octeontx2-af: Add support for Marvell PTP coprocessor

Precision Timestamping block found on Octeontx2
platform is an independent coprocessor and has
internal PTP hardware clock. Once configured PTP
runs independently and when a packet arrives
CGX hardware block gets the current timestamp
from PTP block and forwards the packet to NIX
by prepending timestamp to the packet.
This patch adds the pci driver for PTP block.
The driver gets registered by AF driver and does
initial configuration and exposes a mailbox function to
read and adjust PTP hardware clock. The mailbox function
is called by AF consumers like netdev drivers or
userspace drivers. Since PTP being a single block
in platform this driver helps in accessing PTP
block by any AF consumer.
Co-developed-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Aleksey Makarov <amakarov@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/octeontx2/af/Makefile

@@ -8,4 +8,4 @@ obj-$(CONFIG_OCTEONTX2_AF) += octeontx2_af.o
 
 octeontx2_mbox-y := mbox.o
 octeontx2_af-y := cgx.o rvu.o rvu_cgx.o rvu_npa.o rvu_nix.o \
-		  rvu_reg.o rvu_npc.o rvu_debugfs.o
+		  rvu_reg.o rvu_npc.o rvu_debugfs.o ptp.o

drivers/net/ethernet/marvell/octeontx2/af/mbox.h

@@ -127,6 +127,7 @@ M(ATTACH_RESOURCES,	0x002, attach_resources, rsrc_attach, msg_rsp)	\
 M(DETACH_RESOURCES,	0x003, detach_resources, rsrc_detach, msg_rsp)	\
 M(MSIX_OFFSET,		0x005, msix_offset, msg_req, msix_offset_rsp)	\
 M(VF_FLR,		0x006, vf_flr, msg_req, msg_rsp)		\
+M(PTP_OP,		0x007, ptp_op, ptp_req, ptp_rsp)		\
 M(GET_HW_CAP,		0x008, get_hw_cap, msg_req, get_hw_cap_rsp)	\
 /* CGX mbox IDs (range 0x200 - 0x3FF) */				\
 M(CGX_START_RXTX,	0x200, cgx_start_rxtx, msg_req, msg_rsp)	\
@@ -862,4 +863,20 @@ struct npc_get_kex_cfg_rsp {
 	u8 mkex_pfl_name[MKEX_NAME_LEN];
 };
 
+enum ptp_op {
+	PTP_OP_ADJFINE = 0,
+	PTP_OP_GET_CLOCK = 1,
+};
+
+struct ptp_req {
+	struct mbox_msghdr hdr;
+	u8 op;
+	s64 scaled_ppm;
+};
+
+struct ptp_rsp {
+	struct mbox_msghdr hdr;
+	u64 clk;
+};
+
 #endif /* MBOX_H */

drivers/net/ethernet/marvell/octeontx2/af/ptp.c

+// SPDX-License-Identifier: GPL-2.0
+/* Marvell PTP driver
+ *
+ * Copyright (C) 2020 Marvell International Ltd.
+ */
+
+#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_LOKI_PTP		0xB400
+#define PCI_SUBSYS_DEVID_OCTX2_95MM_PTP		0xB500
+#define PCI_DEVID_OCTEONTX2_RST			0xA085
+
+#define PCI_PTP_BAR_NO				0
+#define PCI_RST_BAR_NO				0
+
+#define PTP_CLOCK_CFG				0xF00ULL
+#define PTP_CLOCK_CFG_PTP_EN			BIT_ULL(0)
+#define PTP_CLOCK_LO				0xF08ULL
+#define PTP_CLOCK_HI				0xF10ULL
+#define PTP_CLOCK_COMP				0xF18ULL
+
+#define RST_BOOT				0x1600ULL
+#define RST_MUL_BITS				GENMASK_ULL(38, 33)
+#define CLOCK_BASE_RATE				50000000ULL
+
+static u64 get_clock_rate(void)
+{
+	u64 cfg, ret = CLOCK_BASE_RATE * 16;
+	struct pci_dev *pdev;
+	void __iomem *base;
+
+	/* To get the input clock frequency with which PTP co-processor
+	 * block is running the base frequency(50 MHz) needs to be multiplied
+	 * with multiplier bits present in RST_BOOT register of RESET block.
+	 * Hence below code gets the multiplier bits from the RESET PCI
+	 * device present in the system.
+	 */
+	pdev = pci_get_device(PCI_VENDOR_ID_CAVIUM,
+			      PCI_DEVID_OCTEONTX2_RST, NULL);
+	if (!pdev)
+		goto error;
+
+	base = pci_ioremap_bar(pdev, PCI_RST_BAR_NO);
+	if (!base)
+		goto error_put_pdev;
+
+	cfg = readq(base + RST_BOOT);
+	ret = CLOCK_BASE_RATE * FIELD_GET(RST_MUL_BITS, cfg);
+
+	iounmap(base);
+
+error_put_pdev:
+	pci_dev_put(pdev);
+
+error:
+	return ret;
+}
+
+struct ptp *ptp_get(void)
+{
+	struct pci_dev *pdev;
+	struct ptp *ptp;
+
+	/* If the PTP pci device is found on the system and ptp
+	 * driver is bound to it then the PTP pci device is returned
+	 * to the caller(rvu driver).
+	 */
+	pdev = pci_get_device(PCI_VENDOR_ID_CAVIUM,
+			      PCI_DEVID_OCTEONTX2_PTP, NULL);
+	if (!pdev)
+		return ERR_PTR(-ENODEV);
+
+	ptp = pci_get_drvdata(pdev);
+	if (!ptp)
+		ptp = ERR_PTR(-EPROBE_DEFER);
+	if (IS_ERR(ptp))
+		pci_dev_put(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;
+	u64 comp;
+	u64 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.
+	 */
+	comp = ((u64)1000000000ull << 32) / ptp->clock_rate;
+	/* convert scaled_ppm to ppb */
+	ppb = 1 + scaled_ppm;
+	ppb *= 125;
+	ppb >>= 13;
+	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 = readq(ptp->reg_base + PTP_CLOCK_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;
+	u64 clock_comp;
+	u64 clock_cfg;
+	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];
+
+	ptp->clock_rate = get_clock_rate();
+
+	/* Enable 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);
+
+	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);
+
+	pci_set_drvdata(pdev, ptp);
+
+	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));
+	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_LOKI_PTP) },
+	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM, PCI_DEVID_OCTEONTX2_PTP,
+			 PCI_VENDOR_ID_CAVIUM,
+			 PCI_SUBSYS_DEVID_OCTX2_95MM_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;
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}

drivers/net/ethernet/marvell/octeontx2/af/ptp.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/* Marvell PTP driver
+ *
+ * Copyright (C) 2020 Marvell International Ltd.
+ */
+
+#ifndef PTP_H
+#define PTP_H
+
+#include <linux/timecounter.h>
+#include <linux/time64.h>
+#include <linux/spinlock.h>
+
+struct ptp {
+	struct pci_dev *pdev;
+	void __iomem *reg_base;
+	u32 clock_rate;
+};
+
+struct ptp *ptp_get(void);
+void ptp_put(struct ptp *ptp);
+
+extern struct pci_driver ptp_driver;
+
+#endif

drivers/net/ethernet/marvell/octeontx2/af/rvu.c

@@ -18,6 +18,7 @@
 #include "cgx.h"
 #include "rvu.h"
 #include "rvu_reg.h"
+#include "ptp.h"
 
 #define DRV_NAME	"octeontx2-af"
 #define DRV_STRING      "Marvell OcteonTX2 RVU Admin Function Driver"
@@ -2565,13 +2566,21 @@ static int rvu_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	pci_set_master(pdev);
 
+	rvu->ptp = ptp_get();
+	if (IS_ERR(rvu->ptp)) {
+		err = PTR_ERR(rvu->ptp);
+		if (err == -EPROBE_DEFER)
+			goto err_release_regions;
+		rvu->ptp = NULL;
+	}
+
 	/* Map Admin function CSRs */
 	rvu->afreg_base = pcim_iomap(pdev, PCI_AF_REG_BAR_NUM, 0);
 	rvu->pfreg_base = pcim_iomap(pdev, PCI_PF_REG_BAR_NUM, 0);
 	if (!rvu->afreg_base || !rvu->pfreg_base) {
 		dev_err(dev, "Unable to map admin function CSRs, aborting\n");
 		err = -ENOMEM;
-		goto err_release_regions;
+		goto err_put_ptp;
 	}
 
 	/* Store module params in rvu structure */
@@ -2586,7 +2595,7 @@ static int rvu_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	err = rvu_setup_hw_resources(rvu);
 	if (err)
-		goto err_release_regions;
+		goto err_put_ptp;
 
 	/* Init mailbox btw AF and PFs */
 	err = rvu_mbox_init(rvu, &rvu->afpf_wq_info, TYPE_AFPF,
@@ -2626,6 +2635,8 @@ static int rvu_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	rvu_reset_all_blocks(rvu);
 	rvu_free_hw_resources(rvu);
 	rvu_clear_rvum_blk_revid(rvu);
+err_put_ptp:
+	ptp_put(rvu->ptp);
 err_release_regions:
 	pci_release_regions(pdev);
 err_disable_device:
@@ -2651,6 +2662,7 @@ static void rvu_remove(struct pci_dev *pdev)
 	rvu_reset_all_blocks(rvu);
 	rvu_free_hw_resources(rvu);
 	rvu_clear_rvum_blk_revid(rvu);
+	ptp_put(rvu->ptp);
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
 	pci_set_drvdata(pdev, NULL);
@@ -2676,9 +2688,19 @@ static int __init rvu_init_module(void)
 	if (err < 0)
 		return err;
 
+	err = pci_register_driver(&ptp_driver);
+	if (err < 0)
+		goto ptp_err;
+
 	err =  pci_register_driver(&rvu_driver);
 	if (err < 0)
-		pci_unregister_driver(&cgx_driver);
+		goto rvu_err;
+
+	return 0;
+rvu_err:
+	pci_unregister_driver(&ptp_driver);
+ptp_err:
+	pci_unregister_driver(&cgx_driver);
 
 	return err;
 }
@@ -2686,6 +2708,7 @@ static int __init rvu_init_module(void)
 static void __exit rvu_cleanup_module(void)
 {
 	pci_unregister_driver(&rvu_driver);
+	pci_unregister_driver(&ptp_driver);
 	pci_unregister_driver(&cgx_driver);
 }
 

drivers/net/ethernet/marvell/octeontx2/af/rvu.h

@@ -289,6 +289,8 @@ struct rvu_fwdata {
 	u64 reserved[FWDATA_RESERVED_MEM];
 };
 
+struct ptp;
+
 struct rvu {
 	void __iomem		*afreg_base;
 	void __iomem		*pfreg_base;
@@ -337,6 +339,8 @@ struct rvu {
 	/* Firmware data */
 	struct rvu_fwdata	*fwdata;
 
+	struct ptp		*ptp;
+
 #ifdef CONFIG_DEBUG_FS
 	struct rvu_debugfs	rvu_dbg;
 #endif