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 dacb654..b3e669a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
@@ -50,7 +50,9 @@
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 @@
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 @@
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 3ba268e..885c0f9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -338,12 +338,11 @@
/* 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 1a2fce9..1abd80e 100644
--- 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_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 @@
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 @@
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 @@
.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 5a91932..19cc12d 100644
--- 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_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 @@
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 @@
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 @@
.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 c648774..11c7164 100644
--- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
@@ -61,7 +61,7 @@
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 @@
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 @@
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 796d7c6..24c3608 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1991,8 +1991,10 @@
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 @@
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 @@
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.