drivers/staging/media/atomisp/pci/hive_isp_css_common/host/vmem.c

Source file repositories/reference/linux-study-clean/drivers/staging/media/atomisp/pci/hive_isp_css_common/host/vmem.c

File Facts

System
Linux kernel
Corpus path
drivers/staging/media/atomisp/pci/hive_isp_css_common/host/vmem.c
Extension
.c
Size
8121 bytes
Lines
276
Domain
Driver Families
Bucket
drivers/staging
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

// SPDX-License-Identifier: GPL-2.0
/*
 * Support for Intel Camera Imaging ISP subsystem.
 * Copyright (c) 2010 - 2016, Intel Corporation.
 */

#include "isp.h"
#include "vmem.h"
#include "vmem_local.h"

#if !defined(HRT_MEMORY_ACCESS)
#include "ia_css_device_access.h"
#endif
#include "assert_support.h"

typedef unsigned long long hive_uedge;
typedef hive_uedge *hive_wide;

/* Copied from SDK: sim_semantics.c */

/* subword bits move like this:         MSB[____xxxx____]LSB -> MSB[00000000xxxx]LSB */
static inline hive_uedge
subword(hive_uedge w, unsigned int start, unsigned int end)
{
	return (w & (((1ULL << (end - 1)) - 1) << 1 | 1)) >> start;
}

/* inverse subword bits move like this: MSB[xxxx____xxxx]LSB -> MSB[xxxx0000xxxx]LSB */
static inline hive_uedge
inv_subword(hive_uedge w, unsigned int start, unsigned int end)
{
	return w & (~(((1ULL << (end - 1)) - 1) << 1 | 1) | ((1ULL << start) - 1));
}

#define uedge_bits (8 * sizeof(hive_uedge))
#define move_lower_bits(target, target_bit, src, src_bit) move_subword(target, target_bit, src, 0, src_bit)
#define move_upper_bits(target, target_bit, src, src_bit) move_subword(target, target_bit, src, src_bit, uedge_bits)
#define move_word(target, target_bit, src) move_subword(target, target_bit, src, 0, uedge_bits)

static void
move_subword(
    hive_uedge *target,
    unsigned int target_bit,
    hive_uedge src,
    unsigned int src_start,
    unsigned int src_end)
{
	unsigned int start_elem = target_bit / uedge_bits;
	unsigned int start_bit  = target_bit % uedge_bits;
	unsigned int subword_width = src_end - src_start;

	hive_uedge src_subword = subword(src, src_start, src_end);

	if (subword_width + start_bit > uedge_bits) { /* overlap */
		hive_uedge old_val1;
		hive_uedge old_val0 = inv_subword(target[start_elem], start_bit, uedge_bits);

		target[start_elem] = old_val0 | (src_subword << start_bit);
		old_val1 = inv_subword(target[start_elem + 1], 0,
				       subword_width + start_bit - uedge_bits);
		target[start_elem + 1] = old_val1 | (src_subword >> (uedge_bits - start_bit));
	} else {
		hive_uedge old_val = inv_subword(target[start_elem], start_bit,
						 start_bit + subword_width);

		target[start_elem] = old_val | (src_subword << start_bit);
	}
}

static void
hive_sim_wide_unpack(
    hive_wide vector,
    hive_wide elem,
    hive_uint elem_bits,
    hive_uint index)
{
	/* pointers into wide_type: */
	unsigned int start_elem = (elem_bits * index) / uedge_bits;
	unsigned int start_bit  = (elem_bits * index) % uedge_bits;
	unsigned int end_elem   = (elem_bits * (index + 1) - 1) / uedge_bits;
	unsigned int end_bit    = ((elem_bits * (index + 1) - 1) % uedge_bits) + 1;

	if (elem_bits == uedge_bits) {
		/* easy case for speedup: */
		elem[0] = vector[index];
	} else if (start_elem == end_elem) {
		/* only one (<=64 bits) element needs to be (partly) copied: */
		move_subword(elem, 0, vector[start_elem], start_bit, end_bit);
	} else {
		/* general case: handles edge spanning cases (includes >64bit elements) */

Annotation

Implementation Notes