[PATCH 09/11] ath10k_sdio: virtual scatter gather for receive

Erik Stromdahl erik.stromdahl at gmail.com
Wed Oct 4 12:56:13 PDT 2017



On 2017-09-30 19:37, silexcommon at gmail.com wrote:
> From: Alagu Sankar <alagusankar at silex-india.com>
> 
> The existing implementation of initiating multiple sdio transfers for
> receive bundling is slowing down the receive speed. Combining the
> transfers using a scatter gather method would be ideal. This results in
> significant performance improvement.
> 
> Since the sg implementation for sdio transfers are not reliable due to
> buffer start and size alignment, a virtual scatter gather implementation
> is used.
> 
> Signed-off-by: Alagu Sankar <alagusankar at silex-india.com>
> ---
>   drivers/net/wireless/ath/ath10k/htc.h  |   1 +
>   drivers/net/wireless/ath/ath10k/sdio.c | 122 ++++++++++++++++++++++++---------
>   drivers/net/wireless/ath/ath10k/sdio.h |   5 +-
>   3 files changed, 93 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath10k/htc.h b/drivers/net/wireless/ath/ath10k/htc.h
> index 24663b0..5d87908 100644
> --- a/drivers/net/wireless/ath/ath10k/htc.h
> +++ b/drivers/net/wireless/ath/ath10k/htc.h
> @@ -58,6 +58,7 @@ enum ath10k_htc_tx_flags {
>   };
>   
>   enum ath10k_htc_rx_flags {
> +	ATH10K_HTC_FLAGS_RECV_1MORE_BLOCK = 0x01,
>   	ATH10K_HTC_FLAG_TRAILER_PRESENT = 0x02,
>   	ATH10K_HTC_FLAG_BUNDLE_MASK     = 0xF0
>   };
> diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c
> index bb6fa67..45df9db 100644
> --- a/drivers/net/wireless/ath/ath10k/sdio.c
> +++ b/drivers/net/wireless/ath/ath10k/sdio.c
> @@ -35,6 +35,7 @@
>   #include "sdio.h"
>   
>   #define ATH10K_SDIO_DMA_BUF_SIZE	(32 * 1024)
> +#define ATH10K_SDIO_VSG_BUF_SIZE	(32 * 1024)
>   
>   static int ath10k_sdio_read(struct ath10k *ar, u32 addr, void *buf,
>   			    u32 len, bool incr);
> @@ -430,6 +431,7 @@ static int ath10k_sdio_mbox_rx_process_packet(struct ath10k *ar,
>   	int ret;
>   
>   	payload_len = le16_to_cpu(htc_hdr->len);
> +	skb->len = payload_len + sizeof(struct ath10k_htc_hdr);
>   
>   	if (trailer_present) {
>   		trailer = skb->data + sizeof(*htc_hdr) +
> @@ -468,12 +470,13 @@ static int ath10k_sdio_mbox_rx_process_packets(struct ath10k *ar,
>   	enum ath10k_htc_ep_id id;
>   	int ret, i, *n_lookahead_local;
>   	u32 *lookaheads_local;
> +	int lookahd_idx = 0;

I think the variable should be named *lookahead_idx* instead of *lookahd_idx*,
since all other variables are using the string lookahead without abbreviations.

>   
>   	for (i = 0; i < ar_sdio->n_rx_pkts; i++) {
>   		lookaheads_local = lookaheads;
>   		n_lookahead_local = n_lookahead;
>   
> -		id = ((struct ath10k_htc_hdr *)&lookaheads[i])->eid;
> +		id = ((struct ath10k_htc_hdr *)&lookaheads[lookahd_idx++])->eid;
>   
>   		if (id >= ATH10K_HTC_EP_COUNT) {
>   			ath10k_warn(ar, "invalid endpoint in look-ahead: %d\n",
> @@ -496,6 +499,7 @@ static int ath10k_sdio_mbox_rx_process_packets(struct ath10k *ar,
>   			/* Only read lookahead's from RX trailers
>   			 * for the last packet in a bundle.
>   			 */
> +			lookahd_idx--;
>   			lookaheads_local = NULL;
>   			n_lookahead_local = NULL;
>   		}
> @@ -529,11 +533,11 @@ static int ath10k_sdio_mbox_rx_process_packets(struct ath10k *ar,
>   	return ret;
>   }
>   
> -static int ath10k_sdio_mbox_alloc_pkt_bundle(struct ath10k *ar,
> -					     struct ath10k_sdio_rx_data *rx_pkts,
> -					     struct ath10k_htc_hdr *htc_hdr,
> -					     size_t full_len, size_t act_len,
> -					     size_t *bndl_cnt)
> +static int ath10k_sdio_mbox_alloc_bundle(struct ath10k *ar,
> +					 struct ath10k_sdio_rx_data *rx_pkts,
> +					 struct ath10k_htc_hdr *htc_hdr,
> +					 size_t full_len, size_t act_len,
> +					 size_t *bndl_cnt)
>   {
>   	int ret, i;
>   
> @@ -574,6 +578,7 @@ static int ath10k_sdio_mbox_rx_alloc(struct ath10k *ar,
>   	size_t full_len, act_len;
>   	bool last_in_bundle;
>   	int ret, i;
> +	int pkt_cnt = 0;
>   
>   	if (n_lookaheads > ATH10K_SDIO_MAX_RX_MSGS) {
>   		ath10k_warn(ar,
> @@ -616,16 +621,22 @@ static int ath10k_sdio_mbox_rx_alloc(struct ath10k *ar,
>   			 * optimally fetched as a full bundle.
>   			 */
>   			size_t bndl_cnt;
> -
> -			ret = ath10k_sdio_mbox_alloc_pkt_bundle(ar,
> -								&ar_sdio->rx_pkts[i],
> -								htc_hdr,
> -								full_len,
> -								act_len,
> -								&bndl_cnt);
> -
> -			n_lookaheads += bndl_cnt;
> -			i += bndl_cnt;
> +			struct ath10k_sdio_rx_data *rx_pkts =
> +				&ar_sdio->rx_pkts[pkt_cnt];
> +
> +			ret = ath10k_sdio_mbox_alloc_bundle(ar,
> +							    rx_pkts,
> +							    htc_hdr,
> +							    full_len,
> +							    act_len,
> +							    &bndl_cnt);
> +
> +			if (ret) {
> +				ath10k_warn(ar, "alloc_bundle error %d\n", ret);
> +				goto err;
> +			}
> +
> +			pkt_cnt += bndl_cnt;
>   			/*Next buffer will be the last in the bundle */
>   			last_in_bundle = true;
>   		}
> @@ -634,14 +645,18 @@ static int ath10k_sdio_mbox_rx_alloc(struct ath10k *ar,
>   		 * ATH10K_HTC_FLAG_BUNDLE_MASK flag set, all bundled
>   		 * packet skb's have been allocated in the previous step.
>   		 */
> -		ret = ath10k_sdio_mbox_alloc_rx_pkt(&ar_sdio->rx_pkts[i],
> +		if (htc_hdr->flags & ATH10K_HTC_FLAGS_RECV_1MORE_BLOCK)
> +			full_len += ATH10K_HIF_MBOX_BLOCK_SIZE;
> +
> +		ret = ath10k_sdio_mbox_alloc_rx_pkt(&ar_sdio->rx_pkts[pkt_cnt],
>   						    act_len,
>   						    full_len,
>   						    last_in_bundle,
>   						    last_in_bundle);
> +		pkt_cnt++;
>   	}
>   
> -	ar_sdio->n_rx_pkts = i;
> +	ar_sdio->n_rx_pkts = pkt_cnt;
>   
>   	return 0;
>   
> @@ -655,41 +670,71 @@ static int ath10k_sdio_mbox_rx_alloc(struct ath10k *ar,
>   	return ret;
>   }
>   
> -static int ath10k_sdio_mbox_rx_packet(struct ath10k *ar,
> -				      struct ath10k_sdio_rx_data *pkt)
> +static int ath10k_sdio_mbox_rx_fetch(struct ath10k *ar)
>   {
>   	struct ath10k_sdio *ar_sdio = ath10k_sdio_priv(ar);
> -	struct sk_buff *skb = pkt->skb;
> +	struct ath10k_sdio_rx_data *pkt = &ar_sdio->rx_pkts[0];
> +	struct sk_buff *skb;
>   	int ret;
>   
> +	skb = pkt->skb;
>   	ret = ath10k_sdio_read(ar, ar_sdio->mbox_info.htc_addr,
>   			       skb->data, pkt->alloc_len, false);
> -	pkt->status = ret;
> -	if (!ret)
> +	if (ret) {
> +		ar_sdio->n_rx_pkts = 0;
> +		ath10k_sdio_mbox_free_rx_pkt(pkt);
> +	} else {
> +		pkt->status = ret;
>   		skb_put(skb, pkt->act_len);
> +	}
>   
>   	return ret;
>   }
>   
> -static int ath10k_sdio_mbox_rx_fetch(struct ath10k *ar)
> +static int ath10k_sdio_mbox_rx_fetch_bundle(struct ath10k *ar)
>   {
>   	struct ath10k_sdio *ar_sdio = ath10k_sdio_priv(ar);
> +	struct ath10k_sdio_rx_data *pkt;
>   	int ret, i;
> +	u32 pkt_offset, virt_pkt_len;
>   
> +	virt_pkt_len = 0;
>   	for (i = 0; i < ar_sdio->n_rx_pkts; i++) {
> -		ret = ath10k_sdio_mbox_rx_packet(ar,
> -						 &ar_sdio->rx_pkts[i]);
> -		if (ret)
> +		virt_pkt_len += ar_sdio->rx_pkts[i].alloc_len;
> +	}
> +	if (virt_pkt_len < ATH10K_SDIO_DMA_BUF_SIZE) {
> +		ret = ath10k_sdio_read(ar, ar_sdio->mbox_info.htc_addr,
> +				       ar_sdio->vsg_buffer, virt_pkt_len,
> +				       false);
> +		if (ret) {
> +			i = 0;
>   			goto err;
> +		}
> +	} else {
> +		ath10k_err(ar, "size exceeding limit %d\n", virt_pkt_len);
> +	}
> +
> +	pkt_offset = 0;
> +	for (i = 0; i < ar_sdio->n_rx_pkts; i++) {
> +		struct sk_buff *skb = ar_sdio->rx_pkts[i].skb;
> +
> +		pkt = &ar_sdio->rx_pkts[i];
> +		memcpy(skb->data, ar_sdio->vsg_buffer + pkt_offset,
> +		       pkt->alloc_len);
> +		pkt->status = 0;
> +		skb_put(skb, pkt->act_len);
> +		pkt_offset += pkt->alloc_len;
>   	}
>   
>   	return 0;
>   
>   err:
>   	/* Free all packets that was not successfully fetched. */

Change comment to: /* Free all packets */
since all packets are freed and not only those that was not successfully fetched.

> -	for (; i < ar_sdio->n_rx_pkts; i++)
> +	for (i = 0; i < ar_sdio->n_rx_pkts; i++)
>   		ath10k_sdio_mbox_free_rx_pkt(&ar_sdio->rx_pkts[i]);
>   
> +	ar_sdio->n_rx_pkts = 0;
> +
>   	return ret;
>   }
>   
> @@ -732,7 +777,10 @@ static int ath10k_sdio_mbox_rxmsg_pending_handler(struct ath10k *ar,
>   			 */
>   			*done = false;
>   
> -		ret = ath10k_sdio_mbox_rx_fetch(ar);
> +		if (ar_sdio->n_rx_pkts > 1)
> +			ret = ath10k_sdio_mbox_rx_fetch_bundle(ar);
> +		else
> +			ret = ath10k_sdio_mbox_rx_fetch(ar);

ret is not checked at all (I noticed this is the case in the current code as well).
I think it would be wise to break the loop if error:

if (ret)
	break;

>   
>   		/* Process fetched packets. This will potentially update
>   		 * n_lookaheads depending on if the packets contain lookahead
> @@ -1136,7 +1184,7 @@ static int ath10k_sdio_bmi_get_rx_lookahead(struct ath10k *ar)
>   					 MBOX_HOST_INT_STATUS_ADDRESS,
>   					 &rx_word);
>   		if (ret) {
> -			ath10k_warn(ar, "unable to read RX_LOOKAHEAD_VALID: %d\n", ret);
> +			ath10k_warn(ar, "unable to read rx_lookahd: %d\n", ret);

Change print to "unable to read RX lookahead: %d\n" as it is more descriptive

>   			return ret;
>   		}
>   
> @@ -1480,7 +1528,7 @@ static int ath10k_sdio_hif_tx_sg(struct ath10k *ar, u8 pipe_id,
>   		skb = items[i].transfer_context;
>   		padded_len = ath10k_sdio_calc_txrx_padded_len(ar_sdio,
>   							      skb->len);
> -		skb_trim(skb, padded_len);
> +		skb->len = padded_len;

Why this change?
I think the skb_ family of functions is the preferred way to manipulate skb's

>   
>   		/* Write TX data to the end of the mbox address space */
>   		address = ar_sdio->mbox_addr[eid] + ar_sdio->mbox_size[eid] -
> @@ -1508,7 +1556,8 @@ static int ath10k_sdio_hif_enable_intrs(struct ath10k *ar)
>   	/* Enable all but CPU interrupts */
>   	regs->int_status_en = FIELD_PREP(MBOX_INT_STATUS_ENABLE_ERROR_MASK, 1) |
>   			      FIELD_PREP(MBOX_INT_STATUS_ENABLE_CPU_MASK, 1) |
> -			      FIELD_PREP(MBOX_INT_STATUS_ENABLE_COUNTER_MASK, 1);
> +			      FIELD_PREP(MBOX_INT_STATUS_ENABLE_COUNTER_MASK,
> +					 1);

Is this a checkpatch-fix?
I would recommend creating a separate patch for style issues.

>   
>   	/* NOTE: There are some cases where HIF can do detection of
>   	 * pending mbox messages which is disabled now.
> @@ -2024,6 +2073,12 @@ static int ath10k_sdio_probe(struct sdio_func *func,
>   		goto err_free_bmi_buf;
>   	}
>   
> +	ar_sdio->vsg_buffer = kzalloc(ATH10K_SDIO_VSG_BUF_SIZE, GFP_KERNEL);
> +	if (!ar_sdio->vsg_buffer) {
> +		ret = -ENOMEM;
> +		goto err_free_bmi_buf;
> +	}
> +
>   	ar_sdio->func = func;
>   	sdio_set_drvdata(func, ar_sdio);
>   
> @@ -2081,7 +2136,7 @@ static int ath10k_sdio_probe(struct sdio_func *func,
>   	}
>   
>   	/* TODO: remove this once SDIO support is fully implemented */
> -	ath10k_warn(ar, "WARNING: ath10k SDIO support is incomplete, don't expect anything to work!\n");
> +	ath10k_warn(ar, "WARNING: ath10k SDIO support is experimental\n");
>   
>   	return 0;
>   
> @@ -2115,6 +2170,7 @@ static void ath10k_sdio_remove(struct sdio_func *func)
>   	ath10k_core_unregister(ar);
>   	ath10k_core_destroy(ar);
>   	kfree(ar_sdio->dma_buffer);
> +	kfree(ar_sdio->vsg_buffer);
>   }
>   
>   static const struct sdio_device_id ath10k_sdio_devices[] = {
> diff --git a/drivers/net/wireless/ath/ath10k/sdio.h b/drivers/net/wireless/ath/ath10k/sdio.h
> index 718b8b7..8b6a86a 100644
> --- a/drivers/net/wireless/ath/ath10k/sdio.h
> +++ b/drivers/net/wireless/ath/ath10k/sdio.h
> @@ -149,8 +149,8 @@ struct ath10k_sdio_irq_proc_regs {
>   	u8 rx_lookahead_valid;
>   	u8 host_int_status2;
>   	u8 gmbox_rx_avail;
> -	__le32 rx_lookahead[2];
> -	__le32 rx_gmbox_lookahead_alias[2];
> +	__le32 rx_lookahead[2 * ATH10K_HIF_MBOX_NUM_MAX];
> +	__le32 int_status_enable;
>   };
>   
>   struct ath10k_sdio_irq_enable_regs {
> @@ -207,6 +207,7 @@ struct ath10k_sdio {
>   	struct ath10k *ar;
>   	struct ath10k_sdio_irq_data irq_data;
>   
> +	u8 *vsg_buffer;
>   	u8 *dma_buffer;
>   
>   	/* protects access to dma_buffer */
> 



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