1 files changed, 267 insertions, 0 deletions
diff --git a/net/caif/cfmuxl.c b/net/caif/cfmuxl.c
new file mode 100644
index 0000000000..4172b0d0db
--- /dev/null
+++ b/net/caif/cfmuxl.c
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author:	Sjur Brendeland
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
+
+#include <linux/stddef.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+#include <net/caif/cfpkt.h>
+#include <net/caif/cfmuxl.h>
+#include <net/caif/cfsrvl.h>
+#include <net/caif/cffrml.h>
+
+#define container_obj(layr) container_of(layr, struct cfmuxl, layer)
+
+#define CAIF_CTRL_CHANNEL 0
+#define UP_CACHE_SIZE 8
+#define DN_CACHE_SIZE 8
+
+struct cfmuxl {
+	struct cflayer layer;
+	struct list_head srvl_list;
+	struct list_head frml_list;
+	struct cflayer *up_cache[UP_CACHE_SIZE];
+	struct cflayer *dn_cache[DN_CACHE_SIZE];
+	/*
+	 * Set when inserting or removing downwards layers.
+	 */
+	spinlock_t transmit_lock;
+
+	/*
+	 * Set when inserting or removing upwards layers.
+	 */
+	spinlock_t receive_lock;
+
+};
+
+static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt);
+static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt);
+static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
+			   int phyid);
+static struct cflayer *get_up(struct cfmuxl *muxl, u16 id);
+
+struct cflayer *cfmuxl_create(void)
+{
+	struct cfmuxl *this = kzalloc(sizeof(struct cfmuxl), GFP_ATOMIC);
+
+	if (!this)
+		return NULL;
+	this->layer.receive = cfmuxl_receive;
+	this->layer.transmit = cfmuxl_transmit;
+	this->layer.ctrlcmd = cfmuxl_ctrlcmd;
+	INIT_LIST_HEAD(&this->srvl_list);
+	INIT_LIST_HEAD(&this->frml_list);
+	spin_lock_init(&this->transmit_lock);
+	spin_lock_init(&this->receive_lock);
+	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "mux");
+	return &this->layer;
+}
+
+int cfmuxl_set_dnlayer(struct cflayer *layr, struct cflayer *dn, u8 phyid)
+{
+	struct cfmuxl *muxl = (struct cfmuxl *) layr;
+
+	spin_lock_bh(&muxl->transmit_lock);
+	list_add_rcu(&dn->node, &muxl->frml_list);
+	spin_unlock_bh(&muxl->transmit_lock);
+	return 0;
+}
+
+static struct cflayer *get_from_id(struct list_head *list, u16 id)
+{
+	struct cflayer *lyr;
+	list_for_each_entry_rcu(lyr, list, node) {
+		if (lyr->id == id)
+			return lyr;
+	}
+
+	return NULL;
+}
+
+int cfmuxl_set_uplayer(struct cflayer *layr, struct cflayer *up, u8 linkid)
+{
+	struct cfmuxl *muxl = container_obj(layr);
+	struct cflayer *old;
+
+	spin_lock_bh(&muxl->receive_lock);
+
+	/* Two entries with same id is wrong, so remove old layer from mux */
+	old = get_from_id(&muxl->srvl_list, linkid);
+	if (old != NULL)
+		list_del_rcu(&old->node);
+
+	list_add_rcu(&up->node, &muxl->srvl_list);
+	spin_unlock_bh(&muxl->receive_lock);
+
+	return 0;
+}
+
+struct cflayer *cfmuxl_remove_dnlayer(struct cflayer *layr, u8 phyid)
+{
+	struct cfmuxl *muxl = container_obj(layr);
+	struct cflayer *dn;
+	int idx = phyid % DN_CACHE_SIZE;
+
+	spin_lock_bh(&muxl->transmit_lock);
+	RCU_INIT_POINTER(muxl->dn_cache[idx], NULL);
+	dn = get_from_id(&muxl->frml_list, phyid);
+	if (dn == NULL)
+		goto out;
+
+	list_del_rcu(&dn->node);
+	caif_assert(dn != NULL);
+out:
+	spin_unlock_bh(&muxl->transmit_lock);
+	return dn;
+}
+
+static struct cflayer *get_up(struct cfmuxl *muxl, u16 id)
+{
+	struct cflayer *up;
+	int idx = id % UP_CACHE_SIZE;
+	up = rcu_dereference(muxl->up_cache[idx]);
+	if (up == NULL || up->id != id) {
+		spin_lock_bh(&muxl->receive_lock);
+		up = get_from_id(&muxl->srvl_list, id);
+		rcu_assign_pointer(muxl->up_cache[idx], up);
+		spin_unlock_bh(&muxl->receive_lock);
+	}
+	return up;
+}
+
+static struct cflayer *get_dn(struct cfmuxl *muxl, struct dev_info *dev_info)
+{
+	struct cflayer *dn;
+	int idx = dev_info->id % DN_CACHE_SIZE;
+	dn = rcu_dereference(muxl->dn_cache[idx]);
+	if (dn == NULL || dn->id != dev_info->id) {
+		spin_lock_bh(&muxl->transmit_lock);
+		dn = get_from_id(&muxl->frml_list, dev_info->id);
+		rcu_assign_pointer(muxl->dn_cache[idx], dn);
+		spin_unlock_bh(&muxl->transmit_lock);
+	}
+	return dn;
+}
+
+struct cflayer *cfmuxl_remove_uplayer(struct cflayer *layr, u8 id)
+{
+	struct cflayer *up;
+	struct cfmuxl *muxl = container_obj(layr);
+	int idx = id % UP_CACHE_SIZE;
+
+	if (id == 0) {
+		pr_warn("Trying to remove control layer\n");
+		return NULL;
+	}
+
+	spin_lock_bh(&muxl->receive_lock);
+	up = get_from_id(&muxl->srvl_list, id);
+	if (up == NULL)
+		goto out;
+
+	RCU_INIT_POINTER(muxl->up_cache[idx], NULL);
+	list_del_rcu(&up->node);
+out:
+	spin_unlock_bh(&muxl->receive_lock);
+	return up;
+}
+
+static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt)
+{
+	int ret;
+	struct cfmuxl *muxl = container_obj(layr);
+	u8 id;
+	struct cflayer *up;
+	if (cfpkt_extr_head(pkt, &id, 1) < 0) {
+		pr_err("erroneous Caif Packet\n");
+		cfpkt_destroy(pkt);
+		return -EPROTO;
+	}
+	rcu_read_lock();
+	up = get_up(muxl, id);
+
+	if (up == NULL) {
+		pr_debug("Received data on unknown link ID = %d (0x%x)"
+			" up == NULL", id, id);
+		cfpkt_destroy(pkt);
+		/*
+		 * Don't return ERROR, since modem misbehaves and sends out
+		 * flow on before linksetup response.
+		 */
+
+		rcu_read_unlock();
+		return /* CFGLU_EPROT; */ 0;
+	}
+
+	/* We can't hold rcu_lock during receive, so take a ref count instead */
+	cfsrvl_get(up);
+	rcu_read_unlock();
+
+	ret = up->receive(up, pkt);
+
+	cfsrvl_put(up);
+	return ret;
+}
+
+static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt)
+{
+	struct cfmuxl *muxl = container_obj(layr);
+	int err;
+	u8 linkid;
+	struct cflayer *dn;
+	struct caif_payload_info *info = cfpkt_info(pkt);
+	BUG_ON(!info);
+
+	rcu_read_lock();
+
+	dn = get_dn(muxl, info->dev_info);
+	if (dn == NULL) {
+		pr_debug("Send data on unknown phy ID = %d (0x%x)\n",
+			info->dev_info->id, info->dev_info->id);
+		rcu_read_unlock();
+		cfpkt_destroy(pkt);
+		return -ENOTCONN;
+	}
+
+	info->hdr_len += 1;
+	linkid = info->channel_id;
+	cfpkt_add_head(pkt, &linkid, 1);
+
+	/* We can't hold rcu_lock during receive, so take a ref count instead */
+	cffrml_hold(dn);
+
+	rcu_read_unlock();
+
+	err = dn->transmit(dn, pkt);
+
+	cffrml_put(dn);
+	return err;
+}
+
+static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
+			   int phyid)
+{
+	struct cfmuxl *muxl = container_obj(layr);
+	struct cflayer *layer;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(layer, &muxl->srvl_list, node) {
+
+		if (cfsrvl_phyid_match(layer, phyid) && layer->ctrlcmd) {
+
+			if ((ctrl == _CAIF_CTRLCMD_PHYIF_DOWN_IND ||
+				ctrl == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND) &&
+					layer->id != 0)
+				cfmuxl_remove_uplayer(layr, layer->id);
+
+			/* NOTE: ctrlcmd is not allowed to block */
+			layer->ctrlcmd(layer, ctrl, phyid);
+		}
+	}
+	rcu_read_unlock();
+}