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 */
pipemux_strap_is_valid(u32 pipemux)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 */
pipemux_strap_read(struct sr_pcie_phy_core * core)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 */
pcie_core_is_for_rc(struct sr_pcie_phy * phy)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
sr_pcie_phy_init(struct phy * p)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
sr_paxc_phy_init(struct phy * p)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
sr_pcie_phy_xlate(struct device * dev,const struct of_phandle_args * args)197 static struct phy *sr_pcie_phy_xlate(struct device *dev,
198 const 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
sr_pcie_phy_probe(struct platform_device * pdev)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