xref: /openbmc/u-boot/drivers/pci/pcie_imx.c (revision 95de1e2f)
1 /*
2  * Freescale i.MX6 PCI Express Root-Complex driver
3  *
4  * Copyright (C) 2013 Marek Vasut <marex@denx.de>
5  *
6  * Based on upstream Linux kernel driver:
7  * pci-imx6.c:		Sean Cross <xobs@kosagi.com>
8  * pcie-designware.c:	Jingoo Han <jg1.han@samsung.com>
9  *
10  * SPDX-License-Identifier:	GPL-2.0
11  */
12 
13 #include <common.h>
14 #include <pci.h>
15 #include <asm/arch/clock.h>
16 #include <asm/arch/iomux.h>
17 #include <asm/arch/crm_regs.h>
18 #include <asm/gpio.h>
19 #include <asm/io.h>
20 #include <linux/sizes.h>
21 #include <errno.h>
22 
23 #define PCI_ACCESS_READ  0
24 #define PCI_ACCESS_WRITE 1
25 
26 #ifdef CONFIG_MX6SX
27 #define MX6_DBI_ADDR	0x08ffc000
28 #define MX6_IO_ADDR	0x08000000
29 #define MX6_MEM_ADDR	0x08100000
30 #define MX6_ROOT_ADDR	0x08f00000
31 #else
32 #define MX6_DBI_ADDR	0x01ffc000
33 #define MX6_IO_ADDR	0x01000000
34 #define MX6_MEM_ADDR	0x01100000
35 #define MX6_ROOT_ADDR	0x01f00000
36 #endif
37 #define MX6_DBI_SIZE	0x4000
38 #define MX6_IO_SIZE	0x100000
39 #define MX6_MEM_SIZE	0xe00000
40 #define MX6_ROOT_SIZE	0xfc000
41 
42 /* PCIe Port Logic registers (memory-mapped) */
43 #define PL_OFFSET 0x700
44 #define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
45 #define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
46 #define PCIE_PHY_DEBUG_R1_LINK_UP		(1 << 4)
47 #define PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING	(1 << 29)
48 
49 #define PCIE_PHY_CTRL (PL_OFFSET + 0x114)
50 #define PCIE_PHY_CTRL_DATA_LOC 0
51 #define PCIE_PHY_CTRL_CAP_ADR_LOC 16
52 #define PCIE_PHY_CTRL_CAP_DAT_LOC 17
53 #define PCIE_PHY_CTRL_WR_LOC 18
54 #define PCIE_PHY_CTRL_RD_LOC 19
55 
56 #define PCIE_PHY_STAT (PL_OFFSET + 0x110)
57 #define PCIE_PHY_STAT_DATA_LOC 0
58 #define PCIE_PHY_STAT_ACK_LOC 16
59 
60 /* PHY registers (not memory-mapped) */
61 #define PCIE_PHY_RX_ASIC_OUT 0x100D
62 
63 #define PHY_RX_OVRD_IN_LO 0x1005
64 #define PHY_RX_OVRD_IN_LO_RX_DATA_EN (1 << 5)
65 #define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1 << 3)
66 
67 #define PCIE_PHY_PUP_REQ		(1 << 7)
68 
69 /* iATU registers */
70 #define PCIE_ATU_VIEWPORT		0x900
71 #define PCIE_ATU_REGION_INBOUND		(0x1 << 31)
72 #define PCIE_ATU_REGION_OUTBOUND	(0x0 << 31)
73 #define PCIE_ATU_REGION_INDEX1		(0x1 << 0)
74 #define PCIE_ATU_REGION_INDEX0		(0x0 << 0)
75 #define PCIE_ATU_CR1			0x904
76 #define PCIE_ATU_TYPE_MEM		(0x0 << 0)
77 #define PCIE_ATU_TYPE_IO		(0x2 << 0)
78 #define PCIE_ATU_TYPE_CFG0		(0x4 << 0)
79 #define PCIE_ATU_TYPE_CFG1		(0x5 << 0)
80 #define PCIE_ATU_CR2			0x908
81 #define PCIE_ATU_ENABLE			(0x1 << 31)
82 #define PCIE_ATU_BAR_MODE_ENABLE	(0x1 << 30)
83 #define PCIE_ATU_LOWER_BASE		0x90C
84 #define PCIE_ATU_UPPER_BASE		0x910
85 #define PCIE_ATU_LIMIT			0x914
86 #define PCIE_ATU_LOWER_TARGET		0x918
87 #define PCIE_ATU_BUS(x)			(((x) & 0xff) << 24)
88 #define PCIE_ATU_DEV(x)			(((x) & 0x1f) << 19)
89 #define PCIE_ATU_FUNC(x)		(((x) & 0x7) << 16)
90 #define PCIE_ATU_UPPER_TARGET		0x91C
91 
92 /*
93  * PHY access functions
94  */
95 static int pcie_phy_poll_ack(void __iomem *dbi_base, int exp_val)
96 {
97 	u32 val;
98 	u32 max_iterations = 10;
99 	u32 wait_counter = 0;
100 
101 	do {
102 		val = readl(dbi_base + PCIE_PHY_STAT);
103 		val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1;
104 		wait_counter++;
105 
106 		if (val == exp_val)
107 			return 0;
108 
109 		udelay(1);
110 	} while (wait_counter < max_iterations);
111 
112 	return -ETIMEDOUT;
113 }
114 
115 static int pcie_phy_wait_ack(void __iomem *dbi_base, int addr)
116 {
117 	u32 val;
118 	int ret;
119 
120 	val = addr << PCIE_PHY_CTRL_DATA_LOC;
121 	writel(val, dbi_base + PCIE_PHY_CTRL);
122 
123 	val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC);
124 	writel(val, dbi_base + PCIE_PHY_CTRL);
125 
126 	ret = pcie_phy_poll_ack(dbi_base, 1);
127 	if (ret)
128 		return ret;
129 
130 	val = addr << PCIE_PHY_CTRL_DATA_LOC;
131 	writel(val, dbi_base + PCIE_PHY_CTRL);
132 
133 	ret = pcie_phy_poll_ack(dbi_base, 0);
134 	if (ret)
135 		return ret;
136 
137 	return 0;
138 }
139 
140 /* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */
141 static int pcie_phy_read(void __iomem *dbi_base, int addr , int *data)
142 {
143 	u32 val, phy_ctl;
144 	int ret;
145 
146 	ret = pcie_phy_wait_ack(dbi_base, addr);
147 	if (ret)
148 		return ret;
149 
150 	/* assert Read signal */
151 	phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC;
152 	writel(phy_ctl, dbi_base + PCIE_PHY_CTRL);
153 
154 	ret = pcie_phy_poll_ack(dbi_base, 1);
155 	if (ret)
156 		return ret;
157 
158 	val = readl(dbi_base + PCIE_PHY_STAT);
159 	*data = val & 0xffff;
160 
161 	/* deassert Read signal */
162 	writel(0x00, dbi_base + PCIE_PHY_CTRL);
163 
164 	ret = pcie_phy_poll_ack(dbi_base, 0);
165 	if (ret)
166 		return ret;
167 
168 	return 0;
169 }
170 
171 static int pcie_phy_write(void __iomem *dbi_base, int addr, int data)
172 {
173 	u32 var;
174 	int ret;
175 
176 	/* write addr */
177 	/* cap addr */
178 	ret = pcie_phy_wait_ack(dbi_base, addr);
179 	if (ret)
180 		return ret;
181 
182 	var = data << PCIE_PHY_CTRL_DATA_LOC;
183 	writel(var, dbi_base + PCIE_PHY_CTRL);
184 
185 	/* capture data */
186 	var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC);
187 	writel(var, dbi_base + PCIE_PHY_CTRL);
188 
189 	ret = pcie_phy_poll_ack(dbi_base, 1);
190 	if (ret)
191 		return ret;
192 
193 	/* deassert cap data */
194 	var = data << PCIE_PHY_CTRL_DATA_LOC;
195 	writel(var, dbi_base + PCIE_PHY_CTRL);
196 
197 	/* wait for ack de-assertion */
198 	ret = pcie_phy_poll_ack(dbi_base, 0);
199 	if (ret)
200 		return ret;
201 
202 	/* assert wr signal */
203 	var = 0x1 << PCIE_PHY_CTRL_WR_LOC;
204 	writel(var, dbi_base + PCIE_PHY_CTRL);
205 
206 	/* wait for ack */
207 	ret = pcie_phy_poll_ack(dbi_base, 1);
208 	if (ret)
209 		return ret;
210 
211 	/* deassert wr signal */
212 	var = data << PCIE_PHY_CTRL_DATA_LOC;
213 	writel(var, dbi_base + PCIE_PHY_CTRL);
214 
215 	/* wait for ack de-assertion */
216 	ret = pcie_phy_poll_ack(dbi_base, 0);
217 	if (ret)
218 		return ret;
219 
220 	writel(0x0, dbi_base + PCIE_PHY_CTRL);
221 
222 	return 0;
223 }
224 
225 static int imx6_pcie_link_up(void)
226 {
227 	u32 rc, ltssm;
228 	int rx_valid, temp;
229 
230 	/* link is debug bit 36, debug register 1 starts at bit 32 */
231 	rc = readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R1);
232 	if ((rc & PCIE_PHY_DEBUG_R1_LINK_UP) &&
233 	    !(rc & PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING))
234 		return -EAGAIN;
235 
236 	/*
237 	 * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
238 	 * Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2).
239 	 * If (MAC/LTSSM.state == Recovery.RcvrLock)
240 	 * && (PHY/rx_valid==0) then pulse PHY/rx_reset. Transition
241 	 * to gen2 is stuck
242 	 */
243 	pcie_phy_read((void *)MX6_DBI_ADDR, PCIE_PHY_RX_ASIC_OUT, &rx_valid);
244 	ltssm = readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R0) & 0x3F;
245 
246 	if (rx_valid & 0x01)
247 		return 0;
248 
249 	if (ltssm != 0x0d)
250 		return 0;
251 
252 	printf("transition to gen2 is stuck, reset PHY!\n");
253 
254 	pcie_phy_read((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, &temp);
255 	temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
256 	pcie_phy_write((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, temp);
257 
258 	udelay(3000);
259 
260 	pcie_phy_read((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, &temp);
261 	temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
262 	pcie_phy_write((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, temp);
263 
264 	return 0;
265 }
266 
267 /*
268  * iATU region setup
269  */
270 static int imx_pcie_regions_setup(void)
271 {
272 	/*
273 	 * i.MX6 defines 16MB in the AXI address map for PCIe.
274 	 *
275 	 * That address space excepted the pcie registers is
276 	 * split and defined into different regions by iATU,
277 	 * with sizes and offsets as follows:
278 	 *
279 	 * 0x0100_0000 --- 0x010F_FFFF 1MB IORESOURCE_IO
280 	 * 0x0110_0000 --- 0x01EF_FFFF 14MB IORESOURCE_MEM
281 	 * 0x01F0_0000 --- 0x01FF_FFFF 1MB Cfg + Registers
282 	 */
283 
284 	/* CMD reg:I/O space, MEM space, and Bus Master Enable */
285 	setbits_le32(MX6_DBI_ADDR | PCI_COMMAND,
286 		     PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);
287 
288 	/* Set the CLASS_REV of RC CFG header to PCI_CLASS_BRIDGE_PCI */
289 	setbits_le32(MX6_DBI_ADDR + PCI_CLASS_REVISION,
290 		     PCI_CLASS_BRIDGE_PCI << 16);
291 
292 	/* Region #0 is used for Outbound CFG space access. */
293 	writel(0, MX6_DBI_ADDR + PCIE_ATU_VIEWPORT);
294 
295 	writel(MX6_ROOT_ADDR, MX6_DBI_ADDR + PCIE_ATU_LOWER_BASE);
296 	writel(0, MX6_DBI_ADDR + PCIE_ATU_UPPER_BASE);
297 	writel(MX6_ROOT_ADDR + MX6_ROOT_SIZE, MX6_DBI_ADDR + PCIE_ATU_LIMIT);
298 
299 	writel(0, MX6_DBI_ADDR + PCIE_ATU_LOWER_TARGET);
300 	writel(0, MX6_DBI_ADDR + PCIE_ATU_UPPER_TARGET);
301 	writel(PCIE_ATU_TYPE_CFG0, MX6_DBI_ADDR + PCIE_ATU_CR1);
302 	writel(PCIE_ATU_ENABLE, MX6_DBI_ADDR + PCIE_ATU_CR2);
303 
304 	return 0;
305 }
306 
307 /*
308  * PCI Express accessors
309  */
310 static uint32_t get_bus_address(pci_dev_t d, int where)
311 {
312 	uint32_t va_address;
313 
314 	/* Reconfigure Region #0 */
315 	writel(0, MX6_DBI_ADDR + PCIE_ATU_VIEWPORT);
316 
317 	if (PCI_BUS(d) < 2)
318 		writel(PCIE_ATU_TYPE_CFG0, MX6_DBI_ADDR + PCIE_ATU_CR1);
319 	else
320 		writel(PCIE_ATU_TYPE_CFG1, MX6_DBI_ADDR + PCIE_ATU_CR1);
321 
322 	if (PCI_BUS(d) == 0) {
323 		va_address = MX6_DBI_ADDR;
324 	} else {
325 		writel(d << 8, MX6_DBI_ADDR + PCIE_ATU_LOWER_TARGET);
326 		va_address = MX6_IO_ADDR + SZ_16M - SZ_1M;
327 	}
328 
329 	va_address += (where & ~0x3);
330 
331 	return va_address;
332 }
333 
334 static int imx_pcie_addr_valid(pci_dev_t d)
335 {
336 	if ((PCI_BUS(d) == 0) && (PCI_DEV(d) > 1))
337 		return -EINVAL;
338 	if ((PCI_BUS(d) == 1) && (PCI_DEV(d) > 0))
339 		return -EINVAL;
340 	return 0;
341 }
342 
343 /*
344  * Replace the original ARM DABT handler with a simple jump-back one.
345  *
346  * The problem here is that if we have a PCIe bridge attached to this PCIe
347  * controller, but no PCIe device is connected to the bridges' downstream
348  * port, the attempt to read/write from/to the config space will produce
349  * a DABT. This is a behavior of the controller and can not be disabled
350  * unfortuatelly.
351  *
352  * To work around the problem, we backup the current DABT handler address
353  * and replace it with our own DABT handler, which only bounces right back
354  * into the code.
355  */
356 static void imx_pcie_fix_dabt_handler(bool set)
357 {
358 	extern uint32_t *_data_abort;
359 	uint32_t *data_abort_addr = (uint32_t *)&_data_abort;
360 
361 	static const uint32_t data_abort_bounce_handler = 0xe25ef004;
362 	uint32_t data_abort_bounce_addr = (uint32_t)&data_abort_bounce_handler;
363 
364 	static uint32_t data_abort_backup;
365 
366 	if (set) {
367 		data_abort_backup = *data_abort_addr;
368 		*data_abort_addr = data_abort_bounce_addr;
369 	} else {
370 		*data_abort_addr = data_abort_backup;
371 	}
372 }
373 
374 static int imx_pcie_read_config(struct pci_controller *hose, pci_dev_t d,
375 				int where, u32 *val)
376 {
377 	uint32_t va_address;
378 	int ret;
379 
380 	ret = imx_pcie_addr_valid(d);
381 	if (ret) {
382 		*val = 0xffffffff;
383 		return ret;
384 	}
385 
386 	va_address = get_bus_address(d, where);
387 
388 	/*
389 	 * Read the PCIe config space. We must replace the DABT handler
390 	 * here in case we got data abort from the PCIe controller, see
391 	 * imx_pcie_fix_dabt_handler() description. Note that writing the
392 	 * "val" with valid value is also imperative here as in case we
393 	 * did got DABT, the val would contain random value.
394 	 */
395 	imx_pcie_fix_dabt_handler(true);
396 	writel(0xffffffff, val);
397 	*val = readl(va_address);
398 	imx_pcie_fix_dabt_handler(false);
399 
400 	return 0;
401 }
402 
403 static int imx_pcie_write_config(struct pci_controller *hose, pci_dev_t d,
404 			int where, u32 val)
405 {
406 	uint32_t va_address = 0;
407 	int ret;
408 
409 	ret = imx_pcie_addr_valid(d);
410 	if (ret)
411 		return ret;
412 
413 	va_address = get_bus_address(d, where);
414 
415 	/*
416 	 * Write the PCIe config space. We must replace the DABT handler
417 	 * here in case we got data abort from the PCIe controller, see
418 	 * imx_pcie_fix_dabt_handler() description.
419 	 */
420 	imx_pcie_fix_dabt_handler(true);
421 	writel(val, va_address);
422 	imx_pcie_fix_dabt_handler(false);
423 
424 	return 0;
425 }
426 
427 /*
428  * Initial bus setup
429  */
430 static int imx6_pcie_assert_core_reset(void)
431 {
432 	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
433 #if defined(CONFIG_MX6SX)
434 	struct gpc *gpc_regs = (struct gpc *)GPC_BASE_ADDR;
435 
436 	/* SSP_EN is not used on MX6SX anymore */
437 	setbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_TEST_POWERDOWN);
438 	/* Force PCIe PHY reset */
439 	setbits_le32(&iomuxc_regs->gpr[5], IOMUXC_GPR5_PCIE_BTNRST);
440 	/* Power up PCIe PHY */
441 	setbits_le32(&gpc_regs->cntr, PCIE_PHY_PUP_REQ);
442 #else
443 	setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_TEST_POWERDOWN);
444 	clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_REF_SSP_EN);
445 #endif
446 
447 	return 0;
448 }
449 
450 static int imx6_pcie_init_phy(void)
451 {
452 	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
453 
454 	clrbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_APPS_LTSSM_ENABLE);
455 
456 	clrsetbits_le32(&iomuxc_regs->gpr[12],
457 			IOMUXC_GPR12_DEVICE_TYPE_MASK,
458 			IOMUXC_GPR12_DEVICE_TYPE_RC);
459 	clrsetbits_le32(&iomuxc_regs->gpr[12],
460 			IOMUXC_GPR12_LOS_LEVEL_MASK,
461 			IOMUXC_GPR12_LOS_LEVEL_9);
462 
463 #ifdef CONFIG_MX6SX
464 	clrsetbits_le32(&iomuxc_regs->gpr[12],
465 			IOMUXC_GPR12_RX_EQ_MASK,
466 			IOMUXC_GPR12_RX_EQ_2);
467 #endif
468 
469 	writel((0x0 << IOMUXC_GPR8_PCS_TX_DEEMPH_GEN1_OFFSET) |
470 	       (0x0 << IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_3P5DB_OFFSET) |
471 	       (20 << IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_6DB_OFFSET) |
472 	       (127 << IOMUXC_GPR8_PCS_TX_SWING_FULL_OFFSET) |
473 	       (127 << IOMUXC_GPR8_PCS_TX_SWING_LOW_OFFSET),
474 	       &iomuxc_regs->gpr[8]);
475 
476 	return 0;
477 }
478 
479 __weak int imx6_pcie_toggle_power(void)
480 {
481 #ifdef CONFIG_PCIE_IMX_POWER_GPIO
482 	gpio_direction_output(CONFIG_PCIE_IMX_POWER_GPIO, 0);
483 	mdelay(20);
484 	gpio_set_value(CONFIG_PCIE_IMX_POWER_GPIO, 1);
485 	mdelay(20);
486 #endif
487 	return 0;
488 }
489 
490 __weak int imx6_pcie_toggle_reset(void)
491 {
492 	/*
493 	 * See 'PCI EXPRESS BASE SPECIFICATION, REV 3.0, SECTION 6.6.1'
494 	 * for detailed understanding of the PCIe CR reset logic.
495 	 *
496 	 * The PCIe #PERST reset line _MUST_ be connected, otherwise your
497 	 * design does not conform to the specification. You must wait at
498 	 * least 20 mS after de-asserting the #PERST so the EP device can
499 	 * do self-initialisation.
500 	 *
501 	 * In case your #PERST pin is connected to a plain GPIO pin of the
502 	 * CPU, you can define CONFIG_PCIE_IMX_PERST_GPIO in your board's
503 	 * configuration file and the condition below will handle the rest
504 	 * of the reset toggling.
505 	 *
506 	 * In case your #PERST toggling logic is more complex, for example
507 	 * connected via CPLD or somesuch, you can override this function
508 	 * in your board file and implement reset logic as needed. You must
509 	 * not forget to wait at least 20 mS after de-asserting #PERST in
510 	 * this case either though.
511 	 *
512 	 * In case your #PERST line of the PCIe EP device is not connected
513 	 * at all, your design is broken and you should fix your design,
514 	 * otherwise you will observe problems like for example the link
515 	 * not coming up after rebooting the system back from running Linux
516 	 * that uses the PCIe as well OR the PCIe link might not come up in
517 	 * Linux at all in the first place since it's in some non-reset
518 	 * state due to being previously used in U-Boot.
519 	 */
520 #ifdef CONFIG_PCIE_IMX_PERST_GPIO
521 	gpio_direction_output(CONFIG_PCIE_IMX_PERST_GPIO, 0);
522 	mdelay(20);
523 	gpio_set_value(CONFIG_PCIE_IMX_PERST_GPIO, 1);
524 	mdelay(20);
525 #else
526 	puts("WARNING: Make sure the PCIe #PERST line is connected!\n");
527 #endif
528 	return 0;
529 }
530 
531 static int imx6_pcie_deassert_core_reset(void)
532 {
533 	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
534 
535 	imx6_pcie_toggle_power();
536 
537 	enable_pcie_clock();
538 
539 	/*
540 	 * Wait for the clock to settle a bit, when the clock are sourced
541 	 * from the CPU, we need about 30mS to settle.
542 	 */
543 	mdelay(50);
544 
545 #if defined(CONFIG_MX6SX)
546 	/* SSP_EN is not used on MX6SX anymore */
547 	clrbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_TEST_POWERDOWN);
548 	/* Clear PCIe PHY reset bit */
549 	clrbits_le32(&iomuxc_regs->gpr[5], IOMUXC_GPR5_PCIE_BTNRST);
550 #else
551 	/* Enable PCIe */
552 	clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_TEST_POWERDOWN);
553 	setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_REF_SSP_EN);
554 #endif
555 
556 	imx6_pcie_toggle_reset();
557 
558 	return 0;
559 }
560 
561 static int imx_pcie_link_up(void)
562 {
563 	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
564 	uint32_t tmp;
565 	int count = 0;
566 
567 	imx6_pcie_assert_core_reset();
568 	imx6_pcie_init_phy();
569 	imx6_pcie_deassert_core_reset();
570 
571 	imx_pcie_regions_setup();
572 
573 	/*
574 	 * FIXME: Force the PCIe RC to Gen1 operation
575 	 * The RC must be forced into Gen1 mode before bringing the link
576 	 * up, otherwise no downstream devices are detected. After the
577 	 * link is up, a managed Gen1->Gen2 transition can be initiated.
578 	 */
579 	tmp = readl(MX6_DBI_ADDR + 0x7c);
580 	tmp &= ~0xf;
581 	tmp |= 0x1;
582 	writel(tmp, MX6_DBI_ADDR + 0x7c);
583 
584 	/* LTSSM enable, starting link. */
585 	setbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_APPS_LTSSM_ENABLE);
586 
587 	while (!imx6_pcie_link_up()) {
588 		udelay(10);
589 		count++;
590 		if (count >= 2000) {
591 #ifdef CONFIG_PCI_SCAN_SHOW
592 			puts("PCI:   pcie phy link never came up\n");
593 #endif
594 			debug("DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
595 			      readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R0),
596 			      readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R1));
597 			return -EINVAL;
598 		}
599 	}
600 
601 	return 0;
602 }
603 
604 void imx_pcie_init(void)
605 {
606 	/* Static instance of the controller. */
607 	static struct pci_controller	pcc;
608 	struct pci_controller		*hose = &pcc;
609 	int ret;
610 
611 	memset(&pcc, 0, sizeof(pcc));
612 
613 	/* PCI I/O space */
614 	pci_set_region(&hose->regions[0],
615 		       MX6_IO_ADDR, MX6_IO_ADDR,
616 		       MX6_IO_SIZE, PCI_REGION_IO);
617 
618 	/* PCI memory space */
619 	pci_set_region(&hose->regions[1],
620 		       MX6_MEM_ADDR, MX6_MEM_ADDR,
621 		       MX6_MEM_SIZE, PCI_REGION_MEM);
622 
623 	/* System memory space */
624 	pci_set_region(&hose->regions[2],
625 		       MMDC0_ARB_BASE_ADDR, MMDC0_ARB_BASE_ADDR,
626 		       0xefffffff, PCI_REGION_MEM | PCI_REGION_SYS_MEMORY);
627 
628 	hose->region_count = 3;
629 
630 	pci_set_ops(hose,
631 		    pci_hose_read_config_byte_via_dword,
632 		    pci_hose_read_config_word_via_dword,
633 		    imx_pcie_read_config,
634 		    pci_hose_write_config_byte_via_dword,
635 		    pci_hose_write_config_word_via_dword,
636 		    imx_pcie_write_config);
637 
638 	/* Start the controller. */
639 	ret = imx_pcie_link_up();
640 
641 	if (!ret) {
642 		pci_register_hose(hose);
643 		hose->last_busno = pci_hose_scan(hose);
644 	}
645 }
646 
647 /* Probe function. */
648 void pci_init_board(void)
649 {
650 	imx_pcie_init();
651 }
652