--- /dev/null
+/*
+ * rcar-fcp.c -- R-Car Frame Compression Processor Driver
+ *
+ * Copyright (C) 2016 Renesas Electronics Corporation
+ *
+ * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.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 by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+#include <media/rcar-fcp.h>
+
+struct rcar_fcp_device {
+ struct list_head list;
+ struct device *dev;
+};
+
+static LIST_HEAD(fcp_devices);
+static DEFINE_MUTEX(fcp_lock);
+
+/* -----------------------------------------------------------------------------
+ * Public API
+ */
+
+/**
+ * rcar_fcp_get - Find and acquire a reference to an FCP instance
+ * @np: Device node of the FCP instance
+ *
+ * Search the list of registered FCP instances for the instance corresponding to
+ * the given device node.
+ *
+ * Return a pointer to the FCP instance, or an ERR_PTR if the instance can't be
+ * found.
+ */
+struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np)
+{
+ struct rcar_fcp_device *fcp;
+
+ mutex_lock(&fcp_lock);
+
+ list_for_each_entry(fcp, &fcp_devices, list) {
+ if (fcp->dev->of_node != np)
+ continue;
+
+ /*
+ * Make sure the module won't be unloaded behind our back. This
+ * is a poor man's safety net, the module should really not be
+ * unloaded while FCP users can be active.
+ */
+ if (!try_module_get(fcp->dev->driver->owner))
+ fcp = NULL;
+
+ goto done;
+ }
+
+ fcp = ERR_PTR(-EPROBE_DEFER);
+
+done:
+ mutex_unlock(&fcp_lock);
+ return fcp;
+}
+EXPORT_SYMBOL_GPL(rcar_fcp_get);
+
+/**
+ * rcar_fcp_put - Release a reference to an FCP instance
+ * @fcp: The FCP instance
+ *
+ * Release the FCP instance acquired by a call to rcar_fcp_get().
+ */
+void rcar_fcp_put(struct rcar_fcp_device *fcp)
+{
+ if (fcp)
+ module_put(fcp->dev->driver->owner);
+}
+EXPORT_SYMBOL_GPL(rcar_fcp_put);
+
+/**
+ * rcar_fcp_enable - Enable an FCP
+ * @fcp: The FCP instance
+ *
+ * Before any memory access through an FCP is performed by a module, the FCP
+ * must be enabled by a call to this function. The enable calls are reference
+ * counted, each successful call must be followed by one rcar_fcp_disable()
+ * call when no more memory transfer can occur through the FCP.
+ *
+ * Return 0 on success or a negative error code if an error occurs. The enable
+ * reference count isn't increased when this function returns an error.
+ */
+int rcar_fcp_enable(struct rcar_fcp_device *fcp)
+{
+ if (!fcp)
+ return 0;
+
+ return pm_runtime_get_sync(fcp->dev);
+}
+EXPORT_SYMBOL_GPL(rcar_fcp_enable);
+
+/**
+ * rcar_fcp_disable - Disable an FCP
+ * @fcp: The FCP instance
+ *
+ * This function is the counterpart of rcar_fcp_enable(). As enable calls are
+ * reference counted a disable call may not disable the FCP synchronously.
+ */
+void rcar_fcp_disable(struct rcar_fcp_device *fcp)
+{
+ if (fcp)
+ pm_runtime_put(fcp->dev);
+}
+EXPORT_SYMBOL_GPL(rcar_fcp_disable);
+
+/* -----------------------------------------------------------------------------
+ * Platform Driver
+ */
+
+static int rcar_fcp_probe(struct platform_device *pdev)
+{
+ struct rcar_fcp_device *fcp;
+
+ fcp = devm_kzalloc(&pdev->dev, sizeof(*fcp), GFP_KERNEL);
+ if (fcp == NULL)
+ return -ENOMEM;
+
+ fcp->dev = &pdev->dev;
+
+ pm_runtime_enable(&pdev->dev);
+
+ mutex_lock(&fcp_lock);
+ list_add_tail(&fcp->list, &fcp_devices);
+ mutex_unlock(&fcp_lock);
+
+ platform_set_drvdata(pdev, fcp);
+
+ return 0;
+}
+
+static int rcar_fcp_remove(struct platform_device *pdev)
+{
+ struct rcar_fcp_device *fcp = platform_get_drvdata(pdev);
+
+ mutex_lock(&fcp_lock);
+ list_del(&fcp->list);
+ mutex_unlock(&fcp_lock);
+
+ pm_runtime_disable(&pdev->dev);
+
+ return 0;
+}
+
+static const struct of_device_id rcar_fcp_of_match[] = {
+ { .compatible = "renesas,fcpv" },
+ { },
+};
+
+static struct platform_driver rcar_fcp_platform_driver = {
+ .probe = rcar_fcp_probe,
+ .remove = rcar_fcp_remove,
+ .driver = {
+ .name = "rcar-fcp",
+ .of_match_table = rcar_fcp_of_match,
+ .suppress_bind_attrs = true,
+ },
+};
+
+module_platform_driver(rcar_fcp_platform_driver);
+
+MODULE_ALIAS("rcar-fcp");
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
+MODULE_DESCRIPTION("Renesas FCP Driver");
+MODULE_LICENSE("GPL");
--- /dev/null
+/*
+ * rcar-fcp.h -- R-Car Frame Compression Processor Driver
+ *
+ * Copyright (C) 2016 Renesas Electronics Corporation
+ *
+ * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.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 by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#ifndef __MEDIA_RCAR_FCP_H__
+#define __MEDIA_RCAR_FCP_H__
+
+struct device_node;
+struct rcar_fcp_device;
+
+#if IS_ENABLED(CONFIG_VIDEO_RENESAS_FCP)
+struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np);
+void rcar_fcp_put(struct rcar_fcp_device *fcp);
+int rcar_fcp_enable(struct rcar_fcp_device *fcp);
+void rcar_fcp_disable(struct rcar_fcp_device *fcp);
+#else
+static inline struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np)
+{
+ return ERR_PTR(-ENOENT);
+}
+static inline void rcar_fcp_put(struct rcar_fcp_device *fcp) { }
+static inline int rcar_fcp_enable(struct rcar_fcp_device *fcp)
+{
+ return -ENOSYS;
+}
+static inline void rcar_fcp_disable(struct rcar_fcp_device *fcp) { }
+#endif
+
+#endif /* __MEDIA_RCAR_FCP_H__ */
projects / cascardo / linux.git / commitdiff