);
+	spin_unlock_irqrestore(&clock->spin_lock, flags);
+
+	/* Sync, for network driver to get latest value */
+	smp_mb();
+
+	return 0;
+}
+
+/**
+ * cavium_ptp_gettime() - Get hardware clock time with adjustment
+ * @ptp: PTP clock info
+ * @ts:  timespec
+ */
+static int cavium_ptp_gettime(struct ptp_clock_info *ptp_info,
+			      struct timespec64 *ts)
+{
+	struct cavium_ptp *clock =
+		container_of(ptp_info, struct cavium_ptp, ptp_info);
+	unsigned long flags;
+	u64 nsec;
+
+	spin_lock_irqsave(&clock->spin_lock, flags);
+	nsec = timecounter_read(&clock->time_counter);
+	spin_unlock_irqrestore(&clock->spin_lock, flags);
+
+	*ts = ns_to_timespec64(nsec);
+
+	return 0;
+}
+
+/**
+ * cavium_ptp_settime() - Set hardware clock time. Reset adjustment
+ * @ptp: PTP clock info
+ * @ts:  timespec
+ */
+static int cavium_ptp_settime(struct ptp_clock_info *ptp_info,
+			      const struct timespec64 *ts)
+{
+	struct cavium_ptp *clock =
+		container_of(ptp_info, struct cavium_ptp, ptp_info);
+	unsigned long flags;
+	u64 nsec;
+
+	nsec = timespec64_to_ns(ts);
+
+	spin_lock_irqsave(&clock->spin_lock, flags);
+	timecounter_init(&clock->time_counter, &clock->cycle_counter, nsec);
+	spin_unlock_irqrestore(&clock->spin_lock, flags);
+
+	return 0;
+}
+
+/**
+ * cavium_ptp_enable() - Check if PTP is enabled
+ * @ptp: PTP clock info
+ * @rq:  request
+ * @on:  is it on
+ */
+static int cavium_ptp_enable(struct ptp_clock_info *ptp_info,
+			     struct ptp_clock_request *rq, int on)
+{
+	return -EOPNOTSUPP;
+}
+
+static u64 cavium_ptp_cc_read(const struct cyclecounter *cc)
+{
+	struct cavium_ptp *clock =
+		container_of(cc, struct cavium_ptp, cycle_counter);
+
+	return cavium_ptp_reg_read(clock, PTP_CLOCK_HI);
+}
+
+static int cavium_ptp_probe(struct pci_dev *pdev,
+			    const struct pci_device_id *ent)
+{
+	struct device *dev = &pdev->dev;
+	struct cavium_ptp *clock;
+	struct cyclecounter *cc;
+	u64 clock_cfg;
+	u64 clock_comp;
+	int err;
+
+	clock = devm_kzalloc(dev, sizeof(*clock), GFP_KERNEL);
+	if (!clock)
+		return -ENOMEM;
+
+	clock->pdev = pdev;
+
+	err = pcim_enable_device(pdev);
+	if (err)
+		return err;
+
+	err = pcim_iomap_regions(pdev, 1 << PCI_PTP_BAR_NO, pci_name(pdev));
+	if (err)
+		return err;
+
+	clock->reg_base = pcim_iomap_table(pdev)[PCI_PTP_BAR_NO];
+
+	spin_lock_init(&clock->spin_lock);
+
+	cc = &clock->cycle_counter;
+	cc->read = cavium_ptp_cc_read;
+	cc->mask = CYCLECOUNTER_MASK(64);
+	cc->mult = 1;
+	cc->shift = 0;
+
+	timecounter_init(&clock->time_counter, &clock->cycle_counter,
+			 ktime_to_ns(ktime_get_real()));
+
+	clock->clock_rate = ptp_cavium_clock_get();
+
+	clock->ptp_info = (struct ptp_clock_info) {
+		.owner		= THIS_MODULE,
+		.name		= "ThunderX PTP",
+		.max_adj	= 1000000000ull,
+		.n_ext_ts	= 0,
+		.n_pins		= 0,
+		.pps		= 0,
+		.adjfreq	= cavium_ptp_adjfreq,
+		.adjtime	= cavium_ptp_adjtime,
+		.gettime64	= cavium_ptp_gettime,
+		.settime64	= cavium_ptp_settime,
+		.enable		= cavium_ptp_enable,
+	};
+
+	clock_cfg = cavium_ptp_reg_read(clock, PTP_CLOCK_CFG);
+	clock_cfg |= PTP_CLOCK_CFG_PTP_EN;
+	cavium_ptp_reg_write(clock, PTP_CLOCK_CFG, clock_cfg);
+
+	clock_comp = ((u64)1000000000ull << 32) / clock->clock_rate;
+	cavium_ptp_reg_write(clock, PTP_CLOCK_COMP, clock_comp);
+
+	clock->ptp_clock = ptp_clock_register(&clock->ptp_info, dev);
+	if (IS_ERR(clock->ptp_clock)) {
+		clock_cfg = cavium_ptp_reg_read(clock, PTP_CLOCK_CFG);
+		clock_cfg &= ~PTP_CLOCK_CFG_PTP_EN;
+		cavium_ptp_reg_write(clock, PTP_CLOCK_CFG, clock_cfg);
+		return PTR_ERR(clock->ptp_clock);
+	}
+
+	pci_set_drvdata(pdev, clock);
+	return 0;
+}
+
+static void cavium_ptp_remove(struct pci_dev *pdev)
+{
+	struct cavium_ptp *clock = pci_get_drvdata(pdev);
+	u64 clock_cfg;
+
+	pci_set_drvdata(pdev, NULL);
+
+	ptp_clock_unregister(clock->ptp_clock);
+
+	clock_cfg = cavium_ptp_reg_read(clock, PTP_CLOCK_CFG);
+	clock_cfg &= ~PTP_CLOCK_CFG_PTP_EN;
+	cavium_ptp_reg_write(clock, PTP_CLOCK_CFG, clock_cfg);
+}
+
+static const struct pci_device_id cavium_ptp_id_table[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, PCI_DEVICE_ID_CAVIUM_PTP) },
+	{ 0, }
+};
+
+static struct pci_driver cavium_ptp_driver = {
+	.name = DRV_NAME,
+	.id_table = cavium_ptp_id_table,
+	.probe = cavium_ptp_probe,
+	.remove = cavium_ptp_remove,
+};
+
+static int __init cavium_ptp_init_module(void)
+{
+	return pci_register_driver(&cavium_ptp_driver);
+}
+
+static void __exit cavium_ptp_cleanup_module(void)
+{
+	pci_unregister_driver(&cavium_ptp_driver);
+}
+
+module_init(cavium_ptp_init_module);
+module_exit(cavium_ptp_cleanup_module);
+
+MODULE_DESCRIPTION(DRV_NAME);
+MODULE_AUTHOR("Cavium Networks <support@cavium.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DEVICE_TABLE(pci, cavium_ptp_id_table);
diff --git a/drivers/net/ethernet/cavium/common/cavium_ptp.h b/drivers/net/ethernet/cavium/common/cavium_ptp.h
new file mode 100644
index 000000000000..7a9dcb027a93
--- /dev/null
+++ b/drivers/net/ethernet/cavium/common/cavium_ptp.h
@@ -0,0 +1,78 @@
+/*
+ * cavium_ptp.h - PTP 1588 clock on Cavium hardware
+ *
+ * Copyright (c) 2003-2015, 2017 Cavium, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License.
+ *
+ * This file may also be available under a different license from Cavium.
+ * Contact Cavium, Inc. for more information
+ */
+
+#ifndef CAVIUM_PTP_H
+#define CAVIUM_PTP_H
+
+#include <linux/ptp_clock_kernel.h>
+#include <linux/timecounter.h>
+
+struct cavium_ptp {
+	struct pci_dev *pdev;
+
+	/* Serialize access to cycle_counter, time_counter and hw_registers */
+	spinlock_t spin_lock;
+	struct cyclecounter cycle_counter;
+	struct timecounter time_counter;
+	void __iomem *reg_base;
+
+	u32 clock_rate;
+
+	struct ptp_clock_info ptp_info;
+	struct ptp_clock *ptp_clock;
+};
+
+#ifdef CONFIG_CAVIUM_PTP
+
+struct cavium_ptp *cavium_ptp_get(void);
+void cavium_ptp_put(struct cavium_ptp *ptp);
+
+static inline u64 cavium_ptp_tstamp2time(struct cavium_ptp *ptp, u64 tstamp)
+{
+	unsigned long flags;
+	u64 ret;
+
+	spin_lock_irqsave(&ptp->spin_lock, flags);
+	ret = timecounter_cyc2time(&ptp->time_counter, tstamp);
+	spin_unlock_irqrestore(&ptp->spin_lock, flags);
+
+	return ret;
+}
+
+static inline int cavium_ptp_clock_index(struct cavium_ptp *clock)
+{
+	return ptp_clock_index(clock->ptp_clock);
+}
+
+#else
+
+static inline struct cavium_ptp *cavium_ptp_get(void)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline void cavium_ptp_put(struct cavium_ptp *ptp) {}
+
+static inline u64 cavium_ptp_tstamp2time(struct cavium_ptp *ptp, u64 tstamp)
+{
+	return 0;
+}
+
+static inline int cavium_ptp_clock_index(struct cavium_ptp *clock)
+{
+	return -1;
+}
+
+#endif
+
+#endif
-- 
2.15.0


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