Subject: Re: [PATCH net-next v3] net: ti: icssg_prueth: add TAPRIO offload support

From: Vinicius Costa Gomes <[email-masked]>
Date: Fri, 29 Sep 2023 19:37:14 -0700

MD Danish Anwar <[email-masked]> writes:

> From: Roger Quadros <[email-masked]>
>
> ICSSG dual-emac f/w supports Enhanced Scheduled Traffic (EST – defined
> in P802.1Qbv/D2.2 that later got included in IEEE 802.1Q-2018)
> configuration. EST allows express queue traffic to be scheduled
> (placed) on the wire at specific repeatable time intervals. In
> Linux kernel, EST configuration is done through tc command and
> the taprio scheduler in the net core implements a software only
> scheduler (SCH_TAPRIO). If the NIC is capable of EST configuration,
> user indicate "flag 2" in the command which is then parsed by
> taprio scheduler in net core and indicate that the command is to
> be offloaded to h/w. taprio then offloads the command to the
> driver by calling ndo_setup_tc() ndo ops. This patch implements
> ndo_setup_tc() to offload EST configuration to ICSSG.
>
> Signed-off-by: Roger Quadros <[email-masked]>
> Signed-off-by: Vignesh Raghavendra <[email-masked]>
> Signed-off-by: MD Danish Anwar <[email-masked]>
> ---
> Cc: Roger Quadros <[email-masked]>
> Cc: Andrew Lunn <[email-masked]>
> Cc: Vinicius Costa Gomes <[email-masked]>
>
> Changes from v2 to v3:
> *) Rebased on the latest next-20230828 linux-next.
> *) Retained original authorship of the patch.
> *) Addressed Roger's comments and modified emac_setup_taprio() and
>    emac_set_taprio() APIs accordingly.
> *) Removed netif_running() check from emac_setup_taprio().
> *) Addressed Vinicius' comments and added check for MIN and MAX cycle time.
> *) Added check for allocation failure of est_new in emac_setup_taprio().
>
> Changes from v1 to v2:
> *) Rebased on the latest next-20230821 linux-next.
> *) Dropped the RFC tag as merge window is open now.
> *) Splitted this patch from the switch mode series [v1].
> *) Removed TODO comment as asked by Andrew and Roger.
> *) Changed Copyright to 2023 as asked by Roger.
>
> v2: https://lore.kernel.org/all/[email-masked]/
> v1: https://lore.kernel.org/all/[email-masked]/
>
>  drivers/net/ethernet/ti/Makefile             |   3 +-
>  drivers/net/ethernet/ti/icssg/icssg_prueth.c |   5 +-
>  drivers/net/ethernet/ti/icssg/icssg_prueth.h |   6 +
>  drivers/net/ethernet/ti/icssg/icssg_qos.c    | 295 +++++++++++++++++++
>  drivers/net/ethernet/ti/icssg/icssg_qos.h    | 124 ++++++++
>  5 files changed, 431 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/net/ethernet/ti/icssg/icssg_qos.c
>  create mode 100644 drivers/net/ethernet/ti/icssg/icssg_qos.h
>
> diff --git a/drivers/net/ethernet/ti/Makefile b/drivers/net/ethernet/ti/Makefile
> index 34fd7a716ba6..0df60ded1b2d 100644
> --- a/drivers/net/ethernet/ti/Makefile
> +++ b/drivers/net/ethernet/ti/Makefile
> @@ -37,5 +37,6 @@ icssg-prueth-y := k3-cppi-desc-pool.o \
>  		  icssg/icssg_config.o \
>  		  icssg/icssg_mii_cfg.o \
>  		  icssg/icssg_stats.o \
> -		  icssg/icssg_ethtool.o
> +		  icssg/icssg_ethtool.o \
> +		  icssg/icssg_qos.o
>  obj-$(CONFIG_TI_ICSS_IEP) += icssg/icss_iep.o
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.c b/drivers/net/ethernet/ti/icssg/icssg_prueth.c
> index 6635b28bc672..89c301716926 100644
> --- a/drivers/net/ethernet/ti/icssg/icssg_prueth.c
> +++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.c
> @@ -1166,7 +1166,7 @@ static int emac_phy_connect(struct prueth_emac *emac)
>  	return 0;
>  }
>  
> -static u64 prueth_iep_gettime(void *clockops_data, struct ptp_system_timestamp *sts)
> +u64 prueth_iep_gettime(void *clockops_data, struct ptp_system_timestamp *sts)
>  {
>  	u32 hi_rollover_count, hi_rollover_count_r;
>  	struct prueth_emac *emac = clockops_data;
> @@ -1403,6 +1403,8 @@ static int emac_ndo_open(struct net_device *ndev)
>  		napi_enable(&emac->tx_chns[i].napi_tx);
>  	napi_enable(&emac->napi_rx);
>  
> +	icssg_qos_tas_init(ndev);
> +
>  	/* start PHY */
>  	phy_start(ndev->phydev);
>  
> @@ -1669,6 +1671,7 @@ static const struct net_device_ops emac_netdev_ops = {
>  	.ndo_set_rx_mode = emac_ndo_set_rx_mode,
>  	.ndo_eth_ioctl = emac_ndo_ioctl,
>  	.ndo_get_stats64 = emac_ndo_get_stats64,
> +	.ndo_setup_tc = icssg_qos_ndo_setup_tc,
>  };
>  
>  /* get emac_port corresponding to eth_node name */
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.h b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
> index 8b6d6b497010..7cbf0e561905 100644
> --- a/drivers/net/ethernet/ti/icssg/icssg_prueth.h
> +++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
> @@ -37,6 +37,7 @@
>  #include "icssg_config.h"
>  #include "icss_iep.h"
>  #include "icssg_switch_map.h"
> +#include "icssg_qos.h"
>  
>  #define PRUETH_MAX_MTU          (2000 - ETH_HLEN - ETH_FCS_LEN)
>  #define PRUETH_MIN_PKT_SIZE     (VLAN_ETH_ZLEN)
> @@ -174,6 +175,8 @@ struct prueth_emac {
>  
>  	struct pruss_mem_region dram;
>  
> +	struct prueth_qos qos;
> +
>  	struct delayed_work stats_work;
>  	u64 stats[ICSSG_NUM_STATS];
>  };
> @@ -285,4 +288,7 @@ u32 icssg_queue_level(struct prueth *prueth, int queue);
>  void emac_stats_work_handler(struct work_struct *work);
>  void emac_update_hardware_stats(struct prueth_emac *emac);
>  int emac_get_stat_by_name(struct prueth_emac *emac, char *stat_name);
> +
> +u64 prueth_iep_gettime(void *clockops_data, struct ptp_system_timestamp *sts);
> +
>  #endif /* __NET_TI_ICSSG_PRUETH_H */
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_qos.c b/drivers/net/ethernet/ti/icssg/icssg_qos.c
> new file mode 100644
> index 000000000000..95a8b1902879
> --- /dev/null
> +++ b/drivers/net/ethernet/ti/icssg/icssg_qos.c
> @@ -0,0 +1,295 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Texas Instruments ICSSG PRUETH QoS submodule
> + * Copyright (C) 2023 Texas Instruments Incorporated - http://www.ti.com/
> + */
> +
> +#include <linux/printk.h>
> +#include "icssg_prueth.h"
> +#include "icssg_switch_map.h"
> +
> +static void tas_update_fw_list_pointers(struct prueth_emac *emac)
> +{
> +	struct tas_config *tas = &emac->qos.tas.config;
> +
> +	if ((readb(tas->active_list)) == TAS_LIST0) {
> +		tas->fw_active_list = emac->dram.va + TAS_GATE_MASK_LIST0;
> +		tas->fw_shadow_list = emac->dram.va + TAS_GATE_MASK_LIST1;
> +	} else {
> +		tas->fw_active_list = emac->dram.va + TAS_GATE_MASK_LIST1;
> +		tas->fw_shadow_list = emac->dram.va + TAS_GATE_MASK_LIST0;
> +	}
> +}
> +
> +static void tas_update_maxsdu_table(struct prueth_emac *emac)
> +{
> +	struct tas_config *tas = &emac->qos.tas.config;
> +	u16 __iomem *max_sdu_tbl_ptr;
> +	u8 gate_idx;
> +
> +	/* update the maxsdu table */
> +	max_sdu_tbl_ptr = emac->dram.va + TAS_QUEUE_MAX_SDU_LIST;
> +
> +	for (gate_idx = 0; gate_idx < TAS_MAX_NUM_QUEUES; gate_idx++)
> +		writew(tas->max_sdu_table.max_sdu[gate_idx], &max_sdu_tbl_ptr[gate_idx]);
> +}
> +
> +static void tas_reset(struct prueth_emac *emac)
> +{
> +	struct tas_config *tas = &emac->qos.tas.config;
> +	int i;
> +
> +	for (i = 0; i < TAS_MAX_NUM_QUEUES; i++)
> +		tas->max_sdu_table.max_sdu[i] = 2048;
> +
> +	tas_update_maxsdu_table(emac);
> +
> +	writeb(TAS_LIST0, tas->active_list);
> +
> +	memset_io(tas->fw_active_list, 0, sizeof(*tas->fw_active_list));
> +	memset_io(tas->fw_shadow_list, 0, sizeof(*tas->fw_shadow_list));
> +}
> +
> +static int tas_set_state(struct prueth_emac *emac, enum tas_state state)
> +{
> +	struct tas_config *tas = &emac->qos.tas.config;
> +	int ret;
> +
> +	if (tas->state == state)
> +		return 0;
> +
> +	switch (state) {
> +	case TAS_STATE_RESET:
> +		tas_reset(emac);
> +		ret = emac_set_port_state(emac, ICSSG_EMAC_PORT_TAS_RESET);
> +		tas->state = TAS_STATE_RESET;
> +		break;
> +	case TAS_STATE_ENABLE:
> +		ret = emac_set_port_state(emac, ICSSG_EMAC_PORT_TAS_ENABLE);
> +		tas->state = TAS_STATE_ENABLE;
> +		break;
> +	case TAS_STATE_DISABLE:
> +		ret = emac_set_port_state(emac, ICSSG_EMAC_PORT_TAS_DISABLE);
> +		tas->state = TAS_STATE_DISABLE;
> +		break;
> +	default:
> +		netdev_err(emac->ndev, "%s: unsupported state\n", __func__);
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	if (ret)
> +		netdev_err(emac->ndev, "TAS set state failed %d\n", ret);
> +	return ret;
> +}
> +
> +static int tas_set_trigger_list_change(struct prueth_emac *emac)
> +{
> +	struct tc_taprio_qopt_offload *admin_list = emac->qos.tas.taprio_admin;
> +	struct tas_config *tas = &emac->qos.tas.config;
> +	struct ptp_system_timestamp sts;
> +	u32 change_cycle_count;
> +	u32 cycle_time;
> +	u64 base_time;
> +	u64 cur_time;
> +
> +	if (admin_list->cycle_time < TAS_MIN_CYCLE_TIME)
> +		return -EINVAL;
> +
> +	cycle_time = admin_list->cycle_time - 4; /* -4ns to compensate for IEP wraparound time */
> +	base_time = admin_list->base_time;
> +	cur_time = prueth_iep_gettime(emac, &sts);
> +
> +	if (base_time > cur_time)
> +		change_cycle_count = DIV_ROUND_UP_ULL(base_time - cur_time, cycle_time);
> +	else
> +		change_cycle_count = 1;
> +
> +	writel(cycle_time, emac->dram.va + TAS_ADMIN_CYCLE_TIME);
> +	writel(change_cycle_count, emac->dram.va + TAS_CONFIG_CHANGE_CYCLE_COUNT);
> +	writeb(admin_list->num_entries, emac->dram.va + TAS_ADMIN_LIST_LENGTH);
> +
> +	/* config_change cleared by f/w to ack reception of new shadow list */
> +	writeb(1, &tas->config_list->config_change);
> +	/* config_pending cleared by f/w when new shadow list is copied to active list */
> +	writeb(1, &tas->config_list->config_pending);
> +
> +	return emac_set_port_state(emac, ICSSG_EMAC_PORT_TAS_TRIGGER);
> +}
> +
> +static int tas_update_oper_list(struct prueth_emac *emac)
> +{
> +	struct tc_taprio_qopt_offload *admin_list = emac->qos.tas.taprio_admin;
> +	struct tas_config *tas = &emac->qos.tas.config;
> +	u32 tas_acc_gate_close_time = 0;
> +	u8 idx, gate_idx, val;
> +	int ret;
> +
> +	if (admin_list->cycle_time > TAS_MAX_CYCLE_TIME)
> +		return -EINVAL;
> +
> +	tas_update_fw_list_pointers(emac);
> +
> +	for (idx = 0; idx < admin_list->num_entries; idx++) {
> +		writeb(admin_list->entries[idx].gate_mask,
> +		       &tas->fw_shadow_list->gate_mask_list[idx]);
> +		tas_acc_gate_close_time += admin_list->entries[idx].interval;
> +
> +		/* extend last entry till end of cycle time */
> +		if (idx == admin_list->num_entries - 1)
> +			writel(admin_list->cycle_time,
> +			       &tas->fw_shadow_list->win_end_time_list[idx]);
> +		else
> +			writel(tas_acc_gate_close_time,
> +			       &tas->fw_shadow_list->win_end_time_list[idx]);
> +	}
> +
> +	/* clear remaining entries */
> +	for (idx = admin_list->num_entries; idx < TAS_MAX_CMD_LISTS; idx++) {
> +		writeb(0, &tas->fw_shadow_list->gate_mask_list[idx]);
> +		writel(0, &tas->fw_shadow_list->win_end_time_list[idx]);
> +	}
> +
> +	/* update the Array of gate close time for each queue in each window */
> +	for (idx = 0 ; idx < admin_list->num_entries; idx++) {
> +		/* On Linux, only PRUETH_MAX_TX_QUEUES are supported per port */
> +		for (gate_idx = 0; gate_idx < PRUETH_MAX_TX_QUEUES; gate_idx++) {
> +			u8 gate_mask_list_idx = readb(&tas->fw_shadow_list->gate_mask_list[idx]);
> +			u32 gate_close_time = 0;
> +
> +			if (gate_mask_list_idx & BIT(gate_idx))
> +				gate_close_time = readl(&tas->fw_shadow_list->win_end_time_list[idx]);
> +
> +			writel(gate_close_time,
> +			       &tas->fw_shadow_list->gate_close_time_list[idx][gate_idx]);
> +		}
> +	}
> +
> +	/* tell f/w to swap active & shadow list */
> +	ret = tas_set_trigger_list_change(emac);
> +	if (ret) {
> +		netdev_err(emac->ndev, "failed to swap f/w config list: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* Wait for completion */
> +	ret = readb_poll_timeout(&tas->config_list->config_change, val, !val,
> +				 USEC_PER_MSEC, 10 * USEC_PER_MSEC);
> +	if (ret) {
> +		netdev_err(emac->ndev, "TAS list change completion time out\n");
> +		return ret;
> +	}
> +
> +	tas_update_fw_list_pointers(emac);
> +
> +	return 0;
> +}
> +
> +static int emac_set_taprio(struct prueth_emac *emac)
> +{
> +	struct tc_taprio_qopt_offload *taprio = emac->qos.tas.taprio_admin;
> +	int ret;
> +
> +	switch (taprio->cmd) {
> +	case TAPRIO_CMD_DESTROY:
> +		ret = tas_set_state(emac, TAS_STATE_DISABLE);
> +		break;
> +	case TAPRIO_CMD_REPLACE:
> +		ret = tas_update_oper_list(emac);
> +		if (ret)
> +			return ret;
> +		ret =  tas_set_state(emac, TAS_STATE_ENABLE);

Double space here.

> +		break;
> +	default:
> +		ret = -EOPNOTSUPP;
> +	}
> +
> +	return ret;
> +}
> +
> +static void emac_cp_taprio(struct tc_taprio_qopt_offload *from,
> +			   struct tc_taprio_qopt_offload *to)
> +{
> +	int i;
> +
> +	*to = *from;
> +	for (i = 0; i < from->num_entries; i++)
> +		to->entries[i] = from->entries[i];
> +}
> +
> +static int emac_setup_taprio(struct net_device *ndev, void *type_data)
> +{
> +	struct tc_taprio_qopt_offload *taprio = type_data;
> +	struct prueth_emac *emac = netdev_priv(ndev);
> +	struct tc_taprio_qopt_offload *est_new;
> +	int ret, idx;
> +
> +	if (taprio->cycle_time_extension) {
> +		netdev_err(ndev, "Failed to set cycle time extension");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	if (taprio->num_entries == 0 ||
> +	    taprio->num_entries > TAS_MAX_CMD_LISTS) {
> +		NL_SET_ERR_MSG_FMT_MOD(taprio->extack, "unsupported num_entries %ld in taprio config\n",
> +				       taprio->num_entries);
> +		return -EINVAL;
> +	}
> +
> +	/* If any time_interval is 0 in between the list, then exit */
> +	for (idx = 0; idx < taprio->num_entries; idx++) {
> +		if (taprio->entries[idx].interval == 0) {
> +			NL_SET_ERR_MSG_MOD(taprio->extack, "0 interval in taprio config not supported\n");
> +			return -EINVAL;
> +		}
> +	}
> +
> +	if (emac->qos.tas.taprio_admin)
> +		devm_kfree(&ndev->dev, emac->qos.tas.taprio_admin);
> +
> +	est_new = devm_kzalloc(&ndev->dev,
> +			       struct_size(est_new, entries, taprio->num_entries),
> +			       GFP_KERNEL);
> +	if (!est_new)
> +		return -ENOMEM;
> +
> +	emac_cp_taprio(taprio, est_new);
> +	emac->qos.tas.taprio_admin = est_new;
> +	ret = emac_set_taprio(emac);

This looks weird. I am thinking about the case that taprio->cmd is
'_DESTROY', the validation that you do will fail, and it will return
-EINVAL, right? Am I missing something?

I was expecting to see something similar to what is done in
emac_set_taprio() here before the validation.

> +	if (ret)
> +		devm_kfree(&ndev->dev, est_new);

Also, in case of error, 'tas.taprio_admin' has an already freed pointer,
and it's possible that you will try to free it again.

> +
> +	return ret;
> +}
> +
> +int icssg_qos_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,
> +			   void *type_data)
> +{
> +	switch (type) {
> +	case TC_SETUP_QDISC_TAPRIO:
> +		return emac_setup_taprio(ndev, type_data);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +void icssg_qos_tas_init(struct net_device *ndev)
> +{
> +	struct prueth_emac *emac = netdev_priv(ndev);
> +	bool need_setup = false;
> +	struct tas_config *tas;
> +
> +	tas = &emac->qos.tas.config;
> +
> +	if (tas->state == TAS_STATE_ENABLE)
> +		need_setup = true;
> +
> +	tas->config_list = emac->dram.va + TAS_CONFIG_CHANGE_TIME;
> +	tas->active_list = emac->dram.va + TAS_ACTIVE_LIST_INDEX;
> +
> +	tas_update_fw_list_pointers(emac);
> +
> +	tas_set_state(emac, TAS_STATE_RESET);
> +
> +	if (need_setup)
> +		emac_set_taprio(emac);
> +}
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_qos.h b/drivers/net/ethernet/ti/icssg/icssg_qos.h
> new file mode 100644
> index 000000000000..c3d455adc0f8
> --- /dev/null
> +++ b/drivers/net/ethernet/ti/icssg/icssg_qos.h
> @@ -0,0 +1,124 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright (C) 2023 Texas Instruments Incorporated - http://www.ti.com/
> + */
> +
> +#ifndef __NET_TI_ICSSG_QOS_H
> +#define __NET_TI_ICSSG_QOS_H
> +
> +#include <linux/atomic.h>
> +#include <linux/netdevice.h>
> +#include <net/pkt_sched.h>
> +
> +/**
> + * Maximum number of gate command entries in each list.
> + */
> +#define TAS_MAX_CMD_LISTS   (16)
> +
> +/**
> + * Maximum number of transmit queues supported by implementation
> + */
> +#define TAS_MAX_NUM_QUEUES  (8)
> +
> +/**
> + * Minimum cycle time supported by implementation (in ns)
> + */
> +#define TAS_MIN_CYCLE_TIME  (1000000)
> +
> +/**
> + * Minimum cycle time supported by implementation (in ns)
> + */
> +#define TAS_MAX_CYCLE_TIME  (4000000000)
> +
> +/**
> + * Minimum TAS window duration supported by implementation (in ns)
> + */
> +#define TAS_MIN_WINDOW_DURATION  (10000)
> +
> +/**
> + * List number 0 or 1. Also the value at memory location TAS_ACTIVE_LIST_INDEX
> + */
> +enum tas_list_num {
> +	TAS_LIST0 = 0,
> +	TAS_LIST1 = 1
> +};
> +
> +/**
> + * state of TAS in f/w
> + */
> +enum tas_state {
> +	/* PRU's are idle */
> +	TAS_STATE_DISABLE = 0,
> +	/* Enable TAS */
> +	TAS_STATE_ENABLE = 1,
> +	/* Firmware will reset the state machine */
> +	TAS_STATE_RESET = 2,
> +};
> +
> +/**
> + * Config state machine variables. See IEEE Std 802.1Q-2018 8.6.8.4
> + */
> +struct tas_config_list {
> +	/* New list is copied at this time */
> +	u64 config_change_time;
> +	/* config change error counter, incremented if
> +	 * admin->BaseTime < current time and TAS_enabled is true
> +	 */
> +	u32 config_change_error_counter;
> +	/* True if list update is pending */
> +	u8 config_pending;
> +	/* Set to true when application trigger updating of admin list
> +	 * to active list, cleared when configChangeTime is updated
> +	 */
> +	u8 config_change;
> +};
> +
> +/**
> + * Max SDU table. See IEEE Std 802.1Q-2018 12.29.1.1
> + */
> +struct tas_max_sdu_table {
> +	u16 max_sdu[TAS_MAX_NUM_QUEUES];
> +};
> +
> +/**
> + * TAS List Structure based on firmware memory map
> + */
> +struct tas_firmware_list {
> +	/* window gate mask list */
> +	u8 gate_mask_list[TAS_MAX_CMD_LISTS];
> +	/* window end time list */
> +	u32 win_end_time_list[TAS_MAX_CMD_LISTS];
> +	/* Array of gate close time for each queue in each window */
> +	u32 gate_close_time_list[TAS_MAX_CMD_LISTS][TAS_MAX_NUM_QUEUES];
> +};
> +
> +/**
> + * Main Time Aware Shaper Handle
> + */
> +struct tas_config {
> +	enum tas_state state;
> +	struct tas_max_sdu_table max_sdu_table;
> +	/* Config change variables */
> +	struct tas_config_list __iomem *config_list;
> +	/* Whether list 1 or list 2 is the operating list */
> +	u8 __iomem *active_list;
> +	/* active List pointer, used by firmware */
> +	struct tas_firmware_list __iomem *fw_active_list;
> +	/* shadow List pointer, used by driver */
> +	struct tas_firmware_list __iomem *fw_shadow_list;
> +};
> +
> +struct prueth_qos_tas {
> +	struct tc_taprio_qopt_offload *taprio_admin;
> +	struct tc_taprio_qopt_offload *taprio_oper;
> +	struct tas_config config;
> +};
> +
> +struct prueth_qos {
> +	/* IET data structure goes here */
> +	struct prueth_qos_tas tas;
> +};
> +
> +void icssg_qos_tas_init(struct net_device *ndev);
> +int icssg_qos_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,
> +			   void *type_data);
> +#endif /* __NET_TI_ICSSG_QOS_H */
> -- 
> 2.34.1
>

-- 
Vinicius