drivers/reset/reset-brcmstb.c

Source file repositories/reference/linux-study-clean/drivers/reset/reset-brcmstb.c

File Facts

System
Linux kernel
Corpus path
drivers/reset/reset-brcmstb.c
Extension
.c
Size
3378 bytes
Lines
127
Domain
Driver Families
Bucket
drivers/reset
Inferred role
Driver Families: implementation source
Status
source 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 brcmstb_reset {
	void __iomem *base;
	struct reset_controller_dev rcdev;
};

#define SW_INIT_SET		0x00
#define SW_INIT_CLEAR		0x04
#define SW_INIT_STATUS		0x08

#define SW_INIT_BIT(id)		BIT((id) & 0x1f)
#define SW_INIT_BANK(id)	((id) >> 5)

/* A full bank contains extra registers that we are not utilizing but still
 * qualify as a single bank.
 */
#define SW_INIT_BANK_SIZE	0x18

static inline
struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev)
{
	return container_of(rcdev, struct brcmstb_reset, rcdev);
}

static int brcmstb_reset_assert(struct reset_controller_dev *rcdev,
				unsigned long id)
{
	unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
	struct brcmstb_reset *priv = to_brcmstb(rcdev);

	writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET);

	return 0;
}

static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev,
				  unsigned long id)
{
	unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
	struct brcmstb_reset *priv = to_brcmstb(rcdev);

	writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR);
	/* Maximum reset delay after de-asserting a line and seeing block
	 * operation is typically 14us for the worst case, build some slack
	 * here.
	 */
	usleep_range(100, 200);

	return 0;
}

static int brcmstb_reset_status(struct reset_controller_dev *rcdev,
				unsigned long id)
{
	unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
	struct brcmstb_reset *priv = to_brcmstb(rcdev);

	return readl_relaxed(priv->base + off + SW_INIT_STATUS) &
			     SW_INIT_BIT(id);
}

static const struct reset_control_ops brcmstb_reset_ops = {
	.assert	= brcmstb_reset_assert,
	.deassert = brcmstb_reset_deassert,
	.status = brcmstb_reset_status,
};

static int brcmstb_reset_probe(struct platform_device *pdev)
{
	struct device *kdev = &pdev->dev;
	struct brcmstb_reset *priv;
	struct resource *res;

	priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
	if (IS_ERR(priv->base))
		return PTR_ERR(priv->base);

	dev_set_drvdata(kdev, priv);

	priv->rcdev.owner = THIS_MODULE;
	priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res),
						   SW_INIT_BANK_SIZE) * 32;
	priv->rcdev.ops = &brcmstb_reset_ops;
	priv->rcdev.of_node = kdev->of_node;
	/* Use defaults: 1 cell and simple xlate function */

	return devm_reset_controller_register(kdev, &priv->rcdev);

Annotation

Implementation Notes