Message-Id: <20210420161310.16189-11-m.chetan.kumar@intel.com>
Date:   Tue, 20 Apr 2021 21:43:04 +0530
From:   M Chetan Kumar <m.chetan.kumar@...el.com>
To:     netdev@...r.kernel.org, linux-wireless@...r.kernel.org
Cc:     johannes@...solutions.net, krishna.c.sudi@...el.com,
        linuxwwan@...el.com
Subject: [PATCH V2 10/16] net: iosm: encode or decode datagram

1) Encode UL packet into datagram.
2) Decode DL datagram and route it to network layer.
3) Supports credit based flow control.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@...el.com>
---
v2:
* Endianness type correction for Host-Device protocol structure.
* Function signature documentation correction.
* Streamline multiple returns using goto.
* Removed vlan tag id & replace with ip link interface id.
---
 drivers/net/wwan/iosm/iosm_ipc_mux_codec.c | 901 +++++++++++++++++++++
 drivers/net/wwan/iosm/iosm_ipc_mux_codec.h | 193 +++++
 2 files changed, 1094 insertions(+)
 create mode 100644 drivers/net/wwan/iosm/iosm_ipc_mux_codec.c
 create mode 100644 drivers/net/wwan/iosm/iosm_ipc_mux_codec.h

diff --git a/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c
new file mode 100644
index 000000000000..e7ec512479b4
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c
@@ -0,0 +1,901 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#include <linux/nospec.h>
+
+#include "iosm_ipc_imem_ops.h"
+#include "iosm_ipc_mux_codec.h"
+#include "iosm_ipc_task_queue.h"
+
+/* Test the link power state and send a MUX command in blocking mode. */
+static int mux_tq_cmd_send(struct iosm_imem *ipc_imem, int arg, void *msg,
+			   size_t size)
+{
+	struct iosm_mux *ipc_mux = ipc_imem->mux;
+	const struct mux_acb *acb = msg;
+
+	skb_queue_tail(&ipc_mux->channel->ul_list, acb->skb);
+	imem_ul_send(ipc_mux->imem);
+
+	return 0;
+}
+
+static int mux_acb_send(struct iosm_mux *ipc_mux, bool blocking)
+{
+	struct completion *completion = &ipc_mux->channel->ul_sem;
+	int ret = ipc_task_queue_send_task(ipc_mux->imem, mux_tq_cmd_send, 0,
+					   &ipc_mux->acb, sizeof(ipc_mux->acb),
+					   false);
+	if (ret) {
+		dev_err(ipc_mux->dev, "unable to send mux command");
+		return ret;
+	}
+
+	/* if blocking, suspend the app and wait for irq in the flash or
+	 * crash phase. return false on timeout to indicate failure.
+	 */
+	if (blocking) {
+		u32 wait_time_milliseconds = IPC_MUX_CMD_RUN_DEFAULT_TIMEOUT;
+
+		reinit_completion(completion);
+
+		if (wait_for_completion_interruptible_timeout
+		   (completion, msecs_to_jiffies(wait_time_milliseconds)) ==
+		   0) {
+			dev_err(ipc_mux->dev, "ch[%d] timeout",
+				ipc_mux->channel_id);
+			ipc_uevent_send(ipc_mux->imem->dev, UEVENT_MDM_TIMEOUT);
+			return -ETIMEDOUT;
+		}
+	}
+
+	return 0;
+}
+
+/* Prepare mux Command */
+static struct mux_lite_cmdh *mux_lite_add_cmd(struct iosm_mux *ipc_mux, u32 cmd,
+					      struct mux_acb *acb, void *param,
+					      u32 param_size)
+{
+	struct mux_lite_cmdh *cmdh = (struct mux_lite_cmdh *)acb->skb->data;
+
+	cmdh->signature = cpu_to_le32(MUX_SIG_CMDH);
+	cmdh->command_type = cpu_to_le32(cmd);
+	cmdh->if_id = acb->if_id;
+
+	acb->cmd = cmd;
+
+	cmdh->cmd_len = cpu_to_le16(offsetof(struct mux_lite_cmdh, param) +
+				    param_size);
+	cmdh->transaction_id = cpu_to_le32(ipc_mux->tx_transaction_id++);
+
+	if (param)
+		memcpy(&cmdh->param, param, param_size);
+
+	skb_put(acb->skb, le16_to_cpu(cmdh->cmd_len));
+
+	return cmdh;
+}
+
+static int mux_acb_alloc(struct iosm_mux *ipc_mux)
+{
+	struct mux_acb *acb = &ipc_mux->acb;
+	struct sk_buff *skb;
+	dma_addr_t mapping;
+
+	/* Allocate skb memory for the uplink buffer. */
+	skb = ipc_pcie_alloc_skb(ipc_mux->pcie, MUX_MAX_UL_ACB_BUF_SIZE,
+				 GFP_ATOMIC, &mapping, DMA_TO_DEVICE, 0);
+	if (!skb)
+		return -ENOMEM;
+
+	/* Save the skb address. */
+	acb->skb = skb;
+
+	memset(skb->data, 0, MUX_MAX_UL_ACB_BUF_SIZE);
+
+	return 0;
+}
+
+int mux_dl_acb_send_cmds(struct iosm_mux *ipc_mux, u32 cmd_type, u8 if_id,
+			 u32 transaction_id, union mux_cmd_param *param,
+			 size_t res_size, bool blocking, bool respond)
+{
+	struct mux_acb *acb = &ipc_mux->acb;
+	struct mux_lite_cmdh *ack_lite;
+	int ret = 0;
+
+	acb->if_id = if_id;
+	ret = mux_acb_alloc(ipc_mux);
+	if (ret)
+		return ret;
+
+	ack_lite = mux_lite_add_cmd(ipc_mux, cmd_type, acb, param, res_size);
+	if (respond)
+		ack_lite->transaction_id = cpu_to_le32(transaction_id);
+
+	ret = mux_acb_send(ipc_mux, blocking);
+
+	return ret;
+}
+
+void mux_netif_tx_flowctrl(struct mux_session *session, int idx, bool on)
+{
+	/* Inform the network interface to start/stop flow ctrl */
+	ipc_wwan_tx_flowctrl(session->wwan, idx, on);
+}
+
+static int mux_dl_cmdresps_decode_process(struct iosm_mux *ipc_mux,
+					  struct mux_lite_cmdh *cmdh)
+{
+	struct mux_acb *acb = &ipc_mux->acb;
+
+	switch (le32_to_cpu(cmdh->command_type)) {
+	case MUX_CMD_OPEN_SESSION_RESP:
+	case MUX_CMD_CLOSE_SESSION_RESP:
+		/* Resume the control application. */
+		acb->got_param = cmdh->param;
+		break;
+
+	case MUX_LITE_CMD_FLOW_CTL_ACK:
+		/* This command type is not expected as response for
+		 * Aggregation version of the protocol. So return non-zero.
+		 */
+		if (ipc_mux->protocol != MUX_LITE)
+			return -EINVAL;
+
+		dev_dbg(ipc_mux->dev, "if %u FLOW_CTL_ACK %u received",
+			cmdh->if_id, le32_to_cpu(cmdh->transaction_id));
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	acb->wanted_response = MUX_CMD_INVALID;
+	acb->got_response = le32_to_cpu(cmdh->command_type);
+	complete(&ipc_mux->channel->ul_sem);
+
+	return 0;
+}
+
+static int mux_dl_dlcmds_decode_process(struct iosm_mux *ipc_mux,
+					struct mux_lite_cmdh *cmdh)
+{
+	union mux_cmd_param *param = &cmdh->param;
+	struct mux_session *session;
+	int new_size;
+
+	dev_dbg(ipc_mux->dev, "if_id[%d]: dlcmds decode process %d",
+		cmdh->if_id, le32_to_cpu(cmdh->command_type));
+
+	switch (le32_to_cpu(cmdh->command_type)) {
+	case MUX_LITE_CMD_FLOW_CTL:
+
+		if (cmdh->if_id >= ipc_mux->nr_sessions) {
+			dev_err(ipc_mux->dev, "if_id [%d] not valid",
+				cmdh->if_id);
+			return -EINVAL; /* No session interface id. */
+		}
+
+		session = &ipc_mux->session[cmdh->if_id];
+
+		new_size = offsetof(struct mux_lite_cmdh, param) +
+			   sizeof(param->flow_ctl);
+		if (param->flow_ctl.mask == cpu_to_le32(0xFFFFFFFF)) {
+			/* Backward Compatibility */
+			if (cmdh->cmd_len == cpu_to_le16(new_size))
+				session->flow_ctl_mask =
+					le32_to_cpu(param->flow_ctl.mask);
+			else
+				session->flow_ctl_mask = ~0;
+			/* if CP asks for FLOW CTRL Enable
+			 * then set our internal flow control Tx flag
+			 * to limit uplink session queueing
+			 */
+			session->net_tx_stop = true;
+			/* Update the stats */
+			session->flow_ctl_en_cnt++;
+		} else if (param->flow_ctl.mask == 0) {
+			/* Just reset the Flow control mask and let
+			 * mux_flow_ctrl_low_thre_b take control on
+			 * our internal Tx flag and enabling kernel
+			 * flow control
+			 */
+			/* Backward Compatibility */
+			if (cmdh->cmd_len == cpu_to_le16(new_size))
+				session->flow_ctl_mask =
+					le32_to_cpu(param->flow_ctl.mask);
+			else
+				session->flow_ctl_mask = 0;
+			/* Update the stats */
+			session->flow_ctl_dis_cnt++;
+		} else {
+			break;
+		}
+
+		dev_dbg(ipc_mux->dev, "if[%u] FLOW CTRL 0x%08X", cmdh->if_id,
+			le32_to_cpu(param->flow_ctl.mask));
+		break;
+
+	case MUX_LITE_CMD_LINK_STATUS_REPORT:
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/* Decode and Send appropriate response to a command block. */
+static void mux_dl_cmd_decode(struct iosm_mux *ipc_mux, struct sk_buff *skb)
+{
+	struct mux_lite_cmdh *cmdh = (struct mux_lite_cmdh *)skb->data;
+
+	if (mux_dl_cmdresps_decode_process(ipc_mux, cmdh)) {
+		/* Unable to decode command response indicates the cmd_type
+		 * may be a command instead of response. So try to decoding it.
+		 */
+		if (!mux_dl_dlcmds_decode_process(ipc_mux, cmdh)) {
+			/* Decoded command may need a response. Give the
+			 * response according to the command type.
+			 */
+			union mux_cmd_param *mux_cmd = NULL;
+			size_t size = 0;
+			u32 cmd = MUX_LITE_CMD_LINK_STATUS_REPORT_RESP;
+
+			if (cmdh->command_type ==
+			    cpu_to_le32(MUX_LITE_CMD_LINK_STATUS_REPORT)) {
+				mux_cmd = &cmdh->param;
+				mux_cmd->link_status_resp.response =
+					cpu_to_le32(MUX_CMD_RESP_SUCCESS);
+				/* response field is u32 */
+				size = sizeof(u32);
+			} else if (cmdh->command_type ==
+				   cpu_to_le32(MUX_LITE_CMD_FLOW_CTL)) {
+				cmd = MUX_LITE_CMD_FLOW_CTL_ACK;
+			} else {
+				return;
+			}
+
+			if (mux_dl_acb_send_cmds(ipc_mux, cmd, cmdh->if_id,
+						 le32_to_cpu(cmdh->transaction_id),
+						 mux_cmd, size, false, true))
+				dev_err(ipc_mux->dev,
+					"if_id %d: cmd send failed",
+					cmdh->if_id);
+		}
+	}
+}
+
+/* Pass the DL packet to the netif layer. */
+static int mux_net_receive(struct iosm_mux *ipc_mux, int if_id,
+			   struct iosm_wwan *wwan, u32 offset, u8 service_class,
+			   struct sk_buff *skb)
+{
+	struct sk_buff *dest_skb = skb_clone(skb, GFP_ATOMIC);
+
+	if (!dest_skb)
+		return -ENOMEM;
+
+	skb_pull(dest_skb, offset);
+	skb_set_tail_pointer(dest_skb, dest_skb->len);
+	/* Pass the packet to the netif layer. */
+	dest_skb->priority = service_class;
+
+	return ipc_wwan_receive(wwan, dest_skb, false, if_id);
+}
+
+/* Decode Flow Credit Table in the block */
+static void mux_dl_fcth_decode(struct iosm_mux *ipc_mux, unsigned char *block)
+{
+	struct ipc_mem_lite_gen_tbl *fct = (struct ipc_mem_lite_gen_tbl *)block;
+	struct iosm_wwan *wwan;
+	int ul_credits;
+	int if_id;
+
+	if (fct->vfl_length != sizeof(fct->vfl.nr_of_bytes)) {
+		dev_err(ipc_mux->dev, "unexpected FCT length: %d",
+			fct->vfl_length);
+		return;
+	}
+
+	if_id = fct->if_id;
+	if (if_id >= ipc_mux->nr_sessions) {
+		dev_err(ipc_mux->dev, "not supported if_id: %d", if_id);
+		return;
+	}
+
+	/* Is the session active ? */
+	if_id = array_index_nospec(if_id, ipc_mux->nr_sessions);
+	wwan = ipc_mux->session[if_id].wwan;
+	if (!wwan) {
+		dev_err(ipc_mux->dev, "session Net ID is NULL");
+		return;
+	}
+
+	ul_credits = fct->vfl.nr_of_bytes;
+
+	dev_dbg(ipc_mux->dev, "Flow_Credit:: if_id[%d] Old: %d Grants: %d",
+		if_id, ipc_mux->session[if_id].ul_flow_credits, ul_credits);
+
+	/* Update the Flow Credit information from ADB */
+	ipc_mux->session[if_id].ul_flow_credits += ul_credits;
+
+	/* Check whether the TX can be started */
+	if (ipc_mux->session[if_id].ul_flow_credits > 0) {
+		ipc_mux->session[if_id].net_tx_stop = false;
+		mux_netif_tx_flowctrl(&ipc_mux->session[if_id],
+				      ipc_mux->session[if_id].if_id, false);
+	}
+}
+
+/* Decode non-aggregated datagram */
+static void mux_dl_adgh_decode(struct iosm_mux *ipc_mux, struct sk_buff *skb)
+{
+	u32 pad_len, packet_offset;
+	struct iosm_wwan *wwan;
+	struct mux_adgh *adgh;
+	u8 *block = skb->data;
+	int rc = 0;
+	u8 if_id;
+
+	adgh = (struct mux_adgh *)block;
+
+	if (adgh->signature != cpu_to_le32(MUX_SIG_ADGH)) {
+		dev_err(ipc_mux->dev, "invalid ADGH signature received");
+		return;
+	}
+
+	if_id = adgh->if_id;
+	if (if_id >= ipc_mux->nr_sessions) {
+		dev_err(ipc_mux->dev, "invalid if_id while decoding %d", if_id);
+		return;
+	}
+
+	/* Is the session active ? */
+	if_id = array_index_nospec(if_id, ipc_mux->nr_sessions);
+	wwan = ipc_mux->session[if_id].wwan;
+	if (!wwan) {
+		dev_err(ipc_mux->dev, "session Net ID is NULL");
+		return;
+	}
+
+	/* Store the pad len for the corresponding session
+	 * Pad bytes as negotiated in the open session less the header size
+	 * (see session management chapter for details).
+	 * If resulting padding is zero or less, the additional head padding is
+	 * omitted. For e.g., if HEAD_PAD_LEN = 16 or less, this field is
+	 * omitted if HEAD_PAD_LEN = 20, then this field will have 4 bytes
+	 * set to zero
+	 */
+	pad_len =
+		ipc_mux->session[if_id].dl_head_pad_len - IPC_MEM_DL_ETH_OFFSET;
+	packet_offset = sizeof(*adgh) + pad_len;
+
+	if_id += ipc_mux->wwan_q_offset;
+
+	/* Pass the packet to the netif layer */
+	rc = mux_net_receive(ipc_mux, if_id, wwan, packet_offset,
+			     adgh->service_class, skb);
+	if (rc) {
+		dev_err(ipc_mux->dev, "mux adgh decoding error");
+		return;
+	}
+	ipc_mux->session[if_id].flush = 1;
+}
+
+void ipc_mux_dl_decode(struct iosm_mux *ipc_mux, struct sk_buff *skb)
+{
+	u32 signature;
+
+	if (!skb->data)
+		return;
+
+	/* Decode the MUX header type. */
+	signature = le32_to_cpup((__le32 *)skb->data);
+
+	switch (signature) {
+	case MUX_SIG_ADGH:
+		mux_dl_adgh_decode(ipc_mux, skb);
+		break;
+
+	case MUX_SIG_FCTH:
+		mux_dl_fcth_decode(ipc_mux, skb->data);
+		break;
+
+	case MUX_SIG_CMDH:
+		mux_dl_cmd_decode(ipc_mux, skb);
+		break;
+
+	default:
+		dev_err(ipc_mux->dev, "invalid ABH signature");
+	}
+
+	ipc_pcie_kfree_skb(ipc_mux->pcie, skb);
+}
+
+static int mux_ul_skb_alloc(struct iosm_mux *ipc_mux, struct mux_adb *ul_adb,
+			    u32 type)
+{
+	/* Take the first element of the free list. */
+	struct sk_buff *skb = skb_dequeue(&ul_adb->free_list);
+	int qlt_size;
+
+	if (!skb)
+		return -EBUSY; /* Wait for a free ADB skb. */
+
+	/* Mark it as UL ADB to select the right free operation. */
+	IPC_CB(skb)->op_type = (u8)UL_MUX_OP_ADB;
+
+	switch (type) {
+	case MUX_SIG_ADGH:
+		/* Save the ADB memory settings. */
+		ul_adb->dest_skb = skb;
+		ul_adb->buf = skb->data;
+		ul_adb->size = IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE;
+		/* reset statistic counter */
+		ul_adb->if_cnt = 0;
+		ul_adb->payload_size = 0;
+		ul_adb->dg_cnt_total = 0;
+
+		ul_adb->adgh = (struct mux_adgh *)skb->data;
+		memset(ul_adb->adgh, 0, sizeof(struct mux_adgh));
+		break;
+
+	case MUX_SIG_QLTH:
+		qlt_size = offsetof(struct ipc_mem_lite_gen_tbl, vfl) +
+			   (MUX_QUEUE_LEVEL * sizeof(struct mux_lite_vfl));
+
+		if (qlt_size > IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE) {
+			dev_err(ipc_mux->dev,
+				"can't support. QLT size:%d SKB size: %d",
+				qlt_size, IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE);
+			return -ERANGE;
+		}
+
+		ul_adb->qlth_skb = skb;
+		memset((ul_adb->qlth_skb)->data, 0, qlt_size);
+		skb_put(skb, qlt_size);
+		break;
+	}
+
+	return 0;
+}
+
+static void mux_ul_adgh_finish(struct iosm_mux *ipc_mux)
+{
+	struct mux_adb *ul_adb = &ipc_mux->ul_adb;
+	u16 adgh_len;
+	long long bytes;
+	char *str;
+
+	if (!ul_adb || !ul_adb->dest_skb) {
+		dev_err(ipc_mux->dev, "no dest skb");
+		return;
+	}
+
+	adgh_len = le16_to_cpu(ul_adb->adgh->length);
+	skb_put(ul_adb->dest_skb, adgh_len);
+	skb_queue_tail(&ipc_mux->channel->ul_list, ul_adb->dest_skb);
+	ul_adb->dest_skb = NULL;
+
+	if (ipc_mux->ul_flow == MUX_UL_ON_CREDITS) {
+		struct mux_session *session;
+
+		session = &ipc_mux->session[ul_adb->adgh->if_id];
+		str = "available_credits";
+		bytes = (long long)session->ul_flow_credits;
+
+	} else {
+		str = "pend_bytes";
+		bytes = ipc_mux->ul_data_pend_bytes;
+		ipc_mux->ul_data_pend_bytes = ipc_mux->ul_data_pend_bytes +
+					      adgh_len;
+	}
+
+	dev_dbg(ipc_mux->dev, "UL ADGH: size=%u, if_id=%d, payload=%d, %s=%lld",
+		adgh_len, ul_adb->adgh->if_id, ul_adb->payload_size,
+		str, bytes);
+}
+
+/* Allocates an ADB from the free list and initializes it with ADBH  */
+static bool mux_ul_adb_allocate(struct iosm_mux *ipc_mux, struct mux_adb *adb,
+				int *size_needed, u32 type)
+{
+	bool ret_val = false;
+	int status;
+
+	if (!adb->dest_skb) {
+		/* Allocate memory for the ADB including of the
+		 * datagram table header.
+		 */
+		status = mux_ul_skb_alloc(ipc_mux, adb, type);
+		if (status)
+			/* Is a pending ADB available ? */
+			ret_val = true; /* None. */
+
+		/* Update size need to zero only for new ADB memory */
+		*size_needed = 0;
+	}
+
+	return ret_val;
+}
+
+/* Informs the network stack to stop sending further packets for all opened
+ * sessions
+ */
+static void mux_stop_tx_for_all_sessions(struct iosm_mux *ipc_mux)
+{
+	struct mux_session *session;
+	int idx;
+
+	for (idx = 0; idx < ipc_mux->nr_sessions; idx++) {
+		session = &ipc_mux->session[idx];
+
+		if (!session->wwan)
+			continue;
+
+		session->net_tx_stop = true;
+	}
+}
+
+/* Sends Queue Level Table of all opened sessions */
+static bool mux_lite_send_qlt(struct iosm_mux *ipc_mux)
+{
+	struct ipc_mem_lite_gen_tbl *qlt;
+	struct mux_session *session;
+	bool qlt_updated = false;
+	int i;
+	int qlt_size;
+
+	if (!ipc_mux->initialized || ipc_mux->state != MUX_S_ACTIVE)
+		return qlt_updated;
+
+	qlt_size = offsetof(struct ipc_mem_lite_gen_tbl, vfl) +
+		   MUX_QUEUE_LEVEL * sizeof(struct mux_lite_vfl);
+
+	for (i = 0; i < ipc_mux->nr_sessions; i++) {
+		session = &ipc_mux->session[i];
+
+		if (!session->wwan || session->flow_ctl_mask)
+			continue;
+
+		if (mux_ul_skb_alloc(ipc_mux, &ipc_mux->ul_adb, MUX_SIG_QLTH)) {
+			dev_err(ipc_mux->dev,
+				"no reserved mem to send QLT of if_id: %d", i);
+			break;
+		}
+
+		/* Prepare QLT */
+		qlt = (struct ipc_mem_lite_gen_tbl *)(ipc_mux->ul_adb.qlth_skb)
+			      ->data;
+		qlt->signature = cpu_to_le32(MUX_SIG_QLTH);
+		qlt->length = cpu_to_le16(qlt_size);
+		qlt->if_id = i;
+		qlt->vfl_length = MUX_QUEUE_LEVEL * sizeof(struct mux_lite_vfl);
+		qlt->reserved[0] = 0;
+		qlt->reserved[1] = 0;
+
+		qlt->vfl.nr_of_bytes = session->ul_list.qlen;
+
+		/* Add QLT to the transfer list. */
+		skb_queue_tail(&ipc_mux->channel->ul_list,
+			       ipc_mux->ul_adb.qlth_skb);
+
+		qlt_updated = true;
+		ipc_mux->ul_adb.qlth_skb = NULL;
+	}
+
+	if (qlt_updated)
+		/* Updates the TDs with ul_list */
+		(void)imem_ul_write_td(ipc_mux->imem);
+
+	return qlt_updated;
+}
+
+/* Checks the available credits for the specified session and returns
+ * number of packets for which credits are available.
+ */
+static int mux_ul_bytes_credits_check(struct iosm_mux *ipc_mux,
+				      struct mux_session *session,
+				      struct sk_buff_head *ul_list,
+				      int max_nr_of_pkts)
+{
+	int pkts_to_send = 0;
+	struct sk_buff *skb;
+	int credits = 0;
+
+	if (ipc_mux->ul_flow == MUX_UL_ON_CREDITS) {
+		credits = session->ul_flow_credits;
+		if (credits <= 0) {
+			dev_dbg(ipc_mux->dev,
+				"FC::if_id[%d] Insuff.Credits/Qlen:%d/%u",
+				session->if_id, session->ul_flow_credits,
+				session->ul_list.qlen); /* nr_of_bytes */
+			return 0;
+		}
+	} else {
+		credits = IPC_MEM_MUX_UL_FLOWCTRL_HIGH_B -
+			  ipc_mux->ul_data_pend_bytes;
+		if (credits <= 0) {
+			mux_stop_tx_for_all_sessions(ipc_mux);
+
+			dev_dbg(ipc_mux->dev,
+				"if_id[%d] Stopped encoding.PendBytes: %llu, high_thresh: %d",
+				session->if_id, ipc_mux->ul_data_pend_bytes,
+				IPC_MEM_MUX_UL_FLOWCTRL_HIGH_B);
+			return 0;
+		}
+	}
+
+	/* Check if there are enough credits/bytes available to send the
+	 * requested max_nr_of_pkts. Otherwise restrict the nr_of_pkts
+	 * depending on available credits.
+	 */
+	skb_queue_walk(ul_list, skb)
+	{
+		if (!(credits >= skb->len && pkts_to_send < max_nr_of_pkts))
+			break;
+		credits -= skb->len;
+		pkts_to_send++;
+	}
+
+	return pkts_to_send;
+}
+
+/* Encode the UL IP packet according to Lite spec. */
+static int mux_ul_adgh_encode(struct iosm_mux *ipc_mux, int session_id,
+			      struct mux_session *session,
+			      struct sk_buff_head *ul_list, struct mux_adb *adb,
+			      int nr_of_pkts)
+{
+	int offset = sizeof(struct mux_adgh);
+	int adb_updated = -EINVAL;
+	struct sk_buff *src_skb;
+	int aligned_size = 0;
+	int nr_of_skb = 0;
+	u32 pad_len = 0;
+
+	/* Re-calculate the number of packets depending on number of bytes to be
+	 * processed/available credits.
+	 */
+	nr_of_pkts = mux_ul_bytes_credits_check(ipc_mux, session, ul_list,
+						nr_of_pkts);
+
+	/* If calculated nr_of_pkts from available credits is <= 0
+	 * then nothing to do.
+	 */
+	if (nr_of_pkts <= 0)
+		return 0;
+
+	/* Read configured UL head_pad_length for session.*/
+	if (session->ul_head_pad_len > IPC_MEM_DL_ETH_OFFSET)
+		pad_len = session->ul_head_pad_len - IPC_MEM_DL_ETH_OFFSET;
+
+	/* Process all pending UL packets for this session
+	 * depending on the allocated datagram table size.
+	 */
+	while (nr_of_pkts > 0) {
+		/* get destination skb allocated */
+		if (mux_ul_adb_allocate(ipc_mux, adb, &ipc_mux->size_needed,
+					MUX_SIG_ADGH)) {
+			dev_err(ipc_mux->dev, "no reserved memory for ADGH");
+			return -ENOMEM;
+		}
+
+		/* Peek at the head of the list. */
+		src_skb = skb_peek(ul_list);
+		if (!src_skb) {
+			dev_err(ipc_mux->dev,
+				"skb peek return NULL with count : %d",
+				nr_of_pkts);
+			break;
+		}
+
+		/* Calculate the memory value. */
+		aligned_size = ALIGN((pad_len + src_skb->len), 4);
+
+		ipc_mux->size_needed = sizeof(struct mux_adgh) + aligned_size;
+
+		if (ipc_mux->size_needed > adb->size) {
+			dev_dbg(ipc_mux->dev, "size needed %d, adgh size %d",
+				ipc_mux->size_needed, adb->size);
+			/* Return 1 if any IP packet is added to the transfer
+			 * list.
+			 */
+			return nr_of_skb ? 1 : 0;
+		}
+
+		/* Add buffer (without head padding to next pending transfer) */
+		memcpy(adb->buf + offset + pad_len, src_skb->data,
+		       src_skb->len);
+
+		adb->adgh->signature = cpu_to_le32(MUX_SIG_ADGH);
+		adb->adgh->if_id = session_id;
+		adb->adgh->length =
+			cpu_to_le16(sizeof(struct mux_adgh) + pad_len + src_skb->len);
+		adb->adgh->service_class = src_skb->priority;
+		adb->adgh->next_count = --nr_of_pkts;
+		adb->dg_cnt_total++;
+		adb->payload_size += src_skb->len;
+
+		if (ipc_mux->ul_flow == MUX_UL_ON_CREDITS)
+			/* Decrement the credit value as we are processing the
+			 * datagram from the UL list.
+			 */
+			session->ul_flow_credits -= src_skb->len;
+
+		/* Remove the processed elements and free it. */
+		src_skb = skb_dequeue(ul_list);
+		dev_kfree_skb(src_skb);
+		nr_of_skb++;
+
+		mux_ul_adgh_finish(ipc_mux);
+	}
+
+	if (nr_of_skb) {
+		/* Send QLT info to modem if pending bytes > high watermark
+		 * in case of mux lite
+		 */
+		if (ipc_mux->ul_flow == MUX_UL_ON_CREDITS ||
+		    ipc_mux->ul_data_pend_bytes >=
+			    IPC_MEM_MUX_UL_FLOWCTRL_LOW_B)
+			adb_updated = mux_lite_send_qlt(ipc_mux);
+		else
+			adb_updated = 1;
+
+		/* Updates the TDs with ul_list */
+		(void)imem_ul_write_td(ipc_mux->imem);
+	}
+
+	return adb_updated;
+}
+
+bool ipc_mux_ul_data_encode(struct iosm_mux *ipc_mux)
+{
+	struct sk_buff_head *ul_list;
+	struct mux_session *session;
+	int updated = 0;
+	int session_id;
+	int dg_n;
+	int i;
+
+	if (!ipc_mux || ipc_mux->state != MUX_S_ACTIVE ||
+	    ipc_mux->adb_prep_ongoing)
+		return false;
+
+	ipc_mux->adb_prep_ongoing = true;
+
+	for (i = 0; i < ipc_mux->nr_sessions; i++) {
+		session_id = ipc_mux->rr_next_session;
+		session = &ipc_mux->session[session_id];
+
+		/* Go to next handle rr_next_session overflow */
+		ipc_mux->rr_next_session++;
+		if (ipc_mux->rr_next_session >= ipc_mux->nr_sessions)
+			ipc_mux->rr_next_session = 0;
+
+		if (!session->wwan || session->flow_ctl_mask ||
+		    session->net_tx_stop)
+			continue;
+
+		ul_list = &session->ul_list;
+
+		/* Is something pending in UL and flow ctrl off */
+		dg_n = skb_queue_len(ul_list);
+		if (dg_n > MUX_MAX_UL_DG_ENTRIES)
+			dg_n = MUX_MAX_UL_DG_ENTRIES;
+
+		if (dg_n == 0)
+			/* Nothing to do for ipc_mux session
+			 * -> try next session id.
+			 */
+			continue;
+
+		updated = mux_ul_adgh_encode(ipc_mux, session_id, session,
+					     ul_list, &ipc_mux->ul_adb, dg_n);
+	}
+
+	ipc_mux->adb_prep_ongoing = false;
+	return updated == 1;
+}
+
+void ipc_mux_ul_encoded_process(struct iosm_mux *ipc_mux, struct sk_buff *skb)
+{
+	struct mux_adgh *adgh;
+	u16 adgh_len;
+
+	adgh = (struct mux_adgh *)skb->data;
+	adgh_len = le16_to_cpu(adgh->length);
+
+	if (adgh->signature == cpu_to_le32(MUX_SIG_ADGH) &&
+	    ipc_mux->ul_flow == MUX_UL)
+		ipc_mux->ul_data_pend_bytes = ipc_mux->ul_data_pend_bytes -
+					      adgh_len;
+
+	if (ipc_mux->ul_flow == MUX_UL)
+		dev_dbg(ipc_mux->dev, "ul_data_pend_bytes: %lld",
+			ipc_mux->ul_data_pend_bytes);
+
+	/* Reset the skb settings. */
+	skb->tail = 0;
+	skb->len = 0;
+
+	/* Add the consumed ADB to the free list. */
+	skb_queue_tail((&ipc_mux->ul_adb.free_list), skb);
+}
+
+/* Start the NETIF uplink send transfer in MUX mode. */
+static int mux_tq_ul_trigger_encode(struct iosm_imem *ipc_imem, int arg,
+				    void *msg, size_t size)
+{
+	struct iosm_mux *ipc_mux = ipc_imem->mux;
+	bool ul_data_pend = false;
+
+	/* Add session UL data to a ADB and ADGH */
+	ul_data_pend = ipc_mux_ul_data_encode(ipc_mux);
+	if (ul_data_pend)
+		/* Delay the doorbell irq */
+		imem_td_update_timer_start(ipc_mux->imem);
+
+	/* reset the debounce flag */
+	ipc_mux->ev_mux_net_transmit_pending = false;
+
+	return 0;
+}
+
+int ipc_mux_ul_trigger_encode(struct iosm_mux *ipc_mux, int if_id,
+			      struct sk_buff *skb)
+{
+	struct mux_session *session = &ipc_mux->session[if_id];
+	int ret = -EINVAL;
+
+	if (ipc_mux->channel &&
+	    ipc_mux->channel->state != IMEM_CHANNEL_ACTIVE) {
+		dev_err(ipc_mux->dev,
+			"channel state is not IMEM_CHANNEL_ACTIVE");
+		goto out;
+	}
+
+	if (!session->wwan) {
+		dev_err(ipc_mux->dev, "session net ID is NULL");
+		ret = -EFAULT;
+		goto out;
+	}
+
+	/* Session is under flow control.
+	 * Check if packet can be queued in session list, if not
+	 * suspend net tx
+	 */
+	if (skb_queue_len(&session->ul_list) >=
+	    (session->net_tx_stop ?
+		     IPC_MEM_MUX_UL_SESS_FCON_THRESHOLD :
+		     (IPC_MEM_MUX_UL_SESS_FCON_THRESHOLD *
+		      IPC_MEM_MUX_UL_SESS_FCOFF_THRESHOLD_FACTOR))) {
+		mux_netif_tx_flowctrl(session, session->if_id, true);
+		ret = -EBUSY;
+		goto out;
+	}
+
+	/* Add skb to the uplink skb accumulator. */
+	skb_queue_tail(&session->ul_list, skb);
+
+	/* Inform the IPC kthread to pass uplink IP packets to CP. */
+	if (!ipc_mux->ev_mux_net_transmit_pending) {
+		ipc_mux->ev_mux_net_transmit_pending = true;
+		ret = ipc_task_queue_send_task(ipc_mux->imem,
+					       mux_tq_ul_trigger_encode, 0,
+					       NULL, 0, false);
+		if (ret)
+			goto out;
+	}
+	dev_dbg(ipc_mux->dev, "mux ul if[%d] qlen=%d/%u, len=%d/%d, prio=%d",
+		if_id, skb_queue_len(&session->ul_list), session->ul_list.qlen,
+		skb->len, skb->truesize, skb->priority);
+	ret = 0;
+out:
+	return ret;
+}
diff --git a/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h
new file mode 100644
index 000000000000..b0ae6c874cd4
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h
@@ -0,0 +1,193 @@
+/* SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#ifndef IOSM_IPC_MUX_CODEC_H
+#define IOSM_IPC_MUX_CODEC_H
+
+#include "iosm_ipc_mux.h"
+
+/* Queue level size and reporting
+ * >1 is enable, 0 is disable
+ */
+#define MUX_QUEUE_LEVEL 1
+
+/* Size of the buffer for the IP MUX commands. */
+#define MUX_MAX_UL_ACB_BUF_SIZE 256
+
+/* Maximum number of packets in a go per session */
+#define MUX_MAX_UL_DG_ENTRIES 100
+
+/* ADGH: Signature of the Datagram Header. */
+#define MUX_SIG_ADGH 0x48474441
+
+/* CMDH: Signature of the Command Header. */
+#define MUX_SIG_CMDH 0x48444D43
+
+/* QLTH: Signature of the Queue Level Table */
+#define MUX_SIG_QLTH 0x48544C51
+
+/* FCTH: Signature of the Flow Credit Table */
+#define MUX_SIG_FCTH 0x48544346
+
+/* MUX UL session threshold factor */
+#define IPC_MEM_MUX_UL_SESS_FCOFF_THRESHOLD_FACTOR (4)
+
+/* Size of the buffer for the IP MUX Lite data buffer. */
+#define IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE (2 * 1024)
+
+/* MUX UL session threshold in number of packets */
+#define IPC_MEM_MUX_UL_SESS_FCON_THRESHOLD (64)
+
+/* Default time out for sending IPC session commands like
+ * open session, close session etc
+ * unit : milliseconds
+ */
+#define IPC_MUX_CMD_RUN_DEFAULT_TIMEOUT 1000 /* 1 second */
+
+/* MUX UL flow control lower threshold in bytes */
+#define IPC_MEM_MUX_UL_FLOWCTRL_LOW_B 10240 /* 10KB */
+
+/* MUX UL flow control higher threshold in bytes (5ms worth of data)*/
+#define IPC_MEM_MUX_UL_FLOWCTRL_HIGH_B (110 * 1024)
+
+/**
+ * struct mux_adgh - Aggregated Datagram Header.
+ * @signature:		Signature of the Aggregated Datagram Header(0x48474441)
+ * @length:		Length (in bytes) of the datagram header. This length
+ *			shall include the header size. Min value: 0x10
+ * @if_id:		ID of the interface the datagrams belong to
+ * @opt_ipv4v6:		Indicates IPv4(=0)/IPv6(=1), It is optional if not
+ *			used set it to zero.
+ * @reserved:		Reserved bits. Set to zero.
+ * @service_class:	Service class identifier for the datagram.
+ * @next_count:		Count of the datagrams that shall be following this
+ *			datagrams for this interface. A count of zero means
+ *			the next datagram may not belong to this interface.
+ * @reserved1:		Reserved bytes, Set to zero
+ */
+struct mux_adgh {
+	__le32 signature;
+	__le16 length;
+	u8 if_id;
+	u8 opt_ipv4v6;
+	u8 service_class;
+	u8 next_count;
+	u8 reserved1[6];
+};
+
+/**
+ * struct mux_lite_cmdh - MUX Lite Command Header
+ * @signature:		Signature of the Command Header(0x48444D43)
+ * @cmd_len:		Length (in bytes) of the command. This length shall
+ *			include the header size. Minimum value: 0x10
+ * @if_id:		ID of the interface the commands in the table belong to.
+ * @reserved:		Reserved Set to zero.
+ * @command_type:	Command Enum.
+ * @transaction_id:	4 byte value shall be generated and sent along with a
+ *			command Responses and ACKs shall have the same
+ *			Transaction ID as their commands. It shall be unique to
+ *			the command transaction on the given interface.
+ * @param:		Optional parameters used with the command.
+ */
+struct mux_lite_cmdh {
+	__le32 signature;
+	__le16 cmd_len;
+	u8 if_id;
+	u8 reserved;
+	__le32 command_type;
+	__le32 transaction_id;
+	union mux_cmd_param param;
+};
+
+/**
+ * struct mux_lite_vfl - value field in generic table
+ * @nr_of_bytes:	Number of bytes available to transmit in the queue.
+ */
+struct mux_lite_vfl {
+	u32 nr_of_bytes;
+};
+
+/**
+ * struct ipc_mem_lite_gen_tbl - Generic table format for Queue Level
+ *				 and Flow Credit
+ * @signature:	Signature of the table
+ * @length:	Length of the table
+ * @if_id:	ID of the interface the table belongs to
+ * @vfl_length:	Value field length
+ * @reserved:	Reserved
+ * @vfl:	Value field of variable length
+ */
+struct ipc_mem_lite_gen_tbl {
+	__le32 signature;
+	__le16 length;
+	u8 if_id;
+	u8 vfl_length;
+	u32 reserved[2];
+	struct mux_lite_vfl vfl;
+};
+
+/**
+ * ipc_mux_dl_decode -Route the DL packet through the IP MUX layer
+ *		      depending on Header.
+ * @ipc_mux:	Pointer to MUX data-struct
+ * @skb:	Pointer to ipc_skb.
+ */
+void ipc_mux_dl_decode(struct iosm_mux *ipc_mux, struct sk_buff *skb);
+
+/**
+ * mux_dl_acb_send_cmds - Respond to the Command blocks.
+ * @ipc_mux:		Pointer to MUX data-struct
+ * @cmd_type:		Command
+ * @if_id:		Session interface id.
+ * @transaction_id:	Command transaction id.
+ * @param:		Pointer to command params.
+ * @res_size:		Response size
+ * @blocking:		True for blocking send
+ * @respond:		If true return transaction ID
+ *
+ * Returns: 0 in success and failure value on error
+ */
+int mux_dl_acb_send_cmds(struct iosm_mux *ipc_mux, u32 cmd_type, u8 if_id,
+			 u32 transaction_id, union mux_cmd_param *param,
+			 size_t res_size, bool blocking, bool respond);
+
+/**
+ * mux_netif_tx_flowctrl - Enable/Disable TX flow control on MUX sessions.
+ * @session:	Pointer to mux_session struct
+ * @idx:	Session ID
+ * @on:		true for Enable and false for disable flow control
+ */
+void mux_netif_tx_flowctrl(struct mux_session *session, int idx, bool on);
+
+/**
+ * ipc_mux_ul_trigger_encode - Route the UL packet through the IP MUX layer
+ *			       for encoding.
+ * @ipc_mux:	Pointer to MUX data-struct
+ * @if_id:	Session ID.
+ * @skb:	Pointer to ipc_skb.
+ *
+ * Returns: 0 if successfully encoded
+ *	    failure value on error
+ *	    -EBUSY if packet has to be retransmitted.
+ */
+int ipc_mux_ul_trigger_encode(struct iosm_mux *ipc_mux, int if_id,
+			      struct sk_buff *skb);
+/**
+ * ipc_mux_ul_data_encode - UL encode function for calling from Tasklet context.
+ * @ipc_mux:	Pointer to MUX data-struct
+ *
+ * Returns: TRUE if any packet of any session is encoded FALSE otherwise.
+ */
+bool ipc_mux_ul_data_encode(struct iosm_mux *ipc_mux);
+
+/**
+ * ipc_mux_ul_encoded_process - Handles the Modem processed UL data by adding
+ *				the SKB to the UL free list.
+ * @ipc_mux:	Pointer to MUX data-struct
+ * @skb:	Pointer to ipc_skb.
+ */
+void ipc_mux_ul_encoded_process(struct iosm_mux *ipc_mux, struct sk_buff *skb);
+
+#endif
-- 
2.25.1

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