pio_copy.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * Copyright(c) 2015, 2016 Intel Corporation.
 */

#include "hfi.h"

/* additive distance between non-SOP and SOP space */
#define SOP_DISTANCE …
#define PIO_BLOCK_MASK …
/* number of QUADWORDs in a block */
#define PIO_BLOCK_QWS …

/**
 * pio_copy - copy data block to MMIO space
 * @dd: hfi1 dev data
 * @pbuf: a number of blocks allocated within a PIO send context
 * @pbc: PBC to send
 * @from: source, must be 8 byte aligned
 * @count: number of DWORD (32-bit) quantities to copy from source
 *
 * Copy data from source to PIO Send Buffer memory, 8 bytes at a time.
 * Must always write full BLOCK_SIZE bytes blocks.  The first block must
 * be written to the corresponding SOP=1 address.
 *
 * Known:
 * o pbuf->start always starts on a block boundary
 * o pbuf can wrap only at a block boundary
 */
void pio_copy(struct hfi1_devdata *dd, struct pio_buf *pbuf, u64 pbc,
	      const void *from, size_t count)
{ … }

/*
 * Handle carry bytes using shifts and masks.
 *
 * NOTE: the value the unused portion of carry is expected to always be zero.
 */

/*
 * "zero" shift - bit shift used to zero out upper bytes.  Input is
 * the count of LSB bytes to preserve.
 */
#define zshift(x) …

/*
 * "merge" shift - bit shift used to merge with carry bytes.  Input is
 * the LSB byte count to move beyond.
 */
#define mshift(x) …

/*
 * Jump copy - no-loop copy for < 8 bytes.
 */
static inline void jcopy(u8 *dest, const u8 *src, u32 n)
{ … }

/*
 * Read nbytes from "from" and place them in the low bytes
 * of pbuf->carry.  Other bytes are left as-is.  Any previous
 * value in pbuf->carry is lost.
 *
 * NOTES:
 * o do not read from from if nbytes is zero
 * o from may _not_ be u64 aligned.
 */
static inline void read_low_bytes(struct pio_buf *pbuf, const void *from,
				  unsigned int nbytes)
{ … }

/*
 * Read nbytes bytes from "from" and put them at the end of pbuf->carry.
 * It is expected that the extra read does not overfill carry.
 *
 * NOTES:
 * o from may _not_ be u64 aligned
 * o nbytes may span a QW boundary
 */
static inline void read_extra_bytes(struct pio_buf *pbuf,
				    const void *from, unsigned int nbytes)
{ … }

/*
 * Write a quad word using parts of pbuf->carry and the next 8 bytes of src.
 * Put the unused part of the next 8 bytes of src into the LSB bytes of
 * pbuf->carry with the upper bytes zeroed..
 *
 * NOTES:
 * o result must keep unused bytes zeroed
 * o src must be u64 aligned
 */
static inline void merge_write8(
	struct pio_buf *pbuf,
	void __iomem *dest,
	const void *src)
{ … }

/*
 * Write a quad word using all bytes of carry.
 */
static inline void carry8_write8(union mix carry, void __iomem *dest)
{ … }

/*
 * Write a quad word using all the valid bytes of carry.  If carry
 * has zero valid bytes, nothing is written.
 * Returns 0 on nothing written, non-zero on quad word written.
 */
static inline int carry_write8(struct pio_buf *pbuf, void __iomem *dest)
{ … }

/*
 * Segmented PIO Copy - start
 *
 * Start a PIO copy.
 *
 * @pbuf: destination buffer
 * @pbc: the PBC for the PIO buffer
 * @from: data source, QWORD aligned
 * @nbytes: bytes to copy
 */
void seg_pio_copy_start(struct pio_buf *pbuf, u64 pbc,
			const void *from, size_t nbytes)
{ … }

/*
 * Mid copy helper, "mixed case" - source is 64-bit aligned but carry
 * bytes are non-zero.
 *
 * Whole u64s must be written to the chip, so bytes must be manually merged.
 *
 * @pbuf: destination buffer
 * @from: data source, is QWORD aligned.
 * @nbytes: bytes to copy
 *
 * Must handle nbytes < 8.
 */
static void mid_copy_mix(struct pio_buf *pbuf, const void *from, size_t nbytes)
{ … }

/*
 * Mid copy helper, "straight case" - source pointer is 64-bit aligned
 * with no carry bytes.
 *
 * @pbuf: destination buffer
 * @from: data source, is QWORD aligned
 * @nbytes: bytes to copy
 *
 * Must handle nbytes < 8.
 */
static void mid_copy_straight(struct pio_buf *pbuf,
			      const void *from, size_t nbytes)
{ … }

/*
 * Segmented PIO Copy - middle
 *
 * Must handle any aligned tail and any aligned source with any byte count.
 *
 * @pbuf: a number of blocks allocated within a PIO send context
 * @from: data source
 * @nbytes: number of bytes to copy
 */
void seg_pio_copy_mid(struct pio_buf *pbuf, const void *from, size_t nbytes)
{ … }

/*
 * Segmented PIO Copy - end
 *
 * Write any remainder (in pbuf->carry) and finish writing the whole block.
 *
 * @pbuf: a number of blocks allocated within a PIO send context
 */
void seg_pio_copy_end(struct pio_buf *pbuf)
{ … }
linux/drivers/infiniband/hw/hfi1/pio_copy.c
