xref: /linux/drivers/net/ethernet/ibm/emac/tah.c (revision 7f71507851fc7764b36a3221839607d3a45c2025) 
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 
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 
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 
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 
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 
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 
88 static int tah_probe(struct platform_device *ofdev)
89 {
90 	struct tah_instance *dev;
91 	int err;
92 
93 	dev = devm_kzalloc(&ofdev->dev, sizeof(struct tah_instance),
94 			   GFP_KERNEL);
95 	if (!dev)
96 		return -ENOMEM;
97 
98 	err = devm_mutex_init(&ofdev->dev, &dev->lock);
99 	if (err)
100 		return err;
101 
102 	dev->ofdev = ofdev;
103 
104 	dev->base = devm_platform_ioremap_resource(ofdev, 0);
105 	if (IS_ERR(dev->base)) {
106 		dev_err(&ofdev->dev, "can't map device registers");
107 		return PTR_ERR(dev->base);
108 	}
109 
110 	platform_set_drvdata(ofdev, dev);
111 
112 	/* Initialize TAH and enable IPv4 checksum verification, no TSO yet */
113 	tah_reset(ofdev);
114 
115 	printk(KERN_INFO "TAH %pOF initialized\n", ofdev->dev.of_node);
116 	wmb();
117 
118 	return 0;
119 }
120 
121 static const struct of_device_id tah_match[] =
122 {
123 	{
124 		.compatible	= "ibm,tah",
125 	},
126 	/* For backward compat with old DT */
127 	{
128 		.type		= "tah",
129 	},
130 	{},
131 };
132 
133 static struct platform_driver tah_driver = {
134 	.driver = {
135 		.name = "emac-tah",
136 		.of_match_table = tah_match,
137 	},
138 	.probe = tah_probe,
139 };
140 
141 int __init tah_init(void)
142 {
143 	return platform_driver_register(&tah_driver);
144 }
145 
146 void tah_exit(void)
147 {
148 	platform_driver_unregister(&tah_driver);
149 }
150