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 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
121static 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
133static struct platform_driver tah_driver = {
134	.driver = {
135		.name = "emac-tah",
136		.of_match_table = tah_match,
137	},
138	.probe = tah_probe,
139};
140
141int __init tah_init(void)
142{
143	return platform_driver_register(&tah_driver);
144}
145
146void tah_exit(void)
147{
148	platform_driver_unregister(&tah_driver);
149}