From d63a6dcf06cb3e6f3d08d79ba23603b03828650e Mon Sep 17 00:00:00 2001 From: Hariprasad Shenai Date: Fri, 26 Sep 2014 00:23:52 +0530 Subject: [PATCH] cxgb4: Use BAR2 Going To Sleep (GTS) for T5 and later. Use BAR2 GTS for T5. If we are on T4 use the old doorbell mechanism; otherwise ue the new BAR2 mechanism. Use BAR2 doorbells for refilling FL's. Based on original work by Casey Leedom Signed-off-by: Hariprasad Shenai Signed-off-by: David S. Miller --- drivers/net/ethernet/chelsio/cxgb4/cxgb4.h | 4 +- drivers/net/ethernet/chelsio/cxgb4/sge.c | 186 +++++++++++++++---- drivers/net/ethernet/chelsio/cxgb4/t4_regs.h | 19 ++ 3 files changed, 167 insertions(+), 42 deletions(-) diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h b/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h index c067b7888ac4..54b10d4c990a 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h +++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h @@ -431,6 +431,7 @@ struct sge_fl { /* SGE free-buffer queue state */ struct rx_sw_desc *sdesc; /* address of SW Rx descriptor ring */ __be64 *desc; /* address of HW Rx descriptor ring */ dma_addr_t addr; /* bus address of HW ring start */ + u64 udb; /* BAR2 offset of User Doorbell area */ }; /* A packet gather list */ @@ -459,6 +460,7 @@ struct sge_rspq { /* state for an SGE response queue */ u16 abs_id; /* absolute SGE id for the response q */ __be64 *desc; /* address of HW response ring */ dma_addr_t phys_addr; /* physical address of the ring */ + u64 udb; /* BAR2 offset of User Doorbell area */ unsigned int iqe_len; /* entry size */ unsigned int size; /* capacity of response queue */ struct adapter *adap; @@ -516,7 +518,7 @@ struct sge_txq { int db_disabled; unsigned short db_pidx; unsigned short db_pidx_inc; - u64 udb; + u64 udb; /* BAR2 offset of User Doorbell area */ }; struct sge_eth_txq { /* state for an SGE Ethernet Tx queue */ diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c b/drivers/net/ethernet/chelsio/cxgb4/sge.c index d22d728d4e5c..87db53343543 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/sge.c +++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c @@ -521,9 +521,23 @@ static inline void ring_fl_db(struct adapter *adap, struct sge_fl *q) val = PIDX(q->pend_cred / 8); if (!is_t4(adap->params.chip)) val |= DBTYPE(1); + val |= DBPRIO(1); wmb(); - t4_write_reg(adap, MYPF_REG(SGE_PF_KDOORBELL), DBPRIO(1) | - QID(q->cntxt_id) | val); + + /* If we're on T4, use the old doorbell mechanism; otherwise + * use the new BAR2 mechanism. + */ + if (is_t4(adap->params.chip)) { + t4_write_reg(adap, MYPF_REG(SGE_PF_KDOORBELL), + val | QID(q->cntxt_id)); + } else { + writel(val, adap->bar2 + q->udb + SGE_UDB_KDOORBELL); + + /* This Write memory Barrier will force the write to + * the User Doorbell area to be flushed. + */ + wmb(); + } q->pend_cred &= 7; } } @@ -859,30 +873,66 @@ static void cxgb_pio_copy(u64 __iomem *dst, u64 *src) */ static inline void ring_tx_db(struct adapter *adap, struct sge_txq *q, int n) { - unsigned int *wr, index; - unsigned long flags; - wmb(); /* write descriptors before telling HW */ - spin_lock_irqsave(&q->db_lock, flags); - if (!q->db_disabled) { - if (is_t4(adap->params.chip)) { + + if (is_t4(adap->params.chip)) { + u32 val = PIDX(n); + unsigned long flags; + + /* For T4 we need to participate in the Doorbell Recovery + * mechanism. + */ + spin_lock_irqsave(&q->db_lock, flags); + if (!q->db_disabled) t4_write_reg(adap, MYPF_REG(SGE_PF_KDOORBELL), - QID(q->cntxt_id) | PIDX(n)); + QID(q->cntxt_id) | val); + else + q->db_pidx_inc += n; + q->db_pidx = q->pidx; + spin_unlock_irqrestore(&q->db_lock, flags); + } else { + u32 val = PIDX_T5(n); + + /* T4 and later chips share the same PIDX field offset within + * the doorbell, but T5 and later shrank the field in order to + * gain a bit for Doorbell Priority. The field was absurdly + * large in the first place (14 bits) so we just use the T5 + * and later limits and warn if a Queue ID is too large. + */ + WARN_ON(val & DBPRIO(1)); + + /* For T5 and later we use the Write-Combine mapped BAR2 User + * Doorbell mechanism. If we're only writing a single TX + * Descriptor and TX Write Combining hasn't been disabled, we + * can use the Write Combining Gather Buffer; otherwise we use + * the simple doorbell. + */ + if (n == 1) { + int index = (q->pidx + ? (q->pidx - 1) + : (q->size - 1)); + unsigned int *wr = (unsigned int *)&q->desc[index]; + + cxgb_pio_copy((u64 __iomem *) + (adap->bar2 + q->udb + + SGE_UDB_WCDOORBELL), + (u64 *)wr); } else { - if (n == 1) { - index = q->pidx ? (q->pidx - 1) : (q->size - 1); - wr = (unsigned int *)&q->desc[index]; - cxgb_pio_copy((u64 __iomem *) - (adap->bar2 + q->udb + 64), - (u64 *)wr); - } else - writel(n, adap->bar2 + q->udb + 8); - wmb(); + writel(val, adap->bar2 + q->udb + SGE_UDB_KDOORBELL); } - } else - q->db_pidx_inc += n; - q->db_pidx = q->pidx; - spin_unlock_irqrestore(&q->db_lock, flags); + + /* This Write Memory Barrier will force the write to the User + * Doorbell area to be flushed. This is needed to prevent + * writes on different CPUs for the same queue from hitting + * the adapter out of order. This is required when some Work + * Requests take the Write Combine Gather Buffer path (user + * doorbell area offset [SGE_UDB_WCDOORBELL..+63]) and some + * take the traditional path where we simply increment the + * PIDX (User Doorbell area SGE_UDB_KDOORBELL) and have the + * hardware DMA read the actual Work Request. + */ + wmb(); + } } /** @@ -1916,6 +1966,7 @@ static int napi_rx_handler(struct napi_struct *napi, int budget) unsigned int params; struct sge_rspq *q = container_of(napi, struct sge_rspq, napi); int work_done = process_responses(q, budget); + u32 val; if (likely(work_done < budget)) { napi_complete(napi); @@ -1924,8 +1975,14 @@ static int napi_rx_handler(struct napi_struct *napi, int budget) } else params = QINTR_TIMER_IDX(7); - t4_write_reg(q->adap, MYPF_REG(SGE_PF_GTS), CIDXINC(work_done) | - INGRESSQID((u32)q->cntxt_id) | SEINTARM(params)); + val = CIDXINC(work_done) | SEINTARM(params); + if (is_t4(q->adap->params.chip)) { + t4_write_reg(q->adap, MYPF_REG(SGE_PF_GTS), + val | INGRESSQID((u32)q->cntxt_id)); + } else { + writel(val, q->adap->bar2 + q->udb + SGE_UDB_GTS); + wmb(); + } return work_done; } @@ -1949,6 +2006,7 @@ static unsigned int process_intrq(struct adapter *adap) unsigned int credits; const struct rsp_ctrl *rc; struct sge_rspq *q = &adap->sge.intrq; + u32 val; spin_lock(&adap->sge.intrq_lock); for (credits = 0; ; credits++) { @@ -1967,8 +2025,14 @@ static unsigned int process_intrq(struct adapter *adap) rspq_next(q); } - t4_write_reg(adap, MYPF_REG(SGE_PF_GTS), CIDXINC(credits) | - INGRESSQID(q->cntxt_id) | SEINTARM(q->intr_params)); + val = CIDXINC(credits) | SEINTARM(q->intr_params); + if (is_t4(adap->params.chip)) { + t4_write_reg(adap, MYPF_REG(SGE_PF_GTS), + val | INGRESSQID(q->cntxt_id)); + } else { + writel(val, adap->bar2 + q->udb + SGE_UDB_GTS); + wmb(); + } spin_unlock(&adap->sge.intrq_lock); return credits; } @@ -2149,6 +2213,51 @@ static void sge_tx_timer_cb(unsigned long data) mod_timer(&s->tx_timer, jiffies + (budget ? TX_QCHECK_PERIOD : 2)); } +/** + * udb_address - return the BAR2 User Doorbell address for a Queue + * @adap: the adapter + * @cntxt_id: the Queue Context ID + * @qpp: Queues Per Page (for all PFs) + * + * Returns the BAR2 address of the user Doorbell associated with the + * indicated Queue Context ID. Note that this is only applicable + * for T5 and later. + */ +static u64 udb_address(struct adapter *adap, unsigned int cntxt_id, + unsigned int qpp) +{ + u64 udb; + unsigned int s_qpp; + unsigned short udb_density; + unsigned long qpshift; + int page; + + BUG_ON(is_t4(adap->params.chip)); + + s_qpp = (QUEUESPERPAGEPF0 + + (QUEUESPERPAGEPF1 - QUEUESPERPAGEPF0) * adap->fn); + udb_density = 1 << ((qpp >> s_qpp) & QUEUESPERPAGEPF0_MASK); + qpshift = PAGE_SHIFT - ilog2(udb_density); + udb = cntxt_id << qpshift; + udb &= PAGE_MASK; + page = udb / PAGE_SIZE; + udb += (cntxt_id - (page * udb_density)) * SGE_UDB_SIZE; + + return udb; +} + +static u64 udb_address_eq(struct adapter *adap, unsigned int cntxt_id) +{ + return udb_address(adap, cntxt_id, + t4_read_reg(adap, SGE_EGRESS_QUEUES_PER_PAGE_PF)); +} + +static u64 udb_address_iq(struct adapter *adap, unsigned int cntxt_id) +{ + return udb_address(adap, cntxt_id, + t4_read_reg(adap, SGE_INGRESS_QUEUES_PER_PAGE_PF)); +} + int t4_sge_alloc_rxq(struct adapter *adap, struct sge_rspq *iq, bool fwevtq, struct net_device *dev, int intr_idx, struct sge_fl *fl, rspq_handler_t hnd) @@ -2214,6 +2323,8 @@ int t4_sge_alloc_rxq(struct adapter *adap, struct sge_rspq *iq, bool fwevtq, iq->next_intr_params = iq->intr_params; iq->cntxt_id = ntohs(c.iqid); iq->abs_id = ntohs(c.physiqid); + if (!is_t4(adap->params.chip)) + iq->udb = udb_address_iq(adap, iq->cntxt_id); iq->size--; /* subtract status entry */ iq->netdev = dev; iq->handler = hnd; @@ -2229,6 +2340,12 @@ int t4_sge_alloc_rxq(struct adapter *adap, struct sge_rspq *iq, bool fwevtq, fl->pidx = fl->cidx = 0; fl->alloc_failed = fl->large_alloc_failed = fl->starving = 0; adap->sge.egr_map[fl->cntxt_id - adap->sge.egr_start] = fl; + + /* Note, we must initialize the Free List User Doorbell + * address before refilling the Free List! + */ + if (!is_t4(adap->params.chip)) + fl->udb = udb_address_eq(adap, fl->cntxt_id); refill_fl(adap, fl, fl_cap(fl), GFP_KERNEL); } return 0; @@ -2254,21 +2371,8 @@ err: static void init_txq(struct adapter *adap, struct sge_txq *q, unsigned int id) { q->cntxt_id = id; - if (!is_t4(adap->params.chip)) { - unsigned int s_qpp; - unsigned short udb_density; - unsigned long qpshift; - int page; - - s_qpp = QUEUESPERPAGEPF1 * adap->fn; - udb_density = 1 << QUEUESPERPAGEPF0_GET((t4_read_reg(adap, - SGE_EGRESS_QUEUES_PER_PAGE_PF) >> s_qpp)); - qpshift = PAGE_SHIFT - ilog2(udb_density); - q->udb = q->cntxt_id << qpshift; - q->udb &= PAGE_MASK; - page = q->udb / PAGE_SIZE; - q->udb += (q->cntxt_id - (page * udb_density)) * 128; - } + if (!is_t4(adap->params.chip)) + q->udb = udb_address_eq(adap, q->cntxt_id); q->in_use = 0; q->cidx = q->pidx = 0; diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h b/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h index 39fb325474f7..847a162af98c 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h +++ b/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h @@ -157,8 +157,27 @@ #define QUEUESPERPAGEPF0_MASK 0x0000000fU #define QUEUESPERPAGEPF0_GET(x) ((x) & QUEUESPERPAGEPF0_MASK) +#define QUEUESPERPAGEPF0 0 #define QUEUESPERPAGEPF1 4 +/* T5 and later support a new BAR2-based doorbell mechanism for Egress Queues. + * The User Doorbells are each 128 bytes in length with a Simple Doorbell at + * offsets 8x and a Write Combining single 64-byte Egress Queue Unit + * (X_IDXSIZE_UNIT) Gather Buffer interface at offset 64. For Ingress Queues, + * we have a Going To Sleep register at offsets 8x+4. + * + * As noted above, we have many instances of the Simple Doorbell and Going To + * Sleep registers at offsets 8x and 8x+4, respectively. We want to use a + * non-64-byte aligned offset for the Simple Doorbell in order to attempt to + * avoid buffering of the writes to the Simple Doorbell and we want to use a + * non-contiguous offset for the Going To Sleep writes in order to avoid + * possible combining between them. + */ +#define SGE_UDB_SIZE 128 +#define SGE_UDB_KDOORBELL 8 +#define SGE_UDB_GTS 20 +#define SGE_UDB_WCDOORBELL 64 + #define SGE_INT_CAUSE1 0x1024 #define SGE_INT_CAUSE2 0x1030 #define SGE_INT_CAUSE3 0x103c -- 2.20.1