1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Atheros AR724X PCI host controller driver
4  *
5  *  Copyright (C) 2011 René Bolldorf <xsecute@googlemail.com>
6  *  Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
7  */
8 
9 #include <linux/irq.h>
10 #include <linux/pci.h>
11 #include <linux/init.h>
12 #include <linux/delay.h>
13 #include <linux/platform_device.h>
14 #include <asm/mach-ath79/ath79.h>
15 #include <asm/mach-ath79/ar71xx_regs.h>
16 
17 #define AR724X_PCI_REG_APP		0x00
18 #define AR724X_PCI_REG_RESET		0x18
19 #define AR724X_PCI_REG_INT_STATUS	0x4c
20 #define AR724X_PCI_REG_INT_MASK		0x50
21 
22 #define AR724X_PCI_APP_LTSSM_ENABLE	BIT(0)
23 
24 #define AR724X_PCI_RESET_LINK_UP	BIT(0)
25 
26 #define AR724X_PCI_INT_DEV0		BIT(14)
27 
28 #define AR724X_PCI_IRQ_COUNT		1
29 
30 #define AR7240_BAR0_WAR_VALUE	0xffff
31 
32 #define AR724X_PCI_CMD_INIT	(PCI_COMMAND_MEMORY |		\
33 				 PCI_COMMAND_MASTER |		\
34 				 PCI_COMMAND_INVALIDATE |	\
35 				 PCI_COMMAND_PARITY |		\
36 				 PCI_COMMAND_SERR |		\
37 				 PCI_COMMAND_FAST_BACK)
38 
39 struct ar724x_pci_controller {
40 	void __iomem *devcfg_base;
41 	void __iomem *ctrl_base;
42 	void __iomem *crp_base;
43 
44 	int irq;
45 	int irq_base;
46 
47 	bool link_up;
48 	bool bar0_is_cached;
49 	u32  bar0_value;
50 
51 	struct pci_controller pci_controller;
52 	struct resource io_res;
53 	struct resource mem_res;
54 };
55 
ar724x_pci_check_link(struct ar724x_pci_controller * apc)56 static inline bool ar724x_pci_check_link(struct ar724x_pci_controller *apc)
57 {
58 	u32 reset;
59 
60 	reset = __raw_readl(apc->ctrl_base + AR724X_PCI_REG_RESET);
61 	return reset & AR724X_PCI_RESET_LINK_UP;
62 }
63 
64 static inline struct ar724x_pci_controller *
pci_bus_to_ar724x_controller(struct pci_bus * bus)65 pci_bus_to_ar724x_controller(struct pci_bus *bus)
66 {
67 	struct pci_controller *hose;
68 
69 	hose = (struct pci_controller *) bus->sysdata;
70 	return container_of(hose, struct ar724x_pci_controller, pci_controller);
71 }
72 
ar724x_pci_local_write(struct ar724x_pci_controller * apc,int where,int size,u32 value)73 static int ar724x_pci_local_write(struct ar724x_pci_controller *apc,
74 				  int where, int size, u32 value)
75 {
76 	void __iomem *base;
77 	u32 data;
78 	int s;
79 
80 	WARN_ON(where & (size - 1));
81 
82 	if (!apc->link_up)
83 		return PCIBIOS_DEVICE_NOT_FOUND;
84 
85 	base = apc->crp_base;
86 	data = __raw_readl(base + (where & ~3));
87 
88 	switch (size) {
89 	case 1:
90 		s = ((where & 3) * 8);
91 		data &= ~(0xff << s);
92 		data |= ((value & 0xff) << s);
93 		break;
94 	case 2:
95 		s = ((where & 2) * 8);
96 		data &= ~(0xffff << s);
97 		data |= ((value & 0xffff) << s);
98 		break;
99 	case 4:
100 		data = value;
101 		break;
102 	default:
103 		return PCIBIOS_BAD_REGISTER_NUMBER;
104 	}
105 
106 	__raw_writel(data, base + (where & ~3));
107 	/* flush write */
108 	__raw_readl(base + (where & ~3));
109 
110 	return PCIBIOS_SUCCESSFUL;
111 }
112 
ar724x_pci_read(struct pci_bus * bus,unsigned int devfn,int where,int size,uint32_t * value)113 static int ar724x_pci_read(struct pci_bus *bus, unsigned int devfn, int where,
114 			    int size, uint32_t *value)
115 {
116 	struct ar724x_pci_controller *apc;
117 	void __iomem *base;
118 	u32 data;
119 
120 	apc = pci_bus_to_ar724x_controller(bus);
121 	if (!apc->link_up)
122 		return PCIBIOS_DEVICE_NOT_FOUND;
123 
124 	if (devfn)
125 		return PCIBIOS_DEVICE_NOT_FOUND;
126 
127 	base = apc->devcfg_base;
128 	data = __raw_readl(base + (where & ~3));
129 
130 	switch (size) {
131 	case 1:
132 		if (where & 1)
133 			data >>= 8;
134 		if (where & 2)
135 			data >>= 16;
136 		data &= 0xff;
137 		break;
138 	case 2:
139 		if (where & 2)
140 			data >>= 16;
141 		data &= 0xffff;
142 		break;
143 	case 4:
144 		break;
145 	default:
146 		return PCIBIOS_BAD_REGISTER_NUMBER;
147 	}
148 
149 	if (where == PCI_BASE_ADDRESS_0 && size == 4 &&
150 	    apc->bar0_is_cached) {
151 		/* use the cached value */
152 		*value = apc->bar0_value;
153 	} else {
154 		*value = data;
155 	}
156 
157 	return PCIBIOS_SUCCESSFUL;
158 }
159 
ar724x_pci_write(struct pci_bus * bus,unsigned int devfn,int where,int size,uint32_t value)160 static int ar724x_pci_write(struct pci_bus *bus, unsigned int devfn, int where,
161 			     int size, uint32_t value)
162 {
163 	struct ar724x_pci_controller *apc;
164 	void __iomem *base;
165 	u32 data;
166 	int s;
167 
168 	apc = pci_bus_to_ar724x_controller(bus);
169 	if (!apc->link_up)
170 		return PCIBIOS_DEVICE_NOT_FOUND;
171 
172 	if (devfn)
173 		return PCIBIOS_DEVICE_NOT_FOUND;
174 
175 	if (soc_is_ar7240() && where == PCI_BASE_ADDRESS_0 && size == 4) {
176 		if (value != 0xffffffff) {
177 			/*
178 			 * WAR for a hw issue. If the BAR0 register of the
179 			 * device is set to the proper base address, the
180 			 * memory space of the device is not accessible.
181 			 *
182 			 * Cache the intended value so it can be read back,
183 			 * and write a SoC specific constant value to the
184 			 * BAR0 register in order to make the device memory
185 			 * accessible.
186 			 */
187 			apc->bar0_is_cached = true;
188 			apc->bar0_value = value;
189 
190 			value = AR7240_BAR0_WAR_VALUE;
191 		} else {
192 			apc->bar0_is_cached = false;
193 		}
194 	}
195 
196 	base = apc->devcfg_base;
197 	data = __raw_readl(base + (where & ~3));
198 
199 	switch (size) {
200 	case 1:
201 		s = ((where & 3) * 8);
202 		data &= ~(0xff << s);
203 		data |= ((value & 0xff) << s);
204 		break;
205 	case 2:
206 		s = ((where & 2) * 8);
207 		data &= ~(0xffff << s);
208 		data |= ((value & 0xffff) << s);
209 		break;
210 	case 4:
211 		data = value;
212 		break;
213 	default:
214 		return PCIBIOS_BAD_REGISTER_NUMBER;
215 	}
216 
217 	__raw_writel(data, base + (where & ~3));
218 	/* flush write */
219 	__raw_readl(base + (where & ~3));
220 
221 	return PCIBIOS_SUCCESSFUL;
222 }
223 
224 static struct pci_ops ar724x_pci_ops = {
225 	.read	= ar724x_pci_read,
226 	.write	= ar724x_pci_write,
227 };
228 
ar724x_pci_irq_handler(struct irq_desc * desc)229 static void ar724x_pci_irq_handler(struct irq_desc *desc)
230 {
231 	struct ar724x_pci_controller *apc;
232 	void __iomem *base;
233 	u32 pending;
234 
235 	apc = irq_desc_get_handler_data(desc);
236 	base = apc->ctrl_base;
237 
238 	pending = __raw_readl(base + AR724X_PCI_REG_INT_STATUS) &
239 		  __raw_readl(base + AR724X_PCI_REG_INT_MASK);
240 
241 	if (pending & AR724X_PCI_INT_DEV0)
242 		generic_handle_irq(apc->irq_base + 0);
243 
244 	else
245 		spurious_interrupt();
246 }
247 
ar724x_pci_irq_unmask(struct irq_data * d)248 static void ar724x_pci_irq_unmask(struct irq_data *d)
249 {
250 	struct ar724x_pci_controller *apc;
251 	void __iomem *base;
252 	int offset;
253 	u32 t;
254 
255 	apc = irq_data_get_irq_chip_data(d);
256 	base = apc->ctrl_base;
257 	offset = apc->irq_base - d->irq;
258 
259 	switch (offset) {
260 	case 0:
261 		t = __raw_readl(base + AR724X_PCI_REG_INT_MASK);
262 		__raw_writel(t | AR724X_PCI_INT_DEV0,
263 			     base + AR724X_PCI_REG_INT_MASK);
264 		/* flush write */
265 		__raw_readl(base + AR724X_PCI_REG_INT_MASK);
266 	}
267 }
268 
ar724x_pci_irq_mask(struct irq_data * d)269 static void ar724x_pci_irq_mask(struct irq_data *d)
270 {
271 	struct ar724x_pci_controller *apc;
272 	void __iomem *base;
273 	int offset;
274 	u32 t;
275 
276 	apc = irq_data_get_irq_chip_data(d);
277 	base = apc->ctrl_base;
278 	offset = apc->irq_base - d->irq;
279 
280 	switch (offset) {
281 	case 0:
282 		t = __raw_readl(base + AR724X_PCI_REG_INT_MASK);
283 		__raw_writel(t & ~AR724X_PCI_INT_DEV0,
284 			     base + AR724X_PCI_REG_INT_MASK);
285 
286 		/* flush write */
287 		__raw_readl(base + AR724X_PCI_REG_INT_MASK);
288 
289 		t = __raw_readl(base + AR724X_PCI_REG_INT_STATUS);
290 		__raw_writel(t | AR724X_PCI_INT_DEV0,
291 			     base + AR724X_PCI_REG_INT_STATUS);
292 
293 		/* flush write */
294 		__raw_readl(base + AR724X_PCI_REG_INT_STATUS);
295 	}
296 }
297 
298 static struct irq_chip ar724x_pci_irq_chip = {
299 	.name		= "AR724X PCI ",
300 	.irq_mask	= ar724x_pci_irq_mask,
301 	.irq_unmask	= ar724x_pci_irq_unmask,
302 	.irq_mask_ack	= ar724x_pci_irq_mask,
303 };
304 
ar724x_pci_irq_init(struct ar724x_pci_controller * apc,int id)305 static void ar724x_pci_irq_init(struct ar724x_pci_controller *apc,
306 				int id)
307 {
308 	void __iomem *base;
309 	int i;
310 
311 	base = apc->ctrl_base;
312 
313 	__raw_writel(0, base + AR724X_PCI_REG_INT_MASK);
314 	__raw_writel(0, base + AR724X_PCI_REG_INT_STATUS);
315 
316 	apc->irq_base = ATH79_PCI_IRQ_BASE + (id * AR724X_PCI_IRQ_COUNT);
317 
318 	for (i = apc->irq_base;
319 	     i < apc->irq_base + AR724X_PCI_IRQ_COUNT; i++) {
320 		irq_set_chip_and_handler(i, &ar724x_pci_irq_chip,
321 					 handle_level_irq);
322 		irq_set_chip_data(i, apc);
323 	}
324 
325 	irq_set_chained_handler_and_data(apc->irq, ar724x_pci_irq_handler,
326 					 apc);
327 }
328 
ar724x_pci_hw_init(struct ar724x_pci_controller * apc)329 static void ar724x_pci_hw_init(struct ar724x_pci_controller *apc)
330 {
331 	u32 ppl, app;
332 	int wait = 0;
333 
334 	/* deassert PCIe host controller and PCIe PHY reset */
335 	ath79_device_reset_clear(AR724X_RESET_PCIE);
336 	ath79_device_reset_clear(AR724X_RESET_PCIE_PHY);
337 
338 	/* remove the reset of the PCIE PLL */
339 	ppl = ath79_pll_rr(AR724X_PLL_REG_PCIE_CONFIG);
340 	ppl &= ~AR724X_PLL_REG_PCIE_CONFIG_PPL_RESET;
341 	ath79_pll_wr(AR724X_PLL_REG_PCIE_CONFIG, ppl);
342 
343 	/* deassert bypass for the PCIE PLL */
344 	ppl = ath79_pll_rr(AR724X_PLL_REG_PCIE_CONFIG);
345 	ppl &= ~AR724X_PLL_REG_PCIE_CONFIG_PPL_BYPASS;
346 	ath79_pll_wr(AR724X_PLL_REG_PCIE_CONFIG, ppl);
347 
348 	/* set PCIE Application Control to ready */
349 	app = __raw_readl(apc->ctrl_base + AR724X_PCI_REG_APP);
350 	app |= AR724X_PCI_APP_LTSSM_ENABLE;
351 	__raw_writel(app, apc->ctrl_base + AR724X_PCI_REG_APP);
352 
353 	/* wait up to 100ms for PHY link up */
354 	do {
355 		mdelay(10);
356 		wait++;
357 	} while (wait < 10 && !ar724x_pci_check_link(apc));
358 }
359 
ar724x_pci_probe(struct platform_device * pdev)360 static int ar724x_pci_probe(struct platform_device *pdev)
361 {
362 	struct ar724x_pci_controller *apc;
363 	struct resource *res;
364 	int id;
365 
366 	id = pdev->id;
367 	if (id == -1)
368 		id = 0;
369 
370 	apc = devm_kzalloc(&pdev->dev, sizeof(struct ar724x_pci_controller),
371 			    GFP_KERNEL);
372 	if (!apc)
373 		return -ENOMEM;
374 
375 	apc->ctrl_base = devm_platform_ioremap_resource_byname(pdev, "ctrl_base");
376 	if (IS_ERR(apc->ctrl_base))
377 		return PTR_ERR(apc->ctrl_base);
378 
379 	apc->devcfg_base = devm_platform_ioremap_resource_byname(pdev, "cfg_base");
380 	if (IS_ERR(apc->devcfg_base))
381 		return PTR_ERR(apc->devcfg_base);
382 
383 	apc->crp_base = devm_platform_ioremap_resource_byname(pdev, "crp_base");
384 	if (IS_ERR(apc->crp_base))
385 		return PTR_ERR(apc->crp_base);
386 
387 	apc->irq = platform_get_irq(pdev, 0);
388 	if (apc->irq < 0)
389 		return -EINVAL;
390 
391 	res = platform_get_resource_byname(pdev, IORESOURCE_IO, "io_base");
392 	if (!res)
393 		return -EINVAL;
394 
395 	apc->io_res.parent = res;
396 	apc->io_res.name = "PCI IO space";
397 	apc->io_res.start = res->start;
398 	apc->io_res.end = res->end;
399 	apc->io_res.flags = IORESOURCE_IO;
400 
401 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem_base");
402 	if (!res)
403 		return -EINVAL;
404 
405 	apc->mem_res.parent = res;
406 	apc->mem_res.name = "PCI memory space";
407 	apc->mem_res.start = res->start;
408 	apc->mem_res.end = res->end;
409 	apc->mem_res.flags = IORESOURCE_MEM;
410 
411 	apc->pci_controller.pci_ops = &ar724x_pci_ops;
412 	apc->pci_controller.io_resource = &apc->io_res;
413 	apc->pci_controller.mem_resource = &apc->mem_res;
414 
415 	/*
416 	 * Do the full PCIE Root Complex Initialization Sequence if the PCIe
417 	 * host controller is in reset.
418 	 */
419 	if (ath79_reset_rr(AR724X_RESET_REG_RESET_MODULE) & AR724X_RESET_PCIE)
420 		ar724x_pci_hw_init(apc);
421 
422 	apc->link_up = ar724x_pci_check_link(apc);
423 	if (!apc->link_up)
424 		dev_warn(&pdev->dev, "PCIe link is down\n");
425 
426 	ar724x_pci_irq_init(apc, id);
427 
428 	ar724x_pci_local_write(apc, PCI_COMMAND, 4, AR724X_PCI_CMD_INIT);
429 
430 	register_pci_controller(&apc->pci_controller);
431 
432 	return 0;
433 }
434 
435 static struct platform_driver ar724x_pci_driver = {
436 	.probe = ar724x_pci_probe,
437 	.driver = {
438 		.name = "ar724x-pci",
439 	},
440 };
441 
ar724x_pci_init(void)442 static int __init ar724x_pci_init(void)
443 {
444 	return platform_driver_register(&ar724x_pci_driver);
445 }
446 
447 postcore_initcall(ar724x_pci_init);
448