stmmac: optimize tx desc management

This patch is to optimize the way to manage the TDES inside the
xmit function. When prepare the frame, some settings (e.g. OWN
bit) can be merged. This has been reworked to improve the tx
performances.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
index dacb6542c6dd3601a417659349cea6397587f5c3..b3e669af30055e234a8910e95f232ba2c47443d1 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
@@ -50,7 +50,9 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
                return -1;
        priv->tx_skbuff_dma[entry].buf = desc->des2;
        priv->tx_skbuff_dma[entry].len = bmax;
-       priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE);
+       /* do not close the descriptor and do not set own bit */
+       priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE,
+                                       0, false);
 
        while (len != 0) {
                priv->tx_skbuff[entry] = NULL;
@@ -66,8 +68,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
                        priv->tx_skbuff_dma[entry].buf = desc->des2;
                        priv->tx_skbuff_dma[entry].len = bmax;
                        priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
-                                                       STMMAC_CHAIN_MODE);
-                       priv->hw->desc->set_tx_owner(desc);
+                                                       STMMAC_CHAIN_MODE, 1,
+                                                       false);
                        len -= bmax;
                        i++;
                } else {
@@ -78,9 +80,10 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
                                return -1;
                        priv->tx_skbuff_dma[entry].buf = desc->des2;
                        priv->tx_skbuff_dma[entry].len = len;
+                       /* last descriptor can be set now */
                        priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
-                                                       STMMAC_CHAIN_MODE);
-                       priv->hw->desc->set_tx_owner(desc);
+                                                       STMMAC_CHAIN_MODE, 1,
+                                                       true);
                        len = 0;
                }
        }

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index 3ba268e93bc909d83084f154c36d7dbbc60819a1..885c0f9808b61f3e3ba60b2995e37ede964f7a25 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -338,12 +338,11 @@ struct stmmac_desc_ops {
 
        /* Invoked by the xmit function to prepare the tx descriptor */
        void (*prepare_tx_desc) (struct dma_desc *p, int is_fs, int len,
-                                int csum_flag, int mode);
+                                bool csum_flag, int mode, bool tx_own,
+                                bool ls_ic);
        /* Set/get the owner of the descriptor */
        void (*set_tx_owner) (struct dma_desc *p);
        int (*get_tx_owner) (struct dma_desc *p);
-       /* Invoked by the xmit function to close the tx descriptor */
-       void (*close_tx_desc) (struct dma_desc *p);
        /* Clean the tx descriptor as soon as the tx irq is received */
        void (*release_tx_desc) (struct dma_desc *p, int mode);
        /* Clear interrupt on tx frame completion. When this bit is

diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
index 1a2fce9885488fff63fe738ab80d61fef492e84e..1abd80ed09f363d0079e5d79e770a71af67fbaed 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
@@ -302,7 +302,8 @@ static void enh_desc_release_tx_desc(struct dma_desc *p, int mode)
 }
 
 static void enh_desc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
-                                    int csum_flag, int mode)
+                                    bool csum_flag, int mode, bool tx_own,
+                                    bool ls_ic)
 {
        unsigned int tdes0 = p->des0;
 
@@ -316,6 +317,19 @@ static void enh_desc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
        else
                tdes0 &= ~(TX_CIC_FULL << ETDES0_CHECKSUM_INSERTION_SHIFT);
 
+       if (tx_own)
+               tdes0 |= ETDES0_OWN;
+
+       if (is_fs & tx_own)
+               /* When the own bit, for the first frame, has to be set, all
+                * descriptors for the same frame has to be set before, to
+                * avoid race condition.
+                */
+               wmb();
+
+       if (ls_ic)
+               tdes0 |= ETDES0_LAST_SEGMENT | ETDES0_INTERRUPT;
+
        p->des0 = tdes0;
 
        if (mode == STMMAC_CHAIN_MODE)
@@ -329,11 +343,6 @@ static void enh_desc_clear_tx_ic(struct dma_desc *p)
        p->des0 &= ~ETDES0_INTERRUPT;
 }
 
-static void enh_desc_close_tx_desc(struct dma_desc *p)
-{
-       p->des0 |= ETDES0_LAST_SEGMENT | ETDES0_INTERRUPT;
-}
-
 static int enh_desc_get_rx_frame_len(struct dma_desc *p, int rx_coe_type)
 {
        unsigned int csum = 0;
@@ -403,7 +412,6 @@ const struct stmmac_desc_ops enh_desc_ops = {
        .release_tx_desc = enh_desc_release_tx_desc,
        .prepare_tx_desc = enh_desc_prepare_tx_desc,
        .clear_tx_ic = enh_desc_clear_tx_ic,
-       .close_tx_desc = enh_desc_close_tx_desc,
        .get_tx_ls = enh_desc_get_tx_ls,
        .set_tx_owner = enh_desc_set_tx_owner,
        .set_rx_owner = enh_desc_set_rx_owner,

diff --git a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
index 5a91932ff6393a3e6d30e112d10429c5286fee54..19cc12dd0f173e99dfaf8c73ed6507d0fe8b77da 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
@@ -185,7 +185,8 @@ static void ndesc_release_tx_desc(struct dma_desc *p, int mode)
 }
 
 static void ndesc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
-                                 int csum_flag, int mode)
+                                 bool csum_flag, int mode, bool tx_own,
+                                 bool ls_ic)
 {
        unsigned int tdes1 = p->des1;
 
@@ -199,6 +200,12 @@ static void ndesc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
        else
                tdes1 &= ~(TX_CIC_FULL << TDES1_CHECKSUM_INSERTION_SHIFT);
 
+       if (tx_own)
+               tdes1 |= TDES0_OWN;
+
+       if (ls_ic)
+               tdes1 |= TDES1_LAST_SEGMENT | TDES1_INTERRUPT;
+
        p->des1 = tdes1;
 
        if (mode == STMMAC_CHAIN_MODE)
@@ -212,11 +219,6 @@ static void ndesc_clear_tx_ic(struct dma_desc *p)
        p->des1 &= ~TDES1_INTERRUPT;
 }
 
-static void ndesc_close_tx_desc(struct dma_desc *p)
-{
-       p->des1 |= TDES1_LAST_SEGMENT | TDES1_INTERRUPT;
-}
-
 static int ndesc_get_rx_frame_len(struct dma_desc *p, int rx_coe_type)
 {
        unsigned int csum = 0;
@@ -278,7 +280,6 @@ const struct stmmac_desc_ops ndesc_ops = {
        .release_tx_desc = ndesc_release_tx_desc,
        .prepare_tx_desc = ndesc_prepare_tx_desc,
        .clear_tx_ic = ndesc_clear_tx_ic,
-       .close_tx_desc = ndesc_close_tx_desc,
        .get_tx_ls = ndesc_get_tx_ls,
        .set_tx_owner = ndesc_set_tx_owner,
        .set_rx_owner = ndesc_set_rx_owner,

diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
index c6487746b235b01dda775440b5ed610495f24442..11c71644f126476baf43c4f432c241c1e798b394 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
@@ -61,7 +61,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
 
                desc->des3 = desc->des2 + BUF_SIZE_4KiB;
                priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
-                                               STMMAC_RING_MODE);
+                                               STMMAC_RING_MODE, 0, false);
                wmb();
                priv->tx_skbuff[entry] = NULL;
                entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
@@ -81,9 +81,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
 
                desc->des3 = desc->des2 + BUF_SIZE_4KiB;
                priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
-                                               STMMAC_RING_MODE);
+                                               STMMAC_RING_MODE, 1, true);
                wmb();
-               priv->hw->desc->set_tx_owner(desc);
        } else {
                desc->des2 = dma_map_single(priv->device, skb->data,
                                            nopaged_len, DMA_TO_DEVICE);
@@ -94,7 +93,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
                priv->tx_skbuff_dma[entry].is_jumbo = true;
                desc->des3 = desc->des2 + BUF_SIZE_4KiB;
                priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum,
-                                               STMMAC_RING_MODE);
+                                               STMMAC_RING_MODE, 0, true);
        }
 
        priv->cur_tx = entry;

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 796d7c69f902fb744e81b3d3b81f2396a004ba92..24c36084e3f5d8fef23dfe30f6612d484aff0be8 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1991,8 +1991,10 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
                        goto dma_map_err;
                priv->tx_skbuff_dma[entry].buf = desc->des2;
                priv->tx_skbuff_dma[entry].len = nopaged_len;
+               /* do not set the own at this stage */
                priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len,
-                                               csum_insertion, priv->mode);
+                                               csum_insertion, priv->mode, 0,
+                                               nfrags == 0);
        } else {
                desc = first;
                entry = priv->hw->mode->jumbo_frm(priv, skb, csum_insertion);
@@ -2003,6 +2005,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
        for (i = 0; i < nfrags; i++) {
                const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
                int len = skb_frag_size(frag);
+               bool last_segment = (i == (nfrags - 1));
 
                priv->tx_skbuff[entry] = NULL;
                entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
@@ -2021,19 +2024,12 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
                priv->tx_skbuff_dma[entry].map_as_page = true;
                priv->tx_skbuff_dma[entry].len = len;
                priv->hw->desc->prepare_tx_desc(desc, 0, len, csum_insertion,
-                                               priv->mode);
-               wmb();
-               priv->hw->desc->set_tx_owner(desc);
-               wmb();
+                                               priv->mode, 1, last_segment);
+               priv->tx_skbuff_dma[entry].last_segment = last_segment;
        }
 
        priv->tx_skbuff[entry] = skb;
 
-       /* Finalize the latest segment. */
-       priv->hw->desc->close_tx_desc(desc);
-       priv->tx_skbuff_dma[entry].last_segment = true;
-
-       wmb();
        /* According to the coalesce parameter the IC bit for the latest
         * segment could be reset and the timer re-started to invoke the
         * stmmac_tx function. This approach takes care about the fragments.