drivers/ata/pata_parport/on26.c

Source file repositories/reference/linux-study-clean/drivers/ata/pata_parport/on26.c

File Facts

System
Linux kernel
Corpus path
drivers/ata/pata_parport/on26.c
Extension
.c
Size
6248 bytes
Lines
316
Domain
Driver Families
Bucket
drivers/ata
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-or-later
/*
 * (c) 1997-1998  Grant R. Guenther <grant@torque.net>
 *
 * on26.c is a low-level protocol driver for the
 * OnSpec 90c26 parallel to IDE adapter chip.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/wait.h>
#include <asm/io.h>
#include "pata_parport.h"

/*
 * mode codes:  0  nybble reads, 8-bit writes
 *		1  8-bit reads and writes
 *		2  8-bit EPP mode
 *		3  EPP-16
 *		4  EPP-32
 */

#define j44(a, b)	(((a >> 4) & 0x0f) | (b & 0xf0))

#define P1						      \
	do {						      \
		w2(5); w2(0xd); w2(5); w2(0xd); w2(5); w2(4); \
	} while (0)

#define P2					\
	do {					\
		w2(5); w2(7); w2(5); w2(4);	\
	} while (0)

/*
 * cont = 0 - access the IDE register file
 * cont = 1 - access the IDE command set
 */

static int on26_read_regr(struct pi_adapter *pi, int cont, int regr)
{
	int a, b, r;

	r = (regr << 2) + 1 + cont;

	switch (pi->mode) {
	case 0:
		w0(1); P1; w0(r); P2; w0(0); P1;
		w2(6); a = r1(); w2(4);
		w2(6); b = r1(); w2(4);
		w2(6); w2(4); w2(6); w2(4);
		return j44(a, b);
	case 1:
		w0(1); P1; w0(r); P2; w0(0); P1;
		w2(0x26); a = r0(); w2(4); w2(0x26); w2(4);
		return a;
	case 2:
	case 3:
	case 4:
		w3(1); w3(1); w2(5); w4(r); w2(4);
		w3(0); w3(0); w2(0x24); a = r4(); w2(4);
		w2(0x24); (void)r4(); w2(4);
		return a;
	}

	return -1;
}

static void on26_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
{
	int r = (regr << 2) + 1 + cont;

	switch (pi->mode) {
	case 0:
	case 1:
		w0(1); P1; w0(r); P2; w0(0); P1;
		w0(val); P2; w0(val); P2;
		break;
	case 2:
	case 3:
	case 4:
		w3(1); w3(1); w2(5); w4(r); w2(4);
		w3(0); w3(0);
		w2(5); w4(val); w2(4);
		w2(5); w4(val); w2(4);
		break;
	}

Annotation

Implementation Notes