drivers/mtd/hyperbus/hbmc-am654.c

Source file repositories/reference/linux-study-clean/drivers/mtd/hyperbus/hbmc-am654.c

File Facts

System
Linux kernel
Corpus path
drivers/mtd/hyperbus/hbmc-am654.c
Extension
.c
Size
6747 bytes
Lines
276
Domain
Driver Families
Bucket
drivers/mtd
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 am654_hbmc_device_priv {
	struct completion rx_dma_complete;
	phys_addr_t device_base;
	struct hyperbus_ctlr *ctlr;
	struct dma_chan *rx_chan;
};

struct am654_hbmc_priv {
	struct hyperbus_ctlr ctlr;
	struct hyperbus_device hbdev;
	struct mux_control *mux_ctrl;
};

static int am654_hbmc_calibrate(struct hyperbus_device *hbdev)
{
	struct map_info *map = &hbdev->map;
	struct cfi_private cfi;
	int count = AM654_HBMC_CALIB_COUNT;
	int pass_count = 0;
	int ret;

	cfi.interleave = 1;
	cfi.device_type = CFI_DEVICETYPE_X16;
	cfi_send_gen_cmd(0xF0, 0, 0, map, &cfi, cfi.device_type, NULL);
	cfi_send_gen_cmd(0x98, 0x55, 0, map, &cfi, cfi.device_type, NULL);

	while (count--) {
		ret = cfi_qry_present(map, 0, &cfi);
		if (ret)
			pass_count++;
		else
			pass_count = 0;
		if (pass_count == 5)
			break;
	}

	cfi_qry_mode_off(0, map, &cfi);

	return ret;
}

static void am654_hbmc_dma_callback(void *param)
{
	struct am654_hbmc_device_priv *priv = param;

	complete(&priv->rx_dma_complete);
}

static int am654_hbmc_dma_read(struct am654_hbmc_device_priv *priv, void *to,
			       unsigned long from, ssize_t len)

{
	enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
	struct dma_chan *rx_chan = priv->rx_chan;
	struct dma_async_tx_descriptor *tx;
	dma_addr_t dma_dst, dma_src;
	dma_cookie_t cookie;
	int ret;

	if (!priv->rx_chan || !virt_addr_valid(to) || object_is_on_stack(to))
		return -EINVAL;

	dma_dst = dma_map_single(rx_chan->device->dev, to, len, DMA_FROM_DEVICE);
	if (dma_mapping_error(rx_chan->device->dev, dma_dst)) {
		dev_dbg(priv->ctlr->dev, "DMA mapping failed\n");
		return -EIO;
	}

	dma_src = priv->device_base + from;
	tx = dmaengine_prep_dma_memcpy(rx_chan, dma_dst, dma_src, len, flags);
	if (!tx) {
		dev_err(priv->ctlr->dev, "device_prep_dma_memcpy error\n");
		ret = -EIO;
		goto unmap_dma;
	}

	reinit_completion(&priv->rx_dma_complete);
	tx->callback = am654_hbmc_dma_callback;
	tx->callback_param = priv;
	cookie = dmaengine_submit(tx);

	ret = dma_submit_error(cookie);
	if (ret) {
		dev_err(priv->ctlr->dev, "dma_submit_error %d\n", cookie);
		goto unmap_dma;
	}

	dma_async_issue_pending(rx_chan);
	if (!wait_for_completion_timeout(&priv->rx_dma_complete,  msecs_to_jiffies(len + 1000))) {
		dmaengine_terminate_sync(rx_chan);

Annotation

Implementation Notes