// SPDX-License-Identifier: GPL-2.0
/* Marvell PTP driver
 *
 * Copyright (C) 2020 Marvell.
 *
 */

#include <linux/bitfield.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/pci.h>

#include "ptp.h"
#include "mbox.h"
#include "rvu.h"

#define DRV_NAME				"Marvell PTP Driver"

#define PCI_DEVID_OCTEONTX2_PTP			0xA00C
#define PCI_SUBSYS_DEVID_OCTX2_98xx_PTP		0xB100
#define PCI_SUBSYS_DEVID_OCTX2_96XX_PTP		0xB200
#define PCI_SUBSYS_DEVID_OCTX2_95XX_PTP		0xB300
#define PCI_SUBSYS_DEVID_OCTX2_95XXN_PTP	0xB400
#define PCI_SUBSYS_DEVID_OCTX2_95MM_PTP		0xB500
#define PCI_SUBSYS_DEVID_OCTX2_95XXO_PTP	0xB600
#define PCI_DEVID_OCTEONTX2_RST			0xA085
#define PCI_DEVID_CN10K_PTP			0xA09E
#define PCI_SUBSYS_DEVID_CN10K_A_PTP		0xB900
#define PCI_SUBSYS_DEVID_CNF10K_A_PTP		0xBA00
#define PCI_SUBSYS_DEVID_CNF10K_B_PTP		0xBC00

#define PCI_PTP_BAR_NO				0

#define PTP_CLOCK_CFG				0xF00ULL
#define PTP_CLOCK_CFG_PTP_EN			BIT_ULL(0)
#define PTP_CLOCK_CFG_EXT_CLK_EN		BIT_ULL(1)
#define PTP_CLOCK_CFG_EXT_CLK_IN_MASK		GENMASK_ULL(7, 2)
#define PTP_CLOCK_CFG_TSTMP_EDGE		BIT_ULL(9)
#define PTP_CLOCK_CFG_TSTMP_EN			BIT_ULL(8)
#define PTP_CLOCK_CFG_TSTMP_IN_MASK		GENMASK_ULL(15, 10)
#define PTP_CLOCK_CFG_PPS_EN			BIT_ULL(30)
#define PTP_CLOCK_CFG_PPS_INV			BIT_ULL(31)

#define PTP_PPS_HI_INCR				0xF60ULL
#define PTP_PPS_LO_INCR				0xF68ULL
#define PTP_PPS_THRESH_HI			0xF58ULL

#define PTP_CLOCK_LO				0xF08ULL
#define PTP_CLOCK_HI				0xF10ULL
#define PTP_CLOCK_COMP				0xF18ULL
#define PTP_TIMESTAMP				0xF20ULL
#define PTP_CLOCK_SEC				0xFD0ULL

#define CYCLE_MULT				1000

static struct ptp *first_ptp_block;
static const struct pci_device_id ptp_id_table[];

static bool cn10k_ptp_errata(struct ptp *ptp)
{
	if (ptp->pdev->subsystem_device == PCI_SUBSYS_DEVID_CN10K_A_PTP ||
	    ptp->pdev->subsystem_device == PCI_SUBSYS_DEVID_CNF10K_A_PTP)
		return true;
	return false;
}

static bool is_ptp_tsfmt_sec_nsec(struct ptp *ptp)
{
	if (ptp->pdev->subsystem_device == PCI_SUBSYS_DEVID_CN10K_A_PTP ||
	    ptp->pdev->subsystem_device == PCI_SUBSYS_DEVID_CNF10K_A_PTP)
		return true;
	return false;
}

static u64 read_ptp_tstmp_sec_nsec(struct ptp *ptp)
{
	u64 sec, sec1, nsec;
	unsigned long flags;

	spin_lock_irqsave(&ptp->ptp_lock, flags);
	sec = readq(ptp->reg_base + PTP_CLOCK_SEC) & 0xFFFFFFFFUL;
	nsec = readq(ptp->reg_base + PTP_CLOCK_HI);
	sec1 = readq(ptp->reg_base + PTP_CLOCK_SEC) & 0xFFFFFFFFUL;
	/* check nsec rollover */
	if (sec1 > sec) {
		nsec = readq(ptp->reg_base + PTP_CLOCK_HI);
		sec = sec1;
	}
	spin_unlock_irqrestore(&ptp->ptp_lock, flags);

	return sec * NSEC_PER_SEC + nsec;
}

static u64 read_ptp_tstmp_nsec(struct ptp *ptp)
{
	return readq(ptp->reg_base + PTP_CLOCK_HI);
}

static u64 ptp_calc_adjusted_comp(u64 ptp_clock_freq)
{
	u64 comp, adj = 0, cycles_per_sec, ns_drift = 0;
	u32 ptp_clock_nsec, cycle_time;
	int cycle;

	/* Errata:
	 * Issue #1: At the time of 1 sec rollover of the nano-second counter,
	 * the nano-second counter is set to 0. However, it should be set to
	 * (existing counter_value - 10^9).
	 *
	 * Issue #2: The nano-second counter rolls over at 0x3B9A_C9FF.
	 * It should roll over at 0x3B9A_CA00.
	 */

	/* calculate ptp_clock_comp value */
	comp = ((u64)1000000000ULL << 32) / ptp_clock_freq;
	/* use CYCLE_MULT to avoid accuracy loss due to integer arithmetic */
	cycle_time = NSEC_PER_SEC * CYCLE_MULT / ptp_clock_freq;
	/* cycles per sec */
	cycles_per_sec = ptp_clock_freq;

	/* check whether ptp nanosecond counter rolls over early */
	cycle = cycles_per_sec - 1;
	ptp_clock_nsec = (cycle * comp) >> 32;
	while (ptp_clock_nsec < NSEC_PER_SEC) {
		if (ptp_clock_nsec == 0x3B9AC9FF)
			goto calc_adj_comp;
		cycle++;
		ptp_clock_nsec = (cycle * comp) >> 32;
	}
	/* compute nanoseconds lost per second when nsec counter rolls over */
	ns_drift = ptp_clock_nsec - NSEC_PER_SEC;
	/* calculate ptp_clock_comp adjustment */
	if (ns_drift > 0) {
		adj = comp * ns_drift;
		adj = adj / 1000000000ULL;
	}
	/* speed up the ptp clock to account for nanoseconds lost */
	comp += adj;
	return comp;

calc_adj_comp:
	/* slow down the ptp clock to not rollover early */
	adj = comp * cycle_time;
	adj = adj / 1000000000ULL;
	adj = adj / CYCLE_MULT;
	comp -= adj;

	return comp;
}

struct ptp *ptp_get(void)
{
	struct ptp *ptp = first_ptp_block;

	/* Check PTP block is present in hardware */
	if (!pci_dev_present(ptp_id_table))
		return ERR_PTR(-ENODEV);
	/* Check driver is bound to PTP block */
	if (!ptp)
		ptp = ERR_PTR(-EPROBE_DEFER);
	else
		pci_dev_get(ptp->pdev);

	return ptp;
}

void ptp_put(struct ptp *ptp)
{
	if (!ptp)
		return;

	pci_dev_put(ptp->pdev);
}

static int ptp_adjfine(struct ptp *ptp, long scaled_ppm)
{
	bool neg_adj = false;
	u32 freq, freq_adj;
	u64 comp, adj;
	s64 ppb;

	if (scaled_ppm < 0) {
		neg_adj = true;
		scaled_ppm = -scaled_ppm;
	}

	/* 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 scaled_ppm represent the ratio in "parts per million" 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 * scaled_ppm / (1M * 2^16)
	 * where tbase is the basic compensation value calculated
	 * initialy in the probe function.
	 */
	/* convert scaled_ppm to ppb */
	ppb = 1 + scaled_ppm;
	ppb *= 125;
	ppb >>= 13;

	if (cn10k_ptp_errata(ptp)) {
		/* calculate the new frequency based on ppb */
		freq_adj = (ptp->clock_rate * ppb) / 1000000000ULL;
		freq = neg_adj ? ptp->clock_rate + freq_adj : ptp->clock_rate - freq_adj;
		comp = ptp_calc_adjusted_comp(freq);
	} else {
		comp = ((u64)1000000000ull << 32) / ptp->clock_rate;
		adj = comp * ppb;
		adj = div_u64(adj, 1000000000ull);
		comp = neg_adj ? comp - adj : comp + adj;
	}
	writeq(comp, ptp->reg_base + PTP_CLOCK_COMP);

	return 0;
}

static int ptp_get_clock(struct ptp *ptp, u64 *clk)
{
	/* Return the current PTP clock */
	*clk = ptp->read_ptp_tstmp(ptp);

	return 0;
}

void ptp_start(struct ptp *ptp, u64 sclk, u32 ext_clk_freq, u32 extts)
{
	struct pci_dev *pdev;
	u64 clock_comp;
	u64 clock_cfg;

	if (!ptp)
		return;

	pdev = ptp->pdev;

	if (!sclk) {
		dev_err(&pdev->dev, "PTP input clock cannot be zero\n");
		return;
	}

	/* sclk is in MHz */
	ptp->clock_rate = sclk * 1000000;

	/* Enable PTP clock */
	clock_cfg = readq(ptp->reg_base + PTP_CLOCK_CFG);

	if (ext_clk_freq) {
		ptp->clock_rate = ext_clk_freq;
		/* Set GPIO as PTP clock source */
		clock_cfg &= ~PTP_CLOCK_CFG_EXT_CLK_IN_MASK;
		clock_cfg |= PTP_CLOCK_CFG_EXT_CLK_EN;
	}

	if (extts) {
		clock_cfg |= PTP_CLOCK_CFG_TSTMP_EDGE;
		/* Set GPIO as timestamping source */
		clock_cfg &= ~PTP_CLOCK_CFG_TSTMP_IN_MASK;
		clock_cfg |= PTP_CLOCK_CFG_TSTMP_EN;
	}

	clock_cfg |= PTP_CLOCK_CFG_PTP_EN;
	clock_cfg |= PTP_CLOCK_CFG_PPS_EN | PTP_CLOCK_CFG_PPS_INV;
	writeq(clock_cfg, ptp->reg_base + PTP_CLOCK_CFG);

	/* Set 50% duty cycle for 1Hz output */
	writeq(0x1dcd650000000000, ptp->reg_base + PTP_PPS_HI_INCR);
	writeq(0x1dcd650000000000, ptp->reg_base + PTP_PPS_LO_INCR);

	if (cn10k_ptp_errata(ptp))
		clock_comp = ptp_calc_adjusted_comp(ptp->clock_rate);
	else
		clock_comp = ((u64)1000000000ull << 32) / ptp->clock_rate;

	/* Initial compensation value to start the nanosecs counter */
	writeq(clock_comp, ptp->reg_base + PTP_CLOCK_COMP);
}

static int ptp_get_tstmp(struct ptp *ptp, u64 *clk)
{
	*clk = readq(ptp->reg_base + PTP_TIMESTAMP);

	return 0;
}

static int ptp_set_thresh(struct ptp *ptp, u64 thresh)
{
	writeq(thresh, ptp->reg_base + PTP_PPS_THRESH_HI);

	return 0;
}

static int ptp_probe(struct pci_dev *pdev,
		     const struct pci_device_id *ent)
{
	struct device *dev = &pdev->dev;
	struct ptp *ptp;
	int err;

	ptp = devm_kzalloc(dev, sizeof(*ptp), GFP_KERNEL);
	if (!ptp) {
		err = -ENOMEM;
		goto error;
	}

	ptp->pdev = pdev;

	err = pcim_enable_device(pdev);
	if (err)
		goto error_free;

	err = pcim_iomap_regions(pdev, 1 << PCI_PTP_BAR_NO, pci_name(pdev));
	if (err)
		goto error_free;

	ptp->reg_base = pcim_iomap_table(pdev)[PCI_PTP_BAR_NO];

	pci_set_drvdata(pdev, ptp);
	if (!first_ptp_block)
		first_ptp_block = ptp;

	spin_lock_init(&ptp->ptp_lock);
	if (is_ptp_tsfmt_sec_nsec(ptp))
		ptp->read_ptp_tstmp = &read_ptp_tstmp_sec_nsec;
	else
		ptp->read_ptp_tstmp = &read_ptp_tstmp_nsec;

	return 0;

error_free:
	devm_kfree(dev, ptp);

error:
	/* For `ptp_get()` we need to differentiate between the case
	 * when the core has not tried to probe this device and the case when
	 * the probe failed.  In the later case we pretend that the
	 * initialization was successful and keep the error in
	 * `dev->driver_data`.
	 */
	pci_set_drvdata(pdev, ERR_PTR(err));
	if (!first_ptp_block)
		first_ptp_block = ERR_PTR(err);

	return 0;
}

static void ptp_remove(struct pci_dev *pdev)
{
	struct ptp *ptp = pci_get_drvdata(pdev);
	u64 clock_cfg;

	if (IS_ERR_OR_NULL(ptp))
		return;

	/* Disable PTP clock */
	clock_cfg = readq(ptp->reg_base + PTP_CLOCK_CFG);
	clock_cfg &= ~PTP_CLOCK_CFG_PTP_EN;
	writeq(clock_cfg, ptp->reg_base + PTP_CLOCK_CFG);
}

static const struct pci_device_id ptp_id_table[] = {
	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM, PCI_DEVID_OCTEONTX2_PTP,
			 PCI_VENDOR_ID_CAVIUM,
			 PCI_SUBSYS_DEVID_OCTX2_98xx_PTP) },
	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM, PCI_DEVID_OCTEONTX2_PTP,
			 PCI_VENDOR_ID_CAVIUM,
			 PCI_SUBSYS_DEVID_OCTX2_96XX_PTP) },
	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM, PCI_DEVID_OCTEONTX2_PTP,
			 PCI_VENDOR_ID_CAVIUM,
			 PCI_SUBSYS_DEVID_OCTX2_95XX_PTP) },
	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM, PCI_DEVID_OCTEONTX2_PTP,
			 PCI_VENDOR_ID_CAVIUM,
			 PCI_SUBSYS_DEVID_OCTX2_95XXN_PTP) },
	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM, PCI_DEVID_OCTEONTX2_PTP,
			 PCI_VENDOR_ID_CAVIUM,
			 PCI_SUBSYS_DEVID_OCTX2_95MM_PTP) },
	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM, PCI_DEVID_OCTEONTX2_PTP,
			 PCI_VENDOR_ID_CAVIUM,
			 PCI_SUBSYS_DEVID_OCTX2_95XXO_PTP) },
	{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, PCI_DEVID_CN10K_PTP) },
	{ 0, }
};

struct pci_driver ptp_driver = {
	.name = DRV_NAME,
	.id_table = ptp_id_table,
	.probe = ptp_probe,
	.remove = ptp_remove,
};

int rvu_mbox_handler_ptp_op(struct rvu *rvu, struct ptp_req *req,
			    struct ptp_rsp *rsp)
{
	int err = 0;

	/* This function is the PTP mailbox handler invoked when
	 * called by AF consumers/netdev drivers via mailbox mechanism.
	 * It is used by netdev driver to get the PTP clock and to set
	 * frequency adjustments. Since mailbox can be called without
	 * notion of whether the driver is bound to ptp device below
	 * validation is needed as first step.
	 */
	if (!rvu->ptp)
		return -ENODEV;

	switch (req->op) {
	case PTP_OP_ADJFINE:
		err = ptp_adjfine(rvu->ptp, req->scaled_ppm);
		break;
	case PTP_OP_GET_CLOCK:
		err = ptp_get_clock(rvu->ptp, &rsp->clk);
		break;
	case PTP_OP_GET_TSTMP:
		err = ptp_get_tstmp(rvu->ptp, &rsp->clk);
		break;
	case PTP_OP_SET_THRESH:
		err = ptp_set_thresh(rvu->ptp, req->thresh);
		break;
	default:
		err = -EINVAL;
		break;
	}

	return err;
}