drivers/media/platform/rcar-fcp.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * rcar-fcp.c  --  R-Car Frame Compression Processor Driver
   4  *
   5  * Copyright (C) 2016 Renesas Electronics Corporation
   6  *
   7  * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/list.h>
  13 #include <linux/module.h>
  14 #include <linux/mod_devicetable.h>
  15 #include <linux/mutex.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/pm_runtime.h>
  18 #include <linux/slab.h>
  19
  20 #include <media/rcar-fcp.h>
  21
  22 struct rcar_fcp_device {
  23         struct list_head list;
  24         struct device *dev;
  25 };
  26
  27 static LIST_HEAD(fcp_devices);
  28 static DEFINE_MUTEX(fcp_lock);
  29
  30 /* -----------------------------------------------------------------------------
  31  * Public API
  32  */
  33
  34 /**
  35  * rcar_fcp_get - Find and acquire a reference to an FCP instance
  36  * @np: Device node of the FCP instance
  37  *
  38  * Search the list of registered FCP instances for the instance corresponding to
  39  * the given device node.
  40  *
  41  * Return a pointer to the FCP instance, or an ERR_PTR if the instance can't be
  42  * found.
  43  */
  44 struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np)
  45 {
  46         struct rcar_fcp_device *fcp;
  47
  48         mutex_lock(&fcp_lock);
  49
  50         list_for_each_entry(fcp, &fcp_devices, list) {
  51                 if (fcp->dev->of_node != np)
  52                         continue;
  53
  54                 get_device(fcp->dev);
  55                 goto done;
  56         }
  57
  58         fcp = ERR_PTR(-EPROBE_DEFER);
  59
  60 done:
  61         mutex_unlock(&fcp_lock);
  62         return fcp;
  63 }
  64 EXPORT_SYMBOL_GPL(rcar_fcp_get);
  65
  66 /**
  67  * rcar_fcp_put - Release a reference to an FCP instance
  68  * @fcp: The FCP instance
  69  *
  70  * Release the FCP instance acquired by a call to rcar_fcp_get().
  71  */
  72 void rcar_fcp_put(struct rcar_fcp_device *fcp)
  73 {
  74         if (fcp)
  75                 put_device(fcp->dev);
  76 }
  77 EXPORT_SYMBOL_GPL(rcar_fcp_put);
  78
  79 struct device *rcar_fcp_get_device(struct rcar_fcp_device *fcp)
  80 {
  81         return fcp->dev;
  82 }
  83 EXPORT_SYMBOL_GPL(rcar_fcp_get_device);
  84
  85 /**
  86  * rcar_fcp_enable - Enable an FCP
  87  * @fcp: The FCP instance
  88  *
  89  * Before any memory access through an FCP is performed by a module, the FCP
  90  * must be enabled by a call to this function. The enable calls are reference
  91  * counted, each successful call must be followed by one rcar_fcp_disable()
  92  * call when no more memory transfer can occur through the FCP.
  93  *
  94  * Return 0 on success or a negative error code if an error occurs. The enable
  95  * reference count isn't increased when this function returns an error.
  96  */
  97 int rcar_fcp_enable(struct rcar_fcp_device *fcp)
  98 {
  99         int ret;
 100
 101         if (!fcp)
 102                 return 0;
 103
 104         ret = pm_runtime_get_sync(fcp->dev);
 105         if (ret < 0) {
 106                 pm_runtime_put_noidle(fcp->dev);
 107                 return ret;
 108         }
 109
 110         return 0;
 111 }
 112 EXPORT_SYMBOL_GPL(rcar_fcp_enable);
 113
 114 /**
 115  * rcar_fcp_disable - Disable an FCP
 116  * @fcp: The FCP instance
 117  *
 118  * This function is the counterpart of rcar_fcp_enable(). As enable calls are
 119  * reference counted a disable call may not disable the FCP synchronously.
 120  */
 121 void rcar_fcp_disable(struct rcar_fcp_device *fcp)
 122 {
 123         if (fcp)
 124                 pm_runtime_put(fcp->dev);
 125 }
 126 EXPORT_SYMBOL_GPL(rcar_fcp_disable);
 127
 128 /* -----------------------------------------------------------------------------
 129  * Platform Driver
 130  */
 131
 132 static int rcar_fcp_probe(struct platform_device *pdev)
 133 {
 134         struct rcar_fcp_device *fcp;
 135
 136         fcp = devm_kzalloc(&pdev->dev, sizeof(*fcp), GFP_KERNEL);
 137         if (fcp == NULL)
 138                 return -ENOMEM;
 139
 140         fcp->dev = &pdev->dev;
 141
 142         dma_set_max_seg_size(fcp->dev, UINT_MAX);
 143
 144         pm_runtime_enable(&pdev->dev);
 145
 146         mutex_lock(&fcp_lock);
 147         list_add_tail(&fcp->list, &fcp_devices);
 148         mutex_unlock(&fcp_lock);
 149
 150         platform_set_drvdata(pdev, fcp);
 151
 152         return 0;
 153 }
 154
 155 static int rcar_fcp_remove(struct platform_device *pdev)
 156 {
 157         struct rcar_fcp_device *fcp = platform_get_drvdata(pdev);
 158
 159         mutex_lock(&fcp_lock);
 160         list_del(&fcp->list);
 161         mutex_unlock(&fcp_lock);
 162
 163         pm_runtime_disable(&pdev->dev);
 164
 165         return 0;
 166 }
 167
 168 static const struct of_device_id rcar_fcp_of_match[] = {
 169         { .compatible = "renesas,fcpf" },
 170         { .compatible = "renesas,fcpv" },
 171         { },
 172 };
 173 MODULE_DEVICE_TABLE(of, rcar_fcp_of_match);
 174
 175 static struct platform_driver rcar_fcp_platform_driver = {
 176         .probe          = rcar_fcp_probe,
 177         .remove         = rcar_fcp_remove,
 178         .driver         = {
 179                 .name   = "rcar-fcp",
 180                 .of_match_table = rcar_fcp_of_match,
 181                 .suppress_bind_attrs = true,
 182         },
 183 };
 184
 185 module_platform_driver(rcar_fcp_platform_driver);
 186
 187 MODULE_ALIAS("rcar-fcp");
 188 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
 189 MODULE_DESCRIPTION("Renesas FCP Driver");
 190 MODULE_LICENSE("GPL");