V4L/DVB (6112): cx25840: use a workqueue to load the firmware

Loading the firmware using the i2c bit-banging code blocks the kernel.
Move the firmware load code into a workqueue so that it plays well with
other processes.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

2 files changed, 39 insertions, 10 deletions

diff --git a/drivers/media/video/cx25840/cx25840-core.c b/drivers/media/video/cx25840/cx25840-core.c
index ae90d1c3d12b..d6f8b3b6af40 100644
--- a/drivers/media/video/cx25840/cx25840-core.c
+++ b/drivers/media/video/cx25840/cx25840-core.c
@@ -179,9 +179,18 @@ static void cx25836_initialize(struct i2c_client *client)
         cx25840_and_or(client, 0x15b, ~0x1e, 0x10);
 }
 
+static void cx25840_work_handler(struct work_struct *work)
+{
+        struct cx25840_state *state = container_of(work, struct cx25840_state, fw_work);
+        cx25840_loadfw(state->c);
+        wake_up(&state->fw_wait);
+}
+
 static void cx25840_initialize(struct i2c_client *client)
 {
+        DEFINE_WAIT(wait);
         struct cx25840_state *state = i2c_get_clientdata(client);
+        struct workqueue_struct *q;
 
         /* datasheet startup in numbered steps, refer to page 3-77 */
         /* 2. */
@@ -197,7 +206,19 @@ static void cx25840_initialize(struct i2c_client *client)
         cx25840_write(client, 0x13c, 0x01);
         cx25840_write(client, 0x13c, 0x00);
         /* 5. */
-        cx25840_loadfw(client);
+        /* Do the firmware load in a work handler to prevent.
+           Otherwise the kernel is blocked waiting for the
+           bit-banging i2c interface to finish uploading the
+           firmware. */
+        INIT_WORK(&state->fw_work, cx25840_work_handler);
+        init_waitqueue_head(&state->fw_wait);
+        q = create_singlethread_workqueue("cx25840_fw");
+        prepare_to_wait(&state->fw_wait, &wait, TASK_UNINTERRUPTIBLE);
+        queue_work(q, &state->fw_work);
+        schedule();
+        finish_wait(&state->fw_wait, &wait);
+        destroy_workqueue(q);
+
         /* 6. */
         cx25840_write(client, 0x115, 0x8c);
         cx25840_write(client, 0x116, 0x07);
@@ -872,17 +893,16 @@ static int cx25840_detect_client(struct i2c_adapter *adapter, int address,
         if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
                 return 0;
 
-        state = kzalloc(sizeof(struct cx25840_state), GFP_KERNEL);
-        if (state == 0)
+        client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
+        if (client == 0)
                 return -ENOMEM;
 
-        client = &state->c;
         client->addr = address;
         client->adapter = adapter;
         client->driver = &i2c_driver_cx25840;
         snprintf(client->name, sizeof(client->name) - 1, "cx25840");
 
-        v4l_dbg(1, cx25840_debug, client, "detecting cx25840 client on address 0x%x\n", address << 1);
+        v4l_dbg(1, cx25840_debug, client, "detecting cx25840 client on address 0x%x\n", client->addr << 1);
 
         device_id = cx25840_read(client, 0x101) << 8;
         device_id |= cx25840_read(client, 0x100);
@@ -891,26 +911,32 @@ static int cx25840_detect_client(struct i2c_adapter *adapter, int address,
          * 0x83 for the cx2583x and 0x84 for the cx2584x */
         if ((device_id & 0xff00) == 0x8300) {
                 id = V4L2_IDENT_CX25836 + ((device_id >> 4) & 0xf) - 6;
-                state->is_cx25836 = 1;
         }
         else if ((device_id & 0xff00) == 0x8400) {
                 id = V4L2_IDENT_CX25840 + ((device_id >> 4) & 0xf);
-                state->is_cx25836 = 0;
         }
         else {
                 v4l_dbg(1, cx25840_debug, client, "cx25840 not found\n");
-                kfree(state);
+                kfree(client);
                 return 0;
         }
 
+        state = kzalloc(sizeof(struct cx25840_state), GFP_KERNEL);
+        if (state == NULL) {
+                kfree(client);
+                return -ENOMEM;
+        }
+
         /* Note: revision '(device_id & 0x0f) == 2' was never built. The
            marking skips from 0x1 == 22 to 0x3 == 23. */
         v4l_info(client, "cx25%3x-2%x found @ 0x%x (%s)\n",
                     (device_id & 0xfff0) >> 4,
                     (device_id & 0x0f) < 3 ? (device_id & 0x0f) + 1 : (device_id & 0x0f),
-                    address << 1, adapter->name);
+                    client->addr << 1, client->adapter->name);
 
         i2c_set_clientdata(client, state);
+        state->c = client;
+        state->is_cx25836 = ((device_id & 0xff00) == 0x8300);
         state->vid_input = CX25840_COMPOSITE7;
         state->aud_input = CX25840_AUDIO8;
         state->audclk_freq = 48000;
@@ -944,6 +970,7 @@ static int cx25840_detach_client(struct i2c_client *client)
         }
 
         kfree(state);
+        kfree(client);
 
         return 0;
 }
diff --git a/drivers/media/video/cx25840/cx25840-core.h b/drivers/media/video/cx25840/cx25840-core.h
index 86e2edfc4941..ea669b1f084d 100644
--- a/drivers/media/video/cx25840/cx25840-core.h
+++ b/drivers/media/video/cx25840/cx25840-core.h
@@ -35,7 +35,7 @@ extern int cx25840_debug;
 #define CX25840_CID_ENABLE_PVR150_WORKAROUND (V4L2_CID_PRIVATE_BASE+0)
 
 struct cx25840_state {
-        struct i2c_client c;
+        struct i2c_client *c;
         int pvr150_workaround;
         int radio;
         enum cx25840_video_input vid_input;
@@ -48,6 +48,8 @@ struct cx25840_state {
         u32 rev;
         int is_cx25836;
         int is_initialized;
+        wait_queue_head_t fw_wait;    /* wake up when the fw load is finished */
+        struct work_struct fw_work;   /* work entry for fw load */
 };
 
 /* ----------------------------------------------------------------------- */