diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c index 1cdce8a98d1d..f8f19a85744c 100644 --- a/drivers/net/dsa/ocelot/felix_vsc9959.c +++ b/drivers/net/dsa/ocelot/felix_vsc9959.c @@ -22,6 +22,7 @@ #define VSC9959_NUM_PORTS 6 #define VSC9959_TAS_GCL_ENTRY_MAX 63 +#define VSC9959_TAS_MIN_GATE_LEN_NS 33 #define VSC9959_VCAP_POLICER_BASE 63 #define VSC9959_VCAP_POLICER_MAX 383 #define VSC9959_SWITCH_PCI_BAR 4 @@ -1478,6 +1479,23 @@ static void vsc9959_mdio_bus_free(struct ocelot *ocelot) mdiobus_free(felix->imdio); } +/* The switch considers any frame (regardless of size) as eligible for + * transmission if the traffic class gate is open for at least 33 ns. + * Overruns are prevented by cropping an interval at the end of the gate time + * slot for which egress scheduling is blocked, but we need to still keep 33 ns + * available for one packet to be transmitted, otherwise the port tc will hang. + * This function returns the size of a gate interval that remains available for + * setting the guard band, after reserving the space for one egress frame. + */ +static u64 vsc9959_tas_remaining_gate_len_ps(u64 gate_len_ns) +{ + /* Gate always open */ + if (gate_len_ns == U64_MAX) + return U64_MAX; + + return (gate_len_ns - VSC9959_TAS_MIN_GATE_LEN_NS) * PSEC_PER_NSEC; +} + /* Extract shortest continuous gate open intervals in ns for each traffic class * of a cyclic tc-taprio schedule. If a gate is always open, the duration is * considered U64_MAX. If the gate is always closed, it is considered 0. @@ -1539,6 +1557,65 @@ static void vsc9959_tas_min_gate_lengths(struct tc_taprio_qopt_offload *taprio, min_gate_len[tc] = 0; } +/* ocelot_write_rix is a macro that concatenates QSYS_MAXSDU_CFG_* with _RSZ, + * so we need to spell out the register access to each traffic class in helper + * functions, to simplify callers + */ +static void vsc9959_port_qmaxsdu_set(struct ocelot *ocelot, int port, int tc, + u32 max_sdu) +{ + switch (tc) { + case 0: + ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_0, + port); + break; + case 1: + ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_1, + port); + break; + case 2: + ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_2, + port); + break; + case 3: + ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_3, + port); + break; + case 4: + ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_4, + port); + break; + case 5: + ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_5, + port); + break; + case 6: + ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_6, + port); + break; + case 7: + ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_7, + port); + break; + } +} + +static u32 vsc9959_port_qmaxsdu_get(struct ocelot *ocelot, int port, int tc) +{ + switch (tc) { + case 0: return ocelot_read_rix(ocelot, QSYS_QMAXSDU_CFG_0, port); + case 1: return ocelot_read_rix(ocelot, QSYS_QMAXSDU_CFG_1, port); + case 2: return ocelot_read_rix(ocelot, QSYS_QMAXSDU_CFG_2, port); + case 3: return ocelot_read_rix(ocelot, QSYS_QMAXSDU_CFG_3, port); + case 4: return ocelot_read_rix(ocelot, QSYS_QMAXSDU_CFG_4, port); + case 5: return ocelot_read_rix(ocelot, QSYS_QMAXSDU_CFG_5, port); + case 6: return ocelot_read_rix(ocelot, QSYS_QMAXSDU_CFG_6, port); + case 7: return ocelot_read_rix(ocelot, QSYS_QMAXSDU_CFG_7, port); + default: + return 0; + } +} + /* Update QSYS_PORT_MAX_SDU to make sure the static guard bands added by the * switch (see the ALWAYS_GUARD_BAND_SCH_Q comment) are correct at all MTU * values (the default value is 1518). Also, for traffic class windows smaller @@ -1595,11 +1672,16 @@ static void vsc9959_tas_guard_bands_update(struct ocelot *ocelot, int port) vsc9959_tas_min_gate_lengths(ocelot_port->taprio, min_gate_len); + mutex_lock(&ocelot->fwd_domain_lock); + for (tc = 0; tc < OCELOT_NUM_TC; tc++) { + u64 remaining_gate_len_ps; u32 max_sdu; - if (min_gate_len[tc] == U64_MAX /* Gate always open */ || - min_gate_len[tc] * PSEC_PER_NSEC > needed_bit_time_ps) { + remaining_gate_len_ps = + vsc9959_tas_remaining_gate_len_ps(min_gate_len[tc]); + + if (remaining_gate_len_ps > needed_bit_time_ps) { /* Setting QMAXSDU_CFG to 0 disables oversized frame * dropping. */ @@ -1612,9 +1694,15 @@ static void vsc9959_tas_guard_bands_update(struct ocelot *ocelot, int port) /* If traffic class doesn't support a full MTU sized * frame, make sure to enable oversize frame dropping * for frames larger than the smallest that would fit. + * + * However, the exact same register, QSYS_QMAXSDU_CFG_*, + * controls not only oversized frame dropping, but also + * per-tc static guard band lengths, so it reduces the + * useful gate interval length. Therefore, be careful + * to calculate a guard band (and therefore max_sdu) + * that still leaves 33 ns available in the time slot. */ - max_sdu = div_u64(min_gate_len[tc] * PSEC_PER_NSEC, - picos_per_byte); + max_sdu = div_u64(remaining_gate_len_ps, picos_per_byte); /* A TC gate may be completely closed, which is a * special case where all packets are oversized. * Any limit smaller than 64 octets accomplishes this @@ -1637,47 +1725,14 @@ static void vsc9959_tas_guard_bands_update(struct ocelot *ocelot, int port) max_sdu); } - /* ocelot_write_rix is a macro that concatenates - * QSYS_MAXSDU_CFG_* with _RSZ, so we need to spell out - * the writes to each traffic class - */ - switch (tc) { - case 0: - ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_0, - port); - break; - case 1: - ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_1, - port); - break; - case 2: - ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_2, - port); - break; - case 3: - ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_3, - port); - break; - case 4: - ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_4, - port); - break; - case 5: - ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_5, - port); - break; - case 6: - ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_6, - port); - break; - case 7: - ocelot_write_rix(ocelot, max_sdu, QSYS_QMAXSDU_CFG_7, - port); - break; - } + vsc9959_port_qmaxsdu_set(ocelot, port, tc, max_sdu); } ocelot_write_rix(ocelot, maxlen, QSYS_PORT_MAX_SDU, port); + + ocelot->ops->cut_through_fwd(ocelot); + + mutex_unlock(&ocelot->fwd_domain_lock); } static void vsc9959_sched_speed_set(struct ocelot *ocelot, int port, @@ -1704,13 +1759,13 @@ static void vsc9959_sched_speed_set(struct ocelot *ocelot, int port, break; } + mutex_lock(&ocelot->tas_lock); + ocelot_rmw_rix(ocelot, QSYS_TAG_CONFIG_LINK_SPEED(tas_speed), QSYS_TAG_CONFIG_LINK_SPEED_M, QSYS_TAG_CONFIG, port); - mutex_lock(&ocelot->tas_lock); - if (ocelot_port->taprio) vsc9959_tas_guard_bands_update(ocelot, port); @@ -2770,7 +2825,7 @@ static void vsc9959_cut_through_fwd(struct ocelot *ocelot) { struct felix *felix = ocelot_to_felix(ocelot); struct dsa_switch *ds = felix->ds; - int port, other_port; + int tc, port, other_port; lockdep_assert_held(&ocelot->fwd_domain_lock); @@ -2814,19 +2869,27 @@ static void vsc9959_cut_through_fwd(struct ocelot *ocelot) min_speed = other_ocelot_port->speed; } - /* Enable cut-through forwarding for all traffic classes. */ - if (ocelot_port->speed == min_speed) + /* Enable cut-through forwarding for all traffic classes that + * don't have oversized dropping enabled, since this check is + * bypassed in cut-through mode. + */ + if (ocelot_port->speed == min_speed) { val = GENMASK(7, 0); + for (tc = 0; tc < OCELOT_NUM_TC; tc++) + if (vsc9959_port_qmaxsdu_get(ocelot, port, tc)) + val &= ~BIT(tc); + } + set: tmp = ocelot_read_rix(ocelot, ANA_CUT_THRU_CFG, port); if (tmp == val) continue; dev_dbg(ocelot->dev, - "port %d fwd mask 0x%lx speed %d min_speed %d, %s cut-through forwarding\n", + "port %d fwd mask 0x%lx speed %d min_speed %d, %s cut-through forwarding on TC mask 0x%x\n", port, mask, ocelot_port->speed, min_speed, - val ? "enabling" : "disabling"); + val ? "enabling" : "disabling", val); ocelot_write_rix(ocelot, val, ANA_CUT_THRU_CFG, port); }