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Commit 0e80bdc9 authored by Giuseppe Cavallaro's avatar Giuseppe Cavallaro Committed by David S. Miller
Browse files

stmmac: first frame prep at the end of xmit routine 



This patch is to fill the first descriptor just before granting
the DMA engine so at the end of the xmit.
The patch takes care about the algorithm adopted to mitigate the
interrupts, then it fixes the last segment in case of no fragments.
Moreover, this new implementation does not pass any "ter" field when
prepare the descriptors because this is not necessary.
The patch also details the memory barrier in the xmit.

As final results, this patch guarantees the same performances
but fixing a case if small datagram are sent. In fact, this
kind of test is impacted if no coalesce is done.

Signed-off-by: default avatarFabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: default avatarGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: default avatarAlexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fbc80823

drivers/net/ethernet/stmicro/stmmac/common.h

+3 −3
Original line number Diff line number Diff line
@@ -100,7 +100,7 @@ struct stmmac_extra_stats { 
	unsigned long napi_poll;

	unsigned long tx_normal_irq_n;

	unsigned long tx_clean;

	unsigned long tx_reset_ic_bit;

	unsigned long tx_set_ic_bit;

	unsigned long irq_receive_pmt_irq_n;

	/* MMC info */

	unsigned long mmc_tx_irq_n;
@@ -347,7 +347,7 @@ 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,

				 bool csum_flag, int mode, bool tx_own,

				 bool ls_ic);

				 bool ls);

	/* Set/get the owner of the descriptor */

	void (*set_tx_owner) (struct dma_desc *p);

	int (*get_tx_owner) (struct dma_desc *p);
@@ -355,7 +355,7 @@ struct stmmac_desc_ops { 
	void (*release_tx_desc) (struct dma_desc *p, int mode);

	/* Clear interrupt on tx frame completion. When this bit is

	 * set an interrupt happens as soon as the frame is transmitted */

	void (*clear_tx_ic) (struct dma_desc *p);

	void (*set_tx_ic)(struct dma_desc *p);

	/* Last tx segment reports the transmit status */

	int (*get_tx_ls) (struct dma_desc *p);

	/* Return the transmit status looking at the TDES1 */

drivers/net/ethernet/stmicro/stmmac/enh_desc.c

+13 −12
Original line number Diff line number Diff line
@@ -311,10 +311,15 @@ 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,

				     bool csum_flag, int mode, bool tx_own,

				     bool ls_ic)

				     bool ls)

{

	unsigned int tdes0 = p->des0;



	if (mode == STMMAC_CHAIN_MODE)

		enh_set_tx_desc_len_on_chain(p, len);

	else

		enh_set_tx_desc_len_on_ring(p, len);



	if (is_fs)

		tdes0 |= ETDES0_FIRST_SEGMENT;

	else
@@ -325,6 +330,10 @@ 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 (ls)

		tdes0 |= ETDES0_LAST_SEGMENT;



	/* Finally set the OWN bit. Later the DMA will start! */

	if (tx_own)

		tdes0 |= ETDES0_OWN;
@@ -335,20 +344,12 @@ static void enh_desc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len, 
		 */

		wmb();



	if (ls_ic)

		tdes0 |= ETDES0_LAST_SEGMENT | ETDES0_INTERRUPT;



	p->des0 = tdes0;



	if (mode == STMMAC_CHAIN_MODE)

		enh_set_tx_desc_len_on_chain(p, len);

	else

		enh_set_tx_desc_len_on_ring(p, len);

}



static void enh_desc_clear_tx_ic(struct dma_desc *p)

static void enh_desc_set_tx_ic(struct dma_desc *p)

{

	p->des0 &= ~ETDES0_INTERRUPT;

	p->des0 |= ETDES0_INTERRUPT;

}



static int enh_desc_get_rx_frame_len(struct dma_desc *p, int rx_coe_type)
@@ -419,7 +420,7 @@ const struct stmmac_desc_ops enh_desc_ops = { 
	.get_tx_owner = enh_desc_get_tx_owner,

	.release_tx_desc = enh_desc_release_tx_desc,

	.prepare_tx_desc = enh_desc_prepare_tx_desc,

	.clear_tx_ic = enh_desc_clear_tx_ic,

	.set_tx_ic = enh_desc_set_tx_ic,

	.get_tx_ls = enh_desc_get_tx_ls,

	.set_tx_owner = enh_desc_set_tx_owner,

	.set_rx_owner = enh_desc_set_rx_owner,

drivers/net/ethernet/stmicro/stmmac/norm_desc.c

+12 −12
Original line number Diff line number Diff line
@@ -195,10 +195,15 @@ 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,

				  bool csum_flag, int mode, bool tx_own,

				  bool ls_ic)

				  bool ls)

{

	unsigned int tdes1 = p->des1;



	if (mode == STMMAC_CHAIN_MODE)

		norm_set_tx_desc_len_on_chain(p, len);

	else

		norm_set_tx_desc_len_on_ring(p, len);



	if (is_fs)

		tdes1 |= TDES1_FIRST_SEGMENT;

	else
@@ -209,23 +214,18 @@ 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 (ls)

		tdes1 |= TDES1_LAST_SEGMENT;



	if (tx_own)

		tdes1 |= TDES0_OWN;



	if (ls_ic)

		tdes1 |= TDES1_LAST_SEGMENT | TDES1_INTERRUPT;



	p->des1 = tdes1;



	if (mode == STMMAC_CHAIN_MODE)

		norm_set_tx_desc_len_on_chain(p, len);

	else

		norm_set_tx_desc_len_on_ring(p, len);

}



static void ndesc_clear_tx_ic(struct dma_desc *p)

static void ndesc_set_tx_ic(struct dma_desc *p)

{

	p->des1 &= ~TDES1_INTERRUPT;

	p->des1 |= TDES1_INTERRUPT;

}



static int ndesc_get_rx_frame_len(struct dma_desc *p, int rx_coe_type)
@@ -288,7 +288,7 @@ const struct stmmac_desc_ops ndesc_ops = { 
	.get_tx_owner = ndesc_get_tx_owner,

	.release_tx_desc = ndesc_release_tx_desc,

	.prepare_tx_desc = ndesc_prepare_tx_desc,

	.clear_tx_ic = ndesc_clear_tx_ic,

	.set_tx_ic = ndesc_set_tx_ic,

	.get_tx_ls = ndesc_get_tx_ls,

	.set_tx_owner = ndesc_set_tx_owner,

	.set_rx_owner = ndesc_set_rx_owner,

drivers/net/ethernet/stmicro/stmmac/ring_mode.c

+0 −2
Original line number Diff line number Diff line
@@ -62,7 +62,6 @@ 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, 0, false);

		wmb();

		priv->tx_skbuff[entry] = NULL;

		entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
@@ -82,7 +81,6 @@ 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, 1, true);

		wmb();

	} else {

		desc->des2 = dma_map_single(priv->device, skb->data,

					    nopaged_len, DMA_TO_DEVICE);

drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c

+1 −1
Original line number Diff line number Diff line
@@ -97,7 +97,7 @@ static const struct stmmac_stats stmmac_gstrings_stats[] = { 
	STMMAC_STAT(napi_poll),

	STMMAC_STAT(tx_normal_irq_n),

	STMMAC_STAT(tx_clean),

	STMMAC_STAT(tx_reset_ic_bit),

	STMMAC_STAT(tx_set_ic_bit),

	STMMAC_STAT(irq_receive_pmt_irq_n),

	/* MMC info */

	STMMAC_STAT(mmc_tx_irq_n),