1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * PCIe host controller driver for ST Microelectronics SPEAr13xx SoCs
4  *
5  * SPEAr13xx PCIe Glue Layer Source Code
6  *
7  * Copyright (C) 2010-2014 ST Microelectronics
8  * Pratyush Anand <pratyush.anand@gmail.com>
9  * Mohit Kumar <mohit.kumar.dhaka@gmail.com>
10  */
11 
12 #include <linux/clk.h>
13 #include <linux/interrupt.h>
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/of.h>
17 #include <linux/pci.h>
18 #include <linux/phy/phy.h>
19 #include <linux/platform_device.h>
20 #include <linux/resource.h>
21 
22 #include "pcie-designware.h"
23 
24 struct spear13xx_pcie {
25 	struct dw_pcie		*pci;
26 	void __iomem		*app_base;
27 	struct phy		*phy;
28 	struct clk		*clk;
29 	bool			is_gen1;
30 };
31 
32 struct pcie_app_reg {
33 	u32	app_ctrl_0;		/* cr0 */
34 	u32	app_ctrl_1;		/* cr1 */
35 	u32	app_status_0;		/* cr2 */
36 	u32	app_status_1;		/* cr3 */
37 	u32	msg_status;		/* cr4 */
38 	u32	msg_payload;		/* cr5 */
39 	u32	int_sts;		/* cr6 */
40 	u32	int_clr;		/* cr7 */
41 	u32	int_mask;		/* cr8 */
42 	u32	mst_bmisc;		/* cr9 */
43 	u32	phy_ctrl;		/* cr10 */
44 	u32	phy_status;		/* cr11 */
45 	u32	cxpl_debug_info_0;	/* cr12 */
46 	u32	cxpl_debug_info_1;	/* cr13 */
47 	u32	ven_msg_ctrl_0;		/* cr14 */
48 	u32	ven_msg_ctrl_1;		/* cr15 */
49 	u32	ven_msg_data_0;		/* cr16 */
50 	u32	ven_msg_data_1;		/* cr17 */
51 	u32	ven_msi_0;		/* cr18 */
52 	u32	ven_msi_1;		/* cr19 */
53 	u32	mst_rmisc;		/* cr20 */
54 };
55 
56 /* CR0 ID */
57 #define APP_LTSSM_ENABLE_ID			3
58 #define DEVICE_TYPE_RC				(4 << 25)
59 #define MISCTRL_EN_ID				30
60 #define REG_TRANSLATION_ENABLE			31
61 
62 /* CR3 ID */
63 #define XMLH_LINK_UP				(1 << 6)
64 
65 /* CR6 */
66 #define MSI_CTRL_INT				(1 << 26)
67 
68 #define EXP_CAP_ID_OFFSET			0x70
69 
70 #define to_spear13xx_pcie(x)	dev_get_drvdata((x)->dev)
71 
72 static int spear13xx_pcie_establish_link(struct spear13xx_pcie *spear13xx_pcie)
73 {
74 	struct dw_pcie *pci = spear13xx_pcie->pci;
75 	struct pcie_port *pp = &pci->pp;
76 	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
77 	u32 val;
78 	u32 exp_cap_off = EXP_CAP_ID_OFFSET;
79 
80 	if (dw_pcie_link_up(pci)) {
81 		dev_err(pci->dev, "link already up\n");
82 		return 0;
83 	}
84 
85 	dw_pcie_setup_rc(pp);
86 
87 	/*
88 	 * this controller support only 128 bytes read size, however its
89 	 * default value in capability register is 512 bytes. So force
90 	 * it to 128 here.
91 	 */
92 	dw_pcie_read(pci->dbi_base + exp_cap_off + PCI_EXP_DEVCTL, 2, &val);
93 	val &= ~PCI_EXP_DEVCTL_READRQ;
94 	dw_pcie_write(pci->dbi_base + exp_cap_off + PCI_EXP_DEVCTL, 2, val);
95 
96 	dw_pcie_write(pci->dbi_base + PCI_VENDOR_ID, 2, 0x104A);
97 	dw_pcie_write(pci->dbi_base + PCI_DEVICE_ID, 2, 0xCD80);
98 
99 	/*
100 	 * if is_gen1 is set then handle it, so that some buggy card
101 	 * also works
102 	 */
103 	if (spear13xx_pcie->is_gen1) {
104 		dw_pcie_read(pci->dbi_base + exp_cap_off + PCI_EXP_LNKCAP,
105 			     4, &val);
106 		if ((val & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) {
107 			val &= ~((u32)PCI_EXP_LNKCAP_SLS);
108 			val |= PCI_EXP_LNKCAP_SLS_2_5GB;
109 			dw_pcie_write(pci->dbi_base + exp_cap_off +
110 				      PCI_EXP_LNKCAP, 4, val);
111 		}
112 
113 		dw_pcie_read(pci->dbi_base + exp_cap_off + PCI_EXP_LNKCTL2,
114 			     2, &val);
115 		if ((val & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) {
116 			val &= ~((u32)PCI_EXP_LNKCAP_SLS);
117 			val |= PCI_EXP_LNKCAP_SLS_2_5GB;
118 			dw_pcie_write(pci->dbi_base + exp_cap_off +
119 				      PCI_EXP_LNKCTL2, 2, val);
120 		}
121 	}
122 
123 	/* enable ltssm */
124 	writel(DEVICE_TYPE_RC | (1 << MISCTRL_EN_ID)
125 			| (1 << APP_LTSSM_ENABLE_ID)
126 			| ((u32)1 << REG_TRANSLATION_ENABLE),
127 			&app_reg->app_ctrl_0);
128 
129 	return dw_pcie_wait_for_link(pci);
130 }
131 
132 static irqreturn_t spear13xx_pcie_irq_handler(int irq, void *arg)
133 {
134 	struct spear13xx_pcie *spear13xx_pcie = arg;
135 	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
136 	struct dw_pcie *pci = spear13xx_pcie->pci;
137 	struct pcie_port *pp = &pci->pp;
138 	unsigned int status;
139 
140 	status = readl(&app_reg->int_sts);
141 
142 	if (status & MSI_CTRL_INT) {
143 		BUG_ON(!IS_ENABLED(CONFIG_PCI_MSI));
144 		dw_handle_msi_irq(pp);
145 	}
146 
147 	writel(status, &app_reg->int_clr);
148 
149 	return IRQ_HANDLED;
150 }
151 
152 static void spear13xx_pcie_enable_interrupts(struct spear13xx_pcie *spear13xx_pcie)
153 {
154 	struct dw_pcie *pci = spear13xx_pcie->pci;
155 	struct pcie_port *pp = &pci->pp;
156 	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
157 
158 	/* Enable MSI interrupt */
159 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
160 		dw_pcie_msi_init(pp);
161 		writel(readl(&app_reg->int_mask) |
162 				MSI_CTRL_INT, &app_reg->int_mask);
163 	}
164 }
165 
166 static int spear13xx_pcie_link_up(struct dw_pcie *pci)
167 {
168 	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pci);
169 	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
170 
171 	if (readl(&app_reg->app_status_1) & XMLH_LINK_UP)
172 		return 1;
173 
174 	return 0;
175 }
176 
177 static int spear13xx_pcie_host_init(struct pcie_port *pp)
178 {
179 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
180 	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pci);
181 
182 	spear13xx_pcie_establish_link(spear13xx_pcie);
183 	spear13xx_pcie_enable_interrupts(spear13xx_pcie);
184 
185 	return 0;
186 }
187 
188 static const struct dw_pcie_host_ops spear13xx_pcie_host_ops = {
189 	.host_init = spear13xx_pcie_host_init,
190 };
191 
192 static int spear13xx_add_pcie_port(struct spear13xx_pcie *spear13xx_pcie,
193 				   struct platform_device *pdev)
194 {
195 	struct dw_pcie *pci = spear13xx_pcie->pci;
196 	struct pcie_port *pp = &pci->pp;
197 	struct device *dev = &pdev->dev;
198 	int ret;
199 
200 	pp->irq = platform_get_irq(pdev, 0);
201 	if (pp->irq < 0)
202 		return pp->irq;
203 
204 	ret = devm_request_irq(dev, pp->irq, spear13xx_pcie_irq_handler,
205 			       IRQF_SHARED | IRQF_NO_THREAD,
206 			       "spear1340-pcie", spear13xx_pcie);
207 	if (ret) {
208 		dev_err(dev, "failed to request irq %d\n", pp->irq);
209 		return ret;
210 	}
211 
212 	pp->ops = &spear13xx_pcie_host_ops;
213 
214 	ret = dw_pcie_host_init(pp);
215 	if (ret) {
216 		dev_err(dev, "failed to initialize host\n");
217 		return ret;
218 	}
219 
220 	return 0;
221 }
222 
223 static const struct dw_pcie_ops dw_pcie_ops = {
224 	.link_up = spear13xx_pcie_link_up,
225 };
226 
227 static int spear13xx_pcie_probe(struct platform_device *pdev)
228 {
229 	struct device *dev = &pdev->dev;
230 	struct dw_pcie *pci;
231 	struct spear13xx_pcie *spear13xx_pcie;
232 	struct device_node *np = dev->of_node;
233 	struct resource *dbi_base;
234 	int ret;
235 
236 	spear13xx_pcie = devm_kzalloc(dev, sizeof(*spear13xx_pcie), GFP_KERNEL);
237 	if (!spear13xx_pcie)
238 		return -ENOMEM;
239 
240 	pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
241 	if (!pci)
242 		return -ENOMEM;
243 
244 	pci->dev = dev;
245 	pci->ops = &dw_pcie_ops;
246 
247 	spear13xx_pcie->pci = pci;
248 
249 	spear13xx_pcie->phy = devm_phy_get(dev, "pcie-phy");
250 	if (IS_ERR(spear13xx_pcie->phy)) {
251 		ret = PTR_ERR(spear13xx_pcie->phy);
252 		if (ret == -EPROBE_DEFER)
253 			dev_info(dev, "probe deferred\n");
254 		else
255 			dev_err(dev, "couldn't get pcie-phy\n");
256 		return ret;
257 	}
258 
259 	phy_init(spear13xx_pcie->phy);
260 
261 	spear13xx_pcie->clk = devm_clk_get(dev, NULL);
262 	if (IS_ERR(spear13xx_pcie->clk)) {
263 		dev_err(dev, "couldn't get clk for pcie\n");
264 		return PTR_ERR(spear13xx_pcie->clk);
265 	}
266 	ret = clk_prepare_enable(spear13xx_pcie->clk);
267 	if (ret) {
268 		dev_err(dev, "couldn't enable clk for pcie\n");
269 		return ret;
270 	}
271 
272 	dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
273 	pci->dbi_base = devm_pci_remap_cfg_resource(dev, dbi_base);
274 	if (IS_ERR(pci->dbi_base)) {
275 		ret = PTR_ERR(pci->dbi_base);
276 		goto fail_clk;
277 	}
278 	spear13xx_pcie->app_base = pci->dbi_base + 0x2000;
279 
280 	if (of_property_read_bool(np, "st,pcie-is-gen1"))
281 		spear13xx_pcie->is_gen1 = true;
282 
283 	platform_set_drvdata(pdev, spear13xx_pcie);
284 
285 	ret = spear13xx_add_pcie_port(spear13xx_pcie, pdev);
286 	if (ret < 0)
287 		goto fail_clk;
288 
289 	return 0;
290 
291 fail_clk:
292 	clk_disable_unprepare(spear13xx_pcie->clk);
293 
294 	return ret;
295 }
296 
297 static const struct of_device_id spear13xx_pcie_of_match[] = {
298 	{ .compatible = "st,spear1340-pcie", },
299 	{},
300 };
301 
302 static struct platform_driver spear13xx_pcie_driver = {
303 	.probe		= spear13xx_pcie_probe,
304 	.driver = {
305 		.name	= "spear-pcie",
306 		.of_match_table = of_match_ptr(spear13xx_pcie_of_match),
307 		.suppress_bind_attrs = true,
308 	},
309 };
310 
311 builtin_platform_driver(spear13xx_pcie_driver);
312