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

Anwar, Md Danish
2023-08-15T10:08:22Z

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@ti.com>
>>
>> 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@ti.com>
>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>> Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
>> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
>> ---
>> 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