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rpmsg: glink: Send READ_NOTIFY command in FIFO full case

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The current design sleeps unconditionally in TX FIFO full case and
wakeup only after sleep timer expires which adds random delays in
clients TX path.

Avoid sleep and use READ_NOTIFY command so that writer can be woken up
when remote notifies about read completion by sending IRQ.

Change-Id: I1b44df0ec437d4e76aff181470fcf4cafbdd098a
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
This commit is contained in:
Arun Kumar Neelakantam 2020-02-17 12:14:21 +05:30 committed by Gerrit - the friendly Code Review server
parent 84b56d3ab5
commit 17a12f2a90
1 changed files with 43 additions and 5 deletions
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48
drivers/rpmsg/qcom_glink_native.c
View file

@ -1,7 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2016-2017, Linaro Ltd
* Copyright (c) 2018-2019, The Linux Foundation. All rights reserved.
* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
*/
#include <linux/idr.h>
@ -121,6 +121,8 @@ struct glink_core_rx_intent {
* @in_reset: reset status of this edge
* @features: remote features
* @intentless: flag to indicate that there is no intent
* @tx_avail_notify: Waitqueue for pending tx tasks
* @sent_read_notify: flag to check cmd sent or not
* @ilc: ipc logging context reference
*/
struct qcom_glink {
@ -154,6 +156,9 @@ struct qcom_glink {
bool intentless;
wait_queue_head_t tx_avail_notify;
bool sent_read_notify;
void *ilc;
};
@ -357,6 +362,22 @@ static void qcom_glink_pipe_reset(struct qcom_glink *glink)
glink->rx_pipe->reset(glink->rx_pipe);
}
static void qcom_glink_send_read_notify(struct qcom_glink *glink)
{
struct glink_msg msg;
msg.cmd = cpu_to_le16(RPM_CMD_READ_NOTIF);
msg.param1 = 0;
msg.param2 = 0;
GLINK_INFO(glink->ilc, "send READ NOTIFY cmd\n");
qcom_glink_tx_write(glink, &msg, sizeof(msg), NULL, 0);
mbox_send_message(glink->mbox_chan, NULL);
mbox_client_txdone(glink->mbox_chan, 0);
}
static int qcom_glink_tx(struct qcom_glink *glink,
const void *hdr, size_t hlen,
const void *data, size_t dlen, bool wait)
@ -380,17 +401,27 @@ static int qcom_glink_tx(struct qcom_glink *glink,
goto out;
}
if (atomic_read(&glink->in_reset)) {
ret = -ECONNRESET;
goto out;
if (!glink->sent_read_notify) {
glink->sent_read_notify = true;
qcom_glink_send_read_notify(glink);
}
/* Wait without holding the tx_lock */
spin_unlock_irqrestore(&glink->tx_lock, flags);
usleep_range(10000, 15000);
wait_event_timeout(glink->tx_avail_notify,
(qcom_glink_tx_avail(glink) >= tlen
|| atomic_read(&glink->in_reset)), 10 * HZ);
spin_lock_irqsave(&glink->tx_lock, flags);
if (atomic_read(&glink->in_reset)) {
ret = -ECONNRESET;
goto out;
}
if (qcom_glink_tx_avail(glink) >= tlen)
glink->sent_read_notify = false;
}
qcom_glink_tx_write(glink, hdr, hlen, data, dlen);
@ -1158,6 +1189,9 @@ static irqreturn_t qcom_glink_native_intr(int irq, void *data)
unsigned int cmd;
int ret = 0;
/* To wakeup any blocking writers */
wake_up_all(&glink->tx_avail_notify);
for (;;) {
avail = qcom_glink_rx_avail(glink);
if (avail < sizeof(msg))
@ -1904,6 +1938,9 @@ static void qcom_glink_notif_reset(void *data)
return;
atomic_inc(&glink->in_reset);
/* To wakeup any blocking writers */
wake_up_all(&glink->tx_avail_notify);
spin_lock_irqsave(&glink->idr_lock, flags);
idr_for_each_entry(&glink->lcids, channel, cid) {
wake_up(&channel->intent_req_event);
@ -1952,6 +1989,7 @@ struct qcom_glink *qcom_glink_native_probe(struct device *dev,
spin_lock_init(&glink->rx_lock);
INIT_LIST_HEAD(&glink->rx_queue);
INIT_WORK(&glink->rx_work, qcom_glink_work);
init_waitqueue_head(&glink->tx_avail_notify);
spin_lock_init(&glink->idr_lock);
idr_init(&glink->lcids);