msm: ipa3: add support for TX of sk_buff's with paged data

This support is needed to enable GSO (Generic Segmentation
Offload) on msmcobalt.

Change-Id: Id9949bef91835318a7b344753983eea0aeab7bdc
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>

drivers/platform/msm/ipa/ipa_v3/ipa_debugfs.c

@@ -921,6 +921,7 @@ static ssize_t ipa3_read_stats(struct file *file, char __user *ubuf,
 	nbytes = scnprintf(dbg_buff, IPA_MAX_MSG_LEN,
 		"sw_tx=%u\n"
 		"hw_tx=%u\n"
+		"tx_non_linear=%u\n"
 		"tx_compl=%u\n"
 		"wan_rx=%u\n"
 		"stat_compl=%u\n"
@@ -936,6 +937,7 @@ static ssize_t ipa3_read_stats(struct file *file, char __user *ubuf,
 		"flow_disable=%u\n",
 		ipa3_ctx->stats.tx_sw_pkts,
 		ipa3_ctx->stats.tx_hw_pkts,
+		ipa3_ctx->stats.tx_non_linear,
 		ipa3_ctx->stats.tx_pkts_compl,
 		ipa3_ctx->stats.rx_pkts,
 		ipa3_ctx->stats.stat_compl,

drivers/platform/msm/ipa/ipa_v3/ipa_dp.c

@@ -113,11 +113,19 @@ static void ipa3_wq_write_done_common(struct ipa3_sys_context *sys,
 		list_del(&tx_pkt->link);
 		sys->len--;
 		spin_unlock_bh(&sys->spinlock);
-		if (!tx_pkt->no_unmap_dma)
+		if (!tx_pkt->no_unmap_dma) {
+			if (tx_pkt->type != IPA_DATA_DESC_SKB_PAGED) {
 				dma_unmap_single(ipa3_ctx->pdev,
 					tx_pkt->mem.phys_base,
 					tx_pkt->mem.size,
 					DMA_TO_DEVICE);
+			} else {
+				dma_unmap_page(ipa3_ctx->pdev,
+					next_pkt->mem.phys_base,
+					next_pkt->mem.size,
+					DMA_TO_DEVICE);
+			}
+		}
 		if (tx_pkt->callback)
 			tx_pkt->callback(tx_pkt->user1, tx_pkt->user2);
 
@@ -547,6 +555,8 @@ int ipa3_send(struct ipa3_sys_context *sys,
 		}
 
 		tx_pkt->type = desc[i].type;
+
+		if (desc[i].type != IPA_DATA_DESC_SKB_PAGED) {
 			tx_pkt->mem.base = desc[i].pyld;
 			tx_pkt->mem.size = desc[i].len;
 
@@ -562,10 +572,31 @@ int ipa3_send(struct ipa3_sys_context *sys,
 					goto failure;
 				}
 			} else {
-			tx_pkt->mem.phys_base = desc[i].dma_address;
+					tx_pkt->mem.phys_base =
+						desc[i].dma_address;
 					tx_pkt->no_unmap_dma = true;
 			}
+		} else {
+			tx_pkt->mem.base = desc[i].frag;
+			tx_pkt->mem.size = desc[i].len;
 
+			if (!desc[i].dma_address_valid) {
+				tx_pkt->mem.phys_base =
+					skb_frag_dma_map(ipa3_ctx->pdev,
+					desc[i].frag,
+					0, tx_pkt->mem.size,
+					DMA_TO_DEVICE);
+				if (!tx_pkt->mem.phys_base) {
+					IPAERR("dma map failed\n");
+					fail_dma_wrap = 1;
+					goto failure;
+				}
+			} else {
+				tx_pkt->mem.phys_base =
+					desc[i].dma_address;
+				tx_pkt->no_unmap_dma = true;
+			}
+		}
 		tx_pkt->sys = sys;
 		tx_pkt->callback = desc[i].callback;
 		tx_pkt->user1 = desc[i].user1;
@@ -664,9 +695,15 @@ failure:
 	for (j = 0; j < i; j++) {
 		next_pkt = list_next_entry(tx_pkt, link);
 		list_del(&tx_pkt->link);
+		if (desc[i].type != IPA_DATA_DESC_SKB_PAGED) {
 			dma_unmap_single(ipa3_ctx->pdev, tx_pkt->mem.phys_base,
 				tx_pkt->mem.size,
 				DMA_TO_DEVICE);
+		} else {
+			dma_unmap_page(ipa3_ctx->pdev, tx_pkt->mem.phys_base,
+				tx_pkt->mem.size,
+				DMA_TO_DEVICE);
+		}
 		kmem_cache_free(ipa3_ctx->tx_pkt_wrapper_cache, tx_pkt);
 		tx_pkt = next_pkt;
 	}
@@ -675,9 +712,9 @@ failure:
 		if (fail_dma_wrap)
 			kmem_cache_free(ipa3_ctx->tx_pkt_wrapper_cache, tx_pkt);
 
-	if (ipa3_ctx->transport_prototype == IPA_TRANSPORT_TYPE_GSI)
+	if (ipa3_ctx->transport_prototype == IPA_TRANSPORT_TYPE_GSI) {
 		kfree(gsi_xfer_elem_array);
-	else {
+	} else {
 		if (transfer.iovec_phys) {
 			if (num_desc == IPA_NUM_DESC_PER_SW_TX) {
 				dma_pool_free(ipa3_ctx->dma_pool,
@@ -1534,20 +1571,42 @@ static void ipa3_tx_cmd_comp(void *user1, int user2)
 int ipa3_tx_dp(enum ipa_client_type dst, struct sk_buff *skb,
 		struct ipa_tx_meta *meta)
 {
-	struct ipa3_desc desc[3];
+	struct ipa3_desc *desc;
+	struct ipa3_desc _desc[3];
 	int dst_ep_idx;
 	struct ipahal_imm_cmd_ip_packet_init cmd;
 	struct ipahal_imm_cmd_pyld *cmd_pyld = NULL;
 	struct ipa3_sys_context *sys;
 	int src_ep_idx;
+	int num_frags, f;
 
-	memset(desc, 0, 3 * sizeof(struct ipa3_desc));
+	if (unlikely(!ipa3_ctx)) {
+		IPAERR("IPA3 driver was not initialized\n");
+		return -EINVAL;
+	}
 
 	if (skb->len == 0) {
 		IPAERR("packet size is 0\n");
 		return -EINVAL;
 	}
 
+	num_frags = skb_shinfo(skb)->nr_frags;
+	if (num_frags) {
+		/* 1 desc for tag to resolve status out-of-order issue;
+		 * 1 desc is needed for the linear portion of skb;
+		 * 1 desc may be needed for the PACKET_INIT;
+		 * 1 desc for each frag
+		 */
+		desc = kzalloc(sizeof(*desc) * (num_frags + 3), GFP_ATOMIC);
+		if (!desc) {
+			IPAERR("failed to alloc desc array\n");
+			goto fail_mem;
+		}
+	} else {
+		memset(_desc, 0, 3 * sizeof(struct ipa3_desc));
+		desc = &_desc[0];
+	}
+
 	/*
 	 * USB_CONS: PKT_INIT ep_idx = dst pipe
 	 * Q6_CONS: PKT_INIT ep_idx = sender pipe
@@ -1562,14 +1621,14 @@ int ipa3_tx_dp(enum ipa_client_type dst, struct sk_buff *skb,
 		if (-1 == src_ep_idx) {
 			IPAERR("Client %u is not mapped\n",
 				IPA_CLIENT_APPS_LAN_WAN_PROD);
-			return -EFAULT;
+			goto fail_gen;
 		}
 		dst_ep_idx = ipa3_get_ep_mapping(dst);
 	} else {
 		src_ep_idx = ipa3_get_ep_mapping(dst);
 		if (-1 == src_ep_idx) {
 			IPAERR("Client %u is not mapped\n", dst);
-			return -EFAULT;
+			goto fail_gen;
 		}
 		if (meta && meta->pkt_init_dst_ep_valid)
 			dst_ep_idx = meta->pkt_init_dst_ep;
@@ -1607,7 +1666,7 @@ int ipa3_tx_dp(enum ipa_client_type dst, struct sk_buff *skb,
 		desc[1].callback = ipa3_tx_cmd_comp;
 		desc[1].user1 = cmd_pyld;
 		desc[2].pyld = skb->data;
-		desc[2].len = skb->len;
+		desc[2].len = skb_headlen(skb);
 		desc[2].type = IPA_DATA_DESC_SKB;
 		desc[2].callback = ipa3_tx_comp_usr_notify_release;
 		desc[2].user1 = skb;
@@ -1620,8 +1679,22 @@ int ipa3_tx_dp(enum ipa_client_type dst, struct sk_buff *skb,
 			desc[2].dma_address = meta->dma_address;
 		}
 
-		if (ipa3_send(sys, 3, desc, true)) {
-			IPAERR("fail to send immediate command\n");
+		for (f = 0; f < num_frags; f++) {
+			desc[3+f].frag = &skb_shinfo(skb)->frags[f];
+			desc[3+f].type = IPA_DATA_DESC_SKB_PAGED;
+			desc[3+f].len = skb_frag_size(desc[3+f].frag);
+		}
+		/* don't free skb till frag mappings are released */
+		if (num_frags) {
+			desc[3+f-1].callback = desc[2].callback;
+			desc[3+f-1].user1 = desc[2].user1;
+			desc[3+f-1].user2 = desc[2].user2;
+			desc[2].callback = NULL;
+		}
+
+		if (ipa3_send(sys, num_frags + 3, desc, true)) {
+			IPAERR("fail to send skb %p num_frags %u SWP\n",
+				skb, num_frags);
 			goto fail_send;
 		}
 		IPA_STATS_INC_CNT(ipa3_ctx->stats.tx_sw_pkts);
@@ -1633,7 +1706,7 @@ int ipa3_tx_dp(enum ipa_client_type dst, struct sk_buff *skb,
 		desc[0].type = IPA_IMM_CMD_DESC;
 		desc[0].callback = ipa3_tag_destroy_imm;
 		desc[1].pyld = skb->data;
-		desc[1].len = skb->len;
+		desc[1].len = skb_headlen(skb);
 		desc[1].type = IPA_DATA_DESC_SKB;
 		desc[1].callback = ipa3_tx_comp_usr_notify_release;
 		desc[1].user1 = skb;
@@ -1643,19 +1716,44 @@ int ipa3_tx_dp(enum ipa_client_type dst, struct sk_buff *skb,
 			desc[1].dma_address_valid = true;
 			desc[1].dma_address = meta->dma_address;
 		}
-
+		if (num_frags == 0) {
 			if (ipa3_send(sys, 2, desc, true)) {
-			IPAERR("fail to send skb\n");
+				IPAERR("fail to send skb %p HWP\n", skb);
 				goto fail_gen;
 			}
+		} else {
+			for (f = 0; f < num_frags; f++) {
+				desc[2+f].frag = &skb_shinfo(skb)->frags[f];
+				desc[2+f].type = IPA_DATA_DESC_SKB_PAGED;
+				desc[2+f].len = skb_frag_size(desc[2+f].frag);
+			}
+			/* don't free skb till frag mappings are released */
+			desc[2+f-1].callback = desc[1].callback;
+			desc[2+f-1].user1 = desc[1].user1;
+			desc[2+f-1].user2 = desc[1].user2;
+			desc[1].callback = NULL;
+
+			if (ipa3_send(sys, num_frags + 2, desc, true)) {
+				IPAERR("fail to send skb %p num_frags %u HWP\n",
+					skb, num_frags);
+				goto fail_gen;
+			}
+		}
 		IPA_STATS_INC_CNT(ipa3_ctx->stats.tx_hw_pkts);
 	}
 
+	if (num_frags) {
+		kfree(desc);
+		IPA_STATS_INC_CNT(ipa3_ctx->stats.tx_non_linear);
+	}
 	return 0;
 
 fail_send:
 	ipahal_destroy_imm_cmd(cmd_pyld);
 fail_gen:
+	if (num_frags)
+		kfree(desc);
+fail_mem:
 	return -EFAULT;
 }
 

drivers/platform/msm/ipa/ipa_v3/ipa_i.h

@@ -703,7 +703,8 @@ struct ipa3_sys_context {
 enum ipa3_desc_type {
 	IPA_DATA_DESC,
 	IPA_DATA_DESC_SKB,
-	IPA_IMM_CMD_DESC
+	IPA_DATA_DESC_SKB_PAGED,
+	IPA_IMM_CMD_DESC,
 };
 
 /**
@@ -767,6 +768,7 @@ struct ipa3_dma_xfer_wrapper {
  * struct ipa3_desc - IPA descriptor
  * @type: skb or immediate command or plain old data
  * @pyld: points to skb
+ * @frag: points to paged fragment
  * or kmalloc'ed immediate command parameters/plain old data
  * @dma_address: dma mapped address of pyld
  * @dma_address_valid: valid field for dma_address
@@ -780,6 +782,7 @@ struct ipa3_dma_xfer_wrapper {
 struct ipa3_desc {
 	enum ipa3_desc_type type;
 	void *pyld;
+	skb_frag_t *frag;
 	dma_addr_t dma_address;
 	bool dma_address_valid;
 	u16 len;
@@ -889,6 +892,7 @@ struct ipa3_stats {
 	u32 lan_repl_rx_empty;
 	u32 flow_enable;
 	u32 flow_disable;
+	u32 tx_non_linear;
 };
 
 struct ipa3_active_clients {