4.19-stable review patch. If anyone has any objections, please let me know.
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From: Arun Kumar Neelakantam aneela@codeaurora.org
[ Upstream commit b16a37e1846c9573a847a56fa2f31ba833dae45a ]
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.
Signed-off-by: Deepak Kumar Singh deesin@codeaurora.org Signed-off-by: Arun Kumar Neelakantam aneela@codeaurora.org Signed-off-by: Bjorn Andersson bjorn.andersson@linaro.org Link: https://lore.kernel.org/r/1596086296-28529-7-git-send-email-deesin@codeauror... Stable-dep-of: 06c59d97f63c ("rpmsg: glink: use only lower 16-bits of param2 for CMD_OPEN name length") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/rpmsg/qcom_glink_native.c | 36 ++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-)
diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c index 5a3ed96af87b8..3db5beb338cd3 100644 --- a/drivers/rpmsg/qcom_glink_native.c +++ b/drivers/rpmsg/qcom_glink_native.c @@ -92,6 +92,8 @@ struct glink_core_rx_intent { * @rcids: idr of all channels with a known remote channel id * @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 */ struct qcom_glink { struct device *dev; @@ -118,6 +120,8 @@ struct qcom_glink { unsigned long features;
bool intentless; + wait_queue_head_t tx_avail_notify; + bool sent_read_notify; };
enum { @@ -305,6 +309,20 @@ static void qcom_glink_tx_write(struct qcom_glink *glink, glink->tx_pipe->write(glink->tx_pipe, hdr, hlen, data, dlen); }
+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; + + 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) @@ -325,12 +343,21 @@ static int qcom_glink_tx(struct qcom_glink *glink, 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, 10 * HZ);
spin_lock_irqsave(&glink->tx_lock, flags); + + if (qcom_glink_tx_avail(glink) >= tlen) + glink->sent_read_notify = false; }
qcom_glink_tx_write(glink, hdr, hlen, data, dlen); @@ -991,6 +1018,9 @@ 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)) @@ -1530,6 +1560,9 @@ static void qcom_glink_rx_close_ack(struct qcom_glink *glink, unsigned int lcid) struct glink_channel *channel; unsigned long flags;
+ /* To wakeup any blocking writers */ + wake_up_all(&glink->tx_avail_notify); + spin_lock_irqsave(&glink->idr_lock, flags); channel = idr_find(&glink->lcids, lcid); if (WARN(!channel, "close ack on unknown channel\n")) { @@ -1636,6 +1669,7 @@ 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);