drivers/char/ipmi/bt-bmc.c

Source file repositories/reference/linux-study-clean/drivers/char/ipmi/bt-bmc.c

File Facts

System
Linux kernel
Corpus path
drivers/char/ipmi/bt-bmc.c
Extension
.c
Size
10742 bytes
Lines
493
Domain
Driver Families
Bucket
drivers/char
Inferred role
Driver Families: operation-table or driver-model contract
Status
pattern 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

static const struct file_operations bt_bmc_fops = {
	.owner		= THIS_MODULE,
	.open		= bt_bmc_open,
	.read		= bt_bmc_read,
	.write		= bt_bmc_write,
	.release	= bt_bmc_release,
	.poll		= bt_bmc_poll,
	.unlocked_ioctl	= bt_bmc_ioctl,
};

static void poll_timer(struct timer_list *t)
{
	struct bt_bmc *bt_bmc = timer_container_of(bt_bmc, t, poll_timer);

	bt_bmc->poll_timer.expires += msecs_to_jiffies(500);
	wake_up(&bt_bmc->queue);
	add_timer(&bt_bmc->poll_timer);
}

static irqreturn_t bt_bmc_irq(int irq, void *arg)
{
	struct bt_bmc *bt_bmc = arg;
	u32 reg;

	reg = readl(bt_bmc->base + BT_CR2);

	reg &= BT_CR2_IRQ_H2B | BT_CR2_IRQ_HBUSY;
	if (!reg)
		return IRQ_NONE;

	/* ack pending IRQs */
	writel(reg, bt_bmc->base + BT_CR2);

	wake_up(&bt_bmc->queue);
	return IRQ_HANDLED;
}

static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
			     struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	int rc;
	u32 reg;

	bt_bmc->irq = platform_get_irq_optional(pdev, 0);
	if (bt_bmc->irq < 0)
		return bt_bmc->irq;

	rc = devm_request_irq(dev, bt_bmc->irq, bt_bmc_irq, IRQF_SHARED,
			      DEVICE_NAME, bt_bmc);
	if (rc < 0) {
		dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq);
		bt_bmc->irq = rc;
		return rc;
	}

	/*
	 * Configure IRQs on the bmc clearing the H2B and HBUSY bits;
	 * H2B will be asserted when the bmc has data for us; HBUSY
	 * will be cleared (along with B2H) when we can write the next
	 * message to the BT buffer
	 */
	reg = readl(bt_bmc->base + BT_CR1);
	reg |= BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY;
	writel(reg, bt_bmc->base + BT_CR1);

	return 0;
}

static int bt_bmc_probe(struct platform_device *pdev)
{
	struct bt_bmc *bt_bmc;
	struct device *dev;
	int rc;

	dev = &pdev->dev;
	dev_info(dev, "Found bt bmc device\n");

	bt_bmc = devm_kzalloc(dev, sizeof(*bt_bmc), GFP_KERNEL);
	if (!bt_bmc)
		return -ENOMEM;

	dev_set_drvdata(&pdev->dev, bt_bmc);

	bt_bmc->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(bt_bmc->base))
		return PTR_ERR(bt_bmc->base);

	mutex_init(&bt_bmc->mutex);
	init_waitqueue_head(&bt_bmc->queue);

Annotation

Implementation Notes