Files
android_kernel_xiaomi_sm8450/drivers/net/dsa/sja1105/sja1105_ptp.h
Vladimir Oltean 834f8933d5 net: dsa: sja1105: implement tc-gate using time-triggered virtual links
Restrict the TTEthernet hardware support on this switch to operate as
closely as possible to IEEE 802.1Qci as possible. This means that it can
perform PTP-time-based ingress admission control on streams identified
by {DMAC, VID, PCP}, which is useful when trying to ensure the
determinism of traffic scheduled via IEEE 802.1Qbv.

The oddity comes from the fact that in hardware (and in TTEthernet at
large), virtual links always need a full-blown action, including not
only the type of policing, but also the list of destination ports. So in
practice, a single tc-gate action will result in all packets getting
dropped. Additional actions (either "trap" or "redirect") need to be
specified in the same filter rule such that the conforming packets are
actually forwarded somewhere.

Apart from the VL Lookup, Policing and Forwarding tables which need to
be programmed for each flow (virtual link), the Schedule engine also
needs to be told to open/close the admission gates for each individual
virtual link. A fairly accurate (and detailed) description of how that
works is already present in sja1105_tas.c, since it is already used to
trigger the egress gates for the tc-taprio offload (IEEE 802.1Qbv). Key
point here, we remember that the schedule engine supports 8
"subschedules" (execution threads that iterate through the global
schedule in parallel, and that no 2 hardware threads must execute a
schedule entry at the same time). For tc-taprio, each egress port used
one of these 8 subschedules, leaving a total of 4 subschedules unused.
In principle we could have allocated 1 subschedule for the tc-gate
offload of each ingress port, but actually the schedules of all virtual
links installed on each ingress port would have needed to be merged
together, before they could have been programmed to hardware. So
simplify our life and just merge the entire tc-gate configuration, for
all virtual links on all ingress ports, into a single subschedule. Be
sure to check that against the usual hardware scheduling conflicts, and
program it to hardware alongside any tc-taprio subschedule that may be
present.

The following scenarios were tested:

1. Quantitative testing:

   tc qdisc add dev swp2 clsact
   tc filter add dev swp2 ingress flower skip_sw \
           dst_mac 42:be:24:9b:76:20 \
           action gate index 1 base-time 0 \
           sched-entry OPEN 1200 -1 -1 \
           sched-entry CLOSE 1200 -1 -1 \
           action trap

   ping 192.168.1.2 -f
   PING 192.168.1.2 (192.168.1.2) 56(84) bytes of data.
   .............................
   --- 192.168.1.2 ping statistics ---
   948 packets transmitted, 467 received, 50.7384% packet loss, time 9671ms

2. Qualitative testing (with a phase-aligned schedule - the clocks are
   synchronized by ptp4l, not shown here):

   Receiver (sja1105):

   tc qdisc add dev swp2 clsact
   now=$(phc_ctl /dev/ptp1 get | awk '/clock time is/ {print $5}') && \
           sec=$(echo $now | awk -F. '{print $1}') && \
           base_time="$(((sec + 2) * 1000000000))" && \
           echo "base time ${base_time}"
   tc filter add dev swp2 ingress flower skip_sw \
           dst_mac 42:be:24:9b:76:20 \
           action gate base-time ${base_time} \
           sched-entry OPEN  60000 -1 -1 \
           sched-entry CLOSE 40000 -1 -1 \
           action trap

   Sender (enetc):
   now=$(phc_ctl /dev/ptp0 get | awk '/clock time is/ {print $5}') && \
           sec=$(echo $now | awk -F. '{print $1}') && \
           base_time="$(((sec + 2) * 1000000000))" && \
           echo "base time ${base_time}"
   tc qdisc add dev eno0 parent root taprio \
           num_tc 8 \
           map 0 1 2 3 4 5 6 7 \
           queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
           base-time ${base_time} \
           sched-entry S 01  50000 \
           sched-entry S 00  50000 \
           flags 2

   ping -A 192.168.1.1
   PING 192.168.1.1 (192.168.1.1): 56 data bytes
   ...
   ^C
   --- 192.168.1.1 ping statistics ---
   1425 packets transmitted, 1424 packets received, 0% packet loss
   round-trip min/avg/max = 0.322/0.361/0.990 ms

   And just for comparison, with the tc-taprio schedule deleted:

   ping -A 192.168.1.1
   PING 192.168.1.1 (192.168.1.1): 56 data bytes
   ...
   ^C
   --- 192.168.1.1 ping statistics ---
   33 packets transmitted, 19 packets received, 42% packet loss
   round-trip min/avg/max = 0.336/0.464/0.597 ms

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-07 17:31:57 -07:00

187 lines
4.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
*/
#ifndef _SJA1105_PTP_H
#define _SJA1105_PTP_H
#if IS_ENABLED(CONFIG_NET_DSA_SJA1105_PTP)
/* Timestamps are in units of 8 ns clock ticks (equivalent to
* a fixed 125 MHz clock).
*/
#define SJA1105_TICK_NS 8
static inline s64 ns_to_sja1105_ticks(s64 ns)
{
return ns / SJA1105_TICK_NS;
}
static inline s64 sja1105_ticks_to_ns(s64 ticks)
{
return ticks * SJA1105_TICK_NS;
}
/* Calculate the first base_time in the future that satisfies this
* relationship:
*
* future_base_time = base_time + N x cycle_time >= now, or
*
* now - base_time
* N >= ---------------
* cycle_time
*
* Because N is an integer, the ceiling value of the above "a / b" ratio
* is in fact precisely the floor value of "(a + b - 1) / b", which is
* easier to calculate only having integer division tools.
*/
static inline s64 future_base_time(s64 base_time, s64 cycle_time, s64 now)
{
s64 a, b, n;
if (base_time >= now)
return base_time;
a = now - base_time;
b = cycle_time;
n = div_s64(a + b - 1, b);
return base_time + n * cycle_time;
}
/* This is not a preprocessor macro because the "ns" argument may or may not be
* s64 at caller side. This ensures it is properly type-cast before div_s64.
*/
static inline s64 ns_to_sja1105_delta(s64 ns)
{
return div_s64(ns, 200);
}
static inline s64 sja1105_delta_to_ns(s64 delta)
{
return delta * 200;
}
struct sja1105_ptp_cmd {
u64 startptpcp; /* start toggling PTP_CLK pin */
u64 stopptpcp; /* stop toggling PTP_CLK pin */
u64 ptpstrtsch; /* start schedule */
u64 ptpstopsch; /* stop schedule */
u64 resptp; /* reset */
u64 corrclk4ts; /* use the corrected clock for timestamps */
u64 ptpclkadd; /* enum sja1105_ptp_clk_mode */
};
struct sja1105_ptp_data {
struct delayed_work extts_work;
struct sk_buff_head skb_rxtstamp_queue;
struct ptp_clock_info caps;
struct ptp_clock *clock;
struct sja1105_ptp_cmd cmd;
/* Serializes all operations on the PTP hardware clock */
struct mutex lock;
u64 ptpsyncts;
};
int sja1105_ptp_clock_register(struct dsa_switch *ds);
void sja1105_ptp_clock_unregister(struct dsa_switch *ds);
void sja1105et_ptp_cmd_packing(u8 *buf, struct sja1105_ptp_cmd *cmd,
enum packing_op op);
void sja1105pqrs_ptp_cmd_packing(u8 *buf, struct sja1105_ptp_cmd *cmd,
enum packing_op op);
int sja1105_get_ts_info(struct dsa_switch *ds, int port,
struct ethtool_ts_info *ts);
void sja1105_ptp_txtstamp_skb(struct dsa_switch *ds, int slot,
struct sk_buff *clone);
bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
struct sk_buff *skb, unsigned int type);
bool sja1105_port_txtstamp(struct dsa_switch *ds, int port,
struct sk_buff *skb, unsigned int type);
int sja1105_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr);
int sja1105_hwtstamp_set(struct dsa_switch *ds, int port, struct ifreq *ifr);
int __sja1105_ptp_gettimex(struct dsa_switch *ds, u64 *ns,
struct ptp_system_timestamp *sts);
int __sja1105_ptp_settime(struct dsa_switch *ds, u64 ns,
struct ptp_system_timestamp *ptp_sts);
int __sja1105_ptp_adjtime(struct dsa_switch *ds, s64 delta);
int sja1105_ptp_commit(struct dsa_switch *ds, struct sja1105_ptp_cmd *cmd,
sja1105_spi_rw_mode_t rw);
#else
struct sja1105_ptp_cmd;
/* Structures cannot be empty in C. Bah!
* Keep the mutex as the only element, which is a bit more difficult to
* refactor out of sja1105_main.c anyway.
*/
struct sja1105_ptp_data {
struct mutex lock;
};
static inline int sja1105_ptp_clock_register(struct dsa_switch *ds)
{
return 0;
}
static inline void sja1105_ptp_clock_unregister(struct dsa_switch *ds) { }
static inline void sja1105_ptp_txtstamp_skb(struct dsa_switch *ds, int slot,
struct sk_buff *clone)
{
}
static inline int __sja1105_ptp_gettimex(struct dsa_switch *ds, u64 *ns,
struct ptp_system_timestamp *sts)
{
return 0;
}
static inline int __sja1105_ptp_settime(struct dsa_switch *ds, u64 ns,
struct ptp_system_timestamp *ptp_sts)
{
return 0;
}
static inline int __sja1105_ptp_adjtime(struct dsa_switch *ds, s64 delta)
{
return 0;
}
static inline int sja1105_ptp_commit(struct dsa_switch *ds,
struct sja1105_ptp_cmd *cmd,
sja1105_spi_rw_mode_t rw)
{
return 0;
}
#define sja1105et_ptp_cmd_packing NULL
#define sja1105pqrs_ptp_cmd_packing NULL
#define sja1105_get_ts_info NULL
#define sja1105_port_rxtstamp NULL
#define sja1105_port_txtstamp NULL
#define sja1105_hwtstamp_get NULL
#define sja1105_hwtstamp_set NULL
#endif /* IS_ENABLED(CONFIG_NET_DSA_SJA1105_PTP) */
#endif /* _SJA1105_PTP_H */