[media] pulse8-cec: serialize communication with adapter

Make sending messages to the adapter serialized within the driver.

send_and_wait is split into send_and_wait_once, which only sends once
and checks for the result, and the higher level send_and_wait, which
performs locking and retries.

Signed-off-by: Johan Fjeldtvedt <jaffe1@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/staging/media/pulse8-cec/pulse8-cec.c b/drivers/staging/media/pulse8-cec/pulse8-cec.c
index 94f8590492dcd1d8b771956d1720f4a7b1191a00..dcda68a569a75ac99dc8aa47578d0dc29795341d 100644 (file)
--- a/drivers/staging/media/pulse8-cec/pulse8-cec.c
+++ b/drivers/staging/media/pulse8-cec/pulse8-cec.c
@@ -99,6 +99,7 @@ struct pulse8 {
        unsigned int idx;
        bool escape;
        bool started;
+       struct mutex write_lock;
 };
 
 static void pulse8_irq_work_handler(struct work_struct *work)
@@ -233,8 +234,9 @@ static int pulse8_send(struct serio *serio, const u8 *command, u8 cmd_len)
        return err;
 }
 
-static int pulse8_send_and_wait(struct pulse8 *pulse8,
-                               const u8 *cmd, u8 cmd_len, u8 response, u8 size)
+static int pulse8_send_and_wait_once(struct pulse8 *pulse8,
+                                    const u8 *cmd, u8 cmd_len,
+                                    u8 response, u8 size)
 {
        int err;
 
@@ -250,24 +252,8 @@ static int pulse8_send_and_wait(struct pulse8 *pulse8,
        if ((pulse8->data[0] & 0x3f) == MSGCODE_COMMAND_REJECTED &&
            cmd[0] != MSGCODE_SET_CONTROLLED &&
            cmd[0] != MSGCODE_SET_AUTO_ENABLED &&
-           cmd[0] != MSGCODE_GET_BUILDDATE) {
-               u8 cmd_sc[2];
-
-               cmd_sc[0] = MSGCODE_SET_CONTROLLED;
-               cmd_sc[1] = 1;
-               err = pulse8_send_and_wait(pulse8, cmd_sc, 2,
-                                          MSGCODE_COMMAND_ACCEPTED, 1);
-               if (err)
-                       return err;
-               init_completion(&pulse8->cmd_done);
-
-               err = pulse8_send(pulse8->serio, cmd, cmd_len);
-               if (err)
-                       return err;
-
-               if (!wait_for_completion_timeout(&pulse8->cmd_done, HZ))
-                       return -ETIMEDOUT;
-       }
+           cmd[0] != MSGCODE_GET_BUILDDATE)
+               return -ENOTTY;
        if (response &&
            ((pulse8->data[0] & 0x3f) != response || pulse8->len < size + 1)) {
                dev_info(pulse8->dev, "transmit: failed %02x\n",
@@ -277,6 +263,31 @@ static int pulse8_send_and_wait(struct pulse8 *pulse8,
        return 0;
 }
 
+static int pulse8_send_and_wait(struct pulse8 *pulse8,
+                               const u8 *cmd, u8 cmd_len, u8 response, u8 size)
+{
+       u8 cmd_sc[2];
+       int err;
+
+       mutex_lock(&pulse8->write_lock);
+       err = pulse8_send_and_wait_once(pulse8, cmd, cmd_len, response, size);
+
+       if (err == -ENOTTY) {
+               cmd_sc[0] = MSGCODE_SET_CONTROLLED;
+               cmd_sc[1] = 1;
+               err = pulse8_send_and_wait_once(pulse8, cmd_sc, 2,
+                                               MSGCODE_COMMAND_ACCEPTED, 1);
+               if (err)
+                       goto unlock;
+               err = pulse8_send_and_wait_once(pulse8, cmd, cmd_len,
+                                               response, size);
+       }
+
+unlock:
+       mutex_unlock(&pulse8->write_lock);
+       return err == -ENOTTY ? -EIO : err;
+}
+
 static int pulse8_setup(struct pulse8 *pulse8, struct serio *serio)
 {
        u8 *data = pulse8->data + 1;
@@ -453,6 +464,7 @@ static int pulse8_connect(struct serio *serio, struct serio_driver *drv)
        pulse8->dev = &serio->dev;
        serio_set_drvdata(serio, pulse8);
        INIT_WORK(&pulse8->work, pulse8_irq_work_handler);
+       mutex_init(&pulse8->write_lock);
 
        err = serio_open(serio, drv);
        if (err)