drivers/soc/amlogic/meson-canvas.c

Source file repositories/reference/linux-study-clean/drivers/soc/amlogic/meson-canvas.c

File Facts

System
Linux kernel
Corpus path
drivers/soc/amlogic/meson-canvas.c
Extension
.c
Size
5459 bytes
Lines
209
Domain
Driver Families
Bucket
drivers/soc
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct meson_canvas {
	struct device *dev;
	void __iomem *reg_base;
	spinlock_t lock; /* canvas device lock */
	u8 used[NUM_CANVAS];
	bool supports_endianness;
};

static void canvas_write(struct meson_canvas *canvas, u32 reg, u32 val)
{
	writel_relaxed(val, canvas->reg_base + reg);
}

static u32 canvas_read(struct meson_canvas *canvas, u32 reg)
{
	return readl_relaxed(canvas->reg_base + reg);
}

struct meson_canvas *meson_canvas_get(struct device *dev)
{
	struct device_node *canvas_node;
	struct platform_device *canvas_pdev;
	struct meson_canvas *canvas;

	canvas_node = of_parse_phandle(dev->of_node, "amlogic,canvas", 0);
	if (!canvas_node)
		return ERR_PTR(-ENODEV);

	canvas_pdev = of_find_device_by_node(canvas_node);
	of_node_put(canvas_node);
	if (!canvas_pdev)
		return ERR_PTR(-EPROBE_DEFER);

	/*
	 * If priv is NULL, it's probably because the canvas hasn't
	 * properly initialized. Bail out with -EINVAL because, in the
	 * current state, this driver probe cannot return -EPROBE_DEFER
	 */
	canvas = dev_get_drvdata(&canvas_pdev->dev);
	put_device(&canvas_pdev->dev);
	if (!canvas)
		return ERR_PTR(-EINVAL);

	return canvas;
}
EXPORT_SYMBOL_GPL(meson_canvas_get);

int meson_canvas_config(struct meson_canvas *canvas, u8 canvas_index,
			u32 addr, u32 stride, u32 height,
			unsigned int wrap,
			unsigned int blkmode,
			unsigned int endian)
{
	unsigned long flags;

	if (endian && !canvas->supports_endianness) {
		dev_err(canvas->dev,
			"Endianness is not supported on this SoC\n");
		return -EINVAL;
	}

	spin_lock_irqsave(&canvas->lock, flags);
	if (!canvas->used[canvas_index]) {
		dev_err(canvas->dev,
			"Trying to setup non allocated canvas %u\n",
			canvas_index);
		spin_unlock_irqrestore(&canvas->lock, flags);
		return -EINVAL;
	}

	canvas_write(canvas, DMC_CAV_LUT_DATAL,
		     ((addr + 7) >> 3) |
		     (((stride + 7) >> 3) << CANVAS_WIDTH_LBIT));

	canvas_write(canvas, DMC_CAV_LUT_DATAH,
		     ((((stride + 7) >> 3) >> CANVAS_WIDTH_LWID) <<
						CANVAS_WIDTH_HBIT) |
		     (height << CANVAS_HEIGHT_BIT) |
		     (wrap << CANVAS_WRAP_BIT) |
		     (blkmode << CANVAS_BLKMODE_BIT) |
		     (endian << CANVAS_ENDIAN_BIT));

	canvas_write(canvas, DMC_CAV_LUT_ADDR,
		     CANVAS_LUT_WR_EN | canvas_index);

	/* Force a read-back to make sure everything is flushed. */
	canvas_read(canvas, DMC_CAV_LUT_DATAH);
	spin_unlock_irqrestore(&canvas->lock, flags);

	return 0;

Annotation

Implementation Notes