1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * MDIO bus driver for the Xilinx TEMAC device
4  *
5  * Copyright (c) 2009 Secret Lab Technologies, Ltd.
6  */
7 
8 #include <linux/io.h>
9 #include <linux/netdevice.h>
10 #include <linux/mutex.h>
11 #include <linux/phy.h>
12 #include <linux/of.h>
13 #include <linux/of_address.h>
14 #include <linux/platform_device.h>
15 #include <linux/slab.h>
16 #include <linux/of_mdio.h>
17 #include <linux/platform_data/xilinx-ll-temac.h>
18 
19 #include "ll_temac.h"
20 
21 /* ---------------------------------------------------------------------
22  * MDIO Bus functions
23  */
24 static int temac_mdio_read(struct mii_bus *bus, int phy_id, int reg)
25 {
26 	struct temac_local *lp = bus->priv;
27 	u32 rc;
28 	unsigned long flags;
29 
30 	/* Write the PHY address to the MIIM Access Initiator register.
31 	 * When the transfer completes, the PHY register value will appear
32 	 * in the LSW0 register
33 	 */
34 	spin_lock_irqsave(lp->indirect_lock, flags);
35 	temac_iow(lp, XTE_LSW0_OFFSET, (phy_id << 5) | reg);
36 	rc = temac_indirect_in32_locked(lp, XTE_MIIMAI_OFFSET);
37 	spin_unlock_irqrestore(lp->indirect_lock, flags);
38 
39 	dev_dbg(lp->dev, "temac_mdio_read(phy_id=%i, reg=%x) == %x\n",
40 		phy_id, reg, rc);
41 
42 	return rc;
43 }
44 
45 static int temac_mdio_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
46 {
47 	struct temac_local *lp = bus->priv;
48 	unsigned long flags;
49 
50 	dev_dbg(lp->dev, "temac_mdio_write(phy_id=%i, reg=%x, val=%x)\n",
51 		phy_id, reg, val);
52 
53 	/* First write the desired value into the write data register
54 	 * and then write the address into the access initiator register
55 	 */
56 	spin_lock_irqsave(lp->indirect_lock, flags);
57 	temac_indirect_out32_locked(lp, XTE_MGTDR_OFFSET, val);
58 	temac_indirect_out32_locked(lp, XTE_MIIMAI_OFFSET, (phy_id << 5) | reg);
59 	spin_unlock_irqrestore(lp->indirect_lock, flags);
60 
61 	return 0;
62 }
63 
64 int temac_mdio_setup(struct temac_local *lp, struct platform_device *pdev)
65 {
66 	struct ll_temac_platform_data *pdata = dev_get_platdata(&pdev->dev);
67 	struct device_node *np = dev_of_node(&pdev->dev);
68 	struct mii_bus *bus;
69 	u32 bus_hz;
70 	int clk_div;
71 	int rc;
72 	struct resource res;
73 
74 	/* Get MDIO bus frequency (if specified) */
75 	bus_hz = 0;
76 	if (np)
77 		of_property_read_u32(np, "clock-frequency", &bus_hz);
78 	else if (pdata)
79 		bus_hz = pdata->mdio_clk_freq;
80 
81 	/* Calculate a reasonable divisor for the clock rate */
82 	clk_div = 0x3f; /* worst-case default setting */
83 	if (bus_hz != 0) {
84 		clk_div = bus_hz / (2500 * 1000 * 2) - 1;
85 		if (clk_div < 1)
86 			clk_div = 1;
87 		if (clk_div > 0x3f)
88 			clk_div = 0x3f;
89 	}
90 
91 	/* Enable the MDIO bus by asserting the enable bit and writing
92 	 * in the clock config
93 	 */
94 	temac_indirect_out32(lp, XTE_MC_OFFSET, 1 << 6 | clk_div);
95 
96 	bus = devm_mdiobus_alloc(&pdev->dev);
97 	if (!bus)
98 		return -ENOMEM;
99 
100 	if (np) {
101 		of_address_to_resource(np, 0, &res);
102 		snprintf(bus->id, MII_BUS_ID_SIZE, "%.8llx",
103 			 (unsigned long long)res.start);
104 	} else if (pdata) {
105 		snprintf(bus->id, MII_BUS_ID_SIZE, "%.8llx",
106 			 pdata->mdio_bus_id);
107 	}
108 
109 	bus->priv = lp;
110 	bus->name = "Xilinx TEMAC MDIO";
111 	bus->read = temac_mdio_read;
112 	bus->write = temac_mdio_write;
113 	bus->parent = lp->dev;
114 
115 	lp->mii_bus = bus;
116 
117 	rc = of_mdiobus_register(bus, np);
118 	if (rc)
119 		return rc;
120 
121 	dev_dbg(lp->dev, "MDIO bus registered;  MC:%x\n",
122 		temac_indirect_in32(lp, XTE_MC_OFFSET));
123 	return 0;
124 }
125 
126 void temac_mdio_teardown(struct temac_local *lp)
127 {
128 	mdiobus_unregister(lp->mii_bus);
129 }
130