sfc: on 8000 series use TX queues for TX timestamps

For this we create and use one or more new TX queues on the PTP channel,
 and enable sync events for it.
Based on a patch by Martin Habets <mhabets@solarflare.com>.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 54 insertions, 13 deletions

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index c31d65eb8ca6..b460e06880e6 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -951,6 +951,11 @@ static int efx_ef10_link_piobufs(struct efx_nic *efx)
 
 	/* Link a buffer to each TX queue */
 	efx_for_each_channel(channel, efx) {
+		/* Extra channels, even those with TXQs (PTP), do not require
+		 * PIO resources.
+		 */
+		if (!channel->type->want_pio)
+			continue;
 		efx_for_each_channel_tx_queue(tx_queue, channel) {
 			/* We assign the PIO buffers to queues in
 			 * reverse order to allow for the following
@@ -1298,7 +1303,9 @@ static int efx_ef10_dimension_resources(struct efx_nic *efx)
 	void __iomem *membase;
 	int rc;
 
-	channel_vis = max(efx->n_channels, efx->n_tx_channels * EFX_TXQ_TYPES);
+	channel_vis = max(efx->n_channels,
+			  (efx->n_tx_channels + efx->n_extra_tx_channels) *
+			  EFX_TXQ_TYPES);
 
 #ifdef EFX_USE_PIO
 	/* Try to allocate PIO buffers if wanted and if the full
@@ -6259,7 +6266,8 @@ static int efx_ef10_ptp_set_ts_sync_events(struct efx_nic *efx, bool en,
 	      efx_ef10_rx_enable_timestamping :
 	      efx_ef10_rx_disable_timestamping;
 
-	efx_for_each_channel(channel, efx) {
+	channel = efx_ptp_channel(efx);
+	if (channel) {
 		int rc = set(channel, temp);
 		if (en && rc != 0) {
 			efx_ef10_ptp_set_ts_sync_events(efx, false, temp);
diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 12f0abc30cb1..456866b05641 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -896,12 +896,20 @@ void efx_schedule_slow_fill(struct efx_rx_queue *rx_queue)
 	mod_timer(&rx_queue->slow_fill, jiffies + msecs_to_jiffies(100));
 }
 
+bool efx_default_channel_want_txqs(struct efx_channel *channel)
+{
+	return channel->channel - channel->efx->tx_channel_offset <
+		channel->efx->n_tx_channels;
+}
+
 static const struct efx_channel_type efx_default_channel_type = {
 	.pre_probe		= efx_channel_dummy_op_int,
 	.post_remove		= efx_channel_dummy_op_void,
 	.get_name		= efx_get_channel_name,
 	.copy			= efx_copy_channel,
+	.want_txqs		= efx_default_channel_want_txqs,
 	.keep_eventq		= false,
+	.want_pio		= true,
 };
 
 int efx_channel_dummy_op_int(struct efx_channel *channel)
@@ -1501,6 +1509,7 @@ static int efx_probe_interrupts(struct efx_nic *efx)
 	}
 
 	/* Assign extra channels if possible */
+	efx->n_extra_tx_channels = 0;
 	j = efx->n_channels;
 	for (i = 0; i < EFX_MAX_EXTRA_CHANNELS; i++) {
 		if (!efx->extra_channel_type[i])
@@ -1512,6 +1521,8 @@ static int efx_probe_interrupts(struct efx_nic *efx)
 			--j;
 			efx_get_channel(efx, j)->type =
 				efx->extra_channel_type[i];
+			if (efx_channel_has_tx_queues(efx_get_channel(efx, j)))
+				efx->n_extra_tx_channels++;
 		}
 	}
 
diff --git a/drivers/net/ethernet/sfc/farch.c b/drivers/net/ethernet/sfc/farch.c
index ca79ac6d0ac3..266b9bee1f3a 100644
--- a/drivers/net/ethernet/sfc/farch.c
+++ b/drivers/net/ethernet/sfc/farch.c
@@ -1085,7 +1085,7 @@ efx_farch_handle_tx_flush_done(struct efx_nic *efx, efx_qword_t *event)
 	int qid;
 
 	qid = EFX_QWORD_FIELD(*event, FSF_AZ_DRIVER_EV_SUBDATA);
-	if (qid < EFX_TXQ_TYPES * efx->n_tx_channels) {
+	if (qid < EFX_TXQ_TYPES * (efx->n_tx_channels + efx->n_extra_tx_channels)) {
 		tx_queue = efx_get_tx_queue(efx, qid / EFX_TXQ_TYPES,
 					    qid % EFX_TXQ_TYPES);
 		if (atomic_cmpxchg(&tx_queue->flush_outstanding, 1, 0)) {
@@ -1669,20 +1669,21 @@ void efx_farch_rx_pull_indir_table(struct efx_nic *efx)
  */
 void efx_farch_dimension_resources(struct efx_nic *efx, unsigned sram_lim_qw)
 {
-	unsigned vi_count, buftbl_min;
+	unsigned vi_count, buftbl_min, total_tx_channels;
 
 #ifdef CONFIG_SFC_SRIOV
 	struct siena_nic_data *nic_data = efx->nic_data;
 #endif
 
+	total_tx_channels = efx->n_tx_channels + efx->n_extra_tx_channels;
 	/* Account for the buffer table entries backing the datapath channels
 	 * and the descriptor caches for those channels.
 	 */
 	buftbl_min = ((efx->n_rx_channels * EFX_MAX_DMAQ_SIZE +
-		       efx->n_tx_channels * EFX_TXQ_TYPES * EFX_MAX_DMAQ_SIZE +
+		       total_tx_channels * EFX_TXQ_TYPES * EFX_MAX_DMAQ_SIZE +
 		       efx->n_channels * EFX_MAX_EVQ_SIZE)
 		      * sizeof(efx_qword_t) / EFX_BUF_SIZE);
-	vi_count = max(efx->n_channels, efx->n_tx_channels * EFX_TXQ_TYPES);
+	vi_count = max(efx->n_channels, total_tx_channels * EFX_TXQ_TYPES);
 
 #ifdef CONFIG_SFC_SRIOV
 	if (efx->type->sriov_wanted) {
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 6b9935f65cfa..d20a8660ee48 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -531,8 +531,12 @@ struct efx_msi_context {
  * @copy: Copy the channel state prior to reallocation.  May be %NULL if
  *	reallocation is not supported.
  * @receive_skb: Handle an skb ready to be passed to netif_receive_skb()
+ * @want_txqs: Determine whether this channel should have TX queues
+ *	created.  If %NULL, TX queues are not created.
  * @keep_eventq: Flag for whether event queue should be kept initialised
  *	while the device is stopped
+ * @want_pio: Flag for whether PIO buffers should be linked to this
+ *	channel's TX queues.
  */
 struct efx_channel_type {
 	void (*handle_no_channel)(struct efx_nic *);
@@ -541,7 +545,9 @@ struct efx_channel_type {
 	void (*get_name)(struct efx_channel *, char *buf, size_t len);
 	struct efx_channel *(*copy)(const struct efx_channel *);
 	bool (*receive_skb)(struct efx_channel *, struct sk_buff *);
+	bool (*want_txqs)(struct efx_channel *);
 	bool keep_eventq;
+	bool want_pio;
 };
 
 enum efx_led_mode {
@@ -744,6 +750,7 @@ struct vfdi_status;
  * @n_channels: Number of channels in use
  * @n_rx_channels: Number of channels used for RX (= number of RX queues)
  * @n_tx_channels: Number of channels used for TX
+ * @n_extra_tx_channels: Number of extra channels with TX queues
  * @rx_ip_align: RX DMA address offset to have IP header aligned in
  *	in accordance with NET_IP_ALIGN
  * @rx_dma_len: Current maximum RX DMA length
@@ -890,6 +897,7 @@ struct efx_nic {
 	unsigned rss_spread;
 	unsigned tx_channel_offset;
 	unsigned n_tx_channels;
+	unsigned n_extra_tx_channels;
 	unsigned int rx_ip_align;
 	unsigned int rx_dma_len;
 	unsigned int rx_buffer_order;
@@ -1372,8 +1380,8 @@ efx_get_tx_queue(struct efx_nic *efx, unsigned index, unsigned type)
 
 static inline bool efx_channel_has_tx_queues(struct efx_channel *channel)
 {
-	return channel->channel - channel->efx->tx_channel_offset <
-		channel->efx->n_tx_channels;
+	return channel->type && channel->type->want_txqs &&
+				channel->type->want_txqs(channel);
 }
 
 static inline struct efx_tx_queue *
diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index 0d0160f15c35..87a72f37141b 100644
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -341,6 +341,14 @@ bool efx_ptp_use_mac_tx_timestamps(struct efx_nic *efx)
 		));
 }
 
+/* PTP 'extra' channel is still a traffic channel, but we only create TX queues
+ * if PTP uses MAC TX timestamps, not if PTP uses the MC directly to transmit.
+ */
+bool efx_ptp_want_txqs(struct efx_channel *channel)
+{
+	return efx_ptp_use_mac_tx_timestamps(channel->efx);
+}
+
 #define PTP_SW_STAT(ext_name, field_name)				\
 	{ #ext_name, 0, offsetof(struct efx_ptp_data, field_name) }
 #define PTP_MC_STAT(ext_name, mcdi_name)				\
@@ -1321,10 +1329,13 @@ int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel)
 		goto fail2;
 	}
 
-	if (efx_ptp_use_mac_tx_timestamps(efx))
+	if (efx_ptp_use_mac_tx_timestamps(efx)) {
 		ptp->xmit_skb = efx_ptp_xmit_skb_queue;
-	else
-		ptp->xmit_skb =	efx_ptp_xmit_skb_mc;
+		/* Request sync events on this channel. */
+		channel->sync_events_state = SYNC_EVENTS_QUIESCENT;
+	} else {
+		ptp->xmit_skb = efx_ptp_xmit_skb_mc;
+	}
 
 	INIT_WORK(&ptp->work, efx_ptp_worker);
 	ptp->config.flags = 0;
@@ -2009,13 +2020,14 @@ static int efx_phc_enable(struct ptp_clock_info *ptp,
 	return 0;
 }
 
-static const struct efx_channel_type efx_ptp_channel_type = {
+const struct efx_channel_type efx_ptp_channel_type = {
 	.handle_no_channel	= efx_ptp_handle_no_channel,
 	.pre_probe		= efx_ptp_probe_channel,
 	.post_remove		= efx_ptp_remove_channel,
 	.get_name		= efx_ptp_get_channel_name,
 	/* no copy operation; there is no need to reallocate this channel */
 	.receive_skb		= efx_ptp_rx,
+	.want_txqs		= efx_ptp_want_txqs,
 	.keep_eventq		= false,
 };
 
diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index f86a0a900f2f..cece961f2e82 100644
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -842,7 +842,8 @@ void efx_init_tx_queue(struct efx_tx_queue *tx_queue)
 	tx_queue->old_read_count = 0;
 	tx_queue->empty_read_count = 0 | EFX_EMPTY_COUNT_VALID;
 	tx_queue->xmit_more_available = false;
-	tx_queue->timestamping = false;
+	tx_queue->timestamping = (efx_ptp_use_mac_tx_timestamps(efx) &&
+				  tx_queue->channel == efx_ptp_channel(efx));
 	tx_queue->completed_desc_ptr = tx_queue->ptr_mask;
 	tx_queue->completed_timestamp_major = 0;
 	tx_queue->completed_timestamp_minor = 0;