drivers/ata/pata_parport/comm.c

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

File Facts

System
Linux kernel
Corpus path
drivers/ata/pata_parport/comm.c
Extension
.c
Size
4211 bytes
Lines
206
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>
 *
 * comm.c is a low-level protocol driver for some older models of the DataStor
 * "Commuter" parallel to IDE adapter. Some of the parallel port devices
 * marketed by Arista currently use this adapter.
 */

#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
 */

#define j44(a, b)	(((a >> 3) & 0x0f) | ((b << 1) & 0xf0))

#define P1	w2(5);w2(0xd);w2(0xd);w2(5);w2(4);
#define P2	w2(5);w2(7);w2(7);w2(5);w2(4);

/*
 * cont = 0 - access the IDE register file
 * cont = 1 - access the IDE command set
 */
static int  cont_map[2] = { 0x08, 0x10 };

static int comm_read_regr(struct pi_adapter *pi, int cont, int regr)
{
	int l, h, r;

	r = regr + cont_map[cont];

	switch (pi->mode) {
	case 0:
		w0(r); P1; w0(0);
		w2(6); l = r1(); w0(0x80); h = r1(); w2(4);
		return j44(l, h);

	case 1:
		w0(r+0x20); P1;
		w0(0); w2(0x26); h = r0(); w2(4);
		return h;

	case 2:
	case 3:
	case 4:
		w3(r+0x20); (void)r1();
		w2(0x24); h = r4(); w2(4);
		return h;
	}

	return -1;
}

static void comm_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
{
	int r = regr + cont_map[cont];

	switch (pi->mode) {
	case 0:
	case 1:
		w0(r); P1; w0(val); P2;
		break;
	case 2:
	case 3:
	case 4:
		w3(r); (void)r1(); w4(val);
		break;
	}
}

static void comm_connect(struct pi_adapter *pi)
{
	pi->saved_r0 = r0();
	pi->saved_r2 = r2();
	w2(4); w0(0xff); w2(6);
	w2(4); w0(0xaa); w2(6);
	w2(4); w0(0x00); w2(6);
	w2(4); w0(0x87); w2(6);
	w2(4); w0(0xe0); w2(0xc); w2(0xc); w2(4);
}

Annotation

Implementation Notes