ice: add E830 Earliest TxTime First Offload support

E830 supports Earliest TxTime First (ETF) hardware offload, which is
configured via the ETF Qdisc on a per-queue basis (see tc-etf(8)). ETF
introduces a new Tx flow mechanism that utilizes a timestamp ring
(tstamp_ring) alongside the standard Tx ring. This timestamp ring is
used to indicate when hardware will transmit a packet. Tx Time is
supported on the first 2048 Tx queues of the device, and the NVM image
limits the maximum number of Tx queues to 2048 for the device.

The allocation and initialization of the timestamp ring occur when the
feature is enabled on a specific Tx queue via tc-etf. The requested Tx
Time queue index cannot be greater than the number of Tx queues
(vsi->num_txq).

To support ETF, the following flags and bitmap are introduced:

 - ICE_F_TXTIME: Device feature flag set for E830 NICs, indicating ETF
   support.
 - txtime_txqs: PF-level bitmap set when ETF is enabled and cleared
   when disabled for a specific Tx queue. It is used by
   ice_is_txtime_ena() to check if ETF is allocated and configured on
   any Tx queue, which is checked during Tx ring allocation.
 - ICE_TX_FLAGS_TXTIME: Per Tx ring flag set when ETF is allocated and
   configured for a specific Tx queue. It determines ETF status during
   packet transmission and is checked by ice_is_txtime_ena() to verify
   if ETF is enabled on any Tx queue.

Due to a hardware issue that can result in a malicious driver detection
event, additional timestamp descriptors are required when wrapping
around the timestamp ring. Up to 64 additional timestamp descriptors
are reserved, reducing the available Tx descriptors.

To accommodate this, ICE_MAX_NUM_DESC_BY_MAC is introduced, defining:

 - E830: Maximum Tx descriptor count of 8096 (8K - 32 - 64 for timestamp
   fetch descriptors).
 - E810 and E82X: Maximum Tx descriptor count of 8160 (8K - 32).

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Co-developed-by: Alice Michael <alice.michael@intel.com>
Signed-off-by: Alice Michael <alice.michael@intel.com>
Signed-off-by: Paul Greenwalt <paul.greenwalt@intel.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 170 insertions, 3 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
index 17cda5e2f6a4..73f08d02f9c7 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
@@ -144,6 +144,56 @@ static struct netdev_queue *txring_txq(const struct ice_tx_ring *ring)
 }
 
 /**
+ * ice_clean_tstamp_ring - clean time stamp ring
+ * @tx_ring: Tx ring to clean the Time Stamp ring for
+ */
+static void ice_clean_tstamp_ring(struct ice_tx_ring *tx_ring)
+{
+	struct ice_tstamp_ring *tstamp_ring = tx_ring->tstamp_ring;
+	u32 size;
+
+	if (!tstamp_ring->desc)
+		return;
+
+	size = ALIGN(tstamp_ring->count * sizeof(struct ice_ts_desc),
+		     PAGE_SIZE);
+	memset(tstamp_ring->desc, 0, size);
+	tstamp_ring->next_to_use = 0;
+}
+
+/**
+ * ice_free_tstamp_ring - free time stamp resources per queue
+ * @tx_ring: Tx ring to free the Time Stamp ring for
+ */
+void ice_free_tstamp_ring(struct ice_tx_ring *tx_ring)
+{
+	struct ice_tstamp_ring *tstamp_ring = tx_ring->tstamp_ring;
+	u32 size;
+
+	if (!tstamp_ring->desc)
+		return;
+
+	ice_clean_tstamp_ring(tx_ring);
+	size = ALIGN(tstamp_ring->count * sizeof(struct ice_ts_desc),
+		     PAGE_SIZE);
+	dmam_free_coherent(tx_ring->dev, size, tstamp_ring->desc,
+			   tstamp_ring->dma);
+	tstamp_ring->desc = NULL;
+}
+
+/**
+ * ice_free_tx_tstamp_ring - free time stamp resources per Tx ring
+ * @tx_ring: Tx ring to free the Time Stamp ring for
+ */
+void ice_free_tx_tstamp_ring(struct ice_tx_ring *tx_ring)
+{
+	ice_free_tstamp_ring(tx_ring);
+	kfree_rcu(tx_ring->tstamp_ring, rcu);
+	tx_ring->tstamp_ring = NULL;
+	tx_ring->flags &= ~ICE_TX_FLAGS_TXTIME;
+}
+
+/**
  * ice_clean_tx_ring - Free any empty Tx buffers
  * @tx_ring: ring to be cleaned
  */
@@ -181,6 +231,9 @@ tx_skip_free:
 
 	/* cleanup Tx queue statistics */
 	netdev_tx_reset_queue(txring_txq(tx_ring));
+
+	if (ice_is_txtime_cfg(tx_ring))
+		ice_free_tx_tstamp_ring(tx_ring);
 }
 
 /**
@@ -332,6 +385,84 @@ static bool ice_clean_tx_irq(struct ice_tx_ring *tx_ring, int napi_budget)
 }
 
 /**
+ * ice_alloc_tstamp_ring - allocate the Time Stamp ring
+ * @tx_ring: Tx ring to allocate the Time Stamp ring for
+ *
+ * Return: 0 on success, negative on error
+ */
+static int ice_alloc_tstamp_ring(struct ice_tx_ring *tx_ring)
+{
+	struct ice_tstamp_ring *tstamp_ring;
+
+	/* allocate with kzalloc(), free with kfree_rcu() */
+	tstamp_ring = kzalloc(sizeof(*tstamp_ring), GFP_KERNEL);
+	if (!tstamp_ring)
+		return -ENOMEM;
+
+	tstamp_ring->tx_ring = tx_ring;
+	tx_ring->tstamp_ring = tstamp_ring;
+	tstamp_ring->desc = NULL;
+	tstamp_ring->count = ice_calc_ts_ring_count(tx_ring);
+	tx_ring->flags |= ICE_TX_FLAGS_TXTIME;
+	return 0;
+}
+
+/**
+ * ice_setup_tstamp_ring - allocate the Time Stamp ring
+ * @tx_ring: Tx ring to set up the Time Stamp ring for
+ *
+ * Return: 0 on success, negative on error
+ */
+static int ice_setup_tstamp_ring(struct ice_tx_ring *tx_ring)
+{
+	struct ice_tstamp_ring *tstamp_ring = tx_ring->tstamp_ring;
+	struct device *dev = tx_ring->dev;
+	u32 size;
+
+	/* round up to nearest page */
+	size = ALIGN(tstamp_ring->count * sizeof(struct ice_ts_desc),
+		     PAGE_SIZE);
+	tstamp_ring->desc = dmam_alloc_coherent(dev, size, &tstamp_ring->dma,
+						GFP_KERNEL);
+	if (!tstamp_ring->desc) {
+		dev_err(dev, "Unable to allocate memory for Time stamp Ring, size=%d\n",
+			size);
+		return -ENOMEM;
+	}
+
+	tstamp_ring->next_to_use = 0;
+	return 0;
+}
+
+/**
+ * ice_alloc_setup_tstamp_ring - Allocate and setup the Time Stamp ring
+ * @tx_ring: Tx ring to allocate and setup the Time Stamp ring for
+ *
+ * Return: 0 on success, negative on error
+ */
+int ice_alloc_setup_tstamp_ring(struct ice_tx_ring *tx_ring)
+{
+	struct device *dev = tx_ring->dev;
+	int err;
+
+	err = ice_alloc_tstamp_ring(tx_ring);
+	if (err) {
+		dev_err(dev, "Unable to allocate Time stamp ring for Tx ring %d\n",
+			tx_ring->q_index);
+		return err;
+	}
+
+	err = ice_setup_tstamp_ring(tx_ring);
+	if (err) {
+		dev_err(dev, "Unable to setup Time stamp ring for Tx ring %d\n",
+			tx_ring->q_index);
+		ice_free_tx_tstamp_ring(tx_ring);
+		return err;
+	}
+	return 0;
+}
+
+/**
  * ice_setup_tx_ring - Allocate the Tx descriptors
  * @tx_ring: the Tx ring to set up
  *
@@ -1822,10 +1953,46 @@ ice_tx_map(struct ice_tx_ring *tx_ring, struct ice_tx_buf *first,
 	/* notify HW of packet */
 	kick = __netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount,
 				      netdev_xmit_more());
-	if (kick)
-		/* notify HW of packet */
-		writel(i, tx_ring->tail);
+	if (!kick)
+		return;
 
+	if (ice_is_txtime_cfg(tx_ring)) {
+		struct ice_tstamp_ring *tstamp_ring = tx_ring->tstamp_ring;
+		u32 tstamp_count = tstamp_ring->count;
+		u32 j = tstamp_ring->next_to_use;
+		struct ice_ts_desc *ts_desc;
+		struct timespec64 ts;
+		u32 tstamp;
+
+		ts = ktime_to_timespec64(first->skb->tstamp);
+		tstamp = ts.tv_nsec >> ICE_TXTIME_CTX_RESOLUTION_128NS;
+
+		ts_desc = ICE_TS_DESC(tstamp_ring, j);
+		ts_desc->tx_desc_idx_tstamp = ice_build_tstamp_desc(i, tstamp);
+
+		j++;
+		if (j == tstamp_count) {
+			u32 fetch = tstamp_count - tx_ring->count;
+
+			j = 0;
+
+			/* To prevent an MDD, when wrapping the tstamp ring
+			 * create additional TS descriptors equal to the number
+			 * of the fetch TS descriptors value. HW will merge the
+			 * TS descriptors with the same timestamp value into a
+			 * single descriptor.
+			 */
+			for (; j < fetch; j++) {
+				ts_desc = ICE_TS_DESC(tstamp_ring, j);
+				ts_desc->tx_desc_idx_tstamp =
+				       ice_build_tstamp_desc(i, tstamp);
+			}
+		}
+		tstamp_ring->next_to_use = j;
+		writel_relaxed(j, tstamp_ring->tail);
+	} else {
+		writel_relaxed(i, tx_ring->tail);
+	}
 	return;
 
 dma_error: