This patch adds a ptp clock driver for the Broadcom SoCs using
the Digital timing Engine (DTE) nco.
Signed-off-by: Arun Parameswaran <arun.parameswaran@xxxxxxxxxxxx>
---
drivers/ptp/Kconfig | 16 +++
drivers/ptp/Makefile | 1 +
drivers/ptp/ptp_dte.c | 353 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 370 insertions(+)
create mode 100644 drivers/ptp/ptp_dte.c
diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
index 384f661..a21ad10 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 5307361..d1f2fb1 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 0000000..00145a3
--- /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");
--
1.9.1
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