drivers/mailbox/arm_mhu.c

Source file repositories/reference/linux-study-clean/drivers/mailbox/arm_mhu.c

File Facts

System
Linux kernel
Corpus path
drivers/mailbox/arm_mhu.c
Extension
.c
Size
3877 bytes
Lines
177
Domain
Driver Families
Bucket
drivers/mailbox
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 mhu_link {
	unsigned irq;
	void __iomem *tx_reg;
	void __iomem *rx_reg;
};

struct arm_mhu {
	void __iomem *base;
	struct mhu_link mlink[MHU_CHANS];
	struct mbox_chan chan[MHU_CHANS];
	struct mbox_controller mbox;
};

static irqreturn_t mhu_rx_interrupt(int irq, void *p)
{
	struct mbox_chan *chan = p;
	struct mhu_link *mlink = chan->con_priv;
	u32 val;

	val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);
	if (!val)
		return IRQ_NONE;

	mbox_chan_received_data(chan, (void *)&val);

	writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);

	return IRQ_HANDLED;
}

static bool mhu_last_tx_done(struct mbox_chan *chan)
{
	struct mhu_link *mlink = chan->con_priv;
	u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);

	return (val == 0);
}

static int mhu_send_data(struct mbox_chan *chan, void *data)
{
	struct mhu_link *mlink = chan->con_priv;
	u32 *arg = data;

	writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);

	return 0;
}

static int mhu_startup(struct mbox_chan *chan)
{
	struct mhu_link *mlink = chan->con_priv;
	u32 val;
	int ret;

	val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
	writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);

	ret = request_irq(mlink->irq, mhu_rx_interrupt,
			  IRQF_SHARED, "mhu_link", chan);
	if (ret) {
		dev_err(chan->mbox->dev,
			"Unable to acquire IRQ %d\n", mlink->irq);
		return ret;
	}

	return 0;
}

static void mhu_shutdown(struct mbox_chan *chan)
{
	struct mhu_link *mlink = chan->con_priv;

	free_irq(mlink->irq, chan);
}

static const struct mbox_chan_ops mhu_ops = {
	.send_data = mhu_send_data,
	.startup = mhu_startup,
	.shutdown = mhu_shutdown,
	.last_tx_done = mhu_last_tx_done,
};

static int mhu_probe(struct amba_device *adev, const struct amba_id *id)
{
	int i, err;
	struct arm_mhu *mhu;
	struct device *dev = &adev->dev;
	int mhu_reg[MHU_CHANS] = {MHU_LP_OFFSET, MHU_HP_OFFSET, MHU_SEC_OFFSET};

	if (!of_device_is_compatible(dev->of_node, "arm,mhu"))

Annotation

Implementation Notes