1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/*
* MDIO bus driver for the Xilinx Axi Ethernet device
*
* Copyright (c) 2009 Secret Lab Technologies, Ltd.
* Copyright (c) 2010 - 2011 Michal Simek <monstr@monstr.eu>
* Copyright (c) 2010 - 2011 PetaLogix
* Copyright (c) 2010 - 2012 Xilinx, Inc. All rights reserved.
*/
#include <linux/of_address.h>
#include <linux/of_mdio.h>
#include <linux/jiffies.h>
#include "xilinx_axienet.h"
#define MAX_MDIO_FREQ 2500000 /* 2.5 MHz */
#define DEFAULT_CLOCK_DIVISOR XAE_MDIO_DIV_DFT
/* Wait till MDIO interface is ready to accept a new transaction.*/
int axienet_mdio_wait_until_ready(struct axienet_local *lp)
{
long end = jiffies + 2;
while (!(axienet_ior(lp, XAE_MDIO_MCR_OFFSET) &
XAE_MDIO_MCR_READY_MASK)) {
if (end - jiffies <= 0) {
WARN_ON(1);
return -ETIMEDOUT;
}
udelay(1);
}
return 0;
}
/**
* axienet_mdio_read - MDIO interface read function
* @bus: Pointer to mii bus structure
* @phy_id: Address of the PHY device
* @reg: PHY register to read
*
* returns: The register contents on success, -ETIMEDOUT on a timeout
*
* Reads the contents of the requested register from the requested PHY
* address by first writing the details into MCR register. After a while
* the register MRD is read to obtain the PHY register content.
*/
static int axienet_mdio_read(struct mii_bus *bus, int phy_id, int reg)
{
u32 rc;
int ret;
struct axienet_local *lp = bus->priv;
ret = axienet_mdio_wait_until_ready(lp);
if (ret < 0)
return ret;
axienet_iow(lp, XAE_MDIO_MCR_OFFSET,
(((phy_id << XAE_MDIO_MCR_PHYAD_SHIFT) &
XAE_MDIO_MCR_PHYAD_MASK) |
((reg << XAE_MDIO_MCR_REGAD_SHIFT) &
XAE_MDIO_MCR_REGAD_MASK) |
XAE_MDIO_MCR_INITIATE_MASK |
XAE_MDIO_MCR_OP_READ_MASK));
ret = axienet_mdio_wait_until_ready(lp);
if (ret < 0)
return ret;
rc = axienet_ior(lp, XAE_MDIO_MRD_OFFSET) & 0x0000FFFF;
dev_dbg(lp->dev, "axienet_mdio_read(phy_id=%i, reg=%x) == %x\n",
phy_id, reg, rc);
return rc;
}
/**
* axienet_mdio_write - MDIO interface write function
* @bus: Pointer to mii bus structure
* @phy_id: Address of the PHY device
* @reg: PHY register to write to
* @val: Value to be written into the register
*
* returns: 0 on success, -ETIMEDOUT on a timeout
*
* Writes the value to the requested register by first writing the value
* into MWD register. The the MCR register is then appropriately setup
* to finish the write operation.
*/
static int axienet_mdio_write(struct mii_bus *bus, int phy_id, int reg,
u16 val)
{
int ret;
struct axienet_local *lp = bus->priv;
dev_dbg(lp->dev, "axienet_mdio_write(phy_id=%i, reg=%x, val=%x)\n",
phy_id, reg, val);
ret = axienet_mdio_wait_until_ready(lp);
if (ret < 0)
return ret;
axienet_iow(lp, XAE_MDIO_MWD_OFFSET, (u32) val);
axienet_iow(lp, XAE_MDIO_MCR_OFFSET,
(((phy_id << XAE_MDIO_MCR_PHYAD_SHIFT) &
XAE_MDIO_MCR_PHYAD_MASK) |
((reg << XAE_MDIO_MCR_REGAD_SHIFT) &
XAE_MDIO_MCR_REGAD_MASK) |
XAE_MDIO_MCR_INITIATE_MASK |
XAE_MDIO_MCR_OP_WRITE_MASK));
ret = axienet_mdio_wait_until_ready(lp);
if (ret < 0)
return ret;
return 0;
}
/**
* axienet_mdio_setup - MDIO setup function
* @lp: Pointer to axienet local data structure.
* @np: Pointer to device node
*
* returns: 0 on success, -ETIMEDOUT on a timeout, -ENOMEM when
* mdiobus_alloc (to allocate memory for mii bus structure) fails.
*
* Sets up the MDIO interface by initializing the MDIO clock and enabling the
* MDIO interface in hardware. Register the MDIO interface.
**/
int axienet_mdio_setup(struct axienet_local *lp, struct device_node *np)
{
int ret;
u32 clk_div, host_clock;
u32 *property_p;
struct mii_bus *bus;
struct resource res;
struct device_node *np1;
/* clk_div can be calculated by deriving it from the equation:
* fMDIO = fHOST / ((1 + clk_div) * 2)
*
* Where fMDIO <= 2500000, so we get:
* fHOST / ((1 + clk_div) * 2) <= 2500000
*
* Then we get:
* 1 / ((1 + clk_div) * 2) <= (2500000 / fHOST)
*
* Then we get:
* 1 / (1 + clk_div) <= ((2500000 * 2) / fHOST)
*
* Then we get:
* 1 / (1 + clk_div) <= (5000000 / fHOST)
*
* So:
* (1 + clk_div) >= (fHOST / 5000000)
*
* And finally:
* clk_div >= (fHOST / 5000000) - 1
*
* fHOST can be read from the flattened device tree as property
* "clock-frequency" from the CPU
*/
np1 = of_find_node_by_name(NULL, "cpu");
if (!np1) {
printk(KERN_WARNING "%s(): Could not find CPU device node.",
__func__);
printk(KERN_WARNING "Setting MDIO clock divisor to "
"default %d\n", DEFAULT_CLOCK_DIVISOR);
clk_div = DEFAULT_CLOCK_DIVISOR;
goto issue;
}
property_p = (u32 *) of_get_property(np1, "clock-frequency", NULL);
if (!property_p) {
printk(KERN_WARNING "%s(): Could not find CPU property: "
"clock-frequency.", __func__);
printk(KERN_WARNING "Setting MDIO clock divisor to "
"default %d\n", DEFAULT_CLOCK_DIVISOR);
clk_div = DEFAULT_CLOCK_DIVISOR;
goto issue;
}
host_clock = be32_to_cpup(property_p);
clk_div = (host_clock / (MAX_MDIO_FREQ * 2)) - 1;
/* If there is any remainder from the division of
* fHOST / (MAX_MDIO_FREQ * 2), then we need to add
* 1 to the clock divisor or we will surely be above 2.5 MHz */
if (host_clock % (MAX_MDIO_FREQ * 2))
clk_div++;
printk(KERN_DEBUG "%s(): Setting MDIO clock divisor to %u based "
"on %u Hz host clock.\n", __func__, clk_div, host_clock);
of_node_put(np1);
issue:
axienet_iow(lp, XAE_MDIO_MC_OFFSET,
(((u32) clk_div) | XAE_MDIO_MC_MDIOEN_MASK));
ret = axienet_mdio_wait_until_ready(lp);
if (ret < 0)
return ret;
bus = mdiobus_alloc();
if (!bus)
return -ENOMEM;
np1 = of_get_parent(lp->phy_node);
of_address_to_resource(np1, 0, &res);
snprintf(bus->id, MII_BUS_ID_SIZE, "%.8llx",
(unsigned long long) res.start);
bus->priv = lp;
bus->name = "Xilinx Axi Ethernet MDIO";
bus->read = axienet_mdio_read;
bus->write = axienet_mdio_write;
bus->parent = lp->dev;
bus->irq = lp->mdio_irqs; /* preallocated IRQ table */
lp->mii_bus = bus;
ret = of_mdiobus_register(bus, np1);
if (ret) {
mdiobus_free(bus);
return ret;
}
return 0;
}
/**
* axienet_mdio_teardown - MDIO remove function
* @lp: Pointer to axienet local data structure.
*
* Unregisters the MDIO and frees any associate memory for mii bus.
*/
void axienet_mdio_teardown(struct axienet_local *lp)
{
mdiobus_unregister(lp->mii_bus);
kfree(lp->mii_bus->irq);
mdiobus_free(lp->mii_bus);
lp->mii_bus = NULL;
}
|
