| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20200824225615.jtikfwyrxa7vxiq2@skbuf>
Date: Tue, 25 Aug 2020 01:56:15 +0300
From: Vladimir Oltean <olteanv@...il.com>
To: Kurt Kanzenbach <kurt@...utronix.de>
Cc: Andrew Lunn <andrew@...n.ch>,
Vivien Didelot <vivien.didelot@...il.com>,
Florian Fainelli <f.fainelli@...il.com>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Richard Cochran <richardcochran@...il.com>,
Kamil Alkhouri <kamil.alkhouri@...offenburg.de>,
ilias.apalodimas@...aro.org
Subject: Re: [PATCH v3 5/8] net: dsa: hellcreek: Add TAPRIO offloading support
On Thu, Aug 20, 2020 at 10:11:15AM +0200, Kurt Kanzenbach wrote:
> The switch has support for the 802.1Qbv Time Aware Shaper (TAS). Traffic
> schedules may be configured individually on each front port. Each port has eight
> egress queues. The traffic is mapped to a traffic class respectively via the PCP
> field of a VLAN tagged frame.
>
> The TAPRIO Qdisc already implements that. Therefore, this interface can simply
> be reused. Add .port_setup_tc() accordingly.
>
> The activation of a schedule on a port is split into two parts:
>
> * Programming the necessary gate control list (GCL)
> * Setup hrtimer for starting the schedule
>
> The hardware supports starting a schedule up to eight seconds in the future. The
> TAPRIO interface provides an absolute base time. Therefore, hrtimers are
> leveraged.
>
> Signed-off-by: Kurt Kanzenbach <kurt@...utronix.de>
> ---
> drivers/net/dsa/hirschmann/hellcreek.c | 294 +++++++++++++++++++++++++
> drivers/net/dsa/hirschmann/hellcreek.h | 21 ++
> 2 files changed, 315 insertions(+)
>
> diff --git a/drivers/net/dsa/hirschmann/hellcreek.c b/drivers/net/dsa/hirschmann/hellcreek.c
> index 745ca60342b4..e5b54f42c635 100644
> --- a/drivers/net/dsa/hirschmann/hellcreek.c
> +++ b/drivers/net/dsa/hirschmann/hellcreek.c
> @@ -22,7 +22,9 @@
> #include <linux/spinlock.h>
> #include <linux/delay.h>
> #include <linux/ktime.h>
> +#include <linux/time.h>
> #include <net/dsa.h>
> +#include <net/pkt_sched.h>
>
> #include "hellcreek.h"
> #include "hellcreek_ptp.h"
> @@ -153,6 +155,15 @@ static void hellcreek_select_vlan(struct hellcreek *hellcreek, int vid,
> hellcreek_write(hellcreek, val, HR_VIDCFG);
> }
>
> +static void hellcreek_select_tgd(struct hellcreek *hellcreek, int port)
> +{
> + u16 val = 0;
> +
> + val |= port << TR_TGDSEL_TDGSEL_SHIFT;
> +
> + hellcreek_write(hellcreek, val, TR_TGDSEL);
> +}
> +
> static int hellcreek_wait_until_ready(struct hellcreek *hellcreek)
> {
> u16 val;
> @@ -958,6 +969,24 @@ static void __hellcreek_setup_tc_identity_mapping(struct hellcreek *hellcreek)
> }
> }
>
> +static void hellcreek_setup_tc_mapping(struct hellcreek *hellcreek,
> + struct net_device *netdev)
> +{
> + int i, j;
> +
> + /* Setup mapping between traffic classes and port queues. */
> + for (i = 0; i < netdev_get_num_tc(netdev); ++i) {
> + for (j = 0; j < netdev->tc_to_txq[i].count; ++j) {
> + const int queue = j + netdev->tc_to_txq[i].offset;
> +
> + hellcreek_select_prio(hellcreek, i);
> + hellcreek_write(hellcreek,
> + queue << HR_PRTCCFG_PCP_TC_MAP_SHIFT,
> + HR_PRTCCFG);
> + }
> + }
> +}
> +
> static void hellcreek_setup_tc_identity_mapping(struct hellcreek *hellcreek)
> {
> unsigned long flags;
> @@ -1081,6 +1110,267 @@ static void hellcreek_phylink_validate(struct dsa_switch *ds, int port,
> __ETHTOOL_LINK_MODE_MASK_NBITS);
> }
>
> +static void hellcreek_setup_gcl(struct hellcreek *hellcreek, int port,
> + const struct hellcreek_schedule *schedule)
> +{
> + size_t i;
> +
> + for (i = 1; i <= schedule->num_entries; ++i) {
> + const struct hellcreek_gcl_entry *cur, *initial, *next;
> + u16 data;
> + u8 gates;
> +
> + cur = &schedule->entries[i - 1];
> + initial = &schedule->entries[0];
> + next = &schedule->entries[i];
> +
> + if (i == schedule->num_entries)
> + gates = initial->gate_states ^
> + cur->gate_states;
> + else
> + gates = next->gate_states ^
> + cur->gate_states;
> +
> + data = gates;
> + if (cur->overrun_ignore)
> + data |= TR_GCLDAT_GCLOVRI;
> +
> + if (i == schedule->num_entries)
> + data |= TR_GCLDAT_GCLWRLAST;
> +
> + /* Gates states */
> + hellcreek_write(hellcreek, data, TR_GCLDAT);
> +
> + /* Time intervall */
> + hellcreek_write(hellcreek,
> + cur->interval & 0x0000ffff,
> + TR_GCLTIL);
> + hellcreek_write(hellcreek,
> + (cur->interval & 0xffff0000) >> 16,
> + TR_GCLTIH);
> +
> + /* Commit entry */
> + data = ((i - 1) << TR_GCLCMD_GCLWRADR_SHIFT) |
> + (initial->gate_states <<
> + TR_GCLCMD_INIT_GATE_STATES_SHIFT);
> + hellcreek_write(hellcreek, data, TR_GCLCMD);
> + }
> +}
> +
> +static void hellcreek_set_cycle_time(struct hellcreek *hellcreek,
> + const struct hellcreek_schedule *schedule)
> +{
> + u32 cycle_time = schedule->cycle_time;
> +
> + hellcreek_write(hellcreek, cycle_time & 0x0000ffff, TR_CTWRL);
> + hellcreek_write(hellcreek, (cycle_time & 0xffff0000) >> 16, TR_CTWRH);
> +}
> +
> +static void hellcreek_start_schedule(struct hellcreek *hellcreek,
> + ktime_t start_time)
> +{
> + struct timespec64 ts = ktime_to_timespec64(start_time);
> +
> + /* Start can be only 8 seconds in the future */
> + ts.tv_sec %= 8;
> +
> + /* Start schedule at this point of time */
> + hellcreek_write(hellcreek, ts.tv_nsec & 0x0000ffff, TR_ESTWRL);
> + hellcreek_write(hellcreek, (ts.tv_nsec & 0xffff0000) >> 16, TR_ESTWRH);
> +
> + /* Arm timer, set seconds and switch schedule */
> + hellcreek_write(hellcreek, TR_ESTCMD_ESTARM | TR_ESTCMD_ESTSWCFG |
> + ((ts.tv_sec & TR_ESTCMD_ESTSEC_MASK) <<
> + TR_ESTCMD_ESTSEC_SHIFT), TR_ESTCMD);
> +}
> +
> +static struct hellcreek_schedule *hellcreek_taprio_to_schedule(
> + const struct tc_taprio_qopt_offload *taprio)
Personal indentation preference:
static struct hellcreek_schedule
*hellcreek_taprio_to_schedule(const struct tc_taprio_qopt_offload *taprio)
> +{
> + struct hellcreek_schedule *schedule;
> + size_t i;
> +
> + /* Allocate some memory first */
> + schedule = kzalloc(sizeof(*schedule), GFP_KERNEL);
> + if (!schedule)
> + return ERR_PTR(-ENOMEM);
> + schedule->entries = kcalloc(taprio->num_entries,
> + sizeof(*schedule->entries),
> + GFP_KERNEL);
> + if (!schedule->entries) {
> + kfree(schedule);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + /* Construct hellcreek schedule */
> + schedule->num_entries = taprio->num_entries;
> + schedule->base_time = taprio->base_time;
> +
> + for (i = 0; i < taprio->num_entries; ++i) {
> + const struct tc_taprio_sched_entry *t = &taprio->entries[i];
> + struct hellcreek_gcl_entry *k = &schedule->entries[i];
> +
> + k->interval = t->interval;
> + k->gate_states = t->gate_mask;
> + k->overrun_ignore = 0;
Tab to align with gate_states and interval?
What does overrun_ignore do, anyway?
> +
> + /* Update complete cycle time */
> + schedule->cycle_time += t->interval;
> + }
> +
> + return schedule;
> +}
> +
> +static enum hrtimer_restart hellcreek_set_schedule(struct hrtimer *timer)
> +{
> + struct hellcreek_port *hellcreek_port =
> + hrtimer_to_hellcreek_port(timer);
That moment when not even the helper macro fits in 80 characters..
I think you should let this line have 81 characters.
> + struct hellcreek *hellcreek = hellcreek_port->hellcreek;
> + struct hellcreek_schedule *schedule;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&hellcreek->reg_lock, flags);
> +
> + /* First select port */
> + hellcreek_select_tgd(hellcreek, hellcreek_port->port);
> +
> + /* Set admin base time and switch schedule */
> + hellcreek_start_schedule(hellcreek,
> + hellcreek_port->current_schedule->base_time);
> +
> + schedule = hellcreek_port->current_schedule;
> + hellcreek_port->current_schedule = NULL;
> +
> + spin_unlock_irqrestore(&hellcreek->reg_lock, flags);
> +
> + dev_dbg(hellcreek->dev, "ARMed EST timer for port %d\n",
> + hellcreek_port->port);
> +
> + /* Free resources */
> + kfree(schedule->entries);
> + kfree(schedule);
> +
> + return HRTIMER_NORESTART;
> +}
> +
> +static int hellcreek_port_set_schedule(struct dsa_switch *ds, int port,
> + const struct tc_taprio_qopt_offload *taprio)
> +{
> + struct net_device *netdev = dsa_to_port(ds, port)->slave;
> + struct hellcreek *hellcreek = ds->priv;
> + struct hellcreek_port *hellcreek_port;
> + struct hellcreek_schedule *schedule;
> + unsigned long flags;
> + ktime_t start;
> + u16 ctrl;
> +
> + hellcreek_port = &hellcreek->ports[port];
> +
> + /* Convert taprio data to hellcreek schedule */
> + schedule = hellcreek_taprio_to_schedule(taprio);
> + if (IS_ERR(schedule))
> + return PTR_ERR(schedule);
> +
> + dev_dbg(hellcreek->dev, "Configure traffic schedule on port %d\n",
> + port);
> +
> + /* Cancel an in flight timer */
> + hrtimer_cancel(&hellcreek_port->cycle_start_timer);
> +
> + spin_lock_irqsave(&hellcreek->reg_lock, flags);
> +
> + if (hellcreek_port->current_schedule) {
> + kfree(hellcreek_port->current_schedule->entries);
> + kfree(hellcreek_port->current_schedule);
> + }
> +
> + hellcreek_port->current_schedule = schedule;
> +
> + /* First select port */
> + hellcreek_select_tgd(hellcreek, port);
> +
> + /* Setup traffic class <-> queue mapping */
> + hellcreek_setup_tc_mapping(hellcreek, netdev);
> +
> + /* Enable gating and set the admin state to forward everything in the
> + * mean time
> + */
> + ctrl = (0xff << TR_TGDCTRL_ADMINGATESTATES_SHIFT) | TR_TGDCTRL_GATE_EN;
> + hellcreek_write(hellcreek, ctrl, TR_TGDCTRL);
> +
> + /* Cancel pending schedule */
> + hellcreek_write(hellcreek, 0x00, TR_ESTCMD);
> +
> + /* Setup a new schedule */
> + hellcreek_setup_gcl(hellcreek, port, schedule);
> +
> + /* Configure cycle time */
> + hellcreek_set_cycle_time(hellcreek, schedule);
> +
> + /* Setup timer for schedule switch: The IP core only allows to set a
> + * cycle start timer 8 seconds in the future. This is why we setup the
> + * hritmer to base_time - 5 seconds. Then, we have enough time to
> + * activate IP core's EST timer.
> + */
> + start = ktime_sub_ns(schedule->base_time, (u64)5 * NSEC_PER_SEC);
> + hrtimer_start_range_ns(&hellcreek_port->cycle_start_timer, start,
> + NSEC_PER_SEC, HRTIMER_MODE_ABS);
Explain again how this works, please? The hrtimer measures the CLOCK_TAI
of the CPU, but you are offloading the CLOCK_TAI domain of the NIC? So
you are assuming that the CPU and the NIC PHC are synchronized? What if
they aren't?
And what if the base-time is in the past, do you deal with that (how
does the hardware deal with a base-time in the past)?
A base-time in the past (example: 0) should work: you should advance the
base-time into the nearest future multiple of the cycle-time, to at
least preserve phase correctness of the schedule.
Just trying to understand if this whole hrtimer thing is worth it. It
complicates the driver by quite a significant amount.
> +
> + spin_unlock_irqrestore(&hellcreek->reg_lock, flags);
> +
> + return 0;
> +}
> +
> +static int hellcreek_port_del_schedule(struct dsa_switch *ds, int port)
> +{
> + struct hellcreek *hellcreek = ds->priv;
> + struct hellcreek_port *hellcreek_port;
> + unsigned long flags;
> +
> + hellcreek_port = &hellcreek->ports[port];
> +
> + dev_dbg(hellcreek->dev, "Remove traffic schedule on port %d\n", port);
> +
> + /* First cancel timer */
> + hrtimer_cancel(&hellcreek_port->cycle_start_timer);
> +
> + spin_lock_irqsave(&hellcreek->reg_lock, flags);
> +
> + if (hellcreek_port->current_schedule) {
> + kfree(hellcreek_port->current_schedule->entries);
> + kfree(hellcreek_port->current_schedule);
> + hellcreek_port->current_schedule = NULL;
> + }
> +
> + /* Then select port */
> + hellcreek_select_tgd(hellcreek, port);
> +
> + /* Revert tc mapping */
> + __hellcreek_setup_tc_identity_mapping(hellcreek);
> +
> + /* Disable gating and return to regular switching flow */
> + hellcreek_write(hellcreek, 0xff << TR_TGDCTRL_ADMINGATESTATES_SHIFT,
> + TR_TGDCTRL);
> +
> + spin_unlock_irqrestore(&hellcreek->reg_lock, flags);
> +
> + return 0;
> +}
> +
> +static int hellcreek_port_setup_tc(struct dsa_switch *ds, int port,
> + enum tc_setup_type type, void *type_data)
> +{
> + const struct tc_taprio_qopt_offload *taprio = type_data;
> +
> + if (type != TC_SETUP_QDISC_TAPRIO)
> + return -EOPNOTSUPP;
> +
> + if (taprio->enable)
> + return hellcreek_port_set_schedule(ds, port, taprio);
> +
> + return hellcreek_port_del_schedule(ds, port);
> +}
> +
> static const struct dsa_switch_ops hellcreek_ds_ops = {
> .get_tag_protocol = hellcreek_get_tag_protocol,
> .setup = hellcreek_setup,
> @@ -1104,6 +1394,7 @@ static const struct dsa_switch_ops hellcreek_ds_ops = {
> .port_hwtstamp_get = hellcreek_port_hwtstamp_get,
> .port_txtstamp = hellcreek_port_txtstamp,
> .port_rxtstamp = hellcreek_port_rxtstamp,
> + .port_setup_tc = hellcreek_port_setup_tc,
> .get_ts_info = hellcreek_get_ts_info,
> };
>
> @@ -1135,6 +1426,9 @@ static int hellcreek_probe(struct platform_device *pdev)
> if (!port->counter_values)
> return -ENOMEM;
>
> + hrtimer_init(&port->cycle_start_timer, CLOCK_TAI,
> + HRTIMER_MODE_ABS);
> + port->cycle_start_timer.function = hellcreek_set_schedule;
> port->hellcreek = hellcreek;
> port->port = i;
> }
> diff --git a/drivers/net/dsa/hirschmann/hellcreek.h b/drivers/net/dsa/hirschmann/hellcreek.h
> index 1d3de72a48a5..d3d1a1144857 100644
> --- a/drivers/net/dsa/hirschmann/hellcreek.h
> +++ b/drivers/net/dsa/hirschmann/hellcreek.h
> @@ -16,6 +16,7 @@
> #include <linux/ptp_clock_kernel.h>
> #include <linux/timecounter.h>
> #include <linux/spinlock.h>
> +#include <linux/hrtimer.h>
> #include <net/dsa.h>
>
> /* Ports:
> @@ -210,6 +211,20 @@ struct hellcreek_counter {
> const char *name;
> };
>
> +struct hellcreek_gcl_entry {
> + u32 interval;
> + u8 gate_states;
> + bool overrun_ignore;
> +};
> +
> +struct hellcreek_schedule {
> + struct hellcreek_gcl_entry *entries;
> + size_t num_entries;
> + ktime_t base_time;
> + u32 cycle_time;
> + int port;
> +};
> +
> struct hellcreek;
>
> /* State flags for hellcreek_port_hwtstamp::state */
> @@ -236,6 +251,8 @@ struct hellcreek_port_hwtstamp {
>
> struct hellcreek_port {
> struct hellcreek *hellcreek;
> + struct hellcreek_schedule *current_schedule;
> + struct hrtimer cycle_start_timer;
> int port;
> u16 ptcfg; /* ptcfg shadow */
> u64 *counter_values;
> @@ -273,4 +290,8 @@ struct hellcreek {
> size_t fdb_entries;
> };
>
> +#define hrtimer_to_hellcreek_port(timer) \
> + container_of(timer, struct hellcreek_port, \
> + cycle_start_timer)
> +
> #endif /* _HELLCREEK_H_ */
> --
> 2.20.1
>
Thanks,
-Vladimir
Powered by blists - more mailing lists