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         struct device_dma_parameters dma_parms;
  26 };
  27
  28 static LIST_HEAD(fcp_devices);
  29 static DEFINE_MUTEX(fcp_lock);
  30
  31 /* -----------------------------------------------------------------------------
  32  * Public API
  33  */
  34
  35 /**
  36  * rcar_fcp_get - Find and acquire a reference to an FCP instance
  37  * @np: Device node of the FCP instance
  38  *
  39  * Search the list of registered FCP instances for the instance corresponding to
  40  * the given device node.
  41  *
  42  * Return a pointer to the FCP instance, or an ERR_PTR if the instance can't be
  43  * found.
  44  */
  45 struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np)
  46 {
  47         struct rcar_fcp_device *fcp;
  48
  49         mutex_lock(&fcp_lock);
  50
  51         list_for_each_entry(fcp, &fcp_devices, list) {
  52                 if (fcp->dev->of_node != np)
  53                         continue;
  54
  55                 get_device(fcp->dev);
  56                 goto done;
  57         }
  58
  59         fcp = ERR_PTR(-EPROBE_DEFER);
  60
  61 done:
  62         mutex_unlock(&fcp_lock);
  63         return fcp;
  64 }
  65 EXPORT_SYMBOL_GPL(rcar_fcp_get);
  66
  67 /**
  68  * rcar_fcp_put - Release a reference to an FCP instance
  69  * @fcp: The FCP instance
  70  *
  71  * Release the FCP instance acquired by a call to rcar_fcp_get().
  72  */
  73 void rcar_fcp_put(struct rcar_fcp_device *fcp)
  74 {
  75         if (fcp)
  76                 put_device(fcp->dev);
  77 }
  78 EXPORT_SYMBOL_GPL(rcar_fcp_put);
  79
  80 struct device *rcar_fcp_get_device(struct rcar_fcp_device *fcp)
  81 {
  82         return fcp->dev;
  83 }
  84 EXPORT_SYMBOL_GPL(rcar_fcp_get_device);
  85
  86 /**
  87  * rcar_fcp_enable - Enable an FCP
  88  * @fcp: The FCP instance
  89  *
  90  * Before any memory access through an FCP is performed by a module, the FCP
  91  * must be enabled by a call to this function. The enable calls are reference
  92  * counted, each successful call must be followed by one rcar_fcp_disable()
  93  * call when no more memory transfer can occur through the FCP.
  94  *
  95  * Return 0 on success or a negative error code if an error occurs. The enable
  96  * reference count isn't increased when this function returns an error.
  97  */
  98 int rcar_fcp_enable(struct rcar_fcp_device *fcp)
  99 {
 100         int ret;
 101
 102         if (!fcp)
 103                 return 0;
 104
 105         ret = pm_runtime_get_sync(fcp->dev);
 106         if (ret < 0)
 107                 return ret;
 108
 109         return 0;
 110 }
 111 EXPORT_SYMBOL_GPL(rcar_fcp_enable);
 112
 113 /**
 114  * rcar_fcp_disable - Disable an FCP
 115  * @fcp: The FCP instance
 116  *
 117  * This function is the counterpart of rcar_fcp_enable(). As enable calls are
 118  * reference counted a disable call may not disable the FCP synchronously.
 119  */
 120 void rcar_fcp_disable(struct rcar_fcp_device *fcp)
 121 {
 122         if (fcp)
 123                 pm_runtime_put(fcp->dev);
 124 }
 125 EXPORT_SYMBOL_GPL(rcar_fcp_disable);
 126
 127 /* -----------------------------------------------------------------------------
 128  * Platform Driver
 129  */
 130
 131 static int rcar_fcp_probe(struct platform_device *pdev)
 132 {
 133         struct rcar_fcp_device *fcp;
 134
 135         fcp = devm_kzalloc(&pdev->dev, sizeof(*fcp), GFP_KERNEL);
 136         if (fcp == NULL)
 137                 return -ENOMEM;
 138
 139         fcp->dev = &pdev->dev;
 140
 141         fcp->dev->dma_parms = &fcp->dma_parms;
 142         dma_set_max_seg_size(fcp->dev, DMA_BIT_MASK(32));
 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");