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net: dsa: sja1105: Add logic for TX timestamping
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On TX, timestamping is performed synchronously from the
port_deferred_xmit worker thread.
In management routes, the switch is requested to take egress timestamps
(again partial), which are reconstructed and appended to a clone of the
skb that was just sent.  The cloning is done by DSA and we retrieve the
pointer from the structure that DSA keeps in skb->cb.
Then these clones are enqueued to the socket's error queue for
application-level processing.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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vladimiroltean authored and davem330 committed Jun 8, 2019
1 parent bb77f36 commit 47ed985
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Showing 6 changed files with 201 additions and 2 deletions.
10 changes: 10 additions & 0 deletions drivers/net/dsa/sja1105/sja1105.h
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@ struct sja1105_regs {
u64 ptpclk;
u64 ptpclkrate;
u64 ptptsclk;
u64 ptpegr_ts[SJA1105_NUM_PORTS];
u64 pad_mii_tx[SJA1105_NUM_PORTS];
u64 cgu_idiv[SJA1105_NUM_PORTS];
u64 rgmii_pad_mii_tx[SJA1105_NUM_PORTS];
Expand All @@ -56,6 +57,15 @@ struct sja1105_info {
* switch core and device_id)
*/
u64 part_no;
/* E/T and P/Q/R/S have partial timestamps of different sizes.
* They must be reconstructed on both families anyway to get the full
* 64-bit values back.
*/
int ptp_ts_bits;
/* Also SPI commands are of different sizes to retrieve
* the egress timestamps.
*/
int ptpegr_ts_bytes;
const struct sja1105_dynamic_table_ops *dyn_ops;
const struct sja1105_table_ops *static_ops;
const struct sja1105_regs *regs;
Expand Down
55 changes: 53 additions & 2 deletions drivers/net/dsa/sja1105/sja1105_main.c
Original file line number Diff line number Diff line change
Expand Up @@ -1565,7 +1565,7 @@ static int sja1105_setup(struct dsa_switch *ds)
}

static int sja1105_mgmt_xmit(struct dsa_switch *ds, int port, int slot,
struct sk_buff *skb)
struct sk_buff *skb, bool takets)
{
struct sja1105_mgmt_entry mgmt_route = {0};
struct sja1105_private *priv = ds->priv;
Expand All @@ -1578,6 +1578,8 @@ static int sja1105_mgmt_xmit(struct dsa_switch *ds, int port, int slot,
mgmt_route.macaddr = ether_addr_to_u64(hdr->h_dest);
mgmt_route.destports = BIT(port);
mgmt_route.enfport = 1;
mgmt_route.tsreg = 0;
mgmt_route.takets = takets;

rc = sja1105_dynamic_config_write(priv, BLK_IDX_MGMT_ROUTE,
slot, &mgmt_route, true);
Expand Down Expand Up @@ -1629,7 +1631,11 @@ static netdev_tx_t sja1105_port_deferred_xmit(struct dsa_switch *ds, int port,
{
struct sja1105_private *priv = ds->priv;
struct sja1105_port *sp = &priv->ports[port];
struct skb_shared_hwtstamps shwt = {0};
int slot = sp->mgmt_slot;
struct sk_buff *clone;
u64 now, ts;
int rc;

/* The tragic fact about the switch having 4x2 slots for installing
* management routes is that all of them except one are actually
Expand All @@ -1647,8 +1653,36 @@ static netdev_tx_t sja1105_port_deferred_xmit(struct dsa_switch *ds, int port,
*/
mutex_lock(&priv->mgmt_lock);

sja1105_mgmt_xmit(ds, port, slot, skb);
/* The clone, if there, was made by dsa_skb_tx_timestamp */
clone = DSA_SKB_CB(skb)->clone;

sja1105_mgmt_xmit(ds, port, slot, skb, !!clone);

if (!clone)
goto out;

skb_shinfo(clone)->tx_flags |= SKBTX_IN_PROGRESS;

mutex_lock(&priv->ptp_lock);

now = priv->tstamp_cc.read(&priv->tstamp_cc);

rc = sja1105_ptpegr_ts_poll(priv, slot, &ts);
if (rc < 0) {
dev_err(ds->dev, "xmit: timed out polling for tstamp\n");
kfree_skb(clone);
goto out_unlock_ptp;
}

ts = sja1105_tstamp_reconstruct(priv, now, ts);
ts = timecounter_cyc2time(&priv->tstamp_tc, ts);

shwt.hwtstamp = ns_to_ktime(ts);
skb_complete_tx_timestamp(clone, &shwt);

out_unlock_ptp:
mutex_unlock(&priv->ptp_lock);
out:
mutex_unlock(&priv->mgmt_lock);
return NETDEV_TX_OK;
}
Expand Down Expand Up @@ -1677,6 +1711,22 @@ static int sja1105_set_ageing_time(struct dsa_switch *ds,
return sja1105_static_config_reload(priv);
}

/* Called from dsa_skb_tx_timestamp. This callback is just to make DSA clone
* the skb and have it available in DSA_SKB_CB in the .port_deferred_xmit
* callback, where we will timestamp it synchronously.
*/
bool sja1105_port_txtstamp(struct dsa_switch *ds, int port,
struct sk_buff *skb, unsigned int type)
{
struct sja1105_private *priv = ds->priv;
struct sja1105_port *sp = &priv->ports[port];

if (!sp->hwts_tx_en)
return false;

return true;
}

static const struct dsa_switch_ops sja1105_switch_ops = {
.get_tag_protocol = sja1105_get_tag_protocol,
.setup = sja1105_setup,
Expand All @@ -1701,6 +1751,7 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
.port_mdb_add = sja1105_mdb_add,
.port_mdb_del = sja1105_mdb_del,
.port_deferred_xmit = sja1105_port_deferred_xmit,
.port_txtstamp = sja1105_port_txtstamp,
};

static int sja1105_check_device_id(struct sja1105_private *priv)
Expand Down
106 changes: 106 additions & 0 deletions drivers/net/dsa/sja1105/sja1105_ptp.c
Original file line number Diff line number Diff line change
Expand Up @@ -113,6 +113,112 @@ int sja1105pqrs_ptp_cmd(const void *ctx, const void *data)
}
EXPORT_SYMBOL_GPL(sja1105pqrs_ptp_cmd);

/* The switch returns partial timestamps (24 bits for SJA1105 E/T, which wrap
* around in 0.135 seconds, and 32 bits for P/Q/R/S, wrapping around in 34.35
* seconds).
*
* This receives the RX or TX MAC timestamps, provided by hardware as
* the lower bits of the cycle counter, sampled at the time the timestamp was
* collected.
*
* To reconstruct into a full 64-bit-wide timestamp, the cycle counter is
* read and the high-order bits are filled in.
*
* Must be called within one wraparound period of the partial timestamp since
* it was generated by the MAC.
*/
u64 sja1105_tstamp_reconstruct(struct sja1105_private *priv, u64 now,
u64 ts_partial)
{
u64 partial_tstamp_mask = CYCLECOUNTER_MASK(priv->info->ptp_ts_bits);
u64 ts_reconstructed;

ts_reconstructed = (now & ~partial_tstamp_mask) | ts_partial;

/* Check lower bits of current cycle counter against the timestamp.
* If the current cycle counter is lower than the partial timestamp,
* then wraparound surely occurred and must be accounted for.
*/
if ((now & partial_tstamp_mask) <= ts_partial)
ts_reconstructed -= (partial_tstamp_mask + 1);

return ts_reconstructed;
}
EXPORT_SYMBOL_GPL(sja1105_tstamp_reconstruct);

/* Reads the SPI interface for an egress timestamp generated by the switch
* for frames sent using management routes.
*
* SJA1105 E/T layout of the 4-byte SPI payload:
*
* 31 23 15 7 0
* | | | | |
* +-----+-----+-----+ ^
* ^ |
* | |
* 24-bit timestamp Update bit
*
*
* SJA1105 P/Q/R/S layout of the 8-byte SPI payload:
*
* 31 23 15 7 0 63 55 47 39 32
* | | | | | | | | | |
* ^ +-----+-----+-----+-----+
* | ^
* | |
* Update bit 32-bit timestamp
*
* Notice that the update bit is in the same place.
* To have common code for E/T and P/Q/R/S for reading the timestamp,
* we need to juggle with the offset and the bit indices.
*/
int sja1105_ptpegr_ts_poll(struct sja1105_private *priv, int port, u64 *ts)
{
const struct sja1105_regs *regs = priv->info->regs;
int tstamp_bit_start, tstamp_bit_end;
int timeout = 10;
u8 packed_buf[8];
u64 update;
int rc;

do {
rc = sja1105_spi_send_packed_buf(priv, SPI_READ,
regs->ptpegr_ts[port],
packed_buf,
priv->info->ptpegr_ts_bytes);
if (rc < 0)
return rc;

sja1105_unpack(packed_buf, &update, 0, 0,
priv->info->ptpegr_ts_bytes);
if (update)
break;

usleep_range(10, 50);
} while (--timeout);

if (!timeout)
return -ETIMEDOUT;

/* Point the end bit to the second 32-bit word on P/Q/R/S,
* no-op on E/T.
*/
tstamp_bit_end = (priv->info->ptpegr_ts_bytes - 4) * 8;
/* Shift the 24-bit timestamp on E/T to be collected from 31:8.
* No-op on P/Q/R/S.
*/
tstamp_bit_end += 32 - priv->info->ptp_ts_bits;
tstamp_bit_start = tstamp_bit_end + priv->info->ptp_ts_bits - 1;

*ts = 0;

sja1105_unpack(packed_buf, ts, tstamp_bit_start, tstamp_bit_end,
priv->info->ptpegr_ts_bytes);

return 0;
}
EXPORT_SYMBOL_GPL(sja1105_ptpegr_ts_poll);

int sja1105_ptp_reset(struct sja1105_private *priv)
{
struct dsa_switch *ds = priv->ds;
Expand Down
17 changes: 17 additions & 0 deletions drivers/net/dsa/sja1105/sja1105_ptp.h
Original file line number Diff line number Diff line change
Expand Up @@ -10,13 +10,18 @@ int sja1105_ptp_clock_register(struct sja1105_private *priv);

void sja1105_ptp_clock_unregister(struct sja1105_private *priv);

int sja1105_ptpegr_ts_poll(struct sja1105_private *priv, int port, u64 *ts);

int sja1105et_ptp_cmd(const void *ctx, const void *data);

int sja1105pqrs_ptp_cmd(const void *ctx, const void *data);

int sja1105_get_ts_info(struct dsa_switch *ds, int port,
struct ethtool_ts_info *ts);

u64 sja1105_tstamp_reconstruct(struct sja1105_private *priv, u64 now,
u64 ts_partial);

int sja1105_ptp_reset(struct sja1105_private *priv);

#else
Expand All @@ -31,6 +36,18 @@ static inline void sja1105_ptp_clock_unregister(struct sja1105_private *priv)
return;
}

static inline int
sja1105_ptpegr_ts_poll(struct sja1105_private *priv, int port, u64 *ts)
{
return 0;
}

static inline u64 sja1105_tstamp_reconstruct(struct sja1105_private *priv,
u64 now, u64 ts_partial)
{
return 0;
}

static inline int sja1105_ptp_reset(struct sja1105_private *priv)
{
return 0;
Expand Down
14 changes: 14 additions & 0 deletions drivers/net/dsa/sja1105/sja1105_spi.c
Original file line number Diff line number Diff line change
Expand Up @@ -514,6 +514,7 @@ static struct sja1105_regs sja1105et_regs = {
.rgmii_tx_clk = {0x100016, 0x10001D, 0x100024, 0x10002B, 0x100032},
.rmii_ref_clk = {0x100015, 0x10001C, 0x100023, 0x10002A, 0x100031},
.rmii_ext_tx_clk = {0x100018, 0x10001F, 0x100026, 0x10002D, 0x100034},
.ptpegr_ts = {0xC0, 0xC2, 0xC4, 0xC6, 0xC8},
.ptp_control = 0x17,
.ptpclk = 0x18, /* Spans 0x18 to 0x19 */
.ptpclkrate = 0x1A,
Expand Down Expand Up @@ -544,6 +545,7 @@ static struct sja1105_regs sja1105pqrs_regs = {
.rmii_ref_clk = {0x100015, 0x10001B, 0x100021, 0x100027, 0x10002D},
.rmii_ext_tx_clk = {0x100017, 0x10001D, 0x100023, 0x100029, 0x10002F},
.qlevel = {0x604, 0x614, 0x624, 0x634, 0x644},
.ptpegr_ts = {0xC0, 0xC4, 0xC8, 0xCC, 0xD0},
.ptp_control = 0x18,
.ptpclk = 0x19,
.ptpclkrate = 0x1B,
Expand All @@ -555,6 +557,8 @@ struct sja1105_info sja1105e_info = {
.part_no = SJA1105ET_PART_NO,
.static_ops = sja1105e_table_ops,
.dyn_ops = sja1105et_dyn_ops,
.ptp_ts_bits = 24,
.ptpegr_ts_bytes = 4,
.reset_cmd = sja1105et_reset_cmd,
.fdb_add_cmd = sja1105et_fdb_add,
.fdb_del_cmd = sja1105et_fdb_del,
Expand All @@ -567,6 +571,8 @@ struct sja1105_info sja1105t_info = {
.part_no = SJA1105ET_PART_NO,
.static_ops = sja1105t_table_ops,
.dyn_ops = sja1105et_dyn_ops,
.ptp_ts_bits = 24,
.ptpegr_ts_bytes = 4,
.reset_cmd = sja1105et_reset_cmd,
.fdb_add_cmd = sja1105et_fdb_add,
.fdb_del_cmd = sja1105et_fdb_del,
Expand All @@ -579,6 +585,8 @@ struct sja1105_info sja1105p_info = {
.part_no = SJA1105P_PART_NO,
.static_ops = sja1105p_table_ops,
.dyn_ops = sja1105pqrs_dyn_ops,
.ptp_ts_bits = 32,
.ptpegr_ts_bytes = 8,
.reset_cmd = sja1105pqrs_reset_cmd,
.fdb_add_cmd = sja1105pqrs_fdb_add,
.fdb_del_cmd = sja1105pqrs_fdb_del,
Expand All @@ -591,6 +599,8 @@ struct sja1105_info sja1105q_info = {
.part_no = SJA1105Q_PART_NO,
.static_ops = sja1105q_table_ops,
.dyn_ops = sja1105pqrs_dyn_ops,
.ptp_ts_bits = 32,
.ptpegr_ts_bytes = 8,
.reset_cmd = sja1105pqrs_reset_cmd,
.fdb_add_cmd = sja1105pqrs_fdb_add,
.fdb_del_cmd = sja1105pqrs_fdb_del,
Expand All @@ -603,6 +613,8 @@ struct sja1105_info sja1105r_info = {
.part_no = SJA1105R_PART_NO,
.static_ops = sja1105r_table_ops,
.dyn_ops = sja1105pqrs_dyn_ops,
.ptp_ts_bits = 32,
.ptpegr_ts_bytes = 8,
.reset_cmd = sja1105pqrs_reset_cmd,
.fdb_add_cmd = sja1105pqrs_fdb_add,
.fdb_del_cmd = sja1105pqrs_fdb_del,
Expand All @@ -616,6 +628,8 @@ struct sja1105_info sja1105s_info = {
.static_ops = sja1105s_table_ops,
.dyn_ops = sja1105pqrs_dyn_ops,
.regs = &sja1105pqrs_regs,
.ptp_ts_bits = 32,
.ptpegr_ts_bytes = 8,
.reset_cmd = sja1105pqrs_reset_cmd,
.fdb_add_cmd = sja1105pqrs_fdb_add,
.fdb_del_cmd = sja1105pqrs_fdb_del,
Expand Down
1 change: 1 addition & 0 deletions include/linux/dsa/sja1105.h
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@

struct sja1105_port {
struct dsa_port *dp;
bool hwts_tx_en;
int mgmt_slot;
};

Expand Down

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