1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * PCIe host controller driver for Rockchip SoCs.
4 *
5 * Copyright (C) 2021 Rockchip Electronics Co., Ltd.
6 * http://www.rock-chips.com
7 *
8 * Author: Simon Xue <xxm@rock-chips.com>
9 */
10
11 #include <linux/clk.h>
12 #include <linux/gpio/consumer.h>
13 #include <linux/mfd/syscon.h>
14 #include <linux/module.h>
15 #include <linux/of_device.h>
16 #include <linux/phy/phy.h>
17 #include <linux/platform_device.h>
18 #include <linux/regmap.h>
19 #include <linux/reset.h>
20
21 #include "pcie-designware.h"
22
23 /*
24 * The upper 16 bits of PCIE_CLIENT_CONFIG are a write
25 * mask for the lower 16 bits.
26 */
27 #define HIWORD_UPDATE(mask, val) (((mask) << 16) | (val))
28 #define HIWORD_UPDATE_BIT(val) HIWORD_UPDATE(val, val)
29
30 #define to_rockchip_pcie(x) dev_get_drvdata((x)->dev)
31
32 #define PCIE_CLIENT_RC_MODE HIWORD_UPDATE_BIT(0x40)
33 #define PCIE_CLIENT_ENABLE_LTSSM HIWORD_UPDATE_BIT(0xc)
34 #define PCIE_SMLH_LINKUP BIT(16)
35 #define PCIE_RDLH_LINKUP BIT(17)
36 #define PCIE_LINKUP (PCIE_SMLH_LINKUP | PCIE_RDLH_LINKUP)
37 #define PCIE_L0S_ENTRY 0x11
38 #define PCIE_CLIENT_GENERAL_CONTROL 0x0
39 #define PCIE_CLIENT_GENERAL_DEBUG 0x104
40 #define PCIE_CLIENT_HOT_RESET_CTRL 0x180
41 #define PCIE_CLIENT_LTSSM_STATUS 0x300
42 #define PCIE_LTSSM_ENABLE_ENHANCE BIT(4)
43 #define PCIE_LTSSM_STATUS_MASK GENMASK(5, 0)
44
45 struct rockchip_pcie {
46 struct dw_pcie pci;
47 void __iomem *apb_base;
48 struct phy *phy;
49 struct clk_bulk_data *clks;
50 unsigned int clk_cnt;
51 struct reset_control *rst;
52 struct gpio_desc *rst_gpio;
53 struct regulator *vpcie3v3;
54 };
55
rockchip_pcie_readl_apb(struct rockchip_pcie * rockchip,u32 reg)56 static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip,
57 u32 reg)
58 {
59 return readl_relaxed(rockchip->apb_base + reg);
60 }
61
rockchip_pcie_writel_apb(struct rockchip_pcie * rockchip,u32 val,u32 reg)62 static void rockchip_pcie_writel_apb(struct rockchip_pcie *rockchip,
63 u32 val, u32 reg)
64 {
65 writel_relaxed(val, rockchip->apb_base + reg);
66 }
67
rockchip_pcie_enable_ltssm(struct rockchip_pcie * rockchip)68 static void rockchip_pcie_enable_ltssm(struct rockchip_pcie *rockchip)
69 {
70 rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_ENABLE_LTSSM,
71 PCIE_CLIENT_GENERAL_CONTROL);
72 }
73
rockchip_pcie_link_up(struct dw_pcie * pci)74 static int rockchip_pcie_link_up(struct dw_pcie *pci)
75 {
76 struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
77 u32 val = rockchip_pcie_readl_apb(rockchip, PCIE_CLIENT_LTSSM_STATUS);
78
79 if ((val & PCIE_LINKUP) == PCIE_LINKUP &&
80 (val & PCIE_LTSSM_STATUS_MASK) == PCIE_L0S_ENTRY)
81 return 1;
82
83 return 0;
84 }
85
rockchip_pcie_start_link(struct dw_pcie * pci)86 static int rockchip_pcie_start_link(struct dw_pcie *pci)
87 {
88 struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
89
90 /* Reset device */
91 gpiod_set_value_cansleep(rockchip->rst_gpio, 0);
92
93 rockchip_pcie_enable_ltssm(rockchip);
94
95 /*
96 * PCIe requires the refclk to be stable for 100µs prior to releasing
97 * PERST. See table 2-4 in section 2.6.2 AC Specifications of the PCI
98 * Express Card Electromechanical Specification, 1.1. However, we don't
99 * know if the refclk is coming from RC's PHY or external OSC. If it's
100 * from RC, so enabling LTSSM is the just right place to release #PERST.
101 * We need more extra time as before, rather than setting just
102 * 100us as we don't know how long should the device need to reset.
103 */
104 msleep(100);
105 gpiod_set_value_cansleep(rockchip->rst_gpio, 1);
106
107 return 0;
108 }
109
rockchip_pcie_host_init(struct pcie_port * pp)110 static int rockchip_pcie_host_init(struct pcie_port *pp)
111 {
112 struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
113 struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
114 u32 val = HIWORD_UPDATE_BIT(PCIE_LTSSM_ENABLE_ENHANCE);
115
116 /* LTSSM enable control mode */
117 rockchip_pcie_writel_apb(rockchip, val, PCIE_CLIENT_HOT_RESET_CTRL);
118
119 rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_RC_MODE,
120 PCIE_CLIENT_GENERAL_CONTROL);
121
122 return 0;
123 }
124
125 static const struct dw_pcie_host_ops rockchip_pcie_host_ops = {
126 .host_init = rockchip_pcie_host_init,
127 };
128
rockchip_pcie_clk_init(struct rockchip_pcie * rockchip)129 static int rockchip_pcie_clk_init(struct rockchip_pcie *rockchip)
130 {
131 struct device *dev = rockchip->pci.dev;
132 int ret;
133
134 ret = devm_clk_bulk_get_all(dev, &rockchip->clks);
135 if (ret < 0)
136 return ret;
137
138 rockchip->clk_cnt = ret;
139
140 return clk_bulk_prepare_enable(rockchip->clk_cnt, rockchip->clks);
141 }
142
rockchip_pcie_resource_get(struct platform_device * pdev,struct rockchip_pcie * rockchip)143 static int rockchip_pcie_resource_get(struct platform_device *pdev,
144 struct rockchip_pcie *rockchip)
145 {
146 rockchip->apb_base = devm_platform_ioremap_resource_byname(pdev, "apb");
147 if (IS_ERR(rockchip->apb_base))
148 return PTR_ERR(rockchip->apb_base);
149
150 rockchip->rst_gpio = devm_gpiod_get_optional(&pdev->dev, "reset",
151 GPIOD_OUT_HIGH);
152 if (IS_ERR(rockchip->rst_gpio))
153 return PTR_ERR(rockchip->rst_gpio);
154
155 return 0;
156 }
157
rockchip_pcie_phy_init(struct rockchip_pcie * rockchip)158 static int rockchip_pcie_phy_init(struct rockchip_pcie *rockchip)
159 {
160 struct device *dev = rockchip->pci.dev;
161 int ret;
162
163 rockchip->phy = devm_phy_get(dev, "pcie-phy");
164 if (IS_ERR(rockchip->phy))
165 return dev_err_probe(dev, PTR_ERR(rockchip->phy),
166 "missing PHY\n");
167
168 ret = phy_init(rockchip->phy);
169 if (ret < 0)
170 return ret;
171
172 ret = phy_power_on(rockchip->phy);
173 if (ret)
174 phy_exit(rockchip->phy);
175
176 return ret;
177 }
178
rockchip_pcie_phy_deinit(struct rockchip_pcie * rockchip)179 static void rockchip_pcie_phy_deinit(struct rockchip_pcie *rockchip)
180 {
181 phy_exit(rockchip->phy);
182 phy_power_off(rockchip->phy);
183 }
184
rockchip_pcie_reset_control_release(struct rockchip_pcie * rockchip)185 static int rockchip_pcie_reset_control_release(struct rockchip_pcie *rockchip)
186 {
187 struct device *dev = rockchip->pci.dev;
188
189 rockchip->rst = devm_reset_control_array_get_exclusive(dev);
190 if (IS_ERR(rockchip->rst))
191 return dev_err_probe(dev, PTR_ERR(rockchip->rst),
192 "failed to get reset lines\n");
193
194 return reset_control_deassert(rockchip->rst);
195 }
196
197 static const struct dw_pcie_ops dw_pcie_ops = {
198 .link_up = rockchip_pcie_link_up,
199 .start_link = rockchip_pcie_start_link,
200 };
201
rockchip_pcie_probe(struct platform_device * pdev)202 static int rockchip_pcie_probe(struct platform_device *pdev)
203 {
204 struct device *dev = &pdev->dev;
205 struct rockchip_pcie *rockchip;
206 struct pcie_port *pp;
207 int ret;
208
209 rockchip = devm_kzalloc(dev, sizeof(*rockchip), GFP_KERNEL);
210 if (!rockchip)
211 return -ENOMEM;
212
213 platform_set_drvdata(pdev, rockchip);
214
215 rockchip->pci.dev = dev;
216 rockchip->pci.ops = &dw_pcie_ops;
217
218 pp = &rockchip->pci.pp;
219 pp->ops = &rockchip_pcie_host_ops;
220
221 ret = rockchip_pcie_resource_get(pdev, rockchip);
222 if (ret)
223 return ret;
224
225 /* DON'T MOVE ME: must be enable before PHY init */
226 rockchip->vpcie3v3 = devm_regulator_get_optional(dev, "vpcie3v3");
227 if (IS_ERR(rockchip->vpcie3v3)) {
228 if (PTR_ERR(rockchip->vpcie3v3) != -ENODEV)
229 return dev_err_probe(dev, PTR_ERR(rockchip->vpcie3v3),
230 "failed to get vpcie3v3 regulator\n");
231 rockchip->vpcie3v3 = NULL;
232 } else {
233 ret = regulator_enable(rockchip->vpcie3v3);
234 if (ret) {
235 dev_err(dev, "failed to enable vpcie3v3 regulator\n");
236 return ret;
237 }
238 }
239
240 ret = rockchip_pcie_phy_init(rockchip);
241 if (ret)
242 goto disable_regulator;
243
244 ret = rockchip_pcie_reset_control_release(rockchip);
245 if (ret)
246 goto deinit_phy;
247
248 ret = rockchip_pcie_clk_init(rockchip);
249 if (ret)
250 goto deinit_phy;
251
252 ret = dw_pcie_host_init(pp);
253 if (!ret)
254 return 0;
255
256 clk_bulk_disable_unprepare(rockchip->clk_cnt, rockchip->clks);
257 deinit_phy:
258 rockchip_pcie_phy_deinit(rockchip);
259 disable_regulator:
260 if (rockchip->vpcie3v3)
261 regulator_disable(rockchip->vpcie3v3);
262
263 return ret;
264 }
265
266 static const struct of_device_id rockchip_pcie_of_match[] = {
267 { .compatible = "rockchip,rk3568-pcie", },
268 {},
269 };
270
271 static struct platform_driver rockchip_pcie_driver = {
272 .driver = {
273 .name = "rockchip-dw-pcie",
274 .of_match_table = rockchip_pcie_of_match,
275 .suppress_bind_attrs = true,
276 },
277 .probe = rockchip_pcie_probe,
278 };
279 builtin_platform_driver(rockchip_pcie_driver);
280