drivers: soc: apr: create glink buffers dynamically

It is not always guaranteed that glink will ack all
tx buffers intime and hence apr might run out of tx
buffers for apr message transactions. Create TX buffers
dynamically instead of preallocating fixed number of
buffers.

Change-Id: I53c9529d1e84a88cc2e0b161a8a5047d5a475620
Signed-off-by: Shiv Maliyappanahalli <smaliyap@codeaurora.org>

2 files changed, 26 insertions, 89 deletions

diff --git a/drivers/soc/qcom/qdsp6v2/apr_tal_glink.c b/drivers/soc/qcom/qdsp6v2/apr_tal_glink.c
index 45ac48eb2241..19974b61ec1c 100644
--- a/drivers/soc/qcom/qdsp6v2/apr_tal_glink.c
+++ b/drivers/soc/qcom/qdsp6v2/apr_tal_glink.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2016 The Linux Foundation.
+/* Copyright (c) 2016-2017 The Linux Foundation.
  * All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
@@ -17,7 +17,6 @@
 #include <linux/uaccess.h>
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
-#include <linux/list.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
 #include <linux/errno.h>
@@ -34,16 +33,10 @@
 #define APR_MAXIMUM_NUM_OF_RETRIES 2
 
 struct apr_tx_buf {
-	struct list_head list;
 	struct apr_pkt_priv pkt_priv;
 	char buf[APR_MAX_BUF];
 };
 
-struct apr_buf_list {
-	struct list_head list;
-	spinlock_t lock;
-};
-
 struct link_state {
 	uint32_t dest;
 	void *handle;
@@ -52,7 +45,6 @@ struct link_state {
 };
 
 static struct link_state link_state[APR_DEST_MAX];
-static struct apr_buf_list buf_list;
 
 static char *svc_names[APR_DEST_MAX][APR_CLIENT_MAX] = {
 	{
@@ -68,44 +60,37 @@ static char *svc_names[APR_DEST_MAX][APR_CLIENT_MAX] = {
 static struct apr_svc_ch_dev
 	apr_svc_ch[APR_DL_MAX][APR_DEST_MAX][APR_CLIENT_MAX];
 
-static struct apr_tx_buf *apr_get_free_buf(int len)
+static struct apr_tx_buf *apr_alloc_buf(int len)
 {
-	struct apr_tx_buf *tx_buf;
-	unsigned long flags;
 
 	if (len > APR_MAX_BUF) {
 		pr_err("%s: buf too large [%d]\n", __func__, len);
 		return ERR_PTR(-EINVAL);
 	}
 
-	spin_lock_irqsave(&buf_list.lock, flags);
-	if (list_empty(&buf_list.list)) {
-		spin_unlock_irqrestore(&buf_list.lock, flags);
-		pr_err("%s: No buf available\n", __func__);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	tx_buf = list_first_entry(&buf_list.list, struct apr_tx_buf, list);
-	list_del(&tx_buf->list);
-	spin_unlock_irqrestore(&buf_list.lock, flags);
-
-	return tx_buf;
+	return kzalloc(sizeof(struct apr_tx_buf), GFP_ATOMIC);
 }
 
-static void apr_buf_add_tail(const void *buf)
+static void apr_free_buf(const void *ptr)
 {
-	struct apr_tx_buf *list;
-	unsigned long flags;
 
-	if (!buf)
+	struct apr_pkt_priv *apr_pkt_priv = (struct apr_pkt_priv *)ptr;
+	struct apr_tx_buf *tx_buf;
+
+	if (!apr_pkt_priv) {
+		pr_err("%s: Invalid apr_pkt_priv\n", __func__);
 		return;
+	}
 
-	spin_lock_irqsave(&buf_list.lock, flags);
-	list = container_of((void *)buf, struct apr_tx_buf, buf);
-	list_add_tail(&list->list, &buf_list.list);
-	spin_unlock_irqrestore(&buf_list.lock, flags);
+	if (apr_pkt_priv->pkt_owner == APR_PKT_OWNER_DRIVER) {
+		tx_buf = container_of((void *)apr_pkt_priv,
+				      struct apr_tx_buf, pkt_priv);
+		pr_debug("%s: Freeing buffer %pK", __func__, tx_buf);
+		kfree(tx_buf);
+	}
 }
 
+
 static int __apr_tal_write(struct apr_svc_ch_dev *apr_ch, void *data,
 			   struct apr_pkt_priv *pkt_priv, int len)
 {
@@ -137,7 +122,7 @@ int apr_tal_write(struct apr_svc_ch_dev *apr_ch, void *data,
 		return -EINVAL;
 
 	if (pkt_priv->pkt_owner == APR_PKT_OWNER_DRIVER) {
-		tx_buf = apr_get_free_buf(len);
+		tx_buf = apr_alloc_buf(len);
 		if (IS_ERR_OR_NULL(tx_buf)) {
 			rc = -EINVAL;
 			goto exit;
@@ -160,7 +145,7 @@ int apr_tal_write(struct apr_svc_ch_dev *apr_ch, void *data,
 	if (rc < 0) {
 		pr_err("%s: Unable to send the packet, rc:%d\n", __func__, rc);
 		if (pkt_priv->pkt_owner == APR_PKT_OWNER_DRIVER)
-			apr_buf_add_tail(pkt_data);
+			kfree(tx_buf);
 	}
 exit:
 	return rc;
@@ -189,39 +174,17 @@ void apr_tal_notify_rx(void *handle, const void *priv, const void *pkt_priv,
 static void apr_tal_notify_tx_abort(void *handle, const void *priv,
 				    const void *pkt_priv)
 {
-	struct apr_pkt_priv *apr_pkt_priv_ptr =
-				(struct apr_pkt_priv *)pkt_priv;
-	struct apr_tx_buf *list_node;
-
-	if (!apr_pkt_priv_ptr) {
-		pr_err("%s: Invalid pkt_priv\n", __func__);
-		return;
-	}
-
-	pr_debug("%s: tx_abort received for apr_pkt_priv_ptr:%pK\n",
-		 __func__, apr_pkt_priv_ptr);
-
-	if (apr_pkt_priv_ptr->pkt_owner == APR_PKT_OWNER_DRIVER) {
-		list_node = container_of(apr_pkt_priv_ptr,
-					 struct apr_tx_buf, pkt_priv);
-		apr_buf_add_tail(list_node->buf);
-	}
+	pr_debug("%s: tx_abort received for pkt_priv:%pK\n",
+		 __func__, pkt_priv);
+	apr_free_buf(pkt_priv);
 }
 
 void apr_tal_notify_tx_done(void *handle, const void *priv,
 			    const void *pkt_priv, const void *ptr)
 {
-	struct apr_pkt_priv *apr_pkt_priv = (struct apr_pkt_priv *)pkt_priv;
-
-	if (!pkt_priv || !ptr) {
-		pr_err("%s: Invalid pkt_priv or ptr\n", __func__);
-		return;
-	}
-
-	pr_debug("%s: tx_done received\n", __func__);
-
-	if (apr_pkt_priv->pkt_owner == APR_PKT_OWNER_DRIVER)
-		apr_buf_add_tail(ptr);
+	pr_debug("%s: tx_done received for pkt_priv:%pK\n",
+		 __func__, pkt_priv);
+	apr_free_buf(pkt_priv);
 }
 
 bool apr_tal_notify_rx_intent_req(void *handle, const void *priv,
@@ -457,8 +420,6 @@ static struct glink_link_info lpass_link_info = {
 static int __init apr_tal_init(void)
 {
 	int i, j, k;
-	struct apr_tx_buf *buf;
-	struct list_head *ptr, *next;
 
 	for (i = 0; i < APR_DL_MAX; i++) {
 		for (j = 0; j < APR_DEST_MAX; j++) {
@@ -474,21 +435,6 @@ static int __init apr_tal_init(void)
 	for (i = 0; i < APR_DEST_MAX; i++)
 		init_waitqueue_head(&link_state[i].wait);
 
-	spin_lock_init(&buf_list.lock);
-	INIT_LIST_HEAD(&buf_list.list);
-	for (i = 0; i < APR_NUM_OF_TX_BUF; i++) {
-		buf = kzalloc(sizeof(struct apr_tx_buf), GFP_KERNEL);
-		if (!buf) {
-			pr_err("%s: Unable to allocate tx buf\n", __func__);
-			goto tx_buf_alloc_fail;
-		}
-
-		INIT_LIST_HEAD(&buf->list);
-		spin_lock(&buf_list.lock);
-		list_add_tail(&buf->list, &buf_list.list);
-		spin_unlock(&buf_list.lock);
-	}
-
 	link_state[APR_DEST_MODEM].link_state = GLINK_LINK_STATE_DOWN;
 	link_state[APR_DEST_MODEM].handle =
 		glink_register_link_state_cb(&mpss_link_info, NULL);
@@ -502,13 +448,5 @@ static int __init apr_tal_init(void)
 		pr_err("%s: Unable to register lpass link state\n", __func__);
 
 	return 0;
-
-tx_buf_alloc_fail:
-	list_for_each_safe(ptr, next, &buf_list.list) {
-		buf = list_entry(ptr, struct apr_tx_buf, list);
-		list_del(&buf->list);
-		kfree(buf);
-	}
-	return -ENOMEM;
 }
 device_initcall(apr_tal_init);
diff --git a/include/linux/qdsp6v2/apr_tal.h b/include/linux/qdsp6v2/apr_tal.h
index c2c49dd748de..bf324064960b 100644
--- a/include/linux/qdsp6v2/apr_tal.h
+++ b/include/linux/qdsp6v2/apr_tal.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2010-2011, 2016 The Linux Foundation. All rights reserved.
+/* Copyright (c) 2010-2011, 2016-2017 The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -32,7 +32,6 @@
 #if defined(CONFIG_MSM_QDSP6_APRV2_GLINK) || \
 	defined(CONFIG_MSM_QDSP6_APRV3_GLINK)
 #define APR_MAX_BUF			512
-#define APR_NUM_OF_TX_BUF		30
 #else
 #define APR_MAX_BUF			8092
 #endif