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/mod_devicetable.h>
18#include <linux/of_address.h>
19#include <linux/platform_device.h>
20#include <asm/io.h>
21
22#include "emac.h"
23#include "core.h"
24
25int tah_attach(struct platform_device *ofdev, int channel)
26{
27	struct tah_instance *dev = platform_get_drvdata(ofdev);
28
29	mutex_lock(&dev->lock);
30	/* Reset has been done at probe() time... nothing else to do for now */
31	++dev->users;
32	mutex_unlock(&dev->lock);
33
34	return 0;
35}
36
37void tah_detach(struct platform_device *ofdev, int channel)
38{
39	struct tah_instance *dev = platform_get_drvdata(ofdev);
40
41	mutex_lock(&dev->lock);
42	--dev->users;
43	mutex_unlock(&dev->lock);
44}
45
46void tah_reset(struct platform_device *ofdev)
47{
48	struct tah_instance *dev = platform_get_drvdata(ofdev);
49	struct tah_regs __iomem *p = dev->base;
50	int n;
51
52	/* Reset TAH */
53	out_be32(&p->mr, TAH_MR_SR);
54	n = 100;
55	while ((in_be32(&p->mr) & TAH_MR_SR) && n)
56		--n;
57
58	if (unlikely(!n))
59		printk(KERN_ERR "%pOF: reset timeout\n", ofdev->dev.of_node);
60
61	/* 10KB TAH TX FIFO accommodates the max MTU of 9000 */
62	out_be32(&p->mr,
63		 TAH_MR_CVR | TAH_MR_ST_768 | TAH_MR_TFS_10KB | TAH_MR_DTFP |
64		 TAH_MR_DIG);
65}
66
67int tah_get_regs_len(struct platform_device *ofdev)
68{
69	return sizeof(struct emac_ethtool_regs_subhdr) +
70		sizeof(struct tah_regs);
71}
72
73void *tah_dump_regs(struct platform_device *ofdev, void *buf)
74{
75	struct tah_instance *dev = platform_get_drvdata(ofdev);
76	struct emac_ethtool_regs_subhdr *hdr = buf;
77	struct tah_regs *regs = (struct tah_regs *)(hdr + 1);
78
79	hdr->version = 0;
80	hdr->index = 0; /* for now, are there chips with more than one
81			 * zmii ? if yes, then we'll add a cell_index
82			 * like we do for emac
83			 */
84	memcpy_fromio(regs, dev->base, sizeof(struct tah_regs));
85	return regs + 1;
86}
87
88static int tah_probe(struct platform_device *ofdev)
89{
90	struct device_node *np = ofdev->dev.of_node;
91	struct tah_instance *dev;
92	struct resource regs;
93	int rc;
94
95	rc = -ENOMEM;
96	dev = kzalloc(sizeof(struct tah_instance), GFP_KERNEL);
97	if (dev == NULL)
98		goto err_gone;
99
100	mutex_init(&dev->lock);
101	dev->ofdev = ofdev;
102
103	rc = -ENXIO;
104	if (of_address_to_resource(np, 0, &regs)) {
105		printk(KERN_ERR "%pOF: Can't get registers address\n", np);
106		goto err_free;
107	}
108
109	rc = -ENOMEM;
110	dev->base = (struct tah_regs __iomem *)ioremap(regs.start,
111					       sizeof(struct tah_regs));
112	if (dev->base == NULL) {
113		printk(KERN_ERR "%pOF: Can't map device registers!\n", np);
114		goto err_free;
115	}
116
117	platform_set_drvdata(ofdev, dev);
118
119	/* Initialize TAH and enable IPv4 checksum verification, no TSO yet */
120	tah_reset(ofdev);
121
122	printk(KERN_INFO "TAH %pOF initialized\n", ofdev->dev.of_node);
123	wmb();
124
125	return 0;
126
127 err_free:
128	kfree(dev);
129 err_gone:
130	return rc;
131}
132
133static void tah_remove(struct platform_device *ofdev)
134{
135	struct tah_instance *dev = platform_get_drvdata(ofdev);
136
137	WARN_ON(dev->users != 0);
138
139	iounmap(dev->base);
140	kfree(dev);
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_new = 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