[PATCH v2 11/17] media: rockchip: rga: use components to manage multiple cores

[Sven Püschel]

Use component helpers to manage multiple cores and aggregate them into a
central master device. This gives us a dedicated master device and
ensures that all cores (components) are properly set up before creating
the video device.

This commit only sets up a basic component device. Instead of the
rga_disable_multicore function only the first core is added to the
master device. To avoid the secondary core creating an additional video
device the whole core probe implementation is moved to the bind method,
which is only called when the core is bound to a master device.

As we use devres (devm_*) functions for resource cleanup in the probe,
it is technically incorrect to use them in a component bind function.
It'll be properly split out again in the follow-up commits to avoid
having one big migration commit.

The implementation is based on the etnaviv gpu driver, which also groups
multiple gpu cores under a single etnaviv master device.

Signed-off-by: Sven Püschel <s.pueschel@xxxxxxxxxxxxxx>

---
v2
- clarify that devres in component bind functions is technically
  incorrect and only done to keep the commits split up
- use dev_err_probe instead of dev_err + return for a failed
  component_add
- remove if (!match) check in rga_probe, as it's only called when we
  have found at least one dt entry (and sashiko pointed out that it's
  an err ptr)
- add platform_device_id table to avoid a manual binding
---
 drivers/media/platform/rockchip/rga/rga.c | 263 ++++++++++++++++++++++++------
 1 file changed, 209 insertions(+), 54 deletions(-)

diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c
index bcfc19d29af74..367df0ee7b02f 100644
--- a/drivers/media/platform/rockchip/rga/rga.c
+++ b/drivers/media/platform/rockchip/rga/rga.c
@@ -5,6 +5,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/component.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/fs.h>
@@ -737,51 +738,9 @@ static int rga_parse_dt(struct rga_core *core)
 	return 0;
 }
 
-/*
- * Some SoCs, like RK3588 have multiple identical RGA3 cores, but the
- * kernel is currently missing support for multi-core handling. Exposing
- * separate devices for each core to userspace is bad, since that does
- * not allow scheduling tasks properly (and creates ABI). With this workaround
- * the driver will only probe for the first core and early exit for the other
- * cores. Once the driver gains multi-core support, the same technique
- * for detecting the main core can be used to cluster all cores together.
- */
-static int rga_disable_multicore(struct device *dev)
-{
-	struct device_node *node = NULL;
-	const char *compatible;
-	bool is_main_core;
-	int ret;
-
-	/* Intentionally ignores the fallback strings */
-	ret = of_property_read_string(dev->of_node, "compatible", &compatible);
-	if (ret)
-		return ret;
-
-	/* The first compatible and available node found is considered the main core */
-	do {
-		node = of_find_compatible_node(node, NULL, compatible);
-		if (of_device_is_available(node))
-			break;
-	} while (node);
-
-	if (!node)
-		return -EINVAL;
-
-	is_main_core = (dev->of_node == node);
-
-	of_node_put(node);
-
-	if (!is_main_core) {
-		dev_info(dev, "missing multi-core support, ignoring this instance\n");
-		return -ENODEV;
-	}
-
-	return 0;
-}
-
-static int rga_probe(struct platform_device *pdev)
+static int rga_core_bind(struct device *dev, struct device *master, void *data)
 {
+	struct platform_device *pdev = to_platform_device(dev);
 	struct rockchip_rga *rga;
 	struct rga_core *core;
 	struct video_device *vfd;
@@ -791,10 +750,6 @@ static int rga_probe(struct platform_device *pdev)
 	if (!pdev->dev.of_node)
 		return -ENODEV;
 
-	ret = rga_disable_multicore(&pdev->dev);
-	if (ret)
-		return ret;
-
 	rga = devm_kzalloc(&pdev->dev, sizeof(*rga) + 1 * sizeof(*rga->cores), GFP_KERNEL);
 	if (!rga)
 		return -ENOMEM;
@@ -900,9 +855,10 @@ static int rga_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static void rga_remove(struct platform_device *pdev)
+static void rga_core_unbind(struct device *dev, struct device *master,
+			    void *data)
 {
-	struct rga_core *core = platform_get_drvdata(pdev);
+	struct rga_core *core = dev_get_drvdata(dev);
 	struct rockchip_rga *rga = core->rga;
 
 	v4l2_info(&rga->v4l2_dev, "Removing\n");
@@ -912,6 +868,27 @@ static void rga_remove(struct platform_device *pdev)
 	v4l2_device_unregister(&rga->v4l2_dev);
 }
 
+static const struct component_ops rga_core_ops = {
+	.bind = rga_core_bind,
+	.unbind = rga_core_unbind,
+};
+
+static int rga_core_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+
+	ret = component_add(&pdev->dev, &rga_core_ops);
+	if (ret < 0)
+		return dev_err_probe(&pdev->dev, ret, "failed to register component\n");
+
+	return 0;
+}
+
+static void rga_core_remove(struct platform_device *pdev)
+{
+	component_del(&pdev->dev, &rga_core_ops);
+}
+
 static int __maybe_unused rga_runtime_suspend(struct device *dev)
 {
 	struct rga_core *core = dev_get_drvdata(dev);
@@ -928,11 +905,12 @@ static int __maybe_unused rga_runtime_resume(struct device *dev)
 	return clk_bulk_prepare_enable(core->num_clks, core->clks);
 }
 
-static const struct dev_pm_ops rga_pm = {
+static const struct dev_pm_ops rga_core_pm = {
 	SET_RUNTIME_PM_OPS(rga_runtime_suspend,
 			   rga_runtime_resume, NULL)
 };
 
+/* add new compatibles also to the rga_ids struct */
 static const struct of_device_id rockchip_rga_match[] = {
 	{
 		.compatible = "rockchip,rk3288-rga",
@@ -951,17 +929,194 @@ static const struct of_device_id rockchip_rga_match[] = {
 
 MODULE_DEVICE_TABLE(of, rockchip_rga_match);
 
+static struct platform_driver rga_core_pdrv = {
+	.probe = rga_core_probe,
+	.remove = rga_core_remove,
+	.driver = {
+		.name = RGA_NAME "-core",
+		.pm = &rga_core_pm,
+		.of_match_table = rockchip_rga_match,
+	},
+};
+
+static int rga_bind(struct device *dev)
+{
+	int ret;
+
+	ret = component_bind_all(dev, NULL);
+	if (ret) {
+		dev_err(dev, "component bind failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void rga_unbind(struct device *dev)
+{
+	component_unbind_all(dev, NULL);
+}
+
+struct component_master_ops rga_master_ops = {
+	.bind = rga_bind,
+	.unbind = rga_unbind,
+};
+
+static int rga_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match_desc = pdev->dev.platform_data;
+	struct device *dev = &pdev->dev;
+	struct component_match *match = NULL;
+	struct device_node *core_node;
+
+	if (!match_desc)
+		return dev_err_probe(dev, -ENODEV, "missing platform data\n");
+
+	for_each_compatible_node(core_node, NULL, match_desc->compatible) {
+		if (!of_device_is_available(core_node))
+			continue;
+
+		of_node_get(core_node);
+		component_match_add_release(dev, &match, component_release_of,
+					    component_compare_of, core_node);
+
+		/*
+		 * As multi core is not implemented yet,
+		 * break out of the loop to only have one core per rockchip_rga struct.
+		 * Also put the node, which otherwise would've been done by the loop iteration.
+		 */
+		of_node_put(core_node);
+		break;
+	}
+
+	return component_master_add_with_match(dev, &rga_master_ops, match);
+}
+
+static void rga_remove(struct platform_device *pdev)
+{
+	component_master_del(&pdev->dev, &rga_master_ops);
+}
+
+/*
+ * Keep in sync with the compatible names of rockchip_rga_match, as we name the
+ * virtual component master platform device (allocating the /dev/video device)
+ * based on the compatible value.
+ */
+static struct platform_device_id rga_ids[] = {
+	{
+		.name = "rockchip,rk3288-rga",
+	},
+	{
+		.name = "rockchip,rk3399-rga",
+	},
+	{
+		.name = "rockchip,rk3588-rga3",
+	},
+	{},
+};
+
 static struct platform_driver rga_pdrv = {
 	.probe = rga_probe,
 	.remove = rga_remove,
 	.driver = {
 		.name = RGA_NAME,
-		.pm = &rga_pm,
-		.of_match_table = rockchip_rga_match,
 	},
+	.id_table = rga_ids,
 };
 
-module_platform_driver(rga_pdrv);
+static bool rga_of_has_available_node(const char *compat)
+{
+	struct device_node *node;
+
+	for_each_compatible_node(node, NULL, compat) {
+		if (of_device_is_available(node)) {
+			of_node_put(node);
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static int rga_create_platform_device(struct platform_device **ppdev,
+				      const struct of_device_id *match)
+{
+	struct platform_device *pdev;
+	int ret;
+
+	pdev = platform_device_alloc(match->compatible, PLATFORM_DEVID_NONE);
+	if (!pdev)
+		return -ENOMEM;
+
+	ret = platform_device_add_data(pdev, match, sizeof(*match));
+	if (ret)
+		goto free_platform_device;
+
+	ret = platform_device_add(pdev);
+	if (ret)
+		goto free_platform_device;
+
+	*ppdev = pdev;
+
+	return 0;
+
+free_platform_device:
+	platform_device_put(pdev);
+	return ret;
+}
+
+static struct platform_device *master_pdevs[ARRAY_SIZE(rockchip_rga_match) - 1];
+
+static int __init rga_init(void)
+{
+	int ret;
+	unsigned int i;
+
+	ret = platform_driver_register(&rga_core_pdrv);
+	if (ret != 0)
+		return ret;
+
+	ret = platform_driver_register(&rga_pdrv);
+	if (ret != 0)
+		goto unregister_core_driver;
+
+	for (i = 0; i < ARRAY_SIZE(master_pdevs); i++) {
+		if (!rga_of_has_available_node(
+			    rockchip_rga_match[i].compatible))
+			continue;
+
+		ret = rga_create_platform_device(&master_pdevs[i],
+						 &rockchip_rga_match[i]);
+		if (ret)
+			goto unregister_platform_devices;
+	}
+
+	return 0;
+
+unregister_platform_devices:
+	for (i = 0; i < ARRAY_SIZE(master_pdevs); i++) {
+		platform_device_unregister(master_pdevs[i]);
+		master_pdevs[i] = NULL;
+	}
+	platform_driver_unregister(&rga_pdrv);
+unregister_core_driver:
+	platform_driver_unregister(&rga_core_pdrv);
+	return ret;
+}
+module_init(rga_init);
+
+static void __exit rga_exit(void)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(master_pdevs); i++) {
+		platform_device_unregister(master_pdevs[i]);
+		master_pdevs[i] = NULL;
+	}
+	platform_driver_unregister(&rga_pdrv);
+	platform_driver_unregister(&rga_core_pdrv);
+}
+module_exit(rga_exit);
 
 MODULE_AUTHOR("Jacob Chen <jacob-chen@xxxxxxxxxx>");
 MODULE_DESCRIPTION("Rockchip Raster 2d Graphic Acceleration Unit");

-- 
2.55.0