net/nfc/digital_core.c

File Facts

System

Linux kernel

Corpus path

net/nfc/digital_core.c

Extension

.c

Size

20585 bytes

Lines

867

Domain

Networking Core

Bucket

Sockets, Protocols, Packet Path, And Network Policy

Inferred role

Networking Core: exported/initcall integration point

Status

integration implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

• Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.
• Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/module.h
• digital.h

Detected Declarations

• struct digital_cmd
• function digital_skb_add_crc
• function digital_skb_check_crc
• function digital_switch_rf
• function digital_abort_cmd
• function digital_wq_cmd_complete
• function digital_send_cmd_complete
• function digital_wq_cmd
• function digital_send_cmd
• function digital_in_configure_hw
• function digital_tg_configure_hw
• function digital_tg_listen_mdaa
• function digital_tg_listen_md
• function digital_target_found
• function digital_poll_next_tech
• function digital_wq_poll
• function digital_add_poll_tech
• function technologies
• function digital_stop_poll
• function digital_dev_up
• function digital_dev_down
• function digital_dep_link_up
• function digital_dep_link_down
• function digital_activate_target
• function digital_deactivate_target
• function digital_tg_send
• function digital_in_send_complete
• function digital_in_send
• function nfc_digital_free_device
• function nfc_digital_register_device
• function nfc_digital_unregister_device
• function list_for_each_entry_safe
• export nfc_digital_allocate_device
• export nfc_digital_free_device
• export nfc_digital_register_device
• export nfc_digital_unregister_device

Annotated Snippet

struct digital_cmd {
	struct list_head queue;

	u8 type;
	u8 pending;

	u16 timeout;
	struct sk_buff *req;
	struct sk_buff *resp;
	struct digital_tg_mdaa_params *mdaa_params;

	nfc_digital_cmd_complete_t cmd_cb;
	void *cb_context;
};

struct sk_buff *digital_skb_alloc(struct nfc_digital_dev *ddev,
				  unsigned int len)
{
	struct sk_buff *skb;

	skb = alloc_skb(len + ddev->tx_headroom + ddev->tx_tailroom,
			GFP_KERNEL);
	if (skb)
		skb_reserve(skb, ddev->tx_headroom);

	return skb;
}

void digital_skb_add_crc(struct sk_buff *skb, crc_func_t crc_func, u16 init,
			 u8 bitwise_inv, u8 msb_first)
{
	u16 crc;

	crc = crc_func(init, skb->data, skb->len);

	if (bitwise_inv)
		crc = ~crc;

	if (msb_first)
		crc = __fswab16(crc);

	skb_put_u8(skb, crc & 0xFF);
	skb_put_u8(skb, (crc >> 8) & 0xFF);
}

int digital_skb_check_crc(struct sk_buff *skb, crc_func_t crc_func,
			  u16 crc_init, u8 bitwise_inv, u8 msb_first)
{
	int rc;
	u16 crc;

	if (skb->len <= 2)
		return -EIO;

	crc = crc_func(crc_init, skb->data, skb->len - 2);

	if (bitwise_inv)
		crc = ~crc;

	if (msb_first)
		crc = __swab16(crc);

	rc = (skb->data[skb->len - 2] - (crc & 0xFF)) +
	     (skb->data[skb->len - 1] - ((crc >> 8) & 0xFF));

	if (rc)
		return -EIO;

	skb_trim(skb, skb->len - 2);

	return 0;
}

static inline void digital_switch_rf(struct nfc_digital_dev *ddev, bool on)
{
	ddev->ops->switch_rf(ddev, on);
}

static inline void digital_abort_cmd(struct nfc_digital_dev *ddev)
{
	ddev->ops->abort_cmd(ddev);
}

static void digital_wq_cmd_complete(struct work_struct *work)
{
	struct digital_cmd *cmd;
	struct nfc_digital_dev *ddev = container_of(work,
						    struct nfc_digital_dev,
						    cmd_complete_work);

Annotation

• Immediate include surface: `linux/module.h`, `digital.h`.
• Detected declarations: `struct digital_cmd`, `function digital_skb_add_crc`, `function digital_skb_check_crc`, `function digital_switch_rf`, `function digital_abort_cmd`, `function digital_wq_cmd_complete`, `function digital_send_cmd_complete`, `function digital_wq_cmd`, `function digital_send_cmd`, `function digital_in_configure_hw`.
• Atlas domain: Networking Core / Sockets, Protocols, Packet Path, And Network Policy.
• Implementation status: integration implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.