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
tah_attach(struct platform_device * ofdev,int channel)25 int 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
tah_detach(struct platform_device * ofdev,int channel)37 void 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
tah_reset(struct platform_device * ofdev)46 void 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
tah_get_regs_len(struct platform_device * ofdev)67 int tah_get_regs_len(struct platform_device *ofdev)
68 {
69 return sizeof(struct emac_ethtool_regs_subhdr) +
70 sizeof(struct tah_regs);
71 }
72
tah_dump_regs(struct platform_device * ofdev,void * buf)73 void *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
tah_probe(struct platform_device * ofdev)88 static 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, ®s)) {
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
tah_remove(struct platform_device * ofdev)133 static int 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 return 0;
143 }
144
145 static const struct of_device_id tah_match[] =
146 {
147 {
148 .compatible = "ibm,tah",
149 },
150 /* For backward compat with old DT */
151 {
152 .type = "tah",
153 },
154 {},
155 };
156
157 static struct platform_driver tah_driver = {
158 .driver = {
159 .name = "emac-tah",
160 .of_match_table = tah_match,
161 },
162 .probe = tah_probe,
163 .remove = tah_remove,
164 };
165
tah_init(void)166 int __init tah_init(void)
167 {
168 return platform_driver_register(&tah_driver);
169 }
170
tah_exit(void)171 void tah_exit(void)
172 {
173 platform_driver_unregister(&tah_driver);
174 }
175