1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * drivers/net/ethernet/ibm/emac/tah.c
4 *
5 * Driver for PowerPC 4xx on-chip ethernet controller, TAH support.
6 *
7 * Copyright 2007 Benjamin Herrenschmidt, IBM Corp.
8 *                <benh@kernel.crashing.org>
9 *
10 * Based on the arch/ppc version of the driver:
11 *
12 * Copyright 2004 MontaVista Software, Inc.
13 * Matt Porter <mporter@kernel.crashing.org>
14 *
15 * Copyright (c) 2005 Eugene Surovegin <ebs@ebshome.net>
16 */
17#include <linux/of_address.h>
18#include <asm/io.h>
19
20#include "emac.h"
21#include "core.h"
22
23int tah_attach(struct platform_device *ofdev, int channel)
24{
25	struct tah_instance *dev = platform_get_drvdata(ofdev);
26
27	mutex_lock(&dev->lock);
28	/* Reset has been done at probe() time... nothing else to do for now */
29	++dev->users;
30	mutex_unlock(&dev->lock);
31
32	return 0;
33}
34
35void tah_detach(struct platform_device *ofdev, int channel)
36{
37	struct tah_instance *dev = platform_get_drvdata(ofdev);
38
39	mutex_lock(&dev->lock);
40	--dev->users;
41	mutex_unlock(&dev->lock);
42}
43
44void tah_reset(struct platform_device *ofdev)
45{
46	struct tah_instance *dev = platform_get_drvdata(ofdev);
47	struct tah_regs __iomem *p = dev->base;
48	int n;
49
50	/* Reset TAH */
51	out_be32(&p->mr, TAH_MR_SR);
52	n = 100;
53	while ((in_be32(&p->mr) & TAH_MR_SR) && n)
54		--n;
55
56	if (unlikely(!n))
57		printk(KERN_ERR "%pOF: reset timeout\n", ofdev->dev.of_node);
58
59	/* 10KB TAH TX FIFO accommodates the max MTU of 9000 */
60	out_be32(&p->mr,
61		 TAH_MR_CVR | TAH_MR_ST_768 | TAH_MR_TFS_10KB | TAH_MR_DTFP |
62		 TAH_MR_DIG);
63}
64
65int tah_get_regs_len(struct platform_device *ofdev)
66{
67	return sizeof(struct emac_ethtool_regs_subhdr) +
68		sizeof(struct tah_regs);
69}
70
71void *tah_dump_regs(struct platform_device *ofdev, void *buf)
72{
73	struct tah_instance *dev = platform_get_drvdata(ofdev);
74	struct emac_ethtool_regs_subhdr *hdr = buf;
75	struct tah_regs *regs = (struct tah_regs *)(hdr + 1);
76
77	hdr->version = 0;
78	hdr->index = 0; /* for now, are there chips with more than one
79			 * zmii ? if yes, then we'll add a cell_index
80			 * like we do for emac
81			 */
82	memcpy_fromio(regs, dev->base, sizeof(struct tah_regs));
83	return regs + 1;
84}
85
86static int tah_probe(struct platform_device *ofdev)
87{
88	struct device_node *np = ofdev->dev.of_node;
89	struct tah_instance *dev;
90	struct resource regs;
91	int rc;
92
93	rc = -ENOMEM;
94	dev = kzalloc(sizeof(struct tah_instance), GFP_KERNEL);
95	if (dev == NULL)
96		goto err_gone;
97
98	mutex_init(&dev->lock);
99	dev->ofdev = ofdev;
100
101	rc = -ENXIO;
102	if (of_address_to_resource(np, 0, &regs)) {
103		printk(KERN_ERR "%pOF: Can't get registers address\n", np);
104		goto err_free;
105	}
106
107	rc = -ENOMEM;
108	dev->base = (struct tah_regs __iomem *)ioremap(regs.start,
109					       sizeof(struct tah_regs));
110	if (dev->base == NULL) {
111		printk(KERN_ERR "%pOF: Can't map device registers!\n", np);
112		goto err_free;
113	}
114
115	platform_set_drvdata(ofdev, dev);
116
117	/* Initialize TAH and enable IPv4 checksum verification, no TSO yet */
118	tah_reset(ofdev);
119
120	printk(KERN_INFO "TAH %pOF initialized\n", ofdev->dev.of_node);
121	wmb();
122
123	return 0;
124
125 err_free:
126	kfree(dev);
127 err_gone:
128	return rc;
129}
130
131static int tah_remove(struct platform_device *ofdev)
132{
133	struct tah_instance *dev = platform_get_drvdata(ofdev);
134
135	WARN_ON(dev->users != 0);
136
137	iounmap(dev->base);
138	kfree(dev);
139
140	return 0;
141}
142
143static const struct of_device_id tah_match[] =
144{
145	{
146		.compatible	= "ibm,tah",
147	},
148	/* For backward compat with old DT */
149	{
150		.type		= "tah",
151	},
152	{},
153};
154
155static struct platform_driver tah_driver = {
156	.driver = {
157		.name = "emac-tah",
158		.of_match_table = tah_match,
159	},
160	.probe = tah_probe,
161	.remove = tah_remove,
162};
163
164int __init tah_init(void)
165{
166	return platform_driver_register(&tah_driver);
167}
168
169void tah_exit(void)
170{
171	platform_driver_unregister(&tah_driver);
172}
173