Re: [PATCH v4 3/5] net: ti: icss-iep: Add IEP driver

["Anwar, Md Danish" <a0501179@xxxxxx>]

Hi Roger,

On 8/15/2023 3:11 PM, Roger Quadros wrote:
> Hi Danish,
>
> On 14/08/2023 13:08, MD Danish Anwar wrote:
> > From: Roger Quadros <rogerq@xxxxxx>
> >
> > Add a driver for Industrial Ethernet Peripheral (IEP) block of PRUSS to
> > support timestamping of ethernet packets and thus support PTP and PPS
> > for PRU ethernet ports.
> >
> > Signed-off-by: Roger Quadros <rogerq@xxxxxx>
> > Signed-off-by: Lokesh Vutla <lokeshvutla@xxxxxx>
> > Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
> > Signed-off-by: Vignesh Raghavendra <vigneshr@xxxxxx>
> > Signed-off-by: MD Danish Anwar <danishanwar@xxxxxx>
> > ---
> >   drivers/net/ethernet/ti/Kconfig          |  11 +
> >   drivers/net/ethernet/ti/Makefile         |   1 +
> >   drivers/net/ethernet/ti/icssg/icss_iep.c | 921 +++++++++++++++++++++++
> >   drivers/net/ethernet/ti/icssg/icss_iep.h |  38 +
> >   4 files changed, 971 insertions(+)
> >   create mode 100644 drivers/net/ethernet/ti/icssg/icss_iep.c
> >   create mode 100644 drivers/net/ethernet/ti/icssg/icss_iep.h
> >
> > diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig
> > index 63e510b6860f..1af5a90720ec 100644
> > --- a/drivers/net/ethernet/ti/Kconfig
> > +++ b/drivers/net/ethernet/ti/Kconfig
> > @@ -196,4 +196,15 @@ config TI_ICSSG_PRUETH
> >   	  to support the Ethernet operation. Currently, it supports Ethernet
> >   	  with 1G and 100M link speed.
> >   
> > +config TI_ICSS_IEP
> > +	tristate "TI PRU ICSS IEP driver"
> > +	depends on TI_PRUSS
> > +	default TI_PRUSS
> > +	help
> > +	  This driver enables support for the PRU-ICSS Industrial Ethernet
> > +	  Peripheral within a PRU-ICSS subsystem present on various TI SoCs.
> > +
> > +	  To compile this driver as a module, choose M here. The module
> > +	  will be called icss_iep.
> > +
> >   endif # NET_VENDOR_TI
> > diff --git a/drivers/net/ethernet/ti/Makefile b/drivers/net/ethernet/ti/Makefile
> > index 9176d79c36e1..34fd7a716ba6 100644
> > --- a/drivers/net/ethernet/ti/Makefile
> > +++ b/drivers/net/ethernet/ti/Makefile
> > @@ -38,3 +38,4 @@ icssg-prueth-y := k3-cppi-desc-pool.o \
> >   		  icssg/icssg_mii_cfg.o \
> >   		  icssg/icssg_stats.o \
> >   		  icssg/icssg_ethtool.o
> > +obj-$(CONFIG_TI_ICSS_IEP) += icssg/icss_iep.o
> > diff --git a/drivers/net/ethernet/ti/icssg/icss_iep.c b/drivers/net/ethernet/ti/icssg/icss_iep.c
> > new file mode 100644
> > index 000000000000..d123b8ba3f31
> > --- /dev/null
> > +++ b/drivers/net/ethernet/ti/icssg/icss_iep.c
> > @@ -0,0 +1,921 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +/* Texas Instruments ICSSG Industrial Ethernet Peripheral (IEP) Driver
> > + *
> > + * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com
> > + *
> > + */
> > +
> > +#include <linux/bitops.h>
> > +#include <linux/clk.h>
> > +#include <linux/err.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/timekeeping.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/of_irq.h>
> > +
> > +#include "icss_iep.h"
> > +
> > +#define IEP_MAX_DEF_INC		0xf
> > +#define IEP_MAX_COMPEN_INC		0xfff
> > +#define IEP_MAX_COMPEN_COUNT	0xffffff
> > +
> > +#define IEP_GLOBAL_CFG_CNT_ENABLE	BIT(0)
> > +#define IEP_GLOBAL_CFG_DEFAULT_INC_MASK		GENMASK(7, 4)
> > +#define IEP_GLOBAL_CFG_DEFAULT_INC_SHIFT	4
> > +#define IEP_GLOBAL_CFG_COMPEN_INC_MASK		GENMASK(19, 8)
> > +#define IEP_GLOBAL_CFG_COMPEN_INC_SHIFT		8
> > +
> > +#define IEP_GLOBAL_STATUS_CNT_OVF	BIT(0)
> > +
> > +#define IEP_CMP_CFG_SHADOW_EN		BIT(17)
> > +#define IEP_CMP_CFG_CMP0_RST_CNT_EN	BIT(0)
> > +#define IEP_CMP_CFG_CMP_EN(cmp)		(GENMASK(16, 1) & (1 << ((cmp) + 1)))
> > +
> > +#define IEP_CMP_STATUS(cmp)		(1 << (cmp))
> > +
> > +#define IEP_SYNC_CTRL_SYNC_EN		BIT(0)
> > +#define IEP_SYNC_CTRL_SYNC_N_EN(n)	(GENMASK(2, 1) & (BIT(1) << (n)))
> > +
> > +#define IEP_MIN_CMP	0
> > +#define IEP_MAX_CMP	15
> > +
> > +#define ICSS_IEP_64BIT_COUNTER_SUPPORT		BIT(0)
> > +#define ICSS_IEP_SLOW_COMPEN_REG_SUPPORT	BIT(1)
> > +#define ICSS_IEP_SHADOW_MODE_SUPPORT		BIT(2)
> > +
> > +#define LATCH_INDEX(ts_index)			((ts_index) + 6)
> > +#define IEP_CAP_CFG_CAPNR_1ST_EVENT_EN(n)	BIT(LATCH_INDEX(n))
> > +#define IEP_CAP_CFG_CAP_ASYNC_EN(n)		BIT(LATCH_INDEX(n) + 10)
> > +
> > +enum {
> > +	ICSS_IEP_GLOBAL_CFG_REG,
> > +	ICSS_IEP_GLOBAL_STATUS_REG,
> > +	ICSS_IEP_COMPEN_REG,
> > +	ICSS_IEP_SLOW_COMPEN_REG,
> > +	ICSS_IEP_COUNT_REG0,
> > +	ICSS_IEP_COUNT_REG1,
> > +	ICSS_IEP_CAPTURE_CFG_REG,
> > +	ICSS_IEP_CAPTURE_STAT_REG,
> > +
> > +	ICSS_IEP_CAP6_RISE_REG0,
> > +	ICSS_IEP_CAP6_RISE_REG1,
> > +
> > +	ICSS_IEP_CAP7_RISE_REG0,
> > +	ICSS_IEP_CAP7_RISE_REG1,
> > +
> > +	ICSS_IEP_CMP_CFG_REG,
> > +	ICSS_IEP_CMP_STAT_REG,
> > +	ICSS_IEP_CMP0_REG0,
> > +	ICSS_IEP_CMP0_REG1,
> > +	ICSS_IEP_CMP1_REG0,
> > +	ICSS_IEP_CMP1_REG1,
> > +
> > +	ICSS_IEP_CMP8_REG0,
> > +	ICSS_IEP_CMP8_REG1,
> > +	ICSS_IEP_SYNC_CTRL_REG,
> > +	ICSS_IEP_SYNC0_STAT_REG,
> > +	ICSS_IEP_SYNC1_STAT_REG,
> > +	ICSS_IEP_SYNC_PWIDTH_REG,
> > +	ICSS_IEP_SYNC0_PERIOD_REG,
> > +	ICSS_IEP_SYNC1_DELAY_REG,
> > +	ICSS_IEP_SYNC_START_REG,
> > +	ICSS_IEP_MAX_REGS,
> > +};
> > +
> > +/**
> > + * struct icss_iep_plat_data - Plat data to handle SoC variants
> > + * @config: Regmap configuration data
> > + * @reg_offs: register offsets to capture offset differences across SoCs
> > + * @flags: Flags to represent IEP properties
> > + */
> > +struct icss_iep_plat_data {
> > +	struct regmap_config *config;
> > +	u32 reg_offs[ICSS_IEP_MAX_REGS];
> > +	u32 flags;
> > +};
> > +
> > +struct icss_iep {
> > +	struct device *dev;
> > +	void __iomem *base;
> > +	const struct icss_iep_plat_data *plat_data;
> > +	struct regmap *map;
> > +	struct device_node *client_np;
> > +	unsigned long refclk_freq;
> > +	int clk_tick_time;	/* one refclk tick time in ns */
> > +	struct ptp_clock_info ptp_info;
> > +	struct ptp_clock *ptp_clock;
> > +	struct mutex ptp_clk_mutex;	/* PHC access serializer */
> > +	spinlock_t irq_lock; /* CMP IRQ vs icss_iep_ptp_enable access */
> > +	u32 def_inc;
> > +	s16 slow_cmp_inc;
> > +	u32 slow_cmp_count;
> > +	const struct icss_iep_clockops *ops;
> > +	void *clockops_data;
> > +	u32 cycle_time_ns;
> > +	u32 perout_enabled;
> > +	bool pps_enabled;
> > +	int cap_cmp_irq;
> > +	u64 period;
> > +	u32 latch_enable;
> > +};
> > +
>
> Where is the comment you agreed to add on why we are using readl/writel
> instead of regmap in certain areas?

We agreed to add comment on why we are using readl/writel instead of 
regmap in the documentation of the readl / writel helper APIs 
(icss_iep_readl / writel ). But Andrew asked me to drop those helper 
APIs, so I dropped them. Now no helper APIs are there and we are 
directly using readl / writel in total 8 places. Previously with the 
helper APIs, there was a way to document the use of readl / writel 
before the declaration of heper APIs. Now with no helper APIs, I 
couldn't find a good place to add this documentation as all 8 instances 
using readl / writel seems similar. So I dropped it.

> > +/**
> > + * icss_iep_get_count_hi() - Get the upper 32 bit IEP counter
> > + * @iep: Pointer to structure representing IEP.
> > + *
> > + * Return: upper 32 bit IEP counter
> > + */
> > +int icss_iep_get_count_hi(struct icss_iep *iep)
> > +{
> > +	u32 val = 0;
> > +
> > +	if (iep && (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT))
> > +		val = readl(iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG1]);
> > +
> > +	return val;
> > +}
> > +EXPORT_SYMBOL_GPL(icss_iep_get_count_hi);
> > +
> > +/**
> > + * icss_iep_get_count_low() - Get the lower 32 bit IEP counter
> > + * @iep: Pointer to structure representing IEP.
> > + *
> > + * Return: lower 32 bit IEP counter
> > + */
> > +int icss_iep_get_count_low(struct icss_iep *iep)
> > +{
> > +	u32 val = 0;
> > +
> > +	if (iep)
> > +		val = readl(iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG0]);
> > +
> > +	return val;
> > +}
> > +EXPORT_SYMBOL_GPL(icss_iep_get_count_low);
> > +
> > +/**
> > + * icss_iep_get_ptp_clock_idx() - Get PTP clock index using IEP driver
> > + * @iep: Pointer to structure representing IEP.
> > + *
> > + * Return: PTP clock index, -1 if not registered
> > + */
> > +int icss_iep_get_ptp_clock_idx(struct icss_iep *iep)
> > +{
> > +	if (!iep || !iep->ptp_clock)
> > +		return -1;
> > +	return ptp_clock_index(iep->ptp_clock);
> > +}
> > +EXPORT_SYMBOL_GPL(icss_iep_get_ptp_clock_idx);
> > +
> > +static void icss_iep_set_counter(struct icss_iep *iep, u64 ns)
> > +{
> > +	if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT)
> > +		writel(upper_32_bits(ns), iep->base +
> > +		       iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG1]);
> > +	writel(upper_32_bits(ns), iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG0]);
> > +}
> > +
> > +static void icss_iep_update_to_next_boundary(struct icss_iep *iep, u64 start_ns);
> > +
> > +static void icss_iep_settime(struct icss_iep *iep, u64 ns)
> > +{
> > +	unsigned long flags;
> > +
> > +	if (iep->ops && iep->ops->settime) {
> > +		iep->ops->settime(iep->clockops_data, ns);
> > +		return;
> > +	}
> > +
> > +	spin_lock_irqsave(&iep->irq_lock, flags);
> > +	if (iep->pps_enabled || iep->perout_enabled)
> > +		writel(0, iep->base + iep->plat_data->reg_offs[ICSS_IEP_SYNC_CTRL_REG]);
> > +
> > +	icss_iep_set_counter(iep, ns);
> > +
> > +	if (iep->pps_enabled || iep->perout_enabled) {
> > +		icss_iep_update_to_next_boundary(iep, ns);
> > +		writel(IEP_SYNC_CTRL_SYNC_N_EN(0) | IEP_SYNC_CTRL_SYNC_EN,
> > +		       iep->base + iep->plat_data->reg_offs[ICSS_IEP_SYNC_CTRL_REG]);
> > +	}
> > +	spin_unlock_irqrestore(&iep->irq_lock, flags);
> > +}
> > +
> > +static u64 icss_iep_gettime(struct icss_iep *iep,
> > +			    struct ptp_system_timestamp *sts)
> > +{
> > +	u32 ts_hi = 0, ts_lo;
> > +	unsigned long flags;
> > +
> > +	if (iep->ops && iep->ops->gettime)
> > +		return iep->ops->gettime(iep->clockops_data, sts);
> > +
> > +	/* use local_irq_x() to make it work for both RT/non-RT */
> > +	local_irq_save(flags);
> > +
> > +	/* no need to play with hi-lo, hi is latched when lo is read */
> > +	ptp_read_system_prets(sts);
> > +	ts_lo = readl(iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG0]);
> > +	ptp_read_system_postts(sts);
> > +	if (iep->plat_data->flags & ICSS_IEP_64BIT_COUNTER_SUPPORT)
> > +		ts_hi = readl(iep->base + iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG1]);
> > +
> > +	local_irq_restore(flags);
> > +
> > +	return (u64)ts_lo | (u64)ts_hi << 32;
> > +}
> > +
> > +static void icss_iep_enable(struct icss_iep *iep)
> > +{
> > +	regmap_update_bits(iep->map, ICSS_IEP_GLOBAL_CFG_REG,
> > +			   IEP_GLOBAL_CFG_CNT_ENABLE,
> > +			   IEP_GLOBAL_CFG_CNT_ENABLE);
> > +}
> > +
> <snip>

--
Thanks and Regards,
Md Danish Anwar