diff options
Diffstat (limited to 'drivers/net/dsa/sja1105/sja1105_ptp.c')
| -rw-r--r-- | drivers/net/dsa/sja1105/sja1105_ptp.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/drivers/net/dsa/sja1105/sja1105_ptp.c b/drivers/net/dsa/sja1105/sja1105_ptp.c index 47313a6ec932..01ecc8fb1b30 100644 --- a/drivers/net/dsa/sja1105/sja1105_ptp.c +++ b/drivers/net/dsa/sja1105/sja1105_ptp.c @@ -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; |