[PATCH net-next v2] net: mana: Implement get_ringparam/set_ringparam for mana

[Shradha Gupta <shradhagupta@linux.microsoft.com>]

Currently the values of WQs for RX and TX queues for MANA devices
are hardcoded to default sizes.
Allow configuring these values for MANA devices as ringparam
configuration(get/set) through ethtool_ops.

Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
---
 Changes in v2:
 * Removed unnecessary validations in mana_set_ringparam()
 * Fixed codespell error
 * Improved error message to indicate issue with the parameter
---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 20 +++---
 .../ethernet/microsoft/mana/mana_ethtool.c    | 66 +++++++++++++++++++
 include/net/mana/mana.h                       | 21 +++++-
 3 files changed, 96 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index d2f07e179e86..598ac62be47d 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -618,7 +618,7 @@ static int mana_pre_alloc_rxbufs(struct mana_port_context *mpc, int new_mtu)
 
 	dev = mpc->ac->gdma_dev->gdma_context->dev;
 
-	num_rxb = mpc->num_queues * RX_BUFFERS_PER_QUEUE;
+	num_rxb = mpc->num_queues * mpc->rx_queue_size;
 
 	WARN(mpc->rxbufs_pre, "mana rxbufs_pre exists\n");
 	mpc->rxbufs_pre = kmalloc_array(num_rxb, sizeof(void *), GFP_KERNEL);
@@ -1899,14 +1899,15 @@ static int mana_create_txq(struct mana_port_context *apc,
 		return -ENOMEM;
 
 	/*  The minimum size of the WQE is 32 bytes, hence
-	 *  MAX_SEND_BUFFERS_PER_QUEUE represents the maximum number of WQEs
+	 *  apc->tx_queue_size represents the maximum number of WQEs
 	 *  the SQ can store. This value is then used to size other queues
 	 *  to prevent overflow.
+	 *  Also note that the txq_size is always going to be MANA_PAGE_ALIGNED,
+	 *  as tx_queue_size is always a power of 2.
 	 */
-	txq_size = MAX_SEND_BUFFERS_PER_QUEUE * 32;
-	BUILD_BUG_ON(!MANA_PAGE_ALIGNED(txq_size));
+	txq_size = apc->tx_queue_size * 32;
 
-	cq_size = MAX_SEND_BUFFERS_PER_QUEUE * COMP_ENTRY_SIZE;
+	cq_size = apc->tx_queue_size * COMP_ENTRY_SIZE;
 	cq_size = MANA_PAGE_ALIGN(cq_size);
 
 	gc = gd->gdma_context;
@@ -2145,10 +2146,11 @@ static int mana_push_wqe(struct mana_rxq *rxq)
 
 static int mana_create_page_pool(struct mana_rxq *rxq, struct gdma_context *gc)
 {
+	struct mana_port_context *mpc = netdev_priv(rxq->ndev);
 	struct page_pool_params pprm = {};
 	int ret;
 
-	pprm.pool_size = RX_BUFFERS_PER_QUEUE;
+	pprm.pool_size = mpc->rx_queue_size;
 	pprm.nid = gc->numa_node;
 	pprm.napi = &rxq->rx_cq.napi;
 	pprm.netdev = rxq->ndev;
@@ -2180,13 +2182,13 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
 
 	gc = gd->gdma_context;
 
-	rxq = kzalloc(struct_size(rxq, rx_oobs, RX_BUFFERS_PER_QUEUE),
+	rxq = kzalloc(struct_size(rxq, rx_oobs, apc->rx_queue_size),
 		      GFP_KERNEL);
 	if (!rxq)
 		return NULL;
 
 	rxq->ndev = ndev;
-	rxq->num_rx_buf = RX_BUFFERS_PER_QUEUE;
+	rxq->num_rx_buf = apc->rx_queue_size;
 	rxq->rxq_idx = rxq_idx;
 	rxq->rxobj = INVALID_MANA_HANDLE;
 
@@ -2734,6 +2736,8 @@ static int mana_probe_port(struct mana_context *ac, int port_idx,
 	apc->ndev = ndev;
 	apc->max_queues = gc->max_num_queues;
 	apc->num_queues = gc->max_num_queues;
+	apc->tx_queue_size = DEF_TX_BUFFERS_PER_QUEUE;
+	apc->rx_queue_size = DEF_RX_BUFFERS_PER_QUEUE;
 	apc->port_handle = INVALID_MANA_HANDLE;
 	apc->pf_filter_handle = INVALID_MANA_HANDLE;
 	apc->port_idx = port_idx;
diff --git a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
index 146d5db1792f..34707da6ff68 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
@@ -369,6 +369,70 @@ static int mana_set_channels(struct net_device *ndev,
 	return err;
 }
 
+static void mana_get_ringparam(struct net_device *ndev,
+			       struct ethtool_ringparam *ring,
+			       struct kernel_ethtool_ringparam *kernel_ring,
+			       struct netlink_ext_ack *extack)
+{
+	struct mana_port_context *apc = netdev_priv(ndev);
+
+	ring->rx_pending = apc->rx_queue_size;
+	ring->tx_pending = apc->tx_queue_size;
+	ring->rx_max_pending = MAX_RX_BUFFERS_PER_QUEUE;
+	ring->tx_max_pending = MAX_TX_BUFFERS_PER_QUEUE;
+}
+
+static int mana_set_ringparam(struct net_device *ndev,
+			      struct ethtool_ringparam *ring,
+			      struct kernel_ethtool_ringparam *kernel_ring,
+			      struct netlink_ext_ack *extack)
+{
+	struct mana_port_context *apc = netdev_priv(ndev);
+	u32 new_tx, new_rx;
+	u32 old_tx, old_rx;
+	int err1, err2;
+
+	old_tx = apc->tx_queue_size;
+	old_rx = apc->rx_queue_size;
+	new_tx = clamp_t(u32, ring->tx_pending, MIN_TX_BUFFERS_PER_QUEUE, MAX_TX_BUFFERS_PER_QUEUE);
+	new_rx = clamp_t(u32, ring->rx_pending, MIN_RX_BUFFERS_PER_QUEUE, MAX_RX_BUFFERS_PER_QUEUE);
+
+	if (!is_power_of_2(new_tx)) {
+		netdev_err(ndev, "%s:Tx:%d not supported. Needs to be a power of 2\n",
+			   __func__, new_tx);
+		return -EINVAL;
+	}
+
+	if (!is_power_of_2(new_rx)) {
+		netdev_err(ndev, "%s:Rx:%d not supported. Needs to be a power of 2\n",
+			   __func__, new_rx);
+		return -EINVAL;
+	}
+
+	err1 = mana_detach(ndev, false);
+	if (err1) {
+		netdev_err(ndev, "mana_detach failed: %d\n", err1);
+		return err1;
+	}
+
+	apc->tx_queue_size = new_tx;
+	apc->rx_queue_size = new_rx;
+	err1 = mana_attach(ndev);
+	if (!err1)
+		return 0;
+
+	netdev_err(ndev, "mana_attach failed: %d\n", err1);
+
+	/* Try rolling back to the older values */
+	apc->tx_queue_size = old_tx;
+	apc->rx_queue_size = old_rx;
+	err2 = mana_attach(ndev);
+	if (err2)
+		netdev_err(ndev, "mana_reattach failed: %d\n", err2);
+
+	return err1;
+}
+
 const struct ethtool_ops mana_ethtool_ops = {
 	.get_ethtool_stats	= mana_get_ethtool_stats,
 	.get_sset_count		= mana_get_sset_count,
@@ -380,4 +444,6 @@ const struct ethtool_ops mana_ethtool_ops = {
 	.set_rxfh		= mana_set_rxfh,
 	.get_channels		= mana_get_channels,
 	.set_channels		= mana_set_channels,
+	.get_ringparam          = mana_get_ringparam,
+	.set_ringparam          = mana_set_ringparam,
 };
diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
index 6439fd8b437b..8f922b389883 100644
--- a/include/net/mana/mana.h
+++ b/include/net/mana/mana.h
@@ -38,9 +38,21 @@ enum TRI_STATE {
 
 #define COMP_ENTRY_SIZE 64
 
-#define RX_BUFFERS_PER_QUEUE 512
+/* This Max value for RX buffers is derived from __alloc_page()'s max page
+ * allocation calculation. It allows maximum 2^(MAX_ORDER -1) pages. RX buffer
+ * size beyond this value gets rejected by __alloc_page() call.
+ */
+#define MAX_RX_BUFFERS_PER_QUEUE 8192
+#define DEF_RX_BUFFERS_PER_QUEUE 512
+#define MIN_RX_BUFFERS_PER_QUEUE 128
 
-#define MAX_SEND_BUFFERS_PER_QUEUE 256
+/* This max value for TX buffers is derived as the maximum allocatable
+ * pages supported on host per guest through testing. TX buffer size beyond
+ * this value is rejected by the hardware.
+ */
+#define MAX_TX_BUFFERS_PER_QUEUE 16384
+#define DEF_TX_BUFFERS_PER_QUEUE 256
+#define MIN_TX_BUFFERS_PER_QUEUE 128
 
 #define EQ_SIZE (8 * MANA_PAGE_SIZE)
 
@@ -285,7 +297,7 @@ struct mana_recv_buf_oob {
 	void *buf_va;
 	bool from_pool; /* allocated from a page pool */
 
-	/* SGL of the buffer going to be sent has part of the work request. */
+	/* SGL of the buffer going to be sent as part of the work request. */
 	u32 num_sge;
 	struct gdma_sge sgl[MAX_RX_WQE_SGL_ENTRIES];
 
@@ -437,6 +449,9 @@ struct mana_port_context {
 	unsigned int max_queues;
 	unsigned int num_queues;
 
+	unsigned int rx_queue_size;
+	unsigned int tx_queue_size;
+
 	mana_handle_t port_handle;
 	mana_handle_t pf_filter_handle;
 
-- 
2.34.1