/* SPDX-License-Identifier: GPL-2.0-only */
/*******************************************************************************
  Header File to describe Normal/enhanced descriptor functions used for RING
  and CHAINED modes.

  Copyright(C) 2011  STMicroelectronics Ltd

  It defines all the functions used to handle the normal/enhanced
  descriptors in case of the DMA is configured to work in chained or
  in ring mode.


  Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
*******************************************************************************/

#ifndef __DESC_COM_H__
#define __DESC_COM_H__

/* Specific functions used for Ring mode */

/* Enhanced descriptors */
static inline void ehn_desc_rx_set_on_ring(struct dma_desc *p, int end,
					   int bfsize)
{
	if (bfsize == BUF_SIZE_16KiB)
		p->des1 |= cpu_to_le32(FIELD_PREP(ERDES1_BUFFER2_SIZE_MASK,
						  BUF_SIZE_8KiB));

	if (end)
		p->des1 |= cpu_to_le32(ERDES1_END_RING);
}

static inline void enh_desc_end_tx_desc_on_ring(struct dma_desc *p, int end)
{
	if (end)
		p->des0 |= cpu_to_le32(ETDES0_END_RING);
	else
		p->des0 &= cpu_to_le32(~ETDES0_END_RING);
}

/* The maximum buffer 1 size is 8KiB - 1. However, we limit to 4KiB. */
static inline void enh_set_tx_desc_len_on_ring(struct dma_desc *p, int len)
{
	unsigned int buffer1_max_length = BUF_SIZE_4KiB;

	if (unlikely(len > buffer1_max_length)) {
		p->des1 |= cpu_to_le32(FIELD_PREP(ETDES1_BUFFER2_SIZE_MASK,
						  len - buffer1_max_length) |
				       FIELD_PREP(ETDES1_BUFFER1_SIZE_MASK,
						  buffer1_max_length));
	} else {
		p->des1 |= cpu_to_le32(FIELD_PREP(ETDES1_BUFFER1_SIZE_MASK,
						  len));
	}
}

/* Normal descriptors */
static inline void ndesc_rx_set_on_ring(struct dma_desc *p, int end, int bfsize)
{
	if (bfsize >= BUF_SIZE_2KiB) {
		int bfsize2;

		bfsize2 = min(bfsize - BUF_SIZE_2KiB + 1, BUF_SIZE_2KiB - 1);
		p->des1 |= cpu_to_le32(FIELD_PREP(RDES1_BUFFER2_SIZE_MASK,
						  bfsize2));
	}

	if (end)
		p->des1 |= cpu_to_le32(RDES1_END_RING);
}

static inline void ndesc_end_tx_desc_on_ring(struct dma_desc *p, int end)
{
	if (end)
		p->des1 |= cpu_to_le32(TDES1_END_RING);
	else
		p->des1 &= cpu_to_le32(~TDES1_END_RING);
}

/* The maximum buffer 1 size is 2KiB - 1, limited by the mask width */
static inline void norm_set_tx_desc_len_on_ring(struct dma_desc *p, int len)
{
	unsigned int buffer1_max_length = BUF_SIZE_2KiB - 1;

	if (unlikely(len > buffer1_max_length)) {
		p->des1 |= cpu_to_le32(FIELD_PREP(TDES1_BUFFER2_SIZE_MASK,
						  len - buffer1_max_length) |
				       FIELD_PREP(TDES1_BUFFER1_SIZE_MASK,
						  buffer1_max_length));
	} else {
		p->des1 |= cpu_to_le32(FIELD_PREP(TDES1_BUFFER1_SIZE_MASK,
						  len));
	}
}

/* Specific functions used for Chain mode */

/* Enhanced descriptors */
static inline void ehn_desc_rx_set_on_chain(struct dma_desc *p)
{
	p->des1 |= cpu_to_le32(ERDES1_SECOND_ADDRESS_CHAINED);
}

static inline void enh_desc_end_tx_desc_on_chain(struct dma_desc *p)
{
	p->des0 |= cpu_to_le32(ETDES0_SECOND_ADDRESS_CHAINED);
}

static inline void enh_set_tx_desc_len_on_chain(struct dma_desc *p, int len)
{
	p->des1 |= cpu_to_le32(len & ETDES1_BUFFER1_SIZE_MASK);
}

/* Normal descriptors */
static inline void ndesc_rx_set_on_chain(struct dma_desc *p, int end)
{
	p->des1 |= cpu_to_le32(RDES1_SECOND_ADDRESS_CHAINED);
}

static inline void ndesc_tx_set_on_chain(struct dma_desc *p)
{
	p->des1 |= cpu_to_le32(TDES1_SECOND_ADDRESS_CHAINED);
}

static inline void norm_set_tx_desc_len_on_chain(struct dma_desc *p, int len)
{
	p->des1 |= cpu_to_le32(len & TDES1_BUFFER1_SIZE_MASK);
}
#endif /* __DESC_COM_H__ */