[PATCH 1/5] rpmsg: smd: Perform handshake during open

From: Bjorn Andersson
Date: Tue Dec 12 2017 - 19:00:44 EST


Validate the the remote side is opening the channel that we've found by
performing a handshake when opening the channel.

Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---
drivers/rpmsg/qcom_smd.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
index b01774e9fac0..58dd44493420 100644
--- a/drivers/rpmsg/qcom_smd.c
+++ b/drivers/rpmsg/qcom_smd.c
@@ -200,6 +200,7 @@ struct qcom_smd_channel {
char *name;
enum smd_channel_state state;
enum smd_channel_state remote_state;
+ wait_queue_head_t state_change_event;

struct smd_channel_info_pair *info;
struct smd_channel_info_word_pair *info_word;
@@ -570,6 +571,8 @@ static bool qcom_smd_channel_intr(struct qcom_smd_channel *channel)
if (remote_state != channel->remote_state) {
channel->remote_state = remote_state;
need_state_scan = true;
+
+ wake_up_interruptible_all(&channel->state_change_event);
}
/* Indicate that we have seen any state change */
SET_RX_CHANNEL_FLAG(channel, fSTATE, 0);
@@ -786,7 +789,9 @@ static int __qcom_smd_send(struct qcom_smd_channel *channel, const void *data,
static int qcom_smd_channel_open(struct qcom_smd_channel *channel,
rpmsg_rx_cb_t cb)
{
+ struct qcom_smd_edge *edge = channel->edge;
size_t bb_size;
+ int ret;

/*
* Packets are maximum 4k, but reduce if the fifo is smaller
@@ -798,9 +803,33 @@ static int qcom_smd_channel_open(struct qcom_smd_channel *channel,

qcom_smd_channel_set_callback(channel, cb);
qcom_smd_channel_set_state(channel, SMD_CHANNEL_OPENING);
+
+ /* Wait for remote to enter opening or opened */
+ ret = wait_event_interruptible_timeout(channel->state_change_event,
+ channel->remote_state == SMD_CHANNEL_OPENING ||
+ channel->remote_state == SMD_CHANNEL_OPENED,
+ HZ);
+ if (!ret) {
+ dev_err(&edge->dev, "remote side did not enter opening state\n");
+ goto out_close_timeout;
+ }
+
qcom_smd_channel_set_state(channel, SMD_CHANNEL_OPENED);

+ /* Wait for remote to enter opened */
+ ret = wait_event_interruptible_timeout(channel->state_change_event,
+ channel->remote_state == SMD_CHANNEL_OPENED,
+ HZ);
+ if (!ret) {
+ dev_err(&edge->dev, "remote side did not enter open state\n");
+ goto out_close_timeout;
+ }
+
return 0;
+
+out_close_timeout:
+ qcom_smd_channel_set_state(channel, SMD_CHANNEL_CLOSED);
+ return -ETIMEDOUT;
}

/*
@@ -1055,6 +1084,7 @@ static struct qcom_smd_channel *qcom_smd_create_channel(struct qcom_smd_edge *ed
mutex_init(&channel->tx_lock);
spin_lock_init(&channel->recv_lock);
init_waitqueue_head(&channel->fblockread_event);
+ init_waitqueue_head(&channel->state_change_event);

info = qcom_smem_get(edge->remote_pid, smem_info_item, &info_size);
if (IS_ERR(info)) {
--
2.15.0