1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2016-2018 Broadcom
4  */
5 
6 #include <linux/clk.h>
7 #include <linux/delay.h>
8 #include <linux/io.h>
9 #include <linux/module.h>
10 #include <linux/mfd/syscon.h>
11 #include <linux/of.h>
12 #include <linux/phy/phy.h>
13 #include <linux/platform_device.h>
14 #include <linux/regmap.h>
15 
16 /* we have up to 8 PAXB based RC. The 9th one is always PAXC */
17 #define SR_NR_PCIE_PHYS               9
18 #define SR_PAXC_PHY_IDX               (SR_NR_PCIE_PHYS - 1)
19 
20 #define PCIE_PIPEMUX_CFG_OFFSET       0x10c
21 #define PCIE_PIPEMUX_SELECT_STRAP     0xf
22 
23 #define CDRU_STRAP_DATA_LSW_OFFSET    0x5c
24 #define PCIE_PIPEMUX_SHIFT            19
25 #define PCIE_PIPEMUX_MASK             0xf
26 
27 #define MHB_MEM_PW_PAXC_OFFSET        0x1c0
28 #define MHB_PWR_ARR_POWERON           0x8
29 #define MHB_PWR_ARR_POWEROK           0x4
30 #define MHB_PWR_POWERON               0x2
31 #define MHB_PWR_POWEROK               0x1
32 #define MHB_PWR_STATUS_MASK           (MHB_PWR_ARR_POWERON | \
33 				       MHB_PWR_ARR_POWEROK | \
34 				       MHB_PWR_POWERON | \
35 				       MHB_PWR_POWEROK)
36 
37 struct sr_pcie_phy_core;
38 
39 /**
40  * struct sr_pcie_phy - Stingray PCIe PHY
41  *
42  * @core: pointer to the Stingray PCIe PHY core control
43  * @index: PHY index
44  * @phy: pointer to the kernel PHY device
45  */
46 struct sr_pcie_phy {
47 	struct sr_pcie_phy_core *core;
48 	unsigned int index;
49 	struct phy *phy;
50 };
51 
52 /**
53  * struct sr_pcie_phy_core - Stingray PCIe PHY core control
54  *
55  * @dev: pointer to device
56  * @base: base register of PCIe SS
57  * @cdru: regmap to the CDRU device
58  * @mhb: regmap to the MHB device
59  * @pipemux: pipemuex strap
60  * @phys: array of PCIe PHYs
61  */
62 struct sr_pcie_phy_core {
63 	struct device *dev;
64 	void __iomem *base;
65 	struct regmap *cdru;
66 	struct regmap *mhb;
67 	u32 pipemux;
68 	struct sr_pcie_phy phys[SR_NR_PCIE_PHYS];
69 };
70 
71 /*
72  * PCIe PIPEMUX lookup table
73  *
74  * Each array index represents a PIPEMUX strap setting
75  * The array element represents a bitmap where a set bit means the PCIe
76  * core and associated serdes has been enabled as RC and is available for use
77  */
78 static const u8 pipemux_table[] = {
79 	/* PIPEMUX = 0, EP 1x16 */
80 	0x00,
81 	/* PIPEMUX = 1, EP 1x8 + RC 1x8, core 7 */
82 	0x80,
83 	/* PIPEMUX = 2, EP 4x4 */
84 	0x00,
85 	/* PIPEMUX = 3, RC 2x8, cores 0, 7 */
86 	0x81,
87 	/* PIPEMUX = 4, RC 4x4, cores 0, 1, 6, 7 */
88 	0xc3,
89 	/* PIPEMUX = 5, RC 8x2, all 8 cores */
90 	0xff,
91 	/* PIPEMUX = 6, RC 3x4 + 2x2, cores 0, 2, 3, 6, 7 */
92 	0xcd,
93 	/* PIPEMUX = 7, RC 1x4 + 6x2, cores 0, 2, 3, 4, 5, 6, 7 */
94 	0xfd,
95 	/* PIPEMUX = 8, EP 1x8 + RC 4x2, cores 4, 5, 6, 7 */
96 	0xf0,
97 	/* PIPEMUX = 9, EP 1x8 + RC 2x4, cores 6, 7 */
98 	0xc0,
99 	/* PIPEMUX = 10, EP 2x4 + RC 2x4, cores 1, 6 */
100 	0x42,
101 	/* PIPEMUX = 11, EP 2x4 + RC 4x2, cores 2, 3, 4, 5 */
102 	0x3c,
103 	/* PIPEMUX = 12, EP 1x4 + RC 6x2, cores 2, 3, 4, 5, 6, 7 */
104 	0xfc,
105 	/* PIPEMUX = 13, RC 2x4 + RC 1x4 + 2x2, cores 2, 3, 6 */
106 	0x4c,
107 };
108 
109 /*
110  * Return true if the strap setting is valid
111  */
112 static bool pipemux_strap_is_valid(u32 pipemux)
113 {
114 	return !!(pipemux < ARRAY_SIZE(pipemux_table));
115 }
116 
117 /*
118  * Read the PCIe PIPEMUX from strap
119  */
120 static u32 pipemux_strap_read(struct sr_pcie_phy_core *core)
121 {
122 	u32 pipemux;
123 
124 	/*
125 	 * Read PIPEMUX configuration register to determine the pipemux setting
126 	 *
127 	 * In the case when the value indicates using HW strap, fall back to
128 	 * use HW strap
129 	 */
130 	pipemux = readl(core->base + PCIE_PIPEMUX_CFG_OFFSET);
131 	pipemux &= PCIE_PIPEMUX_MASK;
132 	if (pipemux == PCIE_PIPEMUX_SELECT_STRAP) {
133 		regmap_read(core->cdru, CDRU_STRAP_DATA_LSW_OFFSET, &pipemux);
134 		pipemux >>= PCIE_PIPEMUX_SHIFT;
135 		pipemux &= PCIE_PIPEMUX_MASK;
136 	}
137 
138 	return pipemux;
139 }
140 
141 /*
142  * Given a PIPEMUX strap and PCIe core index, this function returns true if the
143  * PCIe core needs to be enabled
144  */
145 static bool pcie_core_is_for_rc(struct sr_pcie_phy *phy)
146 {
147 	struct sr_pcie_phy_core *core = phy->core;
148 	unsigned int core_idx = phy->index;
149 
150 	return !!((pipemux_table[core->pipemux] >> core_idx) & 0x1);
151 }
152 
153 static int sr_pcie_phy_init(struct phy *p)
154 {
155 	struct sr_pcie_phy *phy = phy_get_drvdata(p);
156 
157 	/*
158 	 * Check whether this PHY is for root complex or not. If yes, return
159 	 * zero so the host driver can proceed to enumeration. If not, return
160 	 * an error and that will force the host driver to bail out
161 	 */
162 	if (pcie_core_is_for_rc(phy))
163 		return 0;
164 
165 	return -ENODEV;
166 }
167 
168 static int sr_paxc_phy_init(struct phy *p)
169 {
170 	struct sr_pcie_phy *phy = phy_get_drvdata(p);
171 	struct sr_pcie_phy_core *core = phy->core;
172 	unsigned int core_idx = phy->index;
173 	u32 val;
174 
175 	if (core_idx != SR_PAXC_PHY_IDX)
176 		return -EINVAL;
177 
178 	regmap_read(core->mhb, MHB_MEM_PW_PAXC_OFFSET, &val);
179 	if ((val & MHB_PWR_STATUS_MASK) != MHB_PWR_STATUS_MASK) {
180 		dev_err(core->dev, "PAXC is not powered up\n");
181 		return -ENODEV;
182 	}
183 
184 	return 0;
185 }
186 
187 static const struct phy_ops sr_pcie_phy_ops = {
188 	.init = sr_pcie_phy_init,
189 	.owner = THIS_MODULE,
190 };
191 
192 static const struct phy_ops sr_paxc_phy_ops = {
193 	.init = sr_paxc_phy_init,
194 	.owner = THIS_MODULE,
195 };
196 
197 static struct phy *sr_pcie_phy_xlate(struct device *dev,
198 				     struct of_phandle_args *args)
199 {
200 	struct sr_pcie_phy_core *core;
201 	int phy_idx;
202 
203 	core = dev_get_drvdata(dev);
204 	if (!core)
205 		return ERR_PTR(-EINVAL);
206 
207 	phy_idx = args->args[0];
208 
209 	if (WARN_ON(phy_idx >= SR_NR_PCIE_PHYS))
210 		return ERR_PTR(-ENODEV);
211 
212 	return core->phys[phy_idx].phy;
213 }
214 
215 static int sr_pcie_phy_probe(struct platform_device *pdev)
216 {
217 	struct device *dev = &pdev->dev;
218 	struct device_node *node = dev->of_node;
219 	struct sr_pcie_phy_core *core;
220 	struct phy_provider *provider;
221 	unsigned int phy_idx = 0;
222 
223 	core = devm_kzalloc(dev, sizeof(*core), GFP_KERNEL);
224 	if (!core)
225 		return -ENOMEM;
226 
227 	core->dev = dev;
228 	core->base = devm_platform_ioremap_resource(pdev, 0);
229 	if (IS_ERR(core->base))
230 		return PTR_ERR(core->base);
231 
232 	core->cdru = syscon_regmap_lookup_by_phandle(node, "brcm,sr-cdru");
233 	if (IS_ERR(core->cdru)) {
234 		dev_err(core->dev, "unable to find CDRU device\n");
235 		return PTR_ERR(core->cdru);
236 	}
237 
238 	core->mhb = syscon_regmap_lookup_by_phandle(node, "brcm,sr-mhb");
239 	if (IS_ERR(core->mhb)) {
240 		dev_err(core->dev, "unable to find MHB device\n");
241 		return PTR_ERR(core->mhb);
242 	}
243 
244 	/* read the PCIe PIPEMUX strap setting */
245 	core->pipemux = pipemux_strap_read(core);
246 	if (!pipemux_strap_is_valid(core->pipemux)) {
247 		dev_err(core->dev, "invalid PCIe PIPEMUX strap %u\n",
248 			core->pipemux);
249 		return -EIO;
250 	}
251 
252 	for (phy_idx = 0; phy_idx < SR_NR_PCIE_PHYS; phy_idx++) {
253 		struct sr_pcie_phy *p = &core->phys[phy_idx];
254 		const struct phy_ops *ops;
255 
256 		if (phy_idx == SR_PAXC_PHY_IDX)
257 			ops = &sr_paxc_phy_ops;
258 		else
259 			ops = &sr_pcie_phy_ops;
260 
261 		p->phy = devm_phy_create(dev, NULL, ops);
262 		if (IS_ERR(p->phy)) {
263 			dev_err(dev, "failed to create PCIe PHY\n");
264 			return PTR_ERR(p->phy);
265 		}
266 
267 		p->core = core;
268 		p->index = phy_idx;
269 		phy_set_drvdata(p->phy, p);
270 	}
271 
272 	dev_set_drvdata(dev, core);
273 
274 	provider = devm_of_phy_provider_register(dev, sr_pcie_phy_xlate);
275 	if (IS_ERR(provider)) {
276 		dev_err(dev, "failed to register PHY provider\n");
277 		return PTR_ERR(provider);
278 	}
279 
280 	dev_info(dev, "Stingray PCIe PHY driver initialized\n");
281 
282 	return 0;
283 }
284 
285 static const struct of_device_id sr_pcie_phy_match_table[] = {
286 	{ .compatible = "brcm,sr-pcie-phy" },
287 	{ }
288 };
289 MODULE_DEVICE_TABLE(of, sr_pcie_phy_match_table);
290 
291 static struct platform_driver sr_pcie_phy_driver = {
292 	.driver = {
293 		.name		= "sr-pcie-phy",
294 		.of_match_table	= sr_pcie_phy_match_table,
295 	},
296 	.probe	= sr_pcie_phy_probe,
297 };
298 module_platform_driver(sr_pcie_phy_driver);
299 
300 MODULE_AUTHOR("Ray Jui <ray.jui@broadcom.com>");
301 MODULE_DESCRIPTION("Broadcom Stingray PCIe PHY driver");
302 MODULE_LICENSE("GPL v2");
303