Optimize tx_clean by avoiding a des3 read in stmmac_clean_desc3().
In ring mode, TX, des3 seems only used when xmit a jumbo frame.
In case of normal descriptors, it may also be used for time
stamping.
Clean it in the above two case, without reading it.
Signed-off-by: Fabrice Gasnier <fabrice.gasn...@st.com>
Signed-off-by: Giuseppe Cavallaro <peppe.cavall...@st.com>
---
drivers/net/ethernet/stmicro/stmmac/chain_mode.c | 3 ++-
drivers/net/ethernet/stmicro/stmmac/ring_mode.c | 11 ++++++++++-
drivers/net/ethernet/stmicro/stmmac/stmmac.h | 1 +
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 1 +
4 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
index e985459..d6d56ee 100644
--- a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
@@ -154,7 +154,8 @@ static void stmmac_clean_desc3(void *priv_ptr, struct
dma_desc *p)
struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
unsigned int entry = priv->dirty_tx;
- if (priv->tx_skbuff_dma[entry].last_segment && !priv->extend_desc)
+ if (priv->tx_skbuff_dma[entry].last_segment && !priv->extend_desc &&
+ priv->hwts_tx_en)
/* NOTE: Device will overwrite des3 with timestamp value if
* 1588-2002 time stamping is enabled, hence reinitialize it
* to keep explicit chaining in the descriptor.
diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
index 3300029..ffab4d7 100644
--- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
@@ -58,6 +58,7 @@ 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->tx_skbuff_dma[entry].is_jumbo = true;
desc->des3 = desc->des2 + BUF_SIZE_4KiB;
priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
@@ -78,6 +79,7 @@ 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;
+ priv->tx_skbuff_dma[entry].is_jumbo = true;
desc->des3 = desc->des2 + BUF_SIZE_4KiB;
priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
@@ -91,6 +93,7 @@ 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 = nopaged_len;
+ 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);
@@ -128,7 +131,13 @@ static void stmmac_init_desc3(struct dma_desc *p)
static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
{
- if (unlikely(p->des3))
+ struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
+ unsigned int entry = priv->dirty_tx;
+
+ /* des3 is only used for jumbo frames tx or time stamping */
+ if (unlikely(priv->tx_skbuff_dma[entry].is_jumbo ||
+ (priv->tx_skbuff_dma[entry].last_segment &&
+ !priv->extend_desc && priv->hwts_tx_en)))
p->des3 = 0;
}
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index f15c493..b73e8d8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -47,6 +47,7 @@ struct stmmac_tx_info {
bool map_as_page;
unsigned len;
bool last_segment;
+ bool is_jumbo;
};
struct stmmac_priv {
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index cb24779..9094aa6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1378,6 +1378,7 @@ static void stmmac_tx_clean(struct stmmac_priv *priv)
}
priv->hw->mode->clean_desc3(priv, p);
priv->tx_skbuff_dma[entry].last_segment = false;
+ priv->tx_skbuff_dma[entry].is_jumbo = false;
if (likely(skb != NULL)) {
pkts_compl++;
--
1.7.4.4
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