[v2] ptp: add ToD device driver for Intel FPGA cards

Message ID	20230322143547.233250-1-tianfei.zhang@intel.com (mailing list archive)
State	New
Headers	show Return-Path: <linux-fpga-owner@vger.kernel.org> From: Tianfei Zhang <tianfei.zhang@intel.com> To: richardcochran@gmail.com Cc: netdev@vger.kernel.org, linux-fpga@vger.kernel.org, ilpo.jarvinen@linux.intel.com, andriy.shevchenko@linux.intel.com, vinicius.gomes@intel.com, pierre-louis.bossart@linux.intel.com, marpagan@redhat.com, russell.h.weight@intel.com, matthew.gerlach@linux.intel.com, nico@fluxnic.net, Tianfei Zhang <tianfei.zhang@intel.com>, Raghavendra Khadatare <raghavendrax.anand.khadatare@intel.com> Subject: [PATCH v2] ptp: add ToD device driver for Intel FPGA cards Date: Wed, 22 Mar 2023 10:35:47 -0400 Message-Id: <20230322143547.233250-1-tianfei.zhang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	[v2] ptp: add ToD device driver for Intel FPGA cards \| expand [v2] ptp: add ToD device driver for Intel FPGA cards

diff --git a/MAINTAINERS b/MAINTAINERS index d8ebab595b2a..3fd603369464 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15623,6 +15623,13 @@ L: netdev@vger.kernel.org S: Maintained F: drivers/ptp/ptp_ocp.c +INTEL PTP DFL ToD DRIVER +M: Tianfei Zhang <tianfei.zhang@intel.com> +L: linux-fpga@vger.kernel.org +L: netdev@vger.kernel.org +S: Maintained +F: drivers/ptp/ptp_dfl_tod.c + OPENCORES I2C BUS DRIVER M: Peter Korsgaard <peter@korsgaard.com> M: Andrew Lunn <andrew@lunn.ch> diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig index fe4971b65c64..e0d6f136ee46 100644 --- a/drivers/ptp/Kconfig +++ b/drivers/ptp/Kconfig @@ -186,4 +186,17 @@ config PTP_1588_CLOCK_OCP More information is available at http://www.timingcard.com/ +config PTP_DFL_TOD + tristate "FPGA DFL ToD Driver" + depends on FPGA_DFL + help + The DFL (Device Feature List) device driver for the Intel ToD + (Time-of-Day) device in FPGA card. The ToD IP within the FPGA + is exposed as PTP Hardware Clock (PHC) device to the Linux PTP + stack to synchronize the system clock to its ToD information + using phc2sys utility of the Linux PTP stack. + + To compile this driver as a module, choose M here: the module + will be called ptp_dfl_tod. + endmenu diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile index 28a6fe342d3e..553f18bf3c83 100644 --- a/drivers/ptp/Makefile +++ b/drivers/ptp/Makefile @@ -18,3 +18,4 @@ obj-$(CONFIG_PTP_1588_CLOCK_IDTCM) += ptp_clockmatrix.o obj-$(CONFIG_PTP_1588_CLOCK_IDT82P33) += ptp_idt82p33.o obj-$(CONFIG_PTP_1588_CLOCK_VMW) += ptp_vmw.o obj-$(CONFIG_PTP_1588_CLOCK_OCP) += ptp_ocp.o +obj-$(CONFIG_PTP_DFL_TOD) += ptp_dfl_tod.o diff --git a/drivers/ptp/ptp_dfl_tod.c b/drivers/ptp/ptp_dfl_tod.c new file mode 100644 index 000000000000..d1532778c6b7 --- /dev/null +++ b/drivers/ptp/ptp_dfl_tod.c @@ -0,0 +1,333 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * DFL device driver for Time-of-Day (ToD) private feature + * + * Copyright (C) 2023 Intel Corporation + */ + +#include <linux/bitfield.h> +#include <linux/delay.h> +#include <linux/dfl.h> +#include <linux/gcd.h> +#include <linux/iopoll.h> +#include <linux/module.h> +#include <linux/ptp_clock_kernel.h> +#include <linux/spinlock.h> +#include <linux/units.h> + +#define FME_FEATURE_ID_TOD 0x22 + +/* ToD clock register space. */ +#define TOD_CLK_FREQ 0x038 + +/* + * The read sequence of ToD timestamp registers: TOD_NANOSEC, TOD_SECONDSL and + * TOD_SECONDSH, because there is a hardware snapshot whenever the TOD_NANOSEC + * register is read. + * + * The ToD IP requires writing registers in the reverse order to the read sequence. + * The timestamp is corrected when the TOD_NANOSEC register is written, so the + * sequence of write TOD registers: TOD_SECONDSH, TOD_SECONDSL and TOD_NANOSEC. + */ +#define TOD_SECONDSH 0x100 +#define TOD_SECONDSL 0x104 +#define TOD_NANOSEC 0x108 +#define TOD_PERIOD 0x110 +#define TOD_ADJUST_PERIOD 0x114 +#define TOD_ADJUST_COUNT 0x118 +#define TOD_DRIFT_ADJUST 0x11c +#define TOD_DRIFT_ADJUST_RATE 0x120 +#define PERIOD_FRAC_OFFSET 16 +#define SECONDS_MSB GENMASK_ULL(47, 32) +#define SECONDS_LSB GENMASK_ULL(31, 0) +#define TOD_SECONDSH_SEC_MSB GENMASK_ULL(15, 0) + +#define CAL_SECONDS(m, l) ((FIELD_GET(TOD_SECONDSH_SEC_MSB, (m)) << 32) | (l)) + +#define TOD_PERIOD_MASK GENMASK_ULL(19, 0) +#define TOD_PERIOD_MAX FIELD_MAX(TOD_PERIOD_MASK) +#define TOD_PERIOD_MIN 0 +#define TOD_DRIFT_ADJUST_MASK GENMASK_ULL(15, 0) +#define TOD_DRIFT_ADJUST_FNS_MAX FIELD_MAX(TOD_DRIFT_ADJUST_MASK) +#define TOD_DRIFT_ADJUST_RATE_MAX TOD_DRIFT_ADJUST_FNS_MAX +#define TOD_ADJUST_COUNT_MASK GENMASK_ULL(19, 0) +#define TOD_ADJUST_COUNT_MAX FIELD_MAX(TOD_ADJUST_COUNT_MASK) +#define TOD_ADJUST_INTERVAL_US 10 +#define TOD_ADJUST_MS \ + (((TOD_PERIOD_MAX >> 16) + 1) * (TOD_ADJUST_COUNT_MAX + 1)) +#define TOD_ADJUST_MS_MAX (TOD_ADJUST_MS / MICRO) +#define TOD_ADJUST_MAX_US (TOD_ADJUST_MS_MAX * USEC_PER_MSEC) +#define TOD_MAX_ADJ (500 * MEGA) + +struct dfl_tod { + struct ptp_clock_info ptp_clock_ops; + struct device *dev; + struct ptp_clock *ptp_clock; + + /* ToD Clock address space */ + void __iomem *tod_ctrl; + + /* ToD clock registers protection */ + spinlock_t tod_lock; +}; + +/* + * A fine ToD HW clock offset adjustment. To perform the fine offset adjustment, the + * adjust_period and adjust_count argument are used to update the TOD_ADJUST_PERIOD + * and TOD_ADJUST_COUNT register for in hardware. The dt->tod_lock spinlock must be + * held when calling this function. + */ +static int fine_adjust_tod_clock(struct dfl_tod *dt, u32 adjust_period, + u32 adjust_count) +{ + void __iomem *base = dt->tod_ctrl; + u32 val; + + writel(adjust_period, base + TOD_ADJUST_PERIOD); + writel(adjust_count, base + TOD_ADJUST_COUNT); + + /* Wait for present offset adjustment update to complete */ + return readl_poll_timeout_atomic(base + TOD_ADJUST_COUNT, val, !val, TOD_ADJUST_INTERVAL_US, + TOD_ADJUST_MAX_US); +} + +/* + * A coarse ToD HW clock offset adjustment. + * The coarse time adjustment performs by adding or subtracting the delta value + * from the current ToD HW clock time. + */ +static int coarse_adjust_tod_clock(struct dfl_tod *dt, s64 delta) +{ + u32 seconds_msb, seconds_lsb, nanosec; + void __iomem *base = dt->tod_ctrl; + u64 seconds, now; + + if (delta == 0) + return 0; + + nanosec = readl(base + TOD_NANOSEC); + seconds_lsb = readl(base + TOD_SECONDSL); + seconds_msb = readl(base + TOD_SECONDSH); + + /* Calculate new time */ + seconds = CAL_SECONDS(seconds_msb, seconds_lsb); + now = seconds * NSEC_PER_SEC + nanosec + delta; + + seconds = div_u64_rem(now, NSEC_PER_SEC, &nanosec); + seconds_msb = FIELD_GET(SECONDS_MSB, seconds); + seconds_lsb = FIELD_GET(SECONDS_LSB, seconds); + + writel(seconds_msb, base + TOD_SECONDSH); + writel(seconds_lsb, base + TOD_SECONDSL); + writel(nanosec, base + TOD_NANOSEC); + + return 0; +} + +static int dfl_tod_adjust_fine(struct ptp_clock_info *ptp, long scaled_ppm) +{ + struct dfl_tod *dt = container_of(ptp, struct dfl_tod, ptp_clock_ops); + u32 tod_period, tod_rem, tod_drift_adjust_fns, tod_drift_adjust_rate; + void __iomem *base = dt->tod_ctrl; + unsigned long flags, rate; + u64 ppb; + + /* Get the clock rate from clock frequency register offset */ + rate = readl(base + TOD_CLK_FREQ); + + /* add GIGA as nominal ppb */ + ppb = scaled_ppm_to_ppb(scaled_ppm) + GIGA; + + tod_period = div_u64_rem(ppb << PERIOD_FRAC_OFFSET, rate, &tod_rem); + if (tod_period > TOD_PERIOD_MAX) + return -ERANGE; + + /* + * The drift of ToD adjusted periodically by adding a drift_adjust_fns + * correction value every drift_adjust_rate count of clock cycles. + */ + tod_drift_adjust_fns = tod_rem / gcd(tod_rem, rate); + tod_drift_adjust_rate = rate / gcd(tod_rem, rate); + + while ((tod_drift_adjust_fns > TOD_DRIFT_ADJUST_FNS_MAX) || + (tod_drift_adjust_rate > TOD_DRIFT_ADJUST_RATE_MAX)) { + tod_drift_adjust_fns >>= 1; + tod_drift_adjust_rate >>= 1; + } + + if (tod_drift_adjust_fns == 0) + tod_drift_adjust_rate = 0; + + spin_lock_irqsave(&dt->tod_lock, flags); + writel(tod_period, base + TOD_PERIOD); + writel(0, base + TOD_ADJUST_PERIOD); + writel(0, base + TOD_ADJUST_COUNT); + writel(tod_drift_adjust_fns, base + TOD_DRIFT_ADJUST); + writel(tod_drift_adjust_rate, base + TOD_DRIFT_ADJUST_RATE); + spin_unlock_irqrestore(&dt->tod_lock, flags); + + return 0; +} + +static int dfl_tod_adjust_time(struct ptp_clock_info *ptp, s64 delta) +{ + struct dfl_tod *dt = container_of(ptp, struct dfl_tod, ptp_clock_ops); + u32 period, diff, rem, rem_period, adj_period; + void __iomem *base = dt->tod_ctrl; + unsigned long flags; + bool neg_adj; + u64 count; + int ret; + + neg_adj = delta < 0; + if (neg_adj) + delta = -delta; + + spin_lock_irqsave(&dt->tod_lock, flags); + + /* + * Get the maximum possible value of the Period register offset + * adjustment in nanoseconds scale. This depends on the current + * Period register setting and the maximum and minimum possible + * values of the Period register. + */ + period = readl(base + TOD_PERIOD); + + if (neg_adj) { + diff = (period - TOD_PERIOD_MIN) >> PERIOD_FRAC_OFFSET; + adj_period = period - (diff << PERIOD_FRAC_OFFSET); + count = div_u64_rem(delta, diff, &rem); + rem_period = period - (rem << PERIOD_FRAC_OFFSET); + } else { + diff = (TOD_PERIOD_MAX - period) >> PERIOD_FRAC_OFFSET; + adj_period = period + (diff << PERIOD_FRAC_OFFSET); + count = div_u64_rem(delta, diff, &rem); + rem_period = period + (rem << PERIOD_FRAC_OFFSET); + } + + ret = 0; + + if (count > TOD_ADJUST_COUNT_MAX) { + ret = coarse_adjust_tod_clock(dt, delta); + } else { + /* Adjust the period by count cycles to adjust the time */ + if (count) + ret = fine_adjust_tod_clock(dt, adj_period, count); + + /* If there is a remainder, adjust the period for an additional cycle */ + if (rem) + ret = fine_adjust_tod_clock(dt, rem_period, 1); + } + + spin_unlock_irqrestore(&dt->tod_lock, flags); + + return ret; +} + +static int dfl_tod_get_timex(struct ptp_clock_info *ptp, struct timespec64 *ts, + struct ptp_system_timestamp *sts) +{ + struct dfl_tod *dt = container_of(ptp, struct dfl_tod, ptp_clock_ops); + u32 seconds_msb, seconds_lsb, nanosec; + void __iomem *base = dt->tod_ctrl; + unsigned long flags; + u64 seconds; + + spin_lock_irqsave(&dt->tod_lock, flags); + ptp_read_system_prets(sts); + nanosec = readl(base + TOD_NANOSEC); + seconds_lsb = readl(base + TOD_SECONDSL); + seconds_msb = readl(base + TOD_SECONDSH); + ptp_read_system_postts(sts); + spin_unlock_irqrestore(&dt->tod_lock, flags); + + seconds = CAL_SECONDS(seconds_msb, seconds_lsb); + + ts->tv_nsec = nanosec; + ts->tv_sec = seconds; + + return 0; +} + +static int dfl_tod_set_time(struct ptp_clock_info *ptp, + const struct timespec64 *ts) +{ + struct dfl_tod *dt = container_of(ptp, struct dfl_tod, ptp_clock_ops); + u32 seconds_msb = FIELD_GET(SECONDS_MSB, ts->tv_sec); + u32 seconds_lsb = FIELD_GET(SECONDS_LSB, ts->tv_sec); + u32 nanosec = FIELD_GET(SECONDS_LSB, ts->tv_nsec); + void __iomem *base = dt->tod_ctrl; + unsigned long flags; + + spin_lock_irqsave(&dt->tod_lock, flags); + writel(seconds_msb, base + TOD_SECONDSH); + writel(seconds_lsb, base + TOD_SECONDSL); + writel(nanosec, base + TOD_NANOSEC); + spin_unlock_irqrestore(&dt->tod_lock, flags); + + return 0; +} + +static struct ptp_clock_info dfl_tod_clock_ops = { + .owner = THIS_MODULE, + .name = "dfl_tod", + .max_adj = TOD_MAX_ADJ, + .adjfine = dfl_tod_adjust_fine, + .adjtime = dfl_tod_adjust_time, + .gettimex64 = dfl_tod_get_timex, + .settime64 = dfl_tod_set_time, +}; + +static int dfl_tod_probe(struct dfl_device *ddev) +{ + struct device *dev = &ddev->dev; + struct dfl_tod *dt; + + dt = devm_kzalloc(dev, sizeof(*dt), GFP_KERNEL); + if (!dt) + return -ENOMEM; + + dt->tod_ctrl = devm_ioremap_resource(dev, &ddev->mmio_res); + if (IS_ERR(dt->tod_ctrl)) + return PTR_ERR(dt->tod_ctrl); + + dt->dev = dev; + spin_lock_init(&dt->tod_lock); + dev_set_drvdata(dev, dt); + + dt->ptp_clock_ops = dfl_tod_clock_ops; + + dt->ptp_clock = ptp_clock_register(&dt->ptp_clock_ops, dev); + if (IS_ERR_OR_NULL(dt->ptp_clock)) + return dev_err_probe(dt->dev, PTR_ERR_OR_ZERO(dt->ptp_clock), + "Unable to register PTP clock\n"); + + return 0; +} + +static void dfl_tod_remove(struct dfl_device *ddev) +{ + struct dfl_tod *dt = dev_get_drvdata(&ddev->dev); + + ptp_clock_unregister(dt->ptp_clock); +} + +static const struct dfl_device_id dfl_tod_ids[] = { + { FME_ID, FME_FEATURE_ID_TOD }, + { } +}; +MODULE_DEVICE_TABLE(dfl, dfl_tod_ids); + +static struct dfl_driver dfl_tod_driver = { + .drv = { + .name = "dfl-tod", + }, + .id_table = dfl_tod_ids, + .probe = dfl_tod_probe, + .remove = dfl_tod_remove, +}; +module_dfl_driver(dfl_tod_driver); + +MODULE_DESCRIPTION("FPGA DFL ToD driver"); +MODULE_AUTHOR("Intel Corporation"); +MODULE_LICENSE("GPL");

[v2] ptp: add ToD device driver for Intel FPGA cards

Commit Message

Comments

Patch