[media] s5p-fimc: Change platform subdevs registration method

The previous method of registering platform entities into the main
driver using driver_find() and then iterating over devices bound to
a driver was racy and is being removed here. Nothing was preventing
module from unloading during a call to try_module_get(driver->owner).
Instead, we look up a device first and then check for its driver while
holding device lock.
The platform sub-devices are looked up and registered to the top
level driver. When any sub-device is not yet initialized and ready
the main driver's probe() will be deferred.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 108 insertions, 95 deletions

diff --git a/drivers/media/platform/s5p-fimc/fimc-mdevice.c b/drivers/media/platform/s5p-fimc/fimc-mdevice.c
index 52e1aa3c8982..2b0587204868 100644
--- a/drivers/media/platform/s5p-fimc/fimc-mdevice.c
+++ b/drivers/media/platform/s5p-fimc/fimc-mdevice.c
@@ -1,8 +1,8 @@
 /*
  * S5P/EXYNOS4 SoC series camera host interface media device driver
  *
- * Copyright (C) 2011 Samsung Electronics Co., Ltd.
- * Contact: Sylwester Nawrocki, <s.nawrocki@samsung.com>
+ * Copyright (C) 2011 - 2012 Samsung Electronics Co., Ltd.
+ * Sylwester Nawrocki <s.nawrocki@samsung.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published
@@ -312,138 +312,149 @@ static int fimc_md_register_sensor_entities(struct fimc_md *fmd)
 }
 
 /*
- * MIPI CSIS and FIMC platform devices registration.
+ * MIPI-CSIS, FIMC and FIMC-LITE platform devices registration.
  */
-static int fimc_register_callback(struct device *dev, void *p)
+
+static int register_fimc_lite_entity(struct fimc_md *fmd,
+                                     struct fimc_lite *fimc_lite)
 {
-        struct fimc_dev *fimc = dev_get_drvdata(dev);
         struct v4l2_subdev *sd;
-        struct fimc_md *fmd = p;
         int ret;
 
-        if (fimc == NULL || fimc->id >= FIMC_MAX_DEVS)
-                return 0;
+        if (WARN_ON(fimc_lite->index >= FIMC_LITE_MAX_DEVS ||
+                    fmd->fimc_lite[fimc_lite->index]))
+                return -EBUSY;
 
-        sd = &fimc->vid_cap.subdev;
-        sd->grp_id = GRP_ID_FIMC;
+        sd = &fimc_lite->subdev;
+        sd->grp_id = GRP_ID_FLITE;
         v4l2_set_subdev_hostdata(sd, (void *)&fimc_pipeline_ops);
 
         ret = v4l2_device_register_subdev(&fmd->v4l2_dev, sd);
-        if (ret) {
-                v4l2_err(&fmd->v4l2_dev, "Failed to register FIMC.%d (%d)\n",
-                         fimc->id, ret);
-                return ret;
-        }
-
-        fmd->fimc[fimc->id] = fimc;
-        return 0;
+        if (!ret)
+                fmd->fimc_lite[fimc_lite->index] = fimc_lite;
+        else
+                v4l2_err(&fmd->v4l2_dev, "Failed to register FIMC.LITE%d\n",
+                         fimc_lite->index);
+        return ret;
 }
 
-static int fimc_lite_register_callback(struct device *dev, void *p)
+static int register_fimc_entity(struct fimc_md *fmd, struct fimc_dev *fimc)
 {
-        struct fimc_lite *fimc = dev_get_drvdata(dev);
-        struct fimc_md *fmd = p;
+        struct v4l2_subdev *sd;
         int ret;
 
-        if (fimc == NULL || fimc->index >= FIMC_LITE_MAX_DEVS)
-                return 0;
+        if (WARN_ON(fimc->id >= FIMC_MAX_DEVS || fmd->fimc[fimc->id]))
+                return -EBUSY;
 
-        fimc->subdev.grp_id = GRP_ID_FLITE;
-        v4l2_set_subdev_hostdata(&fimc->subdev, (void *)&fimc_pipeline_ops);
+        sd = &fimc->vid_cap.subdev;
+        sd->grp_id = GRP_ID_FIMC;
+        v4l2_set_subdev_hostdata(sd, (void *)&fimc_pipeline_ops);
 
-        ret = v4l2_device_register_subdev(&fmd->v4l2_dev, &fimc->subdev);
-        if (ret) {
-                v4l2_err(&fmd->v4l2_dev,
-                         "Failed to register FIMC-LITE.%d (%d)\n",
-                         fimc->index, ret);
-                return ret;
+        ret = v4l2_device_register_subdev(&fmd->v4l2_dev, sd);
+        if (!ret) {
+                fmd->fimc[fimc->id] = fimc;
+                fimc->vid_cap.user_subdev_api = fmd->user_subdev_api;
+        } else {
+                v4l2_err(&fmd->v4l2_dev, "Failed to register FIMC.%d (%d)\n",
+                         fimc->id, ret);
         }
-
-        fmd->fimc_lite[fimc->index] = fimc;
-        return 0;
+        return ret;
 }
 
-static int csis_register_callback(struct device *dev, void *p)
+static int register_csis_entity(struct fimc_md *fmd,
+                                struct platform_device *pdev,
+                                struct v4l2_subdev *sd)
 {
-        struct v4l2_subdev *sd = dev_get_drvdata(dev);
-        struct platform_device *pdev;
-        struct fimc_md *fmd = p;
+        struct device_node *node = pdev->dev.of_node;
         int id, ret;
 
-        if (!sd)
-                return 0;
-        pdev = v4l2_get_subdevdata(sd);
-        if (!pdev || pdev->id < 0 || pdev->id >= CSIS_MAX_ENTITIES)
+        id = node ? of_alias_get_id(node, "csis") : max(0, pdev->id);
+
+        if (WARN_ON(id >= CSIS_MAX_ENTITIES || fmd->csis[id].sd))
+                return -EBUSY;
+
+        if (WARN_ON(id >= CSIS_MAX_ENTITIES))
                 return 0;
-        v4l2_info(sd, "csis%d sd: %s\n", pdev->id, sd->name);
 
-        id = pdev->id < 0 ? 0 : pdev->id;
         sd->grp_id = GRP_ID_CSIS;
-
         ret = v4l2_device_register_subdev(&fmd->v4l2_dev, sd);
         if (!ret)
                 fmd->csis[id].sd = sd;
         else
                 v4l2_err(&fmd->v4l2_dev,
-                         "Failed to register CSIS subdevice: %d\n", ret);
+                         "Failed to register MIPI-CSIS.%d (%d)\n", id, ret);
         return ret;
 }
 
-/**
- * fimc_md_register_platform_entities - register FIMC and CSIS media entities
- */
-static int fimc_md_register_platform_entities(struct fimc_md *fmd)
+static int fimc_md_register_platform_entity(struct fimc_md *fmd,
+                                            struct platform_device *pdev,
+                                            int plat_entity)
 {
-        struct s5p_platform_fimc *pdata = fmd->pdev->dev.platform_data;
-        struct device_driver *driver;
-        int ret, i;
-
-        driver = driver_find(FIMC_MODULE_NAME, &platform_bus_type);
-        if (!driver) {
-                v4l2_warn(&fmd->v4l2_dev,
-                         "%s driver not found, deffering probe\n",
-                         FIMC_MODULE_NAME);
-                return -EPROBE_DEFER;
-        }
-
-        ret = driver_for_each_device(driver, NULL, fmd,
-                                     fimc_register_callback);
-        if (ret)
-                return ret;
-
-        driver = driver_find(FIMC_LITE_DRV_NAME, &platform_bus_type);
-        if (driver && try_module_get(driver->owner)) {
-                ret = driver_for_each_device(driver, NULL, fmd,
-                                             fimc_lite_register_callback);
-                if (ret)
-                        return ret;
-                module_put(driver->owner);
-        }
-        /*
-         * Check if there is any sensor on the MIPI-CSI2 bus and
-         * if not skip the s5p-csis module loading.
-         */
-        if (pdata == NULL)
-                return 0;
-        for (i = 0; i < pdata->num_clients; i++) {
-                if (pdata->isp_info[i].bus_type == FIMC_MIPI_CSI2) {
-                        ret = 1;
+        struct device *dev = &pdev->dev;
+        int ret = -EPROBE_DEFER;
+        void *drvdata;
+
+        /* Lock to ensure dev->driver won't change. */
+        device_lock(dev);
+
+        if (!dev->driver || !try_module_get(dev->driver->owner))
+                goto dev_unlock;
+
+        drvdata = dev_get_drvdata(dev);
+        /* Some subdev didn't probe succesfully id drvdata is NULL */
+        if (drvdata) {
+                switch (plat_entity) {
+                case IDX_FIMC:
+                        ret = register_fimc_entity(fmd, drvdata);
+                        break;
+                case IDX_FLITE:
+                        ret = register_fimc_lite_entity(fmd, drvdata);
                         break;
+                case IDX_CSIS:
+                        ret = register_csis_entity(fmd, pdev, drvdata);
+                        break;
+                default:
+                        ret = -ENODEV;
                 }
         }
-        if (!ret)
-                return 0;
 
-        driver = driver_find(CSIS_DRIVER_NAME, &platform_bus_type);
-        if (!driver || !try_module_get(driver->owner)) {
-                v4l2_warn(&fmd->v4l2_dev,
-                         "%s driver not found, deffering probe\n",
-                         CSIS_DRIVER_NAME);
-                return -EPROBE_DEFER;
+        module_put(dev->driver->owner);
+dev_unlock:
+        device_unlock(dev);
+        if (ret == -EPROBE_DEFER)
+                dev_info(&fmd->pdev->dev, "deferring %s device registration\n",
+                        dev_name(dev));
+        else if (ret < 0)
+                dev_err(&fmd->pdev->dev, "%s device registration failed (%d)\n",
+                        dev_name(dev), ret);
+        return ret;
+}
+
+static int fimc_md_pdev_match(struct device *dev, void *data)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        int plat_entity = -1;
+        int ret;
+        char *p;
+
+        if (!get_device(dev))
+                return -ENODEV;
+
+        if (!strcmp(pdev->name, CSIS_DRIVER_NAME)) {
+                plat_entity = IDX_CSIS;
+        } else if (!strcmp(pdev->name, FIMC_LITE_DRV_NAME)) {
+                plat_entity = IDX_FLITE;
+        } else {
+                p = strstr(pdev->name, "fimc");
+                if (p && *(p + 4) == 0)
+                        plat_entity = IDX_FIMC;
         }
 
-        return driver_for_each_device(driver, NULL, fmd,
-                                      csis_register_callback);
+        if (plat_entity >= 0)
+                ret = fimc_md_register_platform_entity(data, pdev,
+                                                       plat_entity);
+        put_device(dev);
+        return 0;
 }
 
 static void fimc_md_unregister_entities(struct fimc_md *fmd)
@@ -477,6 +488,7 @@ static void fimc_md_unregister_entities(struct fimc_md *fmd)
                 fimc_md_unregister_sensor(fmd->sensor[i].subdev);
                 fmd->sensor[i].subdev = NULL;
         }
+        v4l2_info(&fmd->v4l2_dev, "Unregistered all entities\n");
 }
 
 /**
@@ -939,7 +951,8 @@ static int fimc_md_probe(struct platform_device *pdev)
         /* Protect the media graph while we're registering entities */
         mutex_lock(&fmd->media_dev.graph_mutex);
 
-        ret = fimc_md_register_platform_entities(fmd);
+        ret = bus_for_each_dev(&platform_bus_type, NULL, fmd,
+                                        fimc_md_pdev_match);
         if (ret)
                 goto err_unlock;