1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright 2016 Broadcom
4  */
5 #include <linux/clk.h>
6 #include <linux/delay.h>
7 #include <linux/device.h>
8 #include <linux/iopoll.h>
9 #include <linux/mdio-mux.h>
10 #include <linux/module.h>
11 #include <linux/of_mdio.h>
12 #include <linux/phy.h>
13 #include <linux/platform_device.h>
14 
15 #define MDIO_RATE_ADJ_EXT_OFFSET	0x000
16 #define MDIO_RATE_ADJ_INT_OFFSET	0x004
17 #define MDIO_RATE_ADJ_DIVIDENT_SHIFT	16
18 
19 #define MDIO_SCAN_CTRL_OFFSET		0x008
20 #define MDIO_SCAN_CTRL_OVRIDE_EXT_MSTR	28
21 
22 #define MDIO_PARAM_OFFSET		0x23c
23 #define MDIO_PARAM_MIIM_CYCLE		29
24 #define MDIO_PARAM_INTERNAL_SEL		25
25 #define MDIO_PARAM_BUS_ID		22
26 #define MDIO_PARAM_C45_SEL		21
27 #define MDIO_PARAM_PHY_ID		16
28 #define MDIO_PARAM_PHY_DATA		0
29 
30 #define MDIO_READ_OFFSET		0x240
31 #define MDIO_READ_DATA_MASK		0xffff
32 #define MDIO_ADDR_OFFSET		0x244
33 
34 #define MDIO_CTRL_OFFSET		0x248
35 #define MDIO_CTRL_WRITE_OP		0x1
36 #define MDIO_CTRL_READ_OP		0x2
37 
38 #define MDIO_STAT_OFFSET		0x24c
39 #define MDIO_STAT_DONE			1
40 
41 #define BUS_MAX_ADDR			32
42 #define EXT_BUS_START_ADDR		16
43 
44 #define MDIO_REG_ADDR_SPACE_SIZE	0x250
45 
46 #define MDIO_OPERATING_FREQUENCY	11000000
47 #define MDIO_RATE_ADJ_DIVIDENT		1
48 
49 struct iproc_mdiomux_desc {
50 	void *mux_handle;
51 	void __iomem *base;
52 	struct device *dev;
53 	struct mii_bus *mii_bus;
54 	struct clk *core_clk;
55 };
56 
57 static void mdio_mux_iproc_config(struct iproc_mdiomux_desc *md)
58 {
59 	u32 divisor;
60 	u32 val;
61 
62 	/* Disable external mdio master access */
63 	val = readl(md->base + MDIO_SCAN_CTRL_OFFSET);
64 	val |= BIT(MDIO_SCAN_CTRL_OVRIDE_EXT_MSTR);
65 	writel(val, md->base + MDIO_SCAN_CTRL_OFFSET);
66 
67 	if (md->core_clk) {
68 		/* use rate adjust regs to derive the mdio's operating
69 		 * frequency from the specified core clock
70 		 */
71 		divisor = clk_get_rate(md->core_clk) / MDIO_OPERATING_FREQUENCY;
72 		divisor = divisor / (MDIO_RATE_ADJ_DIVIDENT + 1);
73 		val = divisor;
74 		val |= MDIO_RATE_ADJ_DIVIDENT << MDIO_RATE_ADJ_DIVIDENT_SHIFT;
75 		writel(val, md->base + MDIO_RATE_ADJ_EXT_OFFSET);
76 		writel(val, md->base + MDIO_RATE_ADJ_INT_OFFSET);
77 	}
78 }
79 
80 static int iproc_mdio_wait_for_idle(void __iomem *base, bool result)
81 {
82 	u32 val;
83 
84 	return readl_poll_timeout(base + MDIO_STAT_OFFSET, val,
85 				  (val & MDIO_STAT_DONE) == result,
86 				  2000, 1000000);
87 }
88 
89 /* start_miim_ops- Program and start MDIO transaction over mdio bus.
90  * @base: Base address
91  * @phyid: phyid of the selected bus.
92  * @reg: register offset to be read/written.
93  * @val :0 if read op else value to be written in @reg;
94  * @op: Operation that need to be carried out.
95  *      MDIO_CTRL_READ_OP: Read transaction.
96  *      MDIO_CTRL_WRITE_OP: Write transaction.
97  *
98  * Return value: Successful Read operation returns read reg values and write
99  *      operation returns 0. Failure operation returns negative error code.
100  */
101 static int start_miim_ops(void __iomem *base,
102 			  u16 phyid, u32 reg, u16 val, u32 op)
103 {
104 	u32 param;
105 	int ret;
106 
107 	writel(0, base + MDIO_CTRL_OFFSET);
108 	ret = iproc_mdio_wait_for_idle(base, 0);
109 	if (ret)
110 		goto err;
111 
112 	param = readl(base + MDIO_PARAM_OFFSET);
113 	param |= phyid << MDIO_PARAM_PHY_ID;
114 	param |= val << MDIO_PARAM_PHY_DATA;
115 	if (reg & MII_ADDR_C45)
116 		param |= BIT(MDIO_PARAM_C45_SEL);
117 
118 	writel(param, base + MDIO_PARAM_OFFSET);
119 
120 	writel(reg, base + MDIO_ADDR_OFFSET);
121 
122 	writel(op, base + MDIO_CTRL_OFFSET);
123 
124 	ret = iproc_mdio_wait_for_idle(base, 1);
125 	if (ret)
126 		goto err;
127 
128 	if (op == MDIO_CTRL_READ_OP)
129 		ret = readl(base + MDIO_READ_OFFSET) & MDIO_READ_DATA_MASK;
130 err:
131 	return ret;
132 }
133 
134 static int iproc_mdiomux_read(struct mii_bus *bus, int phyid, int reg)
135 {
136 	struct iproc_mdiomux_desc *md = bus->priv;
137 	int ret;
138 
139 	ret = start_miim_ops(md->base, phyid, reg, 0, MDIO_CTRL_READ_OP);
140 	if (ret < 0)
141 		dev_err(&bus->dev, "mdiomux read operation failed!!!");
142 
143 	return ret;
144 }
145 
146 static int iproc_mdiomux_write(struct mii_bus *bus,
147 			       int phyid, int reg, u16 val)
148 {
149 	struct iproc_mdiomux_desc *md = bus->priv;
150 	int ret;
151 
152 	/* Write val at reg offset */
153 	ret = start_miim_ops(md->base, phyid, reg, val, MDIO_CTRL_WRITE_OP);
154 	if (ret < 0)
155 		dev_err(&bus->dev, "mdiomux write operation failed!!!");
156 
157 	return ret;
158 }
159 
160 static int mdio_mux_iproc_switch_fn(int current_child, int desired_child,
161 				    void *data)
162 {
163 	struct iproc_mdiomux_desc *md = data;
164 	u32 param, bus_id;
165 	bool bus_dir;
166 
167 	/* select bus and its properties */
168 	bus_dir = (desired_child < EXT_BUS_START_ADDR);
169 	bus_id = bus_dir ? desired_child : (desired_child - EXT_BUS_START_ADDR);
170 
171 	param = (bus_dir ? 1 : 0) << MDIO_PARAM_INTERNAL_SEL;
172 	param |= (bus_id << MDIO_PARAM_BUS_ID);
173 
174 	writel(param, md->base + MDIO_PARAM_OFFSET);
175 	return 0;
176 }
177 
178 static int mdio_mux_iproc_probe(struct platform_device *pdev)
179 {
180 	struct iproc_mdiomux_desc *md;
181 	struct mii_bus *bus;
182 	struct resource *res;
183 	int rc;
184 
185 	md = devm_kzalloc(&pdev->dev, sizeof(*md), GFP_KERNEL);
186 	if (!md)
187 		return -ENOMEM;
188 	md->dev = &pdev->dev;
189 
190 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
191 	if (res->start & 0xfff) {
192 		/* For backward compatibility in case the
193 		 * base address is specified with an offset.
194 		 */
195 		dev_info(&pdev->dev, "fix base address in dt-blob\n");
196 		res->start &= ~0xfff;
197 		res->end = res->start + MDIO_REG_ADDR_SPACE_SIZE - 1;
198 	}
199 	md->base = devm_ioremap_resource(&pdev->dev, res);
200 	if (IS_ERR(md->base))
201 		return PTR_ERR(md->base);
202 
203 	md->mii_bus = devm_mdiobus_alloc(&pdev->dev);
204 	if (!md->mii_bus) {
205 		dev_err(&pdev->dev, "mdiomux bus alloc failed\n");
206 		return -ENOMEM;
207 	}
208 
209 	md->core_clk = devm_clk_get(&pdev->dev, NULL);
210 	if (md->core_clk == ERR_PTR(-ENOENT) ||
211 	    md->core_clk == ERR_PTR(-EINVAL))
212 		md->core_clk = NULL;
213 	else if (IS_ERR(md->core_clk))
214 		return PTR_ERR(md->core_clk);
215 
216 	rc = clk_prepare_enable(md->core_clk);
217 	if (rc) {
218 		dev_err(&pdev->dev, "failed to enable core clk\n");
219 		return rc;
220 	}
221 
222 	bus = md->mii_bus;
223 	bus->priv = md;
224 	bus->name = "iProc MDIO mux bus";
225 	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
226 	bus->parent = &pdev->dev;
227 	bus->read = iproc_mdiomux_read;
228 	bus->write = iproc_mdiomux_write;
229 
230 	bus->phy_mask = ~0;
231 	bus->dev.of_node = pdev->dev.of_node;
232 	rc = mdiobus_register(bus);
233 	if (rc) {
234 		dev_err(&pdev->dev, "mdiomux registration failed\n");
235 		goto out_clk;
236 	}
237 
238 	platform_set_drvdata(pdev, md);
239 
240 	rc = mdio_mux_init(md->dev, md->dev->of_node, mdio_mux_iproc_switch_fn,
241 			   &md->mux_handle, md, md->mii_bus);
242 	if (rc) {
243 		dev_info(md->dev, "mdiomux initialization failed\n");
244 		goto out_register;
245 	}
246 
247 	mdio_mux_iproc_config(md);
248 
249 	dev_info(md->dev, "iProc mdiomux registered\n");
250 	return 0;
251 
252 out_register:
253 	mdiobus_unregister(bus);
254 out_clk:
255 	clk_disable_unprepare(md->core_clk);
256 	return rc;
257 }
258 
259 static int mdio_mux_iproc_remove(struct platform_device *pdev)
260 {
261 	struct iproc_mdiomux_desc *md = platform_get_drvdata(pdev);
262 
263 	mdio_mux_uninit(md->mux_handle);
264 	mdiobus_unregister(md->mii_bus);
265 	clk_disable_unprepare(md->core_clk);
266 
267 	return 0;
268 }
269 
270 #ifdef CONFIG_PM_SLEEP
271 static int mdio_mux_iproc_suspend(struct device *dev)
272 {
273 	struct iproc_mdiomux_desc *md = dev_get_drvdata(dev);
274 
275 	clk_disable_unprepare(md->core_clk);
276 
277 	return 0;
278 }
279 
280 static int mdio_mux_iproc_resume(struct device *dev)
281 {
282 	struct iproc_mdiomux_desc *md = dev_get_drvdata(dev);
283 	int rc;
284 
285 	rc = clk_prepare_enable(md->core_clk);
286 	if (rc) {
287 		dev_err(md->dev, "failed to enable core clk\n");
288 		return rc;
289 	}
290 	mdio_mux_iproc_config(md);
291 
292 	return 0;
293 }
294 #endif
295 
296 static SIMPLE_DEV_PM_OPS(mdio_mux_iproc_pm_ops,
297 			 mdio_mux_iproc_suspend, mdio_mux_iproc_resume);
298 
299 static const struct of_device_id mdio_mux_iproc_match[] = {
300 	{
301 		.compatible = "brcm,mdio-mux-iproc",
302 	},
303 	{},
304 };
305 MODULE_DEVICE_TABLE(of, mdio_mux_iproc_match);
306 
307 static struct platform_driver mdiomux_iproc_driver = {
308 	.driver = {
309 		.name		= "mdio-mux-iproc",
310 		.of_match_table = mdio_mux_iproc_match,
311 		.pm		= &mdio_mux_iproc_pm_ops,
312 	},
313 	.probe		= mdio_mux_iproc_probe,
314 	.remove		= mdio_mux_iproc_remove,
315 };
316 
317 module_platform_driver(mdiomux_iproc_driver);
318 
319 MODULE_DESCRIPTION("iProc MDIO Mux Bus Driver");
320 MODULE_AUTHOR("Pramod Kumar <pramod.kumar@broadcom.com>");
321 MODULE_LICENSE("GPL v2");
322