drivers/net/wireless/ath/ath5k/dma.c

Source file repositories/reference/linux-study-clean/drivers/net/wireless/ath/ath5k/dma.c

File Facts

System
Linux kernel
Corpus path
drivers/net/wireless/ath/ath5k/dma.c
Extension
.c
Size
24270 bytes
Lines
914
Domain
Driver Families
Bucket
drivers/net
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

switch (ah->ah_txq[queue].tqi_type) {
		case AR5K_TX_QUEUE_DATA:
			tx_queue |= AR5K_CR_TXE0 & ~AR5K_CR_TXD0;
			break;
		case AR5K_TX_QUEUE_BEACON:
			tx_queue |= AR5K_CR_TXE1 & ~AR5K_CR_TXD1;
			ath5k_hw_reg_write(ah, AR5K_BCR_TQ1V | AR5K_BCR_BDMAE,
					AR5K_BSR);
			break;
		case AR5K_TX_QUEUE_CAB:
			tx_queue |= AR5K_CR_TXE1 & ~AR5K_CR_TXD1;
			ath5k_hw_reg_write(ah, AR5K_BCR_TQ1FV | AR5K_BCR_TQ1V |
				AR5K_BCR_BDMAE, AR5K_BSR);
			break;
		default:
			return -EINVAL;
		}
		/* Start queue */
		ath5k_hw_reg_write(ah, tx_queue, AR5K_CR);
		ath5k_hw_reg_read(ah, AR5K_CR);
	} else {
		/* Return if queue is disabled */
		if (AR5K_REG_READ_Q(ah, AR5K_QCU_TXD, queue))
			return -EIO;

		/* Start queue */
		AR5K_REG_WRITE_Q(ah, AR5K_QCU_TXE, queue);
	}

	return 0;
}

/**
 * ath5k_hw_stop_tx_dma() - Stop DMA transmit on a specific queue
 * @ah: The &struct ath5k_hw
 * @queue: The hw queue number
 *
 * Stop DMA transmit on a specific hw queue and drain queue so we don't
 * have any pending frames. Returns -EBUSY if we still have pending frames,
 * -EINVAL if queue number is out of range or inactive.
 */
static int
ath5k_hw_stop_tx_dma(struct ath5k_hw *ah, unsigned int queue)
{
	unsigned int i = 40;
	u32 tx_queue, pending;

	AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);

	/* Return if queue is declared inactive */
	if (ah->ah_txq[queue].tqi_type == AR5K_TX_QUEUE_INACTIVE)
		return -EINVAL;

	if (ah->ah_version == AR5K_AR5210) {
		tx_queue = ath5k_hw_reg_read(ah, AR5K_CR);

		/*
		 * Set by queue type
		 */
		switch (ah->ah_txq[queue].tqi_type) {
		case AR5K_TX_QUEUE_DATA:
			tx_queue |= AR5K_CR_TXD0 & ~AR5K_CR_TXE0;
			break;
		case AR5K_TX_QUEUE_BEACON:
		case AR5K_TX_QUEUE_CAB:
			/* XXX Fix me... */
			tx_queue |= AR5K_CR_TXD1 & ~AR5K_CR_TXD1;
			ath5k_hw_reg_write(ah, 0, AR5K_BSR);
			break;
		default:
			return -EINVAL;
		}

		/* Stop queue */
		ath5k_hw_reg_write(ah, tx_queue, AR5K_CR);
		ath5k_hw_reg_read(ah, AR5K_CR);
	} else {

		/*
		 * Enable DCU early termination to quickly
		 * flush any pending frames from QCU
		 */
		AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
					AR5K_QCU_MISC_DCU_EARLY);

		/*
		 * Schedule TX disable and wait until queue is empty
		 */
		AR5K_REG_WRITE_Q(ah, AR5K_QCU_TXD, queue);

Annotation

Implementation Notes