Merge branch 'Broadcom-DTE-based-PTP-clock'

Arun Parameswaran says:

====================
Add support for Broadcom DTE based PTP clock

This patchset adds support for the DTE based PTP clock for Broadcom SoCs.

The DTE nco based PTP clock can be used in both wired and wireless networks
for precision time-stmaping purposes.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 383 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/ptp/brcm,ptp-dte.txt b/Documentation/devicetree/bindings/ptp/brcm,ptp-dte.txt
new file mode 100644
index 000000000000..07590bcdad15
--- /dev/null
+++ b/Documentation/devicetree/bindings/ptp/brcm,ptp-dte.txt
@@ -0,0 +1,13 @@
+* Broadcom Digital Timing Engine(DTE) based PTP clock driver
+
+Required properties:
+- compatible: should be "brcm,ptp-dte"
+- reg: address and length of the DTE block's NCO registers
+
+Example:
+
+ptp_dte: ptp_dte@180af650 {
+	compatible = "brcm,ptp-dte";
+	reg = <0x180af650 0x10>;
+	status = "okay";
+};
diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
index 384f661a6496..a21ad10d613c 100644
--- a/drivers/ptp/Kconfig
+++ b/drivers/ptp/Kconfig
@@ -25,6 +25,22 @@ config PTP_1588_CLOCK
 	  To compile this driver as a module, choose M here: the module
 	  will be called ptp.
 
+config PTP_1588_CLOCK_DTE
+	tristate "Broadcom DTE as PTP clock"
+	depends on PTP_1588_CLOCK
+	depends on NET && HAS_IOMEM
+	depends on ARCH_BCM_MOBILE || (ARCH_BCM_IPROC && !(ARCH_BCM_NSP || ARCH_BCM_5301X)) || COMPILE_TEST
+	default y
+	help
+	  This driver adds support for using the Digital timing engine
+	  (DTE) in the Broadcom SoC's as a PTP clock.
+
+	  The clock can be used in both wired and wireless networks
+	  for PTP purposes.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called ptp_dte.
+
 config PTP_1588_CLOCK_GIANFAR
 	tristate "Freescale eTSEC as PTP clock"
 	depends on GIANFAR
diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile
index 530736161a8b..d1f2fb19c980 100644
--- a/drivers/ptp/Makefile
+++ b/drivers/ptp/Makefile
@@ -4,6 +4,7 @@
 
 ptp-y					:= ptp_clock.o ptp_chardev.o ptp_sysfs.o
 obj-$(CONFIG_PTP_1588_CLOCK)		+= ptp.o
+obj-$(CONFIG_PTP_1588_CLOCK_DTE)	+= ptp_dte.o
 obj-$(CONFIG_PTP_1588_CLOCK_IXP46X)	+= ptp_ixp46x.o
 obj-$(CONFIG_PTP_1588_CLOCK_PCH)	+= ptp_pch.o
 obj-$(CONFIG_PTP_1588_CLOCK_KVM)	+= ptp_kvm.o
diff --git a/drivers/ptp/ptp_dte.c b/drivers/ptp/ptp_dte.c
new file mode 100644
index 000000000000..00145a3f1e70
--- /dev/null
+++ b/drivers/ptp/ptp_dte.c
@@ -0,0 +1,353 @@
+/*
+ * Copyright 2017 Broadcom
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/ptp_clock_kernel.h>
+#include <linux/types.h>
+
+#define DTE_NCO_LOW_TIME_REG	0x00
+#define DTE_NCO_TIME_REG	0x04
+#define DTE_NCO_OVERFLOW_REG	0x08
+#define DTE_NCO_INC_REG		0x0c
+
+#define DTE_NCO_SUM2_MASK	0xffffffff
+#define DTE_NCO_SUM2_SHIFT	4ULL
+
+#define DTE_NCO_SUM3_MASK	0xff
+#define DTE_NCO_SUM3_SHIFT	36ULL
+#define DTE_NCO_SUM3_WR_SHIFT	8
+
+#define DTE_NCO_TS_WRAP_MASK	0xfff
+#define DTE_NCO_TS_WRAP_LSHIFT	32
+
+#define DTE_NCO_INC_DEFAULT	0x80000000
+#define DTE_NUM_REGS_TO_RESTORE	4
+
+/* Full wrap around is 44bits in ns (~4.887 hrs) */
+#define DTE_WRAP_AROUND_NSEC_SHIFT 44
+
+/* 44 bits NCO */
+#define DTE_NCO_MAX_NS	0xFFFFFFFFFFF
+
+/* 125MHz with 3.29 reg cfg */
+#define DTE_PPB_ADJ(ppb) (u32)(div64_u64((((u64)abs(ppb) * BIT(28)) +\
+				      62500000ULL), 125000000ULL))
+
+/* ptp dte priv structure */
+struct ptp_dte {
+	void __iomem *regs;
+	struct ptp_clock *ptp_clk;
+	struct ptp_clock_info caps;
+	struct device *dev;
+	u32 ts_ovf_last;
+	u32 ts_wrap_cnt;
+	spinlock_t lock;
+	u32 reg_val[DTE_NUM_REGS_TO_RESTORE];
+};
+
+static void dte_write_nco(void __iomem *regs, s64 ns)
+{
+	u32 sum2, sum3;
+
+	sum2 = (u32)((ns >> DTE_NCO_SUM2_SHIFT) & DTE_NCO_SUM2_MASK);
+	/* compensate for ignoring sum1 */
+	if (sum2 != DTE_NCO_SUM2_MASK)
+		sum2++;
+
+	/* to write sum3, bits [15:8] needs to be written */
+	sum3 = (u32)(((ns >> DTE_NCO_SUM3_SHIFT) & DTE_NCO_SUM3_MASK) <<
+		     DTE_NCO_SUM3_WR_SHIFT);
+
+	writel(0, (regs + DTE_NCO_LOW_TIME_REG));
+	writel(sum2, (regs + DTE_NCO_TIME_REG));
+	writel(sum3, (regs + DTE_NCO_OVERFLOW_REG));
+}
+
+static s64 dte_read_nco(void __iomem *regs)
+{
+	u32 sum2, sum3;
+	s64 ns;
+
+	/*
+	 * ignoring sum1 (4 bits) gives a 16ns resolution, which
+	 * works due to the async register read.
+	 */
+	sum3 = readl(regs + DTE_NCO_OVERFLOW_REG) & DTE_NCO_SUM3_MASK;
+	sum2 = readl(regs + DTE_NCO_TIME_REG);
+	ns = ((s64)sum3 << DTE_NCO_SUM3_SHIFT) |
+		 ((s64)sum2 << DTE_NCO_SUM2_SHIFT);
+
+	return ns;
+}
+
+static void dte_write_nco_delta(struct ptp_dte *ptp_dte, s64 delta)
+{
+	s64 ns;
+
+	ns = dte_read_nco(ptp_dte->regs);
+
+	/* handle wraparound conditions */
+	if ((delta < 0) && (abs(delta) > ns)) {
+		if (ptp_dte->ts_wrap_cnt) {
+			ns += DTE_NCO_MAX_NS + delta;
+			ptp_dte->ts_wrap_cnt--;
+		} else {
+			ns = 0;
+		}
+	} else {
+		ns += delta;
+		if (ns > DTE_NCO_MAX_NS) {
+			ptp_dte->ts_wrap_cnt++;
+			ns -= DTE_NCO_MAX_NS;
+		}
+	}
+
+	dte_write_nco(ptp_dte->regs, ns);
+
+	ptp_dte->ts_ovf_last = (ns >> DTE_NCO_TS_WRAP_LSHIFT) &
+			DTE_NCO_TS_WRAP_MASK;
+}
+
+static s64 dte_read_nco_with_ovf(struct ptp_dte *ptp_dte)
+{
+	u32 ts_ovf;
+	s64 ns = 0;
+
+	ns = dte_read_nco(ptp_dte->regs);
+
+	/*Timestamp overflow: 8 LSB bits of sum3, 4 MSB bits of sum2 */
+	ts_ovf = (ns >> DTE_NCO_TS_WRAP_LSHIFT) & DTE_NCO_TS_WRAP_MASK;
+
+	/* Check for wrap around */
+	if (ts_ovf < ptp_dte->ts_ovf_last)
+		ptp_dte->ts_wrap_cnt++;
+
+	ptp_dte->ts_ovf_last = ts_ovf;
+
+	/* adjust for wraparounds */
+	ns += (s64)(BIT_ULL(DTE_WRAP_AROUND_NSEC_SHIFT) * ptp_dte->ts_wrap_cnt);
+
+	return ns;
+}
+
+static int ptp_dte_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
+{
+	u32 nco_incr;
+	unsigned long flags;
+	struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
+
+	if (abs(ppb) > ptp_dte->caps.max_adj) {
+		dev_err(ptp_dte->dev, "ppb adj too big\n");
+		return -EINVAL;
+	}
+
+	if (ppb < 0)
+		nco_incr = DTE_NCO_INC_DEFAULT - DTE_PPB_ADJ(ppb);
+	else
+		nco_incr = DTE_NCO_INC_DEFAULT + DTE_PPB_ADJ(ppb);
+
+	spin_lock_irqsave(&ptp_dte->lock, flags);
+	writel(nco_incr, ptp_dte->regs + DTE_NCO_INC_REG);
+	spin_unlock_irqrestore(&ptp_dte->lock, flags);
+
+	return 0;
+}
+
+static int ptp_dte_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+	unsigned long flags;
+	struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
+
+	spin_lock_irqsave(&ptp_dte->lock, flags);
+	dte_write_nco_delta(ptp_dte, delta);
+	spin_unlock_irqrestore(&ptp_dte->lock, flags);
+
+	return 0;
+}
+
+static int ptp_dte_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
+{
+	unsigned long flags;
+	struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
+
+	spin_lock_irqsave(&ptp_dte->lock, flags);
+	*ts = ns_to_timespec64(dte_read_nco_with_ovf(ptp_dte));
+	spin_unlock_irqrestore(&ptp_dte->lock, flags);
+
+	return 0;
+}
+
+static int ptp_dte_settime(struct ptp_clock_info *ptp,
+			     const struct timespec64 *ts)
+{
+	unsigned long flags;
+	struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
+
+	spin_lock_irqsave(&ptp_dte->lock, flags);
+
+	/* Disable nco increment */
+	writel(0, ptp_dte->regs + DTE_NCO_INC_REG);
+
+	dte_write_nco(ptp_dte->regs, timespec64_to_ns(ts));
+
+	/* reset overflow and wrap counter */
+	ptp_dte->ts_ovf_last = 0;
+	ptp_dte->ts_wrap_cnt = 0;
+
+	/* Enable nco increment */
+	writel(DTE_NCO_INC_DEFAULT, ptp_dte->regs + DTE_NCO_INC_REG);
+
+	spin_unlock_irqrestore(&ptp_dte->lock, flags);
+
+	return 0;
+}
+
+static int ptp_dte_enable(struct ptp_clock_info *ptp,
+			    struct ptp_clock_request *rq, int on)
+{
+	return -EOPNOTSUPP;
+}
+
+static struct ptp_clock_info ptp_dte_caps = {
+	.owner		= THIS_MODULE,
+	.name		= "DTE PTP timer",
+	.max_adj	= 50000000,
+	.n_ext_ts	= 0,
+	.n_pins		= 0,
+	.pps		= 0,
+	.adjfreq	= ptp_dte_adjfreq,
+	.adjtime	= ptp_dte_adjtime,
+	.gettime64	= ptp_dte_gettime,
+	.settime64	= ptp_dte_settime,
+	.enable		= ptp_dte_enable,
+};
+
+static int ptp_dte_probe(struct platform_device *pdev)
+{
+	struct ptp_dte *ptp_dte;
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+
+	ptp_dte = devm_kzalloc(dev, sizeof(struct ptp_dte), GFP_KERNEL);
+	if (!ptp_dte)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ptp_dte->regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ptp_dte->regs)) {
+		dev_err(dev,
+			"%s: io remap failed\n", __func__);
+		return PTR_ERR(ptp_dte->regs);
+	}
+
+	spin_lock_init(&ptp_dte->lock);
+
+	ptp_dte->dev = dev;
+	ptp_dte->caps = ptp_dte_caps;
+	ptp_dte->ptp_clk = ptp_clock_register(&ptp_dte->caps, &pdev->dev);
+	if (IS_ERR(ptp_dte->ptp_clk)) {
+		dev_err(dev,
+			"%s: Failed to register ptp clock\n", __func__);
+		return PTR_ERR(ptp_dte->ptp_clk);
+	}
+
+	platform_set_drvdata(pdev, ptp_dte);
+
+	dev_info(dev, "ptp clk probe done\n");
+
+	return 0;
+}
+
+static int ptp_dte_remove(struct platform_device *pdev)
+{
+	struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
+	u8 i;
+
+	ptp_clock_unregister(ptp_dte->ptp_clk);
+
+	for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++)
+		writel(0, ptp_dte->regs + (i * sizeof(u32)));
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int ptp_dte_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
+	u8 i;
+
+	for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
+		ptp_dte->reg_val[i] =
+			readl(ptp_dte->regs + (i * sizeof(u32)));
+	}
+
+	/* disable the nco */
+	writel(0, ptp_dte->regs + DTE_NCO_INC_REG);
+
+	return 0;
+}
+
+static int ptp_dte_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
+	u8 i;
+
+	for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
+		if ((i * sizeof(u32)) != DTE_NCO_OVERFLOW_REG)
+			writel(ptp_dte->reg_val[i],
+				(ptp_dte->regs + (i * sizeof(u32))));
+		else
+			writel(((ptp_dte->reg_val[i] &
+				DTE_NCO_SUM3_MASK) << DTE_NCO_SUM3_WR_SHIFT),
+				(ptp_dte->regs + (i * sizeof(u32))));
+	}
+
+	return 0;
+}
+
+static const struct dev_pm_ops ptp_dte_pm_ops = {
+	.suspend = ptp_dte_suspend,
+	.resume = ptp_dte_resume
+};
+
+#define PTP_DTE_PM_OPS	(&ptp_dte_pm_ops)
+#else
+#define PTP_DTE_PM_OPS	NULL
+#endif
+
+static const struct of_device_id ptp_dte_of_match[] = {
+	{ .compatible = "brcm,ptp-dte", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ptp_dte_of_match);
+
+static struct platform_driver ptp_dte_driver = {
+	.driver = {
+		.name = "ptp-dte",
+		.pm = PTP_DTE_PM_OPS,
+		.of_match_table = ptp_dte_of_match,
+	},
+	.probe    = ptp_dte_probe,
+	.remove   = ptp_dte_remove,
+};
+module_platform_driver(ptp_dte_driver);
+
+MODULE_AUTHOR("Broadcom");
+MODULE_DESCRIPTION("Broadcom DTE PTP Clock driver");
+MODULE_LICENSE("GPL v2");