Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2061 insertions, 0 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/mei/main.c b/drivers/net/wireless/intel/iwlwifi/mei/main.c
new file mode 100644
index 000000000..27eb28290
--- /dev/null
+++ b/drivers/net/wireless/intel/iwlwifi/mei/main.c
@@ -0,0 +1,2061 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021-2022 Intel Corporation
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/netdevice.h>
+#include <linux/ieee80211.h>
+#include <linux/rtnetlink.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/rcupdate.h>
+#include <linux/debugfs.h>
+#include <linux/skbuff.h>
+#include <linux/wait.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+
+#include <net/cfg80211.h>
+
+#include "internal.h"
+#include "iwl-mei.h"
+#include "trace.h"
+#include "trace-data.h"
+#include "sap.h"
+
+MODULE_DESCRIPTION("The Intel(R) wireless / CSME firmware interface");
+MODULE_LICENSE("GPL");
+
+#define MEI_WLAN_UUID UUID_LE(0x13280904, 0x7792, 0x4fcb, \
+			      0xa1, 0xaa, 0x5e, 0x70, 0xcb, 0xb1, 0xe8, 0x65)
+
+/*
+ * Since iwlwifi calls iwlmei without any context, hold a pointer to the
+ * mei_cl_device structure here.
+ * Define a mutex that will synchronize all the flows between iwlwifi and
+ * iwlmei.
+ * Note that iwlmei can't have several instances, so it ok to have static
+ * variables here.
+ */
+static struct mei_cl_device *iwl_mei_global_cldev;
+static DEFINE_MUTEX(iwl_mei_mutex);
+static unsigned long iwl_mei_status;
+
+enum iwl_mei_status_bits {
+	IWL_MEI_STATUS_SAP_CONNECTED,
+};
+
+bool iwl_mei_is_connected(void)
+{
+	return test_bit(IWL_MEI_STATUS_SAP_CONNECTED, &iwl_mei_status);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_is_connected);
+
+#define SAP_VERSION	3
+#define SAP_CONTROL_BLOCK_ID 0x21504153 /* SAP! in ASCII */
+
+struct iwl_sap_q_ctrl_blk {
+	__le32 wr_ptr;
+	__le32 rd_ptr;
+	__le32 size;
+};
+
+enum iwl_sap_q_idx {
+	SAP_QUEUE_IDX_NOTIF = 0,
+	SAP_QUEUE_IDX_DATA,
+	SAP_QUEUE_IDX_MAX,
+};
+
+struct iwl_sap_dir {
+	__le32 reserved;
+	struct iwl_sap_q_ctrl_blk q_ctrl_blk[SAP_QUEUE_IDX_MAX];
+};
+
+enum iwl_sap_dir_idx {
+	SAP_DIRECTION_HOST_TO_ME = 0,
+	SAP_DIRECTION_ME_TO_HOST,
+	SAP_DIRECTION_MAX,
+};
+
+struct iwl_sap_shared_mem_ctrl_blk {
+	__le32 sap_id;
+	__le32 size;
+	struct iwl_sap_dir dir[SAP_DIRECTION_MAX];
+};
+
+/*
+ * The shared area has the following layout:
+ *
+ * +-----------------------------------+
+ * |struct iwl_sap_shared_mem_ctrl_blk |
+ * +-----------------------------------+
+ * |Host -> ME data queue              |
+ * +-----------------------------------+
+ * |Host -> ME notif queue             |
+ * +-----------------------------------+
+ * |ME -> Host data queue              |
+ * +-----------------------------------+
+ * |ME -> host notif queue             |
+ * +-----------------------------------+
+ * |SAP control block id (SAP!)        |
+ * +-----------------------------------+
+ */
+
+#define SAP_H2M_DATA_Q_SZ	48256
+#define SAP_M2H_DATA_Q_SZ	24128
+#define SAP_H2M_NOTIF_Q_SZ	2240
+#define SAP_M2H_NOTIF_Q_SZ	62720
+
+#define _IWL_MEI_SAP_SHARED_MEM_SZ \
+	(sizeof(struct iwl_sap_shared_mem_ctrl_blk) + \
+	 SAP_H2M_DATA_Q_SZ + SAP_H2M_NOTIF_Q_SZ + \
+	 SAP_M2H_DATA_Q_SZ + SAP_M2H_NOTIF_Q_SZ + 4)
+
+#define IWL_MEI_SAP_SHARED_MEM_SZ \
+	(roundup(_IWL_MEI_SAP_SHARED_MEM_SZ, PAGE_SIZE))
+
+struct iwl_mei_shared_mem_ptrs {
+	struct iwl_sap_shared_mem_ctrl_blk *ctrl;
+	void *q_head[SAP_DIRECTION_MAX][SAP_QUEUE_IDX_MAX];
+	size_t q_size[SAP_DIRECTION_MAX][SAP_QUEUE_IDX_MAX];
+};
+
+struct iwl_mei_filters {
+	struct rcu_head rcu_head;
+	struct iwl_sap_oob_filters filters;
+};
+
+/**
+ * struct iwl_mei - holds the private date for iwl_mei
+ *
+ * @get_nvm_wq: the wait queue for the get_nvm flow
+ * @send_csa_msg_wk: used to defer the transmission of the CHECK_SHARED_AREA
+ *	message. Used so that we can send CHECK_SHARED_AREA from atomic
+ *	contexts.
+ * @get_ownership_wq: the wait queue for the get_ownership_flow
+ * @shared_mem: the memory that is shared between CSME and the host
+ * @cldev: the pointer to the MEI client device
+ * @nvm: the data returned by the CSME for the NVM
+ * @filters: the filters sent by CSME
+ * @got_ownership: true if we own the device
+ * @amt_enabled: true if CSME has wireless enabled
+ * @csa_throttled: when true, we can't send CHECK_SHARED_AREA over the MEI
+ *	bus, but rather need to wait until send_csa_msg_wk runs
+ * @csme_taking_ownership: true when CSME is taking ownership. Used to remember
+ *	to send CSME_OWNERSHIP_CONFIRMED when the driver completes its down
+ *	flow.
+ * @link_prot_state: true when we are in link protection PASSIVE
+ * @device_down: true if the device is down. Used to remember to send
+ *	CSME_OWNERSHIP_CONFIRMED when the driver is already down.
+ * @csa_throttle_end_wk: used when &csa_throttled is true
+ * @data_q_lock: protects the access to the data queues which are
+ *	accessed without the mutex.
+ * @netdev_work: used to defer registering and unregistering of the netdev to
+ *	avoid taking the rtnl lock in the SAP messages handlers.
+ * @sap_seq_no: the sequence number for the SAP messages
+ * @seq_no: the sequence number for the SAP messages
+ * @dbgfs_dir: the debugfs dir entry
+ */
+struct iwl_mei {
+	wait_queue_head_t get_nvm_wq;
+	struct work_struct send_csa_msg_wk;
+	wait_queue_head_t get_ownership_wq;
+	struct iwl_mei_shared_mem_ptrs shared_mem;
+	struct mei_cl_device *cldev;
+	struct iwl_mei_nvm *nvm;
+	struct iwl_mei_filters __rcu *filters;
+	bool got_ownership;
+	bool amt_enabled;
+	bool csa_throttled;
+	bool csme_taking_ownership;
+	bool link_prot_state;
+	bool device_down;
+	struct delayed_work csa_throttle_end_wk;
+	spinlock_t data_q_lock;
+	struct work_struct netdev_work;
+
+	atomic_t sap_seq_no;
+	atomic_t seq_no;
+
+	struct dentry *dbgfs_dir;
+};
+
+/**
+ * struct iwl_mei_cache - cache for the parameters from iwlwifi
+ * @ops: Callbacks to iwlwifi.
+ * @netdev: The netdev that will be used to transmit / receive packets.
+ * @conn_info: The connection info message triggered by iwlwifi's association.
+ * @power_limit: pointer to an array of 10 elements (le16) represents the power
+ *	restrictions per chain.
+ * @rf_kill: rf kill state.
+ * @mcc: MCC info
+ * @mac_address: interface MAC address.
+ * @nvm_address: NVM MAC address.
+ * @priv: A pointer to iwlwifi.
+ *
+ * This used to cache the configurations coming from iwlwifi's way. The data
+ * is cached here so that we can buffer the configuration even if we don't have
+ * a bind from the mei bus and hence, on iwl_mei structure.
+ */
+struct iwl_mei_cache {
+	const struct iwl_mei_ops *ops;
+	struct net_device __rcu *netdev;
+	const struct iwl_sap_notif_connection_info *conn_info;
+	const __le16 *power_limit;
+	u32 rf_kill;
+	u16 mcc;
+	u8 mac_address[6];
+	u8 nvm_address[6];
+	void *priv;
+};
+
+static struct iwl_mei_cache iwl_mei_cache = {
+	.rf_kill = SAP_HW_RFKILL_DEASSERTED | SAP_SW_RFKILL_DEASSERTED
+};
+
+static void iwl_mei_free_shared_mem(struct mei_cl_device *cldev)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+
+	if (mei_cldev_dma_unmap(cldev))
+		dev_err(&cldev->dev, "Couldn't unmap the shared mem properly\n");
+	memset(&mei->shared_mem, 0, sizeof(mei->shared_mem));
+}
+
+#define HBM_DMA_BUF_ID_WLAN 1
+
+static int iwl_mei_alloc_shared_mem(struct mei_cl_device *cldev)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+	struct iwl_mei_shared_mem_ptrs *mem = &mei->shared_mem;
+
+	mem->ctrl = mei_cldev_dma_map(cldev, HBM_DMA_BUF_ID_WLAN,
+				       IWL_MEI_SAP_SHARED_MEM_SZ);
+
+	if (IS_ERR(mem->ctrl)) {
+		int ret = PTR_ERR(mem->ctrl);
+
+		mem->ctrl = NULL;
+
+		return ret;
+	}
+
+	memset(mem->ctrl, 0, IWL_MEI_SAP_SHARED_MEM_SZ);
+
+	return 0;
+}
+
+static void iwl_mei_init_shared_mem(struct iwl_mei *mei)
+{
+	struct iwl_mei_shared_mem_ptrs *mem = &mei->shared_mem;
+	struct iwl_sap_dir *h2m;
+	struct iwl_sap_dir *m2h;
+	int dir, queue;
+	u8 *q_head;
+
+	mem->ctrl->sap_id = cpu_to_le32(SAP_CONTROL_BLOCK_ID);
+
+	mem->ctrl->size = cpu_to_le32(sizeof(*mem->ctrl));
+
+	h2m = &mem->ctrl->dir[SAP_DIRECTION_HOST_TO_ME];
+	m2h = &mem->ctrl->dir[SAP_DIRECTION_ME_TO_HOST];
+
+	h2m->q_ctrl_blk[SAP_QUEUE_IDX_DATA].size =
+		cpu_to_le32(SAP_H2M_DATA_Q_SZ);
+	h2m->q_ctrl_blk[SAP_QUEUE_IDX_NOTIF].size =
+		cpu_to_le32(SAP_H2M_NOTIF_Q_SZ);
+	m2h->q_ctrl_blk[SAP_QUEUE_IDX_DATA].size =
+		cpu_to_le32(SAP_M2H_DATA_Q_SZ);
+	m2h->q_ctrl_blk[SAP_QUEUE_IDX_NOTIF].size =
+		cpu_to_le32(SAP_M2H_NOTIF_Q_SZ);
+
+	/* q_head points to the start of the first queue */
+	q_head = (void *)(mem->ctrl + 1);
+
+	/* Initialize the queue heads */
+	for (dir = 0; dir < SAP_DIRECTION_MAX; dir++) {
+		for (queue = 0; queue < SAP_QUEUE_IDX_MAX; queue++) {
+			mem->q_head[dir][queue] = q_head;
+			q_head +=
+				le32_to_cpu(mem->ctrl->dir[dir].q_ctrl_blk[queue].size);
+			mem->q_size[dir][queue] =
+				le32_to_cpu(mem->ctrl->dir[dir].q_ctrl_blk[queue].size);
+		}
+	}
+
+	*(__le32 *)q_head = cpu_to_le32(SAP_CONTROL_BLOCK_ID);
+}
+
+static ssize_t iwl_mei_write_cyclic_buf(struct mei_cl_device *cldev,
+					struct iwl_sap_q_ctrl_blk *notif_q,
+					u8 *q_head,
+					const struct iwl_sap_hdr *hdr,
+					u32 q_sz)
+{
+	u32 rd = le32_to_cpu(READ_ONCE(notif_q->rd_ptr));
+	u32 wr = le32_to_cpu(READ_ONCE(notif_q->wr_ptr));
+	size_t room_in_buf;
+	size_t tx_sz = sizeof(*hdr) + le16_to_cpu(hdr->len);
+
+	if (rd > q_sz || wr > q_sz) {
+		dev_err(&cldev->dev,
+			"Pointers are past the end of the buffer\n");
+		return -EINVAL;
+	}
+
+	room_in_buf = wr >= rd ? q_sz - wr + rd : rd - wr;
+
+	/* we don't have enough room for the data to write */
+	if (room_in_buf < tx_sz) {
+		dev_err(&cldev->dev,
+			"Not enough room in the buffer\n");
+		return -ENOSPC;
+	}
+
+	if (wr + tx_sz <= q_sz) {
+		memcpy(q_head + wr, hdr, tx_sz);
+	} else {
+		memcpy(q_head + wr, hdr, q_sz - wr);
+		memcpy(q_head, (const u8 *)hdr + q_sz - wr, tx_sz - (q_sz - wr));
+	}
+
+	WRITE_ONCE(notif_q->wr_ptr, cpu_to_le32((wr + tx_sz) % q_sz));
+	return 0;
+}
+
+static bool iwl_mei_host_to_me_data_pending(const struct iwl_mei *mei)
+{
+	struct iwl_sap_q_ctrl_blk *notif_q;
+	struct iwl_sap_dir *dir;
+
+	dir = &mei->shared_mem.ctrl->dir[SAP_DIRECTION_HOST_TO_ME];
+	notif_q = &dir->q_ctrl_blk[SAP_QUEUE_IDX_DATA];
+
+	if (READ_ONCE(notif_q->wr_ptr) != READ_ONCE(notif_q->rd_ptr))
+		return true;
+
+	notif_q = &dir->q_ctrl_blk[SAP_QUEUE_IDX_NOTIF];
+	return READ_ONCE(notif_q->wr_ptr) != READ_ONCE(notif_q->rd_ptr);
+}
+
+static int iwl_mei_send_check_shared_area(struct mei_cl_device *cldev)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+	struct iwl_sap_me_msg_start msg = {
+		.hdr.type = cpu_to_le32(SAP_ME_MSG_CHECK_SHARED_AREA),
+		.hdr.seq_num = cpu_to_le32(atomic_inc_return(&mei->seq_no)),
+	};
+	int ret;
+
+	lockdep_assert_held(&iwl_mei_mutex);
+
+	if (mei->csa_throttled)
+		return 0;
+
+	trace_iwlmei_me_msg(&msg.hdr, true);
+	ret = mei_cldev_send(cldev, (void *)&msg, sizeof(msg));
+	if (ret != sizeof(msg)) {
+		dev_err(&cldev->dev,
+			"failed to send the SAP_ME_MSG_CHECK_SHARED_AREA message %d\n",
+			ret);
+		return ret;
+	}
+
+	mei->csa_throttled = true;
+
+	schedule_delayed_work(&mei->csa_throttle_end_wk,
+			      msecs_to_jiffies(100));
+
+	return 0;
+}
+
+static void iwl_mei_csa_throttle_end_wk(struct work_struct *wk)
+{
+	struct iwl_mei *mei =
+		container_of(wk, struct iwl_mei, csa_throttle_end_wk.work);
+
+	mutex_lock(&iwl_mei_mutex);
+
+	mei->csa_throttled = false;
+
+	if (iwl_mei_host_to_me_data_pending(mei))
+		iwl_mei_send_check_shared_area(mei->cldev);
+
+	mutex_unlock(&iwl_mei_mutex);
+}
+
+static int iwl_mei_send_sap_msg_payload(struct mei_cl_device *cldev,
+					struct iwl_sap_hdr *hdr)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+	struct iwl_sap_q_ctrl_blk *notif_q;
+	struct iwl_sap_dir *dir;
+	void *q_head;
+	u32 q_sz;
+	int ret;
+
+	lockdep_assert_held(&iwl_mei_mutex);
+
+	if (!mei->shared_mem.ctrl) {
+		dev_err(&cldev->dev,
+			"No shared memory, can't send any SAP message\n");
+		return -EINVAL;
+	}
+
+	if (!iwl_mei_is_connected()) {
+		dev_err(&cldev->dev,
+			"Can't send a SAP message if we're not connected\n");
+		return -ENODEV;
+	}
+
+	hdr->seq_num = cpu_to_le32(atomic_inc_return(&mei->sap_seq_no));
+	dev_dbg(&cldev->dev, "Sending %d\n", hdr->type);
+
+	dir = &mei->shared_mem.ctrl->dir[SAP_DIRECTION_HOST_TO_ME];
+	notif_q = &dir->q_ctrl_blk[SAP_QUEUE_IDX_NOTIF];
+	q_head = mei->shared_mem.q_head[SAP_DIRECTION_HOST_TO_ME][SAP_QUEUE_IDX_NOTIF];
+	q_sz = mei->shared_mem.q_size[SAP_DIRECTION_HOST_TO_ME][SAP_QUEUE_IDX_NOTIF];
+	ret = iwl_mei_write_cyclic_buf(q_head, notif_q, q_head, hdr, q_sz);
+
+	if (ret < 0)
+		return ret;
+
+	trace_iwlmei_sap_cmd(hdr, true);
+
+	return iwl_mei_send_check_shared_area(cldev);
+}
+
+void iwl_mei_add_data_to_ring(struct sk_buff *skb, bool cb_tx)
+{
+	struct iwl_sap_q_ctrl_blk *notif_q;
+	struct iwl_sap_dir *dir;
+	struct iwl_mei *mei;
+	size_t room_in_buf;
+	size_t tx_sz;
+	size_t hdr_sz;
+	u32 q_sz;
+	u32 rd;
+	u32 wr;
+	u8 *q_head;
+
+	if (!iwl_mei_global_cldev)
+		return;
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	/*
+	 * We access this path for Rx packets (the more common case)
+	 * and from Tx path when we send DHCP packets, the latter is
+	 * very unlikely.
+	 * Take the lock already here to make sure we see that remove()
+	 * might have cleared the IWL_MEI_STATUS_SAP_CONNECTED bit.
+	 */
+	spin_lock_bh(&mei->data_q_lock);
+
+	if (!iwl_mei_is_connected()) {
+		spin_unlock_bh(&mei->data_q_lock);
+		return;
+	}
+
+	/*
+	 * We are in a RCU critical section and the remove from the CSME bus
+	 * which would free this memory waits for the readers to complete (this
+	 * is done in netdev_rx_handler_unregister).
+	 */
+	dir = &mei->shared_mem.ctrl->dir[SAP_DIRECTION_HOST_TO_ME];
+	notif_q = &dir->q_ctrl_blk[SAP_QUEUE_IDX_DATA];
+	q_head = mei->shared_mem.q_head[SAP_DIRECTION_HOST_TO_ME][SAP_QUEUE_IDX_DATA];
+	q_sz = mei->shared_mem.q_size[SAP_DIRECTION_HOST_TO_ME][SAP_QUEUE_IDX_DATA];
+
+	rd = le32_to_cpu(READ_ONCE(notif_q->rd_ptr));
+	wr = le32_to_cpu(READ_ONCE(notif_q->wr_ptr));
+	hdr_sz = cb_tx ? sizeof(struct iwl_sap_cb_data) :
+			 sizeof(struct iwl_sap_hdr);
+	tx_sz = skb->len + hdr_sz;
+
+	if (rd > q_sz || wr > q_sz) {
+		dev_err(&mei->cldev->dev,
+			"can't write the data: pointers are past the end of the buffer\n");
+		goto out;
+	}
+
+	room_in_buf = wr >= rd ? q_sz - wr + rd : rd - wr;
+
+	/* we don't have enough room for the data to write */
+	if (room_in_buf < tx_sz) {
+		dev_err(&mei->cldev->dev,
+			"Not enough room in the buffer for this data\n");
+		goto out;
+	}
+
+	if (skb_headroom(skb) < hdr_sz) {
+		dev_err(&mei->cldev->dev,
+			"Not enough headroom in the skb to write the SAP header\n");
+		goto out;
+	}
+
+	if (cb_tx) {
+		struct iwl_sap_cb_data *cb_hdr = skb_push(skb, sizeof(*cb_hdr));
+
+		memset(cb_hdr, 0, sizeof(*cb_hdr));
+		cb_hdr->hdr.type = cpu_to_le16(SAP_MSG_CB_DATA_PACKET);
+		cb_hdr->hdr.len = cpu_to_le16(skb->len - sizeof(cb_hdr->hdr));
+		cb_hdr->hdr.seq_num = cpu_to_le32(atomic_inc_return(&mei->sap_seq_no));
+		cb_hdr->to_me_filt_status = cpu_to_le32(BIT(CB_TX_DHCP_FILT_IDX));
+		cb_hdr->data_len = cpu_to_le32(skb->len - sizeof(*cb_hdr));
+		trace_iwlmei_sap_data(skb, IWL_SAP_TX_DHCP);
+	} else {
+		struct iwl_sap_hdr *hdr = skb_push(skb, sizeof(*hdr));
+
+		hdr->type = cpu_to_le16(SAP_MSG_DATA_PACKET);
+		hdr->len = cpu_to_le16(skb->len - sizeof(*hdr));
+		hdr->seq_num = cpu_to_le32(atomic_inc_return(&mei->sap_seq_no));
+		trace_iwlmei_sap_data(skb, IWL_SAP_TX_DATA_FROM_AIR);
+	}
+
+	if (wr + tx_sz <= q_sz) {
+		skb_copy_bits(skb, 0, q_head + wr, tx_sz);
+	} else {
+		skb_copy_bits(skb, 0, q_head + wr, q_sz - wr);
+		skb_copy_bits(skb, q_sz - wr, q_head, tx_sz - (q_sz - wr));
+	}
+
+	WRITE_ONCE(notif_q->wr_ptr, cpu_to_le32((wr + tx_sz) % q_sz));
+
+out:
+	spin_unlock_bh(&mei->data_q_lock);
+}
+
+static int
+iwl_mei_send_sap_msg(struct mei_cl_device *cldev, u16 type)
+{
+	struct iwl_sap_hdr msg = {
+		.type = cpu_to_le16(type),
+	};
+
+	return iwl_mei_send_sap_msg_payload(cldev, &msg);
+}
+
+static void iwl_mei_send_csa_msg_wk(struct work_struct *wk)
+{
+	struct iwl_mei *mei =
+		container_of(wk, struct iwl_mei, send_csa_msg_wk);
+
+	if (!iwl_mei_is_connected())
+		return;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	iwl_mei_send_check_shared_area(mei->cldev);
+
+	mutex_unlock(&iwl_mei_mutex);
+}
+
+/* Called in a RCU read critical section from netif_receive_skb */
+static rx_handler_result_t iwl_mei_rx_handler(struct sk_buff **pskb)
+{
+	struct sk_buff *skb = *pskb;
+	struct iwl_mei *mei =
+		rcu_dereference(skb->dev->rx_handler_data);
+	struct iwl_mei_filters *filters = rcu_dereference(mei->filters);
+	bool rx_for_csme = false;
+	rx_handler_result_t res;
+
+	/*
+	 * remove() unregisters this handler and synchronize_net, so this
+	 * should never happen.
+	 */
+	if (!iwl_mei_is_connected()) {
+		dev_err(&mei->cldev->dev,
+			"Got an Rx packet, but we're not connected to SAP?\n");
+		return RX_HANDLER_PASS;
+	}
+
+	if (filters)
+		res = iwl_mei_rx_filter(skb, &filters->filters, &rx_for_csme);
+	else
+		res = RX_HANDLER_PASS;
+
+	/*
+	 * The data is already on the ring of the shared area, all we
+	 * need to do is to tell the CSME firmware to check what we have
+	 * there.
+	 */
+	if (rx_for_csme)
+		schedule_work(&mei->send_csa_msg_wk);
+
+	if (res != RX_HANDLER_PASS) {
+		trace_iwlmei_sap_data(skb, IWL_SAP_RX_DATA_DROPPED_FROM_AIR);
+		dev_kfree_skb(skb);
+	}
+
+	return res;
+}
+
+static void iwl_mei_netdev_work(struct work_struct *wk)
+{
+	struct iwl_mei *mei =
+		container_of(wk, struct iwl_mei, netdev_work);
+	struct net_device *netdev;
+
+	/*
+	 * First take rtnl and only then the mutex to avoid an ABBA
+	 * with iwl_mei_set_netdev()
+	 */
+	rtnl_lock();
+	mutex_lock(&iwl_mei_mutex);
+
+	netdev = rcu_dereference_protected(iwl_mei_cache.netdev,
+					   lockdep_is_held(&iwl_mei_mutex));
+	if (netdev) {
+		if (mei->amt_enabled)
+			netdev_rx_handler_register(netdev, iwl_mei_rx_handler,
+						   mei);
+		else
+			netdev_rx_handler_unregister(netdev);
+	}
+
+	mutex_unlock(&iwl_mei_mutex);
+	rtnl_unlock();
+}
+
+static void
+iwl_mei_handle_rx_start_ok(struct mei_cl_device *cldev,
+			   const struct iwl_sap_me_msg_start_ok *rsp,
+			   ssize_t len)
+{
+	if (len != sizeof(*rsp)) {
+		dev_err(&cldev->dev,
+			"got invalid SAP_ME_MSG_START_OK from CSME firmware\n");
+		dev_err(&cldev->dev,
+			"size is incorrect: %zd instead of %zu\n",
+			len, sizeof(*rsp));
+		return;
+	}
+
+	if (rsp->supported_version != SAP_VERSION) {
+		dev_err(&cldev->dev,
+			"didn't get the expected version: got %d\n",
+			rsp->supported_version);
+		return;
+	}
+
+	mutex_lock(&iwl_mei_mutex);
+	set_bit(IWL_MEI_STATUS_SAP_CONNECTED, &iwl_mei_status);
+	/*
+	 * We'll receive AMT_STATE SAP message in a bit and
+	 * that will continue the flow
+	 */
+	mutex_unlock(&iwl_mei_mutex);
+}
+
+static void iwl_mei_handle_csme_filters(struct mei_cl_device *cldev,
+					const struct iwl_sap_csme_filters *filters)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+	struct iwl_mei_filters *new_filters;
+	struct iwl_mei_filters *old_filters;
+
+	old_filters =
+		rcu_dereference_protected(mei->filters,
+					  lockdep_is_held(&iwl_mei_mutex));
+
+	new_filters = kzalloc(sizeof(*new_filters), GFP_KERNEL);
+	if (!new_filters)
+		return;
+
+	/* Copy the OOB filters */
+	new_filters->filters = filters->filters;
+
+	rcu_assign_pointer(mei->filters, new_filters);
+
+	if (old_filters)
+		kfree_rcu(old_filters, rcu_head);
+}
+
+static void
+iwl_mei_handle_conn_status(struct mei_cl_device *cldev,
+			   const struct iwl_sap_notif_conn_status *status)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+	struct iwl_mei_conn_info conn_info = {
+		.lp_state = le32_to_cpu(status->link_prot_state),
+		.ssid_len = le32_to_cpu(status->conn_info.ssid_len),
+		.channel = status->conn_info.channel,
+		.band = status->conn_info.band,
+		.auth_mode = le32_to_cpu(status->conn_info.auth_mode),
+		.pairwise_cipher = le32_to_cpu(status->conn_info.pairwise_cipher),
+	};
+
+	if (!iwl_mei_cache.ops ||
+	    conn_info.ssid_len > ARRAY_SIZE(conn_info.ssid))
+		return;
+
+	memcpy(conn_info.ssid, status->conn_info.ssid, conn_info.ssid_len);
+	ether_addr_copy(conn_info.bssid, status->conn_info.bssid);
+
+	iwl_mei_cache.ops->me_conn_status(iwl_mei_cache.priv, &conn_info);
+
+	mei->link_prot_state = status->link_prot_state;
+
+	/*
+	 * Update the Rfkill state in case the host does not own the device:
+	 * if we are in Link Protection, ask to not touch the device, else,
+	 * unblock rfkill.
+	 * If the host owns the device, inform the user space whether it can
+	 * roam.
+	 */
+	if (mei->got_ownership)
+		iwl_mei_cache.ops->roaming_forbidden(iwl_mei_cache.priv,
+						     status->link_prot_state);
+	else
+		iwl_mei_cache.ops->rfkill(iwl_mei_cache.priv,
+					  status->link_prot_state);
+}
+
+static void iwl_mei_set_init_conf(struct iwl_mei *mei)
+{
+	struct iwl_sap_notif_host_link_up link_msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_HOST_LINK_UP),
+		.hdr.len = cpu_to_le16(sizeof(link_msg) - sizeof(link_msg.hdr)),
+	};
+	struct iwl_sap_notif_country_code mcc_msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_COUNTRY_CODE),
+		.hdr.len = cpu_to_le16(sizeof(mcc_msg) - sizeof(mcc_msg.hdr)),
+		.mcc = cpu_to_le16(iwl_mei_cache.mcc),
+	};
+	struct iwl_sap_notif_sar_limits sar_msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_SAR_LIMITS),
+		.hdr.len = cpu_to_le16(sizeof(sar_msg) - sizeof(sar_msg.hdr)),
+	};
+	struct iwl_sap_notif_host_nic_info nic_info_msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_NIC_INFO),
+		.hdr.len = cpu_to_le16(sizeof(nic_info_msg) - sizeof(nic_info_msg.hdr)),
+	};
+	struct iwl_sap_msg_dw rfkill_msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_RADIO_STATE),
+		.hdr.len = cpu_to_le16(sizeof(rfkill_msg) - sizeof(rfkill_msg.hdr)),
+		.val = cpu_to_le32(iwl_mei_cache.rf_kill),
+	};
+
+	/* wifi driver has registered already */
+	if (iwl_mei_cache.ops) {
+		iwl_mei_send_sap_msg(mei->cldev,
+				     SAP_MSG_NOTIF_WIFIDR_UP);
+		iwl_mei_cache.ops->sap_connected(iwl_mei_cache.priv);
+	}
+
+	iwl_mei_send_sap_msg(mei->cldev, SAP_MSG_NOTIF_WHO_OWNS_NIC);
+
+	if (iwl_mei_cache.conn_info) {
+		link_msg.conn_info = *iwl_mei_cache.conn_info;
+		iwl_mei_send_sap_msg_payload(mei->cldev, &link_msg.hdr);
+	}
+
+	iwl_mei_send_sap_msg_payload(mei->cldev, &mcc_msg.hdr);
+
+	if (iwl_mei_cache.power_limit) {
+		memcpy(sar_msg.sar_chain_info_table, iwl_mei_cache.power_limit,
+		       sizeof(sar_msg.sar_chain_info_table));
+		iwl_mei_send_sap_msg_payload(mei->cldev, &sar_msg.hdr);
+	}
+
+	ether_addr_copy(nic_info_msg.mac_address, iwl_mei_cache.mac_address);
+	ether_addr_copy(nic_info_msg.nvm_address, iwl_mei_cache.nvm_address);
+	iwl_mei_send_sap_msg_payload(mei->cldev, &nic_info_msg.hdr);
+
+	iwl_mei_send_sap_msg_payload(mei->cldev, &rfkill_msg.hdr);
+}
+
+static void iwl_mei_handle_amt_state(struct mei_cl_device *cldev,
+				     const struct iwl_sap_msg_dw *dw)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (mei->amt_enabled == !!le32_to_cpu(dw->val))
+		goto out;
+
+	mei->amt_enabled = dw->val;
+
+	if (mei->amt_enabled)
+		iwl_mei_set_init_conf(mei);
+	else if (iwl_mei_cache.ops)
+		iwl_mei_cache.ops->rfkill(iwl_mei_cache.priv, false);
+
+	schedule_work(&mei->netdev_work);
+
+out:
+	mutex_unlock(&iwl_mei_mutex);
+}
+
+static void iwl_mei_handle_nic_owner(struct mei_cl_device *cldev,
+				     const struct iwl_sap_msg_dw *dw)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+
+	mei->got_ownership = dw->val != cpu_to_le32(SAP_NIC_OWNER_ME);
+}
+
+static void iwl_mei_handle_can_release_ownership(struct mei_cl_device *cldev,
+						 const void *payload)
+{
+	/* We can get ownership and driver is registered, go ahead */
+	if (iwl_mei_cache.ops)
+		iwl_mei_send_sap_msg(cldev,
+				     SAP_MSG_NOTIF_HOST_ASKS_FOR_NIC_OWNERSHIP);
+}
+
+static void iwl_mei_handle_csme_taking_ownership(struct mei_cl_device *cldev,
+						 const void *payload)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+
+	dev_info(&cldev->dev, "CSME takes ownership\n");
+
+	mei->got_ownership = false;
+
+	if (iwl_mei_cache.ops && !mei->device_down) {
+		/*
+		 * Remember to send CSME_OWNERSHIP_CONFIRMED when the wifi
+		 * driver is finished taking the device down.
+		 */
+		mei->csme_taking_ownership = true;
+
+		iwl_mei_cache.ops->rfkill(iwl_mei_cache.priv, true);
+	} else {
+		iwl_mei_send_sap_msg(cldev,
+				     SAP_MSG_NOTIF_CSME_OWNERSHIP_CONFIRMED);
+	}
+}
+
+static void iwl_mei_handle_nvm(struct mei_cl_device *cldev,
+			       const struct iwl_sap_nvm *sap_nvm)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+	const struct iwl_mei_nvm *mei_nvm = (const void *)sap_nvm;
+	int i;
+
+	kfree(mei->nvm);
+	mei->nvm = kzalloc(sizeof(*mei_nvm), GFP_KERNEL);
+	if (!mei->nvm)
+		return;
+
+	ether_addr_copy(mei->nvm->hw_addr, sap_nvm->hw_addr);
+	mei->nvm->n_hw_addrs = sap_nvm->n_hw_addrs;
+	mei->nvm->radio_cfg = le32_to_cpu(sap_nvm->radio_cfg);
+	mei->nvm->caps = le32_to_cpu(sap_nvm->caps);
+	mei->nvm->nvm_version = le32_to_cpu(sap_nvm->nvm_version);
+
+	for (i = 0; i < ARRAY_SIZE(mei->nvm->channels); i++)
+		mei->nvm->channels[i] = le32_to_cpu(sap_nvm->channels[i]);
+
+	wake_up_all(&mei->get_nvm_wq);
+}
+
+static void iwl_mei_handle_rx_host_own_req(struct mei_cl_device *cldev,
+					   const struct iwl_sap_msg_dw *dw)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+
+	/*
+	 * This means that we can't use the wifi device right now, CSME is not
+	 * ready to let us use it.
+	 */
+	if (!dw->val) {
+		dev_info(&cldev->dev, "Ownership req denied\n");
+		return;
+	}
+
+	mei->got_ownership = true;
+	wake_up_all(&mei->get_ownership_wq);
+
+	iwl_mei_send_sap_msg(cldev,
+			     SAP_MSG_NOTIF_HOST_OWNERSHIP_CONFIRMED);
+
+	/* We can now start the connection, unblock rfkill */
+	if (iwl_mei_cache.ops)
+		iwl_mei_cache.ops->rfkill(iwl_mei_cache.priv, false);
+}
+
+static void iwl_mei_handle_ping(struct mei_cl_device *cldev,
+				const struct iwl_sap_hdr *hdr)
+{
+	iwl_mei_send_sap_msg(cldev, SAP_MSG_NOTIF_PONG);
+}
+
+static void iwl_mei_handle_sap_msg(struct mei_cl_device *cldev,
+				   const struct iwl_sap_hdr *hdr)
+{
+	u16 len = le16_to_cpu(hdr->len) + sizeof(*hdr);
+	u16 type = le16_to_cpu(hdr->type);
+
+	dev_dbg(&cldev->dev,
+		"Got a new SAP message: type %d, len %d, seq %d\n",
+		le16_to_cpu(hdr->type), len,
+		le32_to_cpu(hdr->seq_num));
+
+#define SAP_MSG_HANDLER(_cmd, _handler, _sz)				\
+	case SAP_MSG_NOTIF_ ## _cmd:					\
+		if (len < _sz) {					\
+			dev_err(&cldev->dev,				\
+				"Bad size for %d: %u < %u\n",		\
+				le16_to_cpu(hdr->type),			\
+				(unsigned int)len,			\
+				(unsigned int)_sz);			\
+			break;						\
+		}							\
+		mutex_lock(&iwl_mei_mutex);				\
+		_handler(cldev, (const void *)hdr);			\
+		mutex_unlock(&iwl_mei_mutex);				\
+		break
+
+#define SAP_MSG_HANDLER_NO_LOCK(_cmd, _handler, _sz)			\
+	case SAP_MSG_NOTIF_ ## _cmd:					\
+		if (len < _sz) {					\
+			dev_err(&cldev->dev,				\
+				"Bad size for %d: %u < %u\n",		\
+				le16_to_cpu(hdr->type),			\
+				(unsigned int)len,			\
+				(unsigned int)_sz);			\
+			break;						\
+		}							\
+		_handler(cldev, (const void *)hdr);			\
+		break
+
+#define SAP_MSG_HANDLER_NO_HANDLER(_cmd, _sz)				\
+	case SAP_MSG_NOTIF_ ## _cmd:					\
+		if (len < _sz) {					\
+			dev_err(&cldev->dev,				\
+				"Bad size for %d: %u < %u\n",		\
+				le16_to_cpu(hdr->type),			\
+				(unsigned int)len,			\
+				(unsigned int)_sz);			\
+			break;						\
+		}							\
+		break
+
+	switch (type) {
+	SAP_MSG_HANDLER(PING, iwl_mei_handle_ping, 0);
+	SAP_MSG_HANDLER(CSME_FILTERS,
+			iwl_mei_handle_csme_filters,
+			sizeof(struct iwl_sap_csme_filters));
+	SAP_MSG_HANDLER(CSME_CONN_STATUS,
+			iwl_mei_handle_conn_status,
+			sizeof(struct iwl_sap_notif_conn_status));
+	SAP_MSG_HANDLER_NO_LOCK(AMT_STATE,
+				iwl_mei_handle_amt_state,
+				sizeof(struct iwl_sap_msg_dw));
+	SAP_MSG_HANDLER_NO_HANDLER(PONG, 0);
+	SAP_MSG_HANDLER(NVM, iwl_mei_handle_nvm,
+			sizeof(struct iwl_sap_nvm));
+	SAP_MSG_HANDLER(CSME_REPLY_TO_HOST_OWNERSHIP_REQ,
+			iwl_mei_handle_rx_host_own_req,
+			sizeof(struct iwl_sap_msg_dw));
+	SAP_MSG_HANDLER(NIC_OWNER, iwl_mei_handle_nic_owner,
+			sizeof(struct iwl_sap_msg_dw));
+	SAP_MSG_HANDLER(CSME_CAN_RELEASE_OWNERSHIP,
+			iwl_mei_handle_can_release_ownership, 0);
+	SAP_MSG_HANDLER(CSME_TAKING_OWNERSHIP,
+			iwl_mei_handle_csme_taking_ownership, 0);
+	default:
+	/*
+	 * This is not really an error, there are message that we decided
+	 * to ignore, yet, it is useful to be able to leave a note if debug
+	 * is enabled.
+	 */
+	dev_dbg(&cldev->dev, "Unsupported message: type %d, len %d\n",
+		le16_to_cpu(hdr->type), len);
+	}
+
+#undef SAP_MSG_HANDLER
+#undef SAP_MSG_HANDLER_NO_LOCK
+}
+
+static void iwl_mei_read_from_q(const u8 *q_head, u32 q_sz,
+				u32 *_rd, u32 wr,
+				void *_buf, u32 len)
+{
+	u8 *buf = _buf;
+	u32 rd = *_rd;
+
+	if (rd + len <= q_sz) {
+		memcpy(buf, q_head + rd, len);
+		rd += len;
+	} else {
+		memcpy(buf, q_head + rd, q_sz - rd);
+		memcpy(buf + q_sz - rd, q_head, len - (q_sz - rd));
+		rd = len - (q_sz - rd);
+	}
+
+	*_rd = rd;
+}
+
+#define QOS_HDR_IV_SNAP_LEN (sizeof(struct ieee80211_qos_hdr) +      \
+			     IEEE80211_TKIP_IV_LEN +                 \
+			     sizeof(rfc1042_header) + ETH_TLEN)
+
+static void iwl_mei_handle_sap_data(struct mei_cl_device *cldev,
+				    const u8 *q_head, u32 q_sz,
+				    u32 rd, u32 wr, ssize_t valid_rx_sz,
+				    struct sk_buff_head *tx_skbs)
+{
+	struct iwl_sap_hdr hdr;
+	struct net_device *netdev =
+		rcu_dereference_protected(iwl_mei_cache.netdev,
+					  lockdep_is_held(&iwl_mei_mutex));
+
+	if (!netdev)
+		return;
+
+	while (valid_rx_sz >= sizeof(hdr)) {
+		struct ethhdr *ethhdr;
+		unsigned char *data;
+		struct sk_buff *skb;
+		u16 len;
+
+		iwl_mei_read_from_q(q_head, q_sz, &rd, wr, &hdr, sizeof(hdr));
+		valid_rx_sz -= sizeof(hdr);
+		len = le16_to_cpu(hdr.len);
+
+		if (valid_rx_sz < len) {
+			dev_err(&cldev->dev,
+				"Data queue is corrupted: valid data len %zd, len %d\n",
+				valid_rx_sz, len);
+			break;
+		}
+
+		if (len < sizeof(*ethhdr)) {
+			dev_err(&cldev->dev,
+				"Data len is smaller than an ethernet header? len = %d\n",
+				len);
+		}
+
+		valid_rx_sz -= len;
+
+		if (le16_to_cpu(hdr.type) != SAP_MSG_DATA_PACKET) {
+			dev_err(&cldev->dev, "Unsupported Rx data: type %d, len %d\n",
+				le16_to_cpu(hdr.type), len);
+			continue;
+		}
+
+		/* We need enough room for the WiFi header + SNAP + IV */
+		skb = netdev_alloc_skb(netdev, len + QOS_HDR_IV_SNAP_LEN);
+		if (!skb)
+			continue;
+
+		skb_reserve(skb, QOS_HDR_IV_SNAP_LEN);
+		ethhdr = skb_push(skb, sizeof(*ethhdr));
+
+		iwl_mei_read_from_q(q_head, q_sz, &rd, wr,
+				    ethhdr, sizeof(*ethhdr));
+		len -= sizeof(*ethhdr);
+
+		skb_reset_mac_header(skb);
+		skb_reset_network_header(skb);
+		skb->protocol = ethhdr->h_proto;
+
+		data = skb_put(skb, len);
+		iwl_mei_read_from_q(q_head, q_sz, &rd, wr, data, len);
+
+		/*
+		 * Enqueue the skb here so that it can be sent later when we
+		 * do not hold the mutex. TX'ing a packet with a mutex held is
+		 * possible, but it wouldn't be nice to forbid the TX path to
+		 * call any of iwlmei's functions, since every API from iwlmei
+		 * needs the mutex.
+		 */
+		__skb_queue_tail(tx_skbs, skb);
+	}
+}
+
+static void iwl_mei_handle_sap_rx_cmd(struct mei_cl_device *cldev,
+				      const u8 *q_head, u32 q_sz,
+				      u32 rd, u32 wr, ssize_t valid_rx_sz)
+{
+	struct page *p = alloc_page(GFP_KERNEL);
+	struct iwl_sap_hdr *hdr;
+
+	if (!p)
+		return;
+
+	hdr = page_address(p);
+
+	while (valid_rx_sz >= sizeof(*hdr)) {
+		u16 len;
+
+		iwl_mei_read_from_q(q_head, q_sz, &rd, wr, hdr, sizeof(*hdr));
+		valid_rx_sz -= sizeof(*hdr);
+		len = le16_to_cpu(hdr->len);
+
+		if (valid_rx_sz < len)
+			break;
+
+		iwl_mei_read_from_q(q_head, q_sz, &rd, wr, hdr + 1, len);
+
+		trace_iwlmei_sap_cmd(hdr, false);
+		iwl_mei_handle_sap_msg(cldev, hdr);
+		valid_rx_sz -= len;
+	}
+
+	/* valid_rx_sz must be 0 now... */
+	if (valid_rx_sz)
+		dev_err(&cldev->dev,
+			"More data in the buffer although we read it all\n");
+
+	__free_page(p);
+}
+
+static void iwl_mei_handle_sap_rx(struct mei_cl_device *cldev,
+				  struct iwl_sap_q_ctrl_blk *notif_q,
+				  const u8 *q_head,
+				  struct sk_buff_head *skbs,
+				  u32 q_sz)
+{
+	u32 rd = le32_to_cpu(READ_ONCE(notif_q->rd_ptr));
+	u32 wr = le32_to_cpu(READ_ONCE(notif_q->wr_ptr));
+	ssize_t valid_rx_sz;
+
+	if (rd > q_sz || wr > q_sz) {
+		dev_err(&cldev->dev,
+			"Pointers are past the buffer limit\n");
+		return;
+	}
+
+	if (rd == wr)
+		return;
+
+	valid_rx_sz = wr > rd ? wr - rd : q_sz - rd + wr;
+
+	if (skbs)
+		iwl_mei_handle_sap_data(cldev, q_head, q_sz, rd, wr,
+					valid_rx_sz, skbs);
+	else
+		iwl_mei_handle_sap_rx_cmd(cldev, q_head, q_sz, rd, wr,
+					  valid_rx_sz);
+
+	/* Increment the read pointer to point to the write pointer */
+	WRITE_ONCE(notif_q->rd_ptr, cpu_to_le32(wr));
+}
+
+static void iwl_mei_handle_check_shared_area(struct mei_cl_device *cldev)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+	struct iwl_sap_q_ctrl_blk *notif_q;
+	struct sk_buff_head tx_skbs;
+	struct iwl_sap_dir *dir;
+	void *q_head;
+	u32 q_sz;
+
+	if (!mei->shared_mem.ctrl)
+		return;
+
+	dir = &mei->shared_mem.ctrl->dir[SAP_DIRECTION_ME_TO_HOST];
+	notif_q = &dir->q_ctrl_blk[SAP_QUEUE_IDX_NOTIF];
+	q_head = mei->shared_mem.q_head[SAP_DIRECTION_ME_TO_HOST][SAP_QUEUE_IDX_NOTIF];
+	q_sz = mei->shared_mem.q_size[SAP_DIRECTION_ME_TO_HOST][SAP_QUEUE_IDX_NOTIF];
+
+	/*
+	 * Do not hold the mutex here, but rather each and every message
+	 * handler takes it.
+	 * This allows message handlers to take it at a certain time.
+	 */
+	iwl_mei_handle_sap_rx(cldev, notif_q, q_head, NULL, q_sz);
+
+	mutex_lock(&iwl_mei_mutex);
+	dir = &mei->shared_mem.ctrl->dir[SAP_DIRECTION_ME_TO_HOST];
+	notif_q = &dir->q_ctrl_blk[SAP_QUEUE_IDX_DATA];
+	q_head = mei->shared_mem.q_head[SAP_DIRECTION_ME_TO_HOST][SAP_QUEUE_IDX_DATA];
+	q_sz = mei->shared_mem.q_size[SAP_DIRECTION_ME_TO_HOST][SAP_QUEUE_IDX_DATA];
+
+	__skb_queue_head_init(&tx_skbs);
+
+	iwl_mei_handle_sap_rx(cldev, notif_q, q_head, &tx_skbs, q_sz);
+
+	if (skb_queue_empty(&tx_skbs)) {
+		mutex_unlock(&iwl_mei_mutex);
+		return;
+	}
+
+	/*
+	 * Take the RCU read lock before we unlock the mutex to make sure that
+	 * even if the netdev is replaced by another non-NULL netdev right after
+	 * we unlock the mutex, the old netdev will still be valid when we
+	 * transmit the frames. We can't allow to replace the netdev here because
+	 * the skbs hold a pointer to the netdev.
+	 */
+	rcu_read_lock();
+
+	mutex_unlock(&iwl_mei_mutex);
+
+	if (!rcu_access_pointer(iwl_mei_cache.netdev)) {
+		dev_err(&cldev->dev, "Can't Tx without a netdev\n");
+		skb_queue_purge(&tx_skbs);
+		goto out;
+	}
+
+	while (!skb_queue_empty(&tx_skbs)) {
+		struct sk_buff *skb = __skb_dequeue(&tx_skbs);
+
+		trace_iwlmei_sap_data(skb, IWL_SAP_RX_DATA_TO_AIR);
+		dev_queue_xmit(skb);
+	}
+
+out:
+	rcu_read_unlock();
+}
+
+static void iwl_mei_rx(struct mei_cl_device *cldev)
+{
+	struct iwl_sap_me_msg_hdr *hdr;
+	u8 msg[100];
+	ssize_t ret;
+
+	ret = mei_cldev_recv(cldev, (u8 *)&msg, sizeof(msg));
+	if (ret < 0) {
+		dev_err(&cldev->dev, "failed to receive data: %zd\n", ret);
+		return;
+	}
+
+	if (ret == 0) {
+		dev_err(&cldev->dev, "got an empty response\n");
+		return;
+	}
+
+	hdr = (void *)msg;
+	trace_iwlmei_me_msg(hdr, false);
+
+	switch (le32_to_cpu(hdr->type)) {
+	case SAP_ME_MSG_START_OK:
+		BUILD_BUG_ON(sizeof(struct iwl_sap_me_msg_start_ok) >
+			     sizeof(msg));
+
+		iwl_mei_handle_rx_start_ok(cldev, (void *)msg, ret);
+		break;
+	case SAP_ME_MSG_CHECK_SHARED_AREA:
+		iwl_mei_handle_check_shared_area(cldev);
+		break;
+	default:
+		dev_err(&cldev->dev, "got a RX notification: %d\n",
+			le32_to_cpu(hdr->type));
+		break;
+	}
+}
+
+static int iwl_mei_send_start(struct mei_cl_device *cldev)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+	struct iwl_sap_me_msg_start msg = {
+		.hdr.type = cpu_to_le32(SAP_ME_MSG_START),
+		.hdr.seq_num = cpu_to_le32(atomic_inc_return(&mei->seq_no)),
+		.hdr.len = cpu_to_le32(sizeof(msg)),
+		.supported_versions[0] = SAP_VERSION,
+		.init_data_seq_num = cpu_to_le16(0x100),
+		.init_notif_seq_num = cpu_to_le16(0x800),
+	};
+	int ret;
+
+	trace_iwlmei_me_msg(&msg.hdr, true);
+	ret = mei_cldev_send(cldev, (void *)&msg, sizeof(msg));
+	if (ret != sizeof(msg)) {
+		dev_err(&cldev->dev,
+			"failed to send the SAP_ME_MSG_START message %d\n",
+			ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int iwl_mei_enable(struct mei_cl_device *cldev)
+{
+	int ret;
+
+	ret = mei_cldev_enable(cldev);
+	if (ret < 0) {
+		dev_err(&cldev->dev, "failed to enable the device: %d\n", ret);
+		return ret;
+	}
+
+	ret = mei_cldev_register_rx_cb(cldev, iwl_mei_rx);
+	if (ret) {
+		dev_err(&cldev->dev,
+			"failed to register to the rx cb: %d\n", ret);
+		mei_cldev_disable(cldev);
+		return ret;
+	}
+
+	return 0;
+}
+
+struct iwl_mei_nvm *iwl_mei_get_nvm(void)
+{
+	struct iwl_mei_nvm *nvm = NULL;
+	struct iwl_mei *mei;
+	int ret;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected())
+		goto out;
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei)
+		goto out;
+
+	ret = iwl_mei_send_sap_msg(iwl_mei_global_cldev,
+				   SAP_MSG_NOTIF_GET_NVM);
+	if (ret)
+		goto out;
+
+	mutex_unlock(&iwl_mei_mutex);
+
+	ret = wait_event_timeout(mei->get_nvm_wq, mei->nvm, 2 * HZ);
+	if (!ret)
+		return NULL;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected())
+		goto out;
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei)
+		goto out;
+
+	if (mei->nvm)
+		nvm = kmemdup(mei->nvm, sizeof(*mei->nvm), GFP_KERNEL);
+
+out:
+	mutex_unlock(&iwl_mei_mutex);
+	return nvm;
+}
+EXPORT_SYMBOL_GPL(iwl_mei_get_nvm);
+
+int iwl_mei_get_ownership(void)
+{
+	struct iwl_mei *mei;
+	int ret;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	/* In case we didn't have a bind */
+	if (!iwl_mei_is_connected()) {
+		ret = 0;
+		goto out;
+	}
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	if (!mei->amt_enabled) {
+		ret = 0;
+		goto out;
+	}
+
+	if (mei->got_ownership) {
+		ret = 0;
+		goto out;
+	}
+
+	ret = iwl_mei_send_sap_msg(mei->cldev,
+				   SAP_MSG_NOTIF_HOST_ASKS_FOR_NIC_OWNERSHIP);
+	if (ret)
+		goto out;
+
+	mutex_unlock(&iwl_mei_mutex);
+
+	ret = wait_event_timeout(mei->get_ownership_wq,
+				 mei->got_ownership, HZ / 2);
+	if (!ret)
+		return -ETIMEDOUT;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	/* In case we didn't have a bind */
+	if (!iwl_mei_is_connected()) {
+		ret = 0;
+		goto out;
+	}
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	ret = !mei->got_ownership;
+
+out:
+	mutex_unlock(&iwl_mei_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iwl_mei_get_ownership);
+
+void iwl_mei_host_associated(const struct iwl_mei_conn_info *conn_info,
+			     const struct iwl_mei_colloc_info *colloc_info)
+{
+	struct iwl_sap_notif_host_link_up msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_HOST_LINK_UP),
+		.hdr.len = cpu_to_le16(sizeof(msg) - sizeof(msg.hdr)),
+		.conn_info = {
+			.ssid_len = cpu_to_le32(conn_info->ssid_len),
+			.channel = conn_info->channel,
+			.band = conn_info->band,
+			.pairwise_cipher = cpu_to_le32(conn_info->pairwise_cipher),
+			.auth_mode = cpu_to_le32(conn_info->auth_mode),
+		},
+	};
+	struct iwl_mei *mei;
+
+	if (conn_info->ssid_len > ARRAY_SIZE(msg.conn_info.ssid))
+		return;
+
+	memcpy(msg.conn_info.ssid, conn_info->ssid, conn_info->ssid_len);
+	memcpy(msg.conn_info.bssid, conn_info->bssid, ETH_ALEN);
+
+	if (colloc_info) {
+		msg.colloc_channel = colloc_info->channel;
+		msg.colloc_band = colloc_info->channel <= 14 ? 0 : 1;
+		memcpy(msg.colloc_bssid, colloc_info->bssid, ETH_ALEN);
+	}
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected())
+		goto out;
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei && !mei->amt_enabled)
+		goto out;
+
+	iwl_mei_send_sap_msg_payload(mei->cldev, &msg.hdr);
+
+out:
+	kfree(iwl_mei_cache.conn_info);
+	iwl_mei_cache.conn_info =
+		kmemdup(&msg.conn_info, sizeof(msg.conn_info), GFP_KERNEL);
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_host_associated);
+
+void iwl_mei_host_disassociated(void)
+{
+	struct iwl_mei *mei;
+	struct iwl_sap_notif_host_link_down msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_HOST_LINK_DOWN),
+		.hdr.len = cpu_to_le16(sizeof(msg) - sizeof(msg.hdr)),
+		.type = HOST_LINK_DOWN_TYPE_LONG,
+	};
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected())
+		goto out;
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei && !mei->amt_enabled)
+		goto out;
+
+	iwl_mei_send_sap_msg_payload(mei->cldev, &msg.hdr);
+
+out:
+	kfree(iwl_mei_cache.conn_info);
+	iwl_mei_cache.conn_info = NULL;
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_host_disassociated);
+
+void iwl_mei_set_rfkill_state(bool hw_rfkill, bool sw_rfkill)
+{
+	struct iwl_mei *mei;
+	u32 rfkill_state = 0;
+	struct iwl_sap_msg_dw msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_RADIO_STATE),
+		.hdr.len = cpu_to_le16(sizeof(msg) - sizeof(msg.hdr)),
+	};
+
+	if (!sw_rfkill)
+		rfkill_state |= SAP_SW_RFKILL_DEASSERTED;
+
+	if (!hw_rfkill)
+		rfkill_state |= SAP_HW_RFKILL_DEASSERTED;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected())
+		goto out;
+
+	msg.val = cpu_to_le32(rfkill_state);
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei && !mei->amt_enabled)
+		goto out;
+
+	iwl_mei_send_sap_msg_payload(mei->cldev, &msg.hdr);
+
+out:
+	iwl_mei_cache.rf_kill = rfkill_state;
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_set_rfkill_state);
+
+void iwl_mei_set_nic_info(const u8 *mac_address, const u8 *nvm_address)
+{
+	struct iwl_mei *mei;
+	struct iwl_sap_notif_host_nic_info msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_NIC_INFO),
+		.hdr.len = cpu_to_le16(sizeof(msg) - sizeof(msg.hdr)),
+	};
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected())
+		goto out;
+
+	ether_addr_copy(msg.mac_address, mac_address);
+	ether_addr_copy(msg.nvm_address, nvm_address);
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei && !mei->amt_enabled)
+		goto out;
+
+	iwl_mei_send_sap_msg_payload(mei->cldev, &msg.hdr);
+
+out:
+	ether_addr_copy(iwl_mei_cache.mac_address, mac_address);
+	ether_addr_copy(iwl_mei_cache.nvm_address, nvm_address);
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_set_nic_info);
+
+void iwl_mei_set_country_code(u16 mcc)
+{
+	struct iwl_mei *mei;
+	struct iwl_sap_notif_country_code msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_COUNTRY_CODE),
+		.hdr.len = cpu_to_le16(sizeof(msg) - sizeof(msg.hdr)),
+		.mcc = cpu_to_le16(mcc),
+	};
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected())
+		goto out;
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei && !mei->amt_enabled)
+		goto out;
+
+	iwl_mei_send_sap_msg_payload(mei->cldev, &msg.hdr);
+
+out:
+	iwl_mei_cache.mcc = mcc;
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_set_country_code);
+
+void iwl_mei_set_power_limit(const __le16 *power_limit)
+{
+	struct iwl_mei *mei;
+	struct iwl_sap_notif_sar_limits msg = {
+		.hdr.type = cpu_to_le16(SAP_MSG_NOTIF_SAR_LIMITS),
+		.hdr.len = cpu_to_le16(sizeof(msg) - sizeof(msg.hdr)),
+	};
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected())
+		goto out;
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei && !mei->amt_enabled)
+		goto out;
+
+	memcpy(msg.sar_chain_info_table, power_limit, sizeof(msg.sar_chain_info_table));
+
+	iwl_mei_send_sap_msg_payload(mei->cldev, &msg.hdr);
+
+out:
+	kfree(iwl_mei_cache.power_limit);
+	iwl_mei_cache.power_limit = kmemdup(power_limit,
+					    sizeof(msg.sar_chain_info_table), GFP_KERNEL);
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_set_power_limit);
+
+void iwl_mei_set_netdev(struct net_device *netdev)
+{
+	struct iwl_mei *mei;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected()) {
+		rcu_assign_pointer(iwl_mei_cache.netdev, netdev);
+		goto out;
+	}
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei)
+		goto out;
+
+	if (!netdev) {
+		struct net_device *dev =
+			rcu_dereference_protected(iwl_mei_cache.netdev,
+						  lockdep_is_held(&iwl_mei_mutex));
+
+		if (!dev)
+			goto out;
+
+		netdev_rx_handler_unregister(dev);
+	}
+
+	rcu_assign_pointer(iwl_mei_cache.netdev, netdev);
+
+	if (netdev && mei->amt_enabled)
+		netdev_rx_handler_register(netdev, iwl_mei_rx_handler, mei);
+
+out:
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_set_netdev);
+
+void iwl_mei_device_state(bool up)
+{
+	struct iwl_mei *mei;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_is_connected())
+		goto out;
+
+	mei = mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+	if (!mei)
+		goto out;
+
+	mei->device_down = !up;
+
+	if (up || !mei->csme_taking_ownership)
+		goto out;
+
+	iwl_mei_send_sap_msg(mei->cldev,
+			     SAP_MSG_NOTIF_CSME_OWNERSHIP_CONFIRMED);
+	mei->csme_taking_ownership = false;
+out:
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_device_state);
+
+int iwl_mei_register(void *priv, const struct iwl_mei_ops *ops)
+{
+	int ret;
+
+	/*
+	 * We must have a non-NULL priv pointer to not crash when there are
+	 * multiple WiFi devices.
+	 */
+	if (!priv)
+		return -EINVAL;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	/* do not allow registration if someone else already registered */
+	if (iwl_mei_cache.priv || iwl_mei_cache.ops) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	iwl_mei_cache.priv = priv;
+	iwl_mei_cache.ops = ops;
+
+	if (iwl_mei_global_cldev) {
+		struct iwl_mei *mei =
+			mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+		/* we have already a SAP connection */
+		if (iwl_mei_is_connected()) {
+			if (mei->amt_enabled)
+				iwl_mei_send_sap_msg(mei->cldev,
+						     SAP_MSG_NOTIF_WIFIDR_UP);
+			ops->rfkill(priv, mei->link_prot_state);
+		}
+	}
+	ret = 0;
+
+out:
+	mutex_unlock(&iwl_mei_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iwl_mei_register);
+
+void iwl_mei_start_unregister(void)
+{
+	mutex_lock(&iwl_mei_mutex);
+
+	/* At this point, the wifi driver should have removed the netdev */
+	if (rcu_access_pointer(iwl_mei_cache.netdev))
+		pr_err("Still had a netdev pointer set upon unregister\n");
+
+	kfree(iwl_mei_cache.conn_info);
+	iwl_mei_cache.conn_info = NULL;
+	kfree(iwl_mei_cache.power_limit);
+	iwl_mei_cache.power_limit = NULL;
+	iwl_mei_cache.ops = NULL;
+	/* leave iwl_mei_cache.priv non-NULL to prevent any new registration */
+
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_start_unregister);
+
+void iwl_mei_unregister_complete(void)
+{
+	mutex_lock(&iwl_mei_mutex);
+
+	iwl_mei_cache.priv = NULL;
+
+	if (iwl_mei_global_cldev) {
+		struct iwl_mei *mei =
+			mei_cldev_get_drvdata(iwl_mei_global_cldev);
+
+		iwl_mei_send_sap_msg(mei->cldev, SAP_MSG_NOTIF_WIFIDR_DOWN);
+		mei->got_ownership = false;
+	}
+
+	mutex_unlock(&iwl_mei_mutex);
+}
+EXPORT_SYMBOL_GPL(iwl_mei_unregister_complete);
+
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+
+static ssize_t
+iwl_mei_dbgfs_send_start_message_write(struct file *file,
+				       const char __user *user_buf,
+				       size_t count, loff_t *ppos)
+{
+	int ret;
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (!iwl_mei_global_cldev) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	ret = iwl_mei_send_start(iwl_mei_global_cldev);
+
+out:
+	mutex_unlock(&iwl_mei_mutex);
+	return ret ?: count;
+}
+
+static const struct file_operations iwl_mei_dbgfs_send_start_message_ops = {
+	.write = iwl_mei_dbgfs_send_start_message_write,
+	.open = simple_open,
+	.llseek = default_llseek,
+};
+
+static ssize_t iwl_mei_dbgfs_req_ownership_write(struct file *file,
+						 const char __user *user_buf,
+						 size_t count, loff_t *ppos)
+{
+	iwl_mei_get_ownership();
+
+	return count;
+}
+
+static const struct file_operations iwl_mei_dbgfs_req_ownership_ops = {
+	.write = iwl_mei_dbgfs_req_ownership_write,
+	.open = simple_open,
+	.llseek = default_llseek,
+};
+
+static void iwl_mei_dbgfs_register(struct iwl_mei *mei)
+{
+	mei->dbgfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+
+	if (!mei->dbgfs_dir)
+		return;
+
+	debugfs_create_ulong("status", S_IRUSR,
+			     mei->dbgfs_dir, &iwl_mei_status);
+	debugfs_create_file("send_start_message", S_IWUSR, mei->dbgfs_dir,
+			    mei, &iwl_mei_dbgfs_send_start_message_ops);
+	debugfs_create_file("req_ownership", S_IWUSR, mei->dbgfs_dir,
+			    mei, &iwl_mei_dbgfs_req_ownership_ops);
+}
+
+static void iwl_mei_dbgfs_unregister(struct iwl_mei *mei)
+{
+	debugfs_remove_recursive(mei->dbgfs_dir);
+	mei->dbgfs_dir = NULL;
+}
+
+#else
+
+static void iwl_mei_dbgfs_register(struct iwl_mei *mei) {}
+static void iwl_mei_dbgfs_unregister(struct iwl_mei *mei) {}
+
+#endif /* CONFIG_DEBUG_FS */
+
+#define ALLOC_SHARED_MEM_RETRY_MAX_NUM	3
+
+/*
+ * iwl_mei_probe - the probe function called by the mei bus enumeration
+ *
+ * This allocates the data needed by iwlmei and sets a pointer to this data
+ * into the mei_cl_device's drvdata.
+ * It starts the SAP protocol by sending the SAP_ME_MSG_START without
+ * waiting for the answer. The answer will be caught later by the Rx callback.
+ */
+static int iwl_mei_probe(struct mei_cl_device *cldev,
+			 const struct mei_cl_device_id *id)
+{
+	int alloc_retry = ALLOC_SHARED_MEM_RETRY_MAX_NUM;
+	struct iwl_mei *mei;
+	int ret;
+
+	mei = devm_kzalloc(&cldev->dev, sizeof(*mei), GFP_KERNEL);
+	if (!mei)
+		return -ENOMEM;
+
+	init_waitqueue_head(&mei->get_nvm_wq);
+	INIT_WORK(&mei->send_csa_msg_wk, iwl_mei_send_csa_msg_wk);
+	INIT_DELAYED_WORK(&mei->csa_throttle_end_wk,
+			  iwl_mei_csa_throttle_end_wk);
+	init_waitqueue_head(&mei->get_ownership_wq);
+	spin_lock_init(&mei->data_q_lock);
+	INIT_WORK(&mei->netdev_work, iwl_mei_netdev_work);
+
+	mei_cldev_set_drvdata(cldev, mei);
+	mei->cldev = cldev;
+	mei->device_down = true;
+
+	do {
+		ret = iwl_mei_alloc_shared_mem(cldev);
+		if (!ret)
+			break;
+		/*
+		 * The CSME firmware needs to boot the internal WLAN client.
+		 * This can take time in certain configurations (usually
+		 * upon resume and when the whole CSME firmware is shut down
+		 * during suspend).
+		 *
+		 * Wait a bit before retrying and hope we'll succeed next time.
+		 */
+
+		dev_dbg(&cldev->dev,
+			"Couldn't allocate the shared memory: %d, attempt %d / %d\n",
+			ret, alloc_retry, ALLOC_SHARED_MEM_RETRY_MAX_NUM);
+		msleep(100);
+		alloc_retry--;
+	} while (alloc_retry);
+
+	if (ret) {
+		dev_err(&cldev->dev, "Couldn't allocate the shared memory: %d\n",
+			ret);
+		goto free;
+	}
+
+	iwl_mei_init_shared_mem(mei);
+
+	ret = iwl_mei_enable(cldev);
+	if (ret)
+		goto free_shared_mem;
+
+	iwl_mei_dbgfs_register(mei);
+
+	/*
+	 * We now have a Rx function in place, start the SAP procotol
+	 * we expect to get the SAP_ME_MSG_START_OK response later on.
+	 */
+	mutex_lock(&iwl_mei_mutex);
+	ret = iwl_mei_send_start(cldev);
+	mutex_unlock(&iwl_mei_mutex);
+	if (ret)
+		goto debugfs_unregister;
+
+	/* must be last */
+	iwl_mei_global_cldev = cldev;
+
+	return 0;
+
+debugfs_unregister:
+	iwl_mei_dbgfs_unregister(mei);
+	mei_cldev_disable(cldev);
+free_shared_mem:
+	iwl_mei_free_shared_mem(cldev);
+free:
+	mei_cldev_set_drvdata(cldev, NULL);
+	devm_kfree(&cldev->dev, mei);
+
+	return ret;
+}
+
+#define SEND_SAP_MAX_WAIT_ITERATION 10
+
+static void iwl_mei_remove(struct mei_cl_device *cldev)
+{
+	struct iwl_mei *mei = mei_cldev_get_drvdata(cldev);
+	int i;
+
+	/*
+	 * We are being removed while the bus is active, it means we are
+	 * going to suspend/ shutdown, so the NIC will disappear.
+	 */
+	if (mei_cldev_enabled(cldev) && iwl_mei_cache.ops)
+		iwl_mei_cache.ops->nic_stolen(iwl_mei_cache.priv);
+
+	if (rcu_access_pointer(iwl_mei_cache.netdev)) {
+		struct net_device *dev;
+
+		/*
+		 * First take rtnl and only then the mutex to avoid an ABBA
+		 * with iwl_mei_set_netdev()
+		 */
+		rtnl_lock();
+		mutex_lock(&iwl_mei_mutex);
+
+		/*
+		 * If we are suspending and the wifi driver hasn't removed it's netdev
+		 * yet, do it now. In any case, don't change the cache.netdev pointer.
+		 */
+		dev = rcu_dereference_protected(iwl_mei_cache.netdev,
+						lockdep_is_held(&iwl_mei_mutex));
+
+		netdev_rx_handler_unregister(dev);
+		mutex_unlock(&iwl_mei_mutex);
+		rtnl_unlock();
+	}
+
+	mutex_lock(&iwl_mei_mutex);
+
+	if (mei->amt_enabled) {
+		/*
+		 * Tell CSME that we are going down so that it won't access the
+		 * memory anymore, make sure this message goes through immediately.
+		 */
+		mei->csa_throttled = false;
+		iwl_mei_send_sap_msg(mei->cldev,
+				     SAP_MSG_NOTIF_HOST_GOES_DOWN);
+
+		for (i = 0; i < SEND_SAP_MAX_WAIT_ITERATION; i++) {
+			if (!iwl_mei_host_to_me_data_pending(mei))
+				break;
+
+			msleep(20);
+		}
+
+		/*
+		 * If we couldn't make sure that CSME saw the HOST_GOES_DOWN
+		 * message, it means that it will probably keep reading memory
+		 * that we are going to unmap and free, expect IOMMU error
+		 * messages.
+		 */
+		if (i == SEND_SAP_MAX_WAIT_ITERATION)
+			dev_err(&mei->cldev->dev,
+				"Couldn't get ACK from CSME on HOST_GOES_DOWN message\n");
+	}
+
+	mutex_unlock(&iwl_mei_mutex);
+
+	/*
+	 * This looks strange, but this lock is taken here to make sure that
+	 * iwl_mei_add_data_to_ring called from the Tx path sees that we
+	 * clear the IWL_MEI_STATUS_SAP_CONNECTED bit.
+	 * Rx isn't a problem because the rx_handler can't be called after
+	 * having been unregistered.
+	 */
+	spin_lock_bh(&mei->data_q_lock);
+	clear_bit(IWL_MEI_STATUS_SAP_CONNECTED, &iwl_mei_status);
+	spin_unlock_bh(&mei->data_q_lock);
+
+	if (iwl_mei_cache.ops)
+		iwl_mei_cache.ops->rfkill(iwl_mei_cache.priv, false);
+
+	/*
+	 * mei_cldev_disable will return only after all the MEI Rx is done.
+	 * It must be called when iwl_mei_mutex is *not* held, since it waits
+	 * for our Rx handler to complete.
+	 * After it returns, no new Rx will start.
+	 */
+	mei_cldev_disable(cldev);
+
+	/*
+	 * Since the netdev was already removed and the netdev's removal
+	 * includes a call to synchronize_net() so that we know there won't be
+	 * any new Rx that will trigger the following workers.
+	 */
+	cancel_work_sync(&mei->send_csa_msg_wk);
+	cancel_delayed_work_sync(&mei->csa_throttle_end_wk);
+	cancel_work_sync(&mei->netdev_work);
+
+	/*
+	 * If someone waits for the ownership, let him know that we are going
+	 * down and that we are not connected anymore. He'll be able to take
+	 * the device.
+	 */
+	wake_up_all(&mei->get_ownership_wq);
+
+	mutex_lock(&iwl_mei_mutex);
+
+	iwl_mei_global_cldev = NULL;
+
+	wake_up_all(&mei->get_nvm_wq);
+
+	iwl_mei_free_shared_mem(cldev);
+
+	iwl_mei_dbgfs_unregister(mei);
+
+	mei_cldev_set_drvdata(cldev, NULL);
+
+	kfree(mei->nvm);
+
+	kfree(rcu_access_pointer(mei->filters));
+
+	devm_kfree(&cldev->dev, mei);
+
+	mutex_unlock(&iwl_mei_mutex);
+}
+
+static const struct mei_cl_device_id iwl_mei_tbl[] = {
+	{
+		.name = KBUILD_MODNAME,
+		.uuid = MEI_WLAN_UUID,
+		.version = MEI_CL_VERSION_ANY,
+	},
+
+	/* required last entry */
+	{ }
+};
+
+/*
+ * Do not export the device table because this module is loaded by
+ * iwlwifi's dependency.
+ */
+
+static struct mei_cl_driver iwl_mei_cl_driver = {
+	.id_table = iwl_mei_tbl,
+	.name = KBUILD_MODNAME,
+	.probe = iwl_mei_probe,
+	.remove = iwl_mei_remove,
+};
+
+module_mei_cl_driver(iwl_mei_cl_driver);