From: Edward Cree <ecree@solarflare.com>
Date: Thu, 25 Jan 2018 17:26:06 +0000
Subject: sfc: on 8000 series use TX queues for TX timestamps
Patch-mainline: v4.16-rc1
Git-commit: 2935e3c38228ad9bf073eeb0eedff5849eea63db
References: bsc#1105555 FATE#326117

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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/sfc/ef10.c       |   12 ++++++++++--
 drivers/net/ethernet/sfc/efx.c        |   11 +++++++++++
 drivers/net/ethernet/sfc/farch.c      |    9 +++++----
 drivers/net/ethernet/sfc/net_driver.h |   12 ++++++++++--
 drivers/net/ethernet/sfc/ptp.c        |   20 ++++++++++++++++----
 drivers/net/ethernet/sfc/tx.c         |    3 ++-
 6 files changed, 54 insertions(+), 13 deletions(-)

--- 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
 
 	/* 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(
 	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_even
 	      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);
--- 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_r
 	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 e
 	}
 
 	/* 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 e
 			--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++;
 		}
 	}
 
--- 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 ef
 	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(struc
  */
 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) {
--- 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, un
 
 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 *
--- 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(struc
 		));
 }
 
+/* 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, s
 		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_clo
 	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,
 };
 
--- 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_que
 	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;