1// SPDX-License-Identifier: GPL-2.0
2/*
3 * (C) Copyright 2021 BayLibre, SAS
4 * Author: Neil Armstrong <narmstrong@baylibre.com>
5 *
6 * Based on linux/drivers/net/phy/mdio-mux-mmioreg.c :
7 *   Copyright 2012 Freescale Semiconductor, Inc.
8 */
9
10#include <dm.h>
11#include <errno.h>
12#include <log.h>
13#include <miiphy.h>
14#include <linux/io.h>
15
16struct mdio_mux_mmioreg_priv {
17	struct udevice *chip;
18	phys_addr_t phys;
19	unsigned int iosize;
20	unsigned int mask;
21};
22
23static int mdio_mux_mmioreg_select(struct udevice *mux, int cur, int sel)
24{
25	struct mdio_mux_mmioreg_priv *priv = dev_get_priv(mux);
26
27	debug("%s: %x -> %x\n", __func__, (u32)cur, (u32)sel);
28
29	/* if last selection didn't change we're good to go */
30	if (cur == sel)
31		return 0;
32
33	switch (priv->iosize) {
34	case sizeof(u8): {
35		u8 x, y;
36
37		x = ioread8((void *)priv->phys);
38		y = (x & ~priv->mask) | (u32)sel;
39		if (x != y) {
40			iowrite8((x & ~priv->mask) | sel, (void *)priv->phys);
41			debug("%s: %02x -> %02x\n", __func__, x, y);
42		}
43
44		break;
45	}
46	case sizeof(u16): {
47		u16 x, y;
48
49		x = ioread16((void *)priv->phys);
50		y = (x & ~priv->mask) | (u32)sel;
51		if (x != y) {
52			iowrite16((x & ~priv->mask) | sel, (void *)priv->phys);
53			debug("%s: %04x -> %04x\n", __func__, x, y);
54		}
55
56		break;
57	}
58	case sizeof(u32): {
59		u32 x, y;
60
61		x = ioread32((void *)priv->phys);
62		y = (x & ~priv->mask) | (u32)sel;
63		if (x != y) {
64			iowrite32((x & ~priv->mask) | sel, (void *)priv->phys);
65			debug("%s: %08x -> %08x\n", __func__, x, y);
66		}
67
68		break;
69	}
70	}
71
72	return 0;
73}
74
75static const struct mdio_mux_ops mdio_mux_mmioreg_ops = {
76	.select = mdio_mux_mmioreg_select,
77};
78
79static int mdio_mux_mmioreg_probe(struct udevice *dev)
80{
81	struct mdio_mux_mmioreg_priv *priv = dev_get_priv(dev);
82	phys_addr_t reg_base, reg_size;
83	u32 reg_mask;
84	int err;
85
86	reg_base = ofnode_get_addr_size_index(dev_ofnode(dev), 0, &reg_size);
87	if (reg_base == FDT_ADDR_T_NONE)
88		return -EINVAL;
89
90	if (reg_size != sizeof(u8) &&
91	    reg_size != sizeof(u16) &&
92	    reg_size != sizeof(u32)) {
93		printf("%s: only 8/16/32-bit registers are supported\n", __func__);
94		return -EINVAL;
95	}
96
97	err = dev_read_u32(dev, "mux-mask", &reg_mask);
98	if (err) {
99		debug("%s: error reading mux-mask property\n", __func__);
100		return err;
101	}
102
103	if (reg_mask >= BIT(reg_size * 8)) {
104		printf("%s: mask doesn't fix in register width\n", __func__);
105		return -EINVAL;
106	}
107
108	priv->phys = reg_base;
109	priv->iosize = reg_size;
110	priv->mask = reg_mask;
111
112	debug("%s: %llx@%lld / %x\n", __func__, reg_base, reg_size, reg_mask);
113
114	return 0;
115}
116
117static const struct udevice_id mdio_mux_mmioreg_ids[] = {
118	{ .compatible = "mdio-mux-mmioreg" },
119	{ }
120};
121
122U_BOOT_DRIVER(mdio_mux_mmioreg) = {
123	.name		= "mdio_mux_mmioreg",
124	.id		= UCLASS_MDIO_MUX,
125	.of_match	= mdio_mux_mmioreg_ids,
126	.probe		= mdio_mux_mmioreg_probe,
127	.ops		= &mdio_mux_mmioreg_ops,
128	.priv_auto	= sizeof(struct mdio_mux_mmioreg_priv),
129};
130