2 * PCIe host controller driver for Freescale i.MX6 SoCs
4 * Copyright (C) 2013 Kosagi
5 * http://www.kosagi.com
7 * Author: Sean Cross <xobs@kosagi.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/clk.h>
15 #include <linux/delay.h>
16 #include <linux/gpio.h>
17 #include <linux/kernel.h>
18 #include <linux/mfd/syscon.h>
19 #include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
20 #include <linux/module.h>
21 #include <linux/of_gpio.h>
22 #include <linux/pci.h>
23 #include <linux/platform_device.h>
24 #include <linux/regmap.h>
25 #include <linux/resource.h>
26 #include <linux/signal.h>
27 #include <linux/types.h>
29 #include "pcie-designware.h"
31 #define to_imx6_pcie(x) container_of(x, struct imx6_pcie, pp)
38 struct clk *lvds_gate;
39 struct clk *sata_ref_100m;
40 struct clk *pcie_ref_125m;
43 struct regmap *iomuxc_gpr;
44 void __iomem *mem_base;
47 /* PCIe Port Logic registers (memory-mapped) */
48 #define PL_OFFSET 0x700
49 #define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
50 #define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
52 #define PCIE_PHY_CTRL (PL_OFFSET + 0x114)
53 #define PCIE_PHY_CTRL_DATA_LOC 0
54 #define PCIE_PHY_CTRL_CAP_ADR_LOC 16
55 #define PCIE_PHY_CTRL_CAP_DAT_LOC 17
56 #define PCIE_PHY_CTRL_WR_LOC 18
57 #define PCIE_PHY_CTRL_RD_LOC 19
59 #define PCIE_PHY_STAT (PL_OFFSET + 0x110)
60 #define PCIE_PHY_STAT_ACK_LOC 16
62 /* PHY registers (not memory-mapped) */
63 #define PCIE_PHY_RX_ASIC_OUT 0x100D
65 #define PHY_RX_OVRD_IN_LO 0x1005
66 #define PHY_RX_OVRD_IN_LO_RX_DATA_EN (1 << 5)
67 #define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1 << 3)
69 static int pcie_phy_poll_ack(void __iomem *dbi_base, int exp_val)
72 u32 max_iterations = 10;
76 val = readl(dbi_base + PCIE_PHY_STAT);
77 val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1;
84 } while (wait_counter < max_iterations);
89 static int pcie_phy_wait_ack(void __iomem *dbi_base, int addr)
94 val = addr << PCIE_PHY_CTRL_DATA_LOC;
95 writel(val, dbi_base + PCIE_PHY_CTRL);
97 val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC);
98 writel(val, dbi_base + PCIE_PHY_CTRL);
100 ret = pcie_phy_poll_ack(dbi_base, 1);
104 val = addr << PCIE_PHY_CTRL_DATA_LOC;
105 writel(val, dbi_base + PCIE_PHY_CTRL);
107 ret = pcie_phy_poll_ack(dbi_base, 0);
114 /* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */
115 static int pcie_phy_read(void __iomem *dbi_base, int addr , int *data)
120 ret = pcie_phy_wait_ack(dbi_base, addr);
124 /* assert Read signal */
125 phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC;
126 writel(phy_ctl, dbi_base + PCIE_PHY_CTRL);
128 ret = pcie_phy_poll_ack(dbi_base, 1);
132 val = readl(dbi_base + PCIE_PHY_STAT);
133 *data = val & 0xffff;
135 /* deassert Read signal */
136 writel(0x00, dbi_base + PCIE_PHY_CTRL);
138 ret = pcie_phy_poll_ack(dbi_base, 0);
145 static int pcie_phy_write(void __iomem *dbi_base, int addr, int data)
152 ret = pcie_phy_wait_ack(dbi_base, addr);
156 var = data << PCIE_PHY_CTRL_DATA_LOC;
157 writel(var, dbi_base + PCIE_PHY_CTRL);
160 var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC);
161 writel(var, dbi_base + PCIE_PHY_CTRL);
163 ret = pcie_phy_poll_ack(dbi_base, 1);
167 /* deassert cap data */
168 var = data << PCIE_PHY_CTRL_DATA_LOC;
169 writel(var, dbi_base + PCIE_PHY_CTRL);
171 /* wait for ack de-assertion */
172 ret = pcie_phy_poll_ack(dbi_base, 0);
176 /* assert wr signal */
177 var = 0x1 << PCIE_PHY_CTRL_WR_LOC;
178 writel(var, dbi_base + PCIE_PHY_CTRL);
181 ret = pcie_phy_poll_ack(dbi_base, 1);
185 /* deassert wr signal */
186 var = data << PCIE_PHY_CTRL_DATA_LOC;
187 writel(var, dbi_base + PCIE_PHY_CTRL);
189 /* wait for ack de-assertion */
190 ret = pcie_phy_poll_ack(dbi_base, 0);
194 writel(0x0, dbi_base + PCIE_PHY_CTRL);
199 /* Added for PCI abort handling */
200 static int imx6q_pcie_abort_handler(unsigned long addr,
201 unsigned int fsr, struct pt_regs *regs)
204 * If it was an imprecise abort, then we need to correct the
205 * return address to be _after_ the instruction.
212 static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
214 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
216 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
217 IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18);
218 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
219 IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);
220 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
221 IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
223 gpio_set_value(imx6_pcie->reset_gpio, 0);
225 gpio_set_value(imx6_pcie->reset_gpio, 1);
230 static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
232 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
235 if (gpio_is_valid(imx6_pcie->power_on_gpio))
236 gpio_set_value(imx6_pcie->power_on_gpio, 1);
238 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
239 IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18);
240 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
241 IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16);
243 ret = clk_prepare_enable(imx6_pcie->sata_ref_100m);
245 dev_err(pp->dev, "unable to enable sata_ref_100m\n");
249 ret = clk_prepare_enable(imx6_pcie->pcie_ref_125m);
251 dev_err(pp->dev, "unable to enable pcie_ref_125m\n");
255 ret = clk_prepare_enable(imx6_pcie->lvds_gate);
257 dev_err(pp->dev, "unable to enable lvds_gate\n");
261 ret = clk_prepare_enable(imx6_pcie->pcie_axi);
263 dev_err(pp->dev, "unable to enable pcie_axi\n");
267 /* allow the clocks to stabilize */
268 usleep_range(200, 500);
273 clk_disable_unprepare(imx6_pcie->lvds_gate);
275 clk_disable_unprepare(imx6_pcie->pcie_ref_125m);
277 clk_disable_unprepare(imx6_pcie->sata_ref_100m);
283 static void imx6_pcie_init_phy(struct pcie_port *pp)
285 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
287 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
288 IMX6Q_GPR12_PCIE_CTL_2, 0 << 10);
290 /* configure constant input signal to the pcie ctrl and phy */
291 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
292 IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
293 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
294 IMX6Q_GPR12_LOS_LEVEL, 9 << 4);
296 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
297 IMX6Q_GPR8_TX_DEEMPH_GEN1, 0 << 0);
298 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
299 IMX6Q_GPR8_TX_DEEMPH_GEN2_3P5DB, 0 << 6);
300 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
301 IMX6Q_GPR8_TX_DEEMPH_GEN2_6DB, 20 << 12);
302 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
303 IMX6Q_GPR8_TX_SWING_FULL, 127 << 18);
304 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
305 IMX6Q_GPR8_TX_SWING_LOW, 127 << 25);
308 static void imx6_pcie_host_init(struct pcie_port *pp)
311 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
313 imx6_pcie_assert_core_reset(pp);
315 imx6_pcie_init_phy(pp);
317 imx6_pcie_deassert_core_reset(pp);
319 dw_pcie_setup_rc(pp);
321 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
322 IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);
324 while (!dw_pcie_link_up(pp)) {
325 usleep_range(100, 1000);
328 dev_err(pp->dev, "phy link never came up\n");
330 "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
331 readl(pp->dbi_base + PCIE_PHY_DEBUG_R0),
332 readl(pp->dbi_base + PCIE_PHY_DEBUG_R1));
340 static int imx6_pcie_link_up(struct pcie_port *pp)
342 u32 rc, ltssm, rx_valid, temp;
344 /* link is debug bit 36, debug register 1 starts at bit 32 */
345 rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) & (0x1 << (36 - 32));
350 * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
351 * Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2).
352 * If (MAC/LTSSM.state == Recovery.RcvrLock)
353 * && (PHY/rx_valid==0) then pulse PHY/rx_reset. Transition
356 pcie_phy_read(pp->dbi_base, PCIE_PHY_RX_ASIC_OUT, &rx_valid);
357 ltssm = readl(pp->dbi_base + PCIE_PHY_DEBUG_R0) & 0x3F;
365 dev_err(pp->dev, "transition to gen2 is stuck, reset PHY!\n");
367 pcie_phy_read(pp->dbi_base,
368 PHY_RX_OVRD_IN_LO, &temp);
369 temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN
370 | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
371 pcie_phy_write(pp->dbi_base,
372 PHY_RX_OVRD_IN_LO, temp);
374 usleep_range(2000, 3000);
376 pcie_phy_read(pp->dbi_base,
377 PHY_RX_OVRD_IN_LO, &temp);
378 temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN
379 | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
380 pcie_phy_write(pp->dbi_base,
381 PHY_RX_OVRD_IN_LO, temp);
386 static struct pcie_host_ops imx6_pcie_host_ops = {
387 .link_up = imx6_pcie_link_up,
388 .host_init = imx6_pcie_host_init,
391 static int imx6_add_pcie_port(struct pcie_port *pp,
392 struct platform_device *pdev)
396 pp->irq = platform_get_irq(pdev, 0);
398 dev_err(&pdev->dev, "failed to get irq\n");
402 pp->root_bus_nr = -1;
403 pp->ops = &imx6_pcie_host_ops;
405 spin_lock_init(&pp->conf_lock);
406 ret = dw_pcie_host_init(pp);
408 dev_err(&pdev->dev, "failed to initialize host\n");
415 static int __init imx6_pcie_probe(struct platform_device *pdev)
417 struct imx6_pcie *imx6_pcie;
418 struct pcie_port *pp;
419 struct device_node *np = pdev->dev.of_node;
420 struct resource *dbi_base;
423 imx6_pcie = devm_kzalloc(&pdev->dev, sizeof(*imx6_pcie), GFP_KERNEL);
428 pp->dev = &pdev->dev;
430 /* Added for PCI abort handling */
431 hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
432 "imprecise external abort");
434 dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
436 dev_err(&pdev->dev, "dbi_base memory resource not found\n");
440 pp->dbi_base = devm_ioremap_resource(&pdev->dev, dbi_base);
441 if (IS_ERR(pp->dbi_base)) {
442 dev_err(&pdev->dev, "unable to remap dbi_base\n");
443 ret = PTR_ERR(pp->dbi_base);
448 imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
449 if (!gpio_is_valid(imx6_pcie->reset_gpio)) {
450 dev_err(&pdev->dev, "no reset-gpio defined\n");
453 ret = devm_gpio_request_one(&pdev->dev,
454 imx6_pcie->reset_gpio,
458 dev_err(&pdev->dev, "unable to get reset gpio\n");
462 imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0);
463 if (gpio_is_valid(imx6_pcie->power_on_gpio)) {
464 ret = devm_gpio_request_one(&pdev->dev,
465 imx6_pcie->power_on_gpio,
467 "PCIe power enable");
469 dev_err(&pdev->dev, "unable to get power-on gpio\n");
474 imx6_pcie->wake_up_gpio = of_get_named_gpio(np, "wake-up-gpio", 0);
475 if (gpio_is_valid(imx6_pcie->wake_up_gpio)) {
476 ret = devm_gpio_request_one(&pdev->dev,
477 imx6_pcie->wake_up_gpio,
481 dev_err(&pdev->dev, "unable to get wake-up gpio\n");
486 imx6_pcie->disable_gpio = of_get_named_gpio(np, "disable-gpio", 0);
487 if (gpio_is_valid(imx6_pcie->disable_gpio)) {
488 ret = devm_gpio_request_one(&pdev->dev,
489 imx6_pcie->disable_gpio,
491 "PCIe disable endpoint");
493 dev_err(&pdev->dev, "unable to get disable-ep gpio\n");
499 imx6_pcie->lvds_gate = devm_clk_get(&pdev->dev, "lvds_gate");
500 if (IS_ERR(imx6_pcie->lvds_gate)) {
502 "lvds_gate clock select missing or invalid\n");
503 ret = PTR_ERR(imx6_pcie->lvds_gate);
507 imx6_pcie->sata_ref_100m = devm_clk_get(&pdev->dev, "sata_ref_100m");
508 if (IS_ERR(imx6_pcie->sata_ref_100m)) {
510 "sata_ref_100m clock source missing or invalid\n");
511 ret = PTR_ERR(imx6_pcie->sata_ref_100m);
515 imx6_pcie->pcie_ref_125m = devm_clk_get(&pdev->dev, "pcie_ref_125m");
516 if (IS_ERR(imx6_pcie->pcie_ref_125m)) {
518 "pcie_ref_125m clock source missing or invalid\n");
519 ret = PTR_ERR(imx6_pcie->pcie_ref_125m);
523 imx6_pcie->pcie_axi = devm_clk_get(&pdev->dev, "pcie_axi");
524 if (IS_ERR(imx6_pcie->pcie_axi)) {
526 "pcie_axi clock source missing or invalid\n");
527 ret = PTR_ERR(imx6_pcie->pcie_axi);
531 /* Grab GPR config register range */
532 imx6_pcie->iomuxc_gpr =
533 syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
534 if (IS_ERR(imx6_pcie->iomuxc_gpr)) {
535 dev_err(&pdev->dev, "unable to find iomuxc registers\n");
536 ret = PTR_ERR(imx6_pcie->iomuxc_gpr);
540 ret = imx6_add_pcie_port(pp, pdev);
544 platform_set_drvdata(pdev, imx6_pcie);
551 static const struct of_device_id imx6_pcie_of_match[] = {
552 { .compatible = "fsl,imx6q-pcie", },
555 MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);
557 static struct platform_driver imx6_pcie_driver = {
559 .name = "imx6q-pcie",
560 .owner = THIS_MODULE,
561 .of_match_table = of_match_ptr(imx6_pcie_of_match),
565 /* Freescale PCIe driver does not allow module unload */
567 static int __init imx6_pcie_init(void)
569 return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
571 module_init(imx6_pcie_init);
573 MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
574 MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver");
575 MODULE_LICENSE("GPL v2");