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)
206 static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
208 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
210 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
211 IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18);
212 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
213 IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);
214 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
215 IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
217 /* Some boards don't have PCIe reset GPIO. */
218 if (gpio_is_valid(imx6_pcie->reset_gpio)) {
219 gpio_set_value(imx6_pcie->reset_gpio, 0);
221 gpio_set_value(imx6_pcie->reset_gpio, 1);
227 static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
229 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
232 if (gpio_is_valid(imx6_pcie->power_on_gpio))
233 gpio_set_value(imx6_pcie->power_on_gpio, 1);
235 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
236 IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18);
237 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
238 IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16);
240 ret = clk_prepare_enable(imx6_pcie->sata_ref_100m);
242 dev_err(pp->dev, "unable to enable sata_ref_100m\n");
246 ret = clk_prepare_enable(imx6_pcie->pcie_ref_125m);
248 dev_err(pp->dev, "unable to enable pcie_ref_125m\n");
252 ret = clk_prepare_enable(imx6_pcie->lvds_gate);
254 dev_err(pp->dev, "unable to enable lvds_gate\n");
258 ret = clk_prepare_enable(imx6_pcie->pcie_axi);
260 dev_err(pp->dev, "unable to enable pcie_axi\n");
264 /* allow the clocks to stabilize */
265 usleep_range(200, 500);
270 clk_disable_unprepare(imx6_pcie->lvds_gate);
272 clk_disable_unprepare(imx6_pcie->pcie_ref_125m);
274 clk_disable_unprepare(imx6_pcie->sata_ref_100m);
280 static void imx6_pcie_init_phy(struct pcie_port *pp)
282 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
284 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
285 IMX6Q_GPR12_PCIE_CTL_2, 0 << 10);
287 /* configure constant input signal to the pcie ctrl and phy */
288 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
289 IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
290 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
291 IMX6Q_GPR12_LOS_LEVEL, 9 << 4);
293 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
294 IMX6Q_GPR8_TX_DEEMPH_GEN1, 0 << 0);
295 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
296 IMX6Q_GPR8_TX_DEEMPH_GEN2_3P5DB, 0 << 6);
297 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
298 IMX6Q_GPR8_TX_DEEMPH_GEN2_6DB, 20 << 12);
299 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
300 IMX6Q_GPR8_TX_SWING_FULL, 127 << 18);
301 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
302 IMX6Q_GPR8_TX_SWING_LOW, 127 << 25);
305 static void imx6_pcie_host_init(struct pcie_port *pp)
308 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
310 imx6_pcie_assert_core_reset(pp);
312 imx6_pcie_init_phy(pp);
314 imx6_pcie_deassert_core_reset(pp);
316 dw_pcie_setup_rc(pp);
318 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
319 IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);
321 while (!dw_pcie_link_up(pp)) {
322 usleep_range(100, 1000);
325 dev_err(pp->dev, "phy link never came up\n");
327 "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
328 readl(pp->dbi_base + PCIE_PHY_DEBUG_R0),
329 readl(pp->dbi_base + PCIE_PHY_DEBUG_R1));
337 static int imx6_pcie_link_up(struct pcie_port *pp)
339 u32 rc, ltssm, rx_valid, temp;
341 /* link is debug bit 36, debug register 1 starts at bit 32 */
342 rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) & (0x1 << (36 - 32));
347 * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
348 * Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2).
349 * If (MAC/LTSSM.state == Recovery.RcvrLock)
350 * && (PHY/rx_valid==0) then pulse PHY/rx_reset. Transition
353 pcie_phy_read(pp->dbi_base, PCIE_PHY_RX_ASIC_OUT, &rx_valid);
354 ltssm = readl(pp->dbi_base + PCIE_PHY_DEBUG_R0) & 0x3F;
362 dev_err(pp->dev, "transition to gen2 is stuck, reset PHY!\n");
364 pcie_phy_read(pp->dbi_base,
365 PHY_RX_OVRD_IN_LO, &temp);
366 temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN
367 | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
368 pcie_phy_write(pp->dbi_base,
369 PHY_RX_OVRD_IN_LO, temp);
371 usleep_range(2000, 3000);
373 pcie_phy_read(pp->dbi_base,
374 PHY_RX_OVRD_IN_LO, &temp);
375 temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN
376 | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
377 pcie_phy_write(pp->dbi_base,
378 PHY_RX_OVRD_IN_LO, temp);
383 static struct pcie_host_ops imx6_pcie_host_ops = {
384 .link_up = imx6_pcie_link_up,
385 .host_init = imx6_pcie_host_init,
388 static int imx6_add_pcie_port(struct pcie_port *pp,
389 struct platform_device *pdev)
393 pp->irq = platform_get_irq(pdev, 0);
395 dev_err(&pdev->dev, "failed to get irq\n");
399 pp->root_bus_nr = -1;
400 pp->ops = &imx6_pcie_host_ops;
402 spin_lock_init(&pp->conf_lock);
403 ret = dw_pcie_host_init(pp);
405 dev_err(&pdev->dev, "failed to initialize host\n");
412 static int __init imx6_pcie_probe(struct platform_device *pdev)
414 struct imx6_pcie *imx6_pcie;
415 struct pcie_port *pp;
416 struct device_node *np = pdev->dev.of_node;
417 struct resource *dbi_base;
420 imx6_pcie = devm_kzalloc(&pdev->dev, sizeof(*imx6_pcie), GFP_KERNEL);
425 pp->dev = &pdev->dev;
427 /* Added for PCI abort handling */
428 hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
429 "imprecise external abort");
431 dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
432 pp->dbi_base = devm_ioremap_resource(&pdev->dev, dbi_base);
433 if (IS_ERR(pp->dbi_base))
434 return PTR_ERR(pp->dbi_base);
437 imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
438 if (gpio_is_valid(imx6_pcie->reset_gpio)) {
439 ret = devm_gpio_request_one(&pdev->dev, imx6_pcie->reset_gpio,
440 GPIOF_OUT_INIT_LOW, "PCIe reset");
442 dev_err(&pdev->dev, "unable to get reset gpio\n");
447 imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0);
448 if (gpio_is_valid(imx6_pcie->power_on_gpio)) {
449 ret = devm_gpio_request_one(&pdev->dev,
450 imx6_pcie->power_on_gpio,
452 "PCIe power enable");
454 dev_err(&pdev->dev, "unable to get power-on gpio\n");
459 imx6_pcie->wake_up_gpio = of_get_named_gpio(np, "wake-up-gpio", 0);
460 if (gpio_is_valid(imx6_pcie->wake_up_gpio)) {
461 ret = devm_gpio_request_one(&pdev->dev,
462 imx6_pcie->wake_up_gpio,
466 dev_err(&pdev->dev, "unable to get wake-up gpio\n");
471 imx6_pcie->disable_gpio = of_get_named_gpio(np, "disable-gpio", 0);
472 if (gpio_is_valid(imx6_pcie->disable_gpio)) {
473 ret = devm_gpio_request_one(&pdev->dev,
474 imx6_pcie->disable_gpio,
476 "PCIe disable endpoint");
478 dev_err(&pdev->dev, "unable to get disable-ep gpio\n");
484 imx6_pcie->lvds_gate = devm_clk_get(&pdev->dev, "lvds_gate");
485 if (IS_ERR(imx6_pcie->lvds_gate)) {
487 "lvds_gate clock select missing or invalid\n");
488 return PTR_ERR(imx6_pcie->lvds_gate);
491 imx6_pcie->sata_ref_100m = devm_clk_get(&pdev->dev, "sata_ref_100m");
492 if (IS_ERR(imx6_pcie->sata_ref_100m)) {
494 "sata_ref_100m clock source missing or invalid\n");
495 return PTR_ERR(imx6_pcie->sata_ref_100m);
498 imx6_pcie->pcie_ref_125m = devm_clk_get(&pdev->dev, "pcie_ref_125m");
499 if (IS_ERR(imx6_pcie->pcie_ref_125m)) {
501 "pcie_ref_125m clock source missing or invalid\n");
502 return PTR_ERR(imx6_pcie->pcie_ref_125m);
505 imx6_pcie->pcie_axi = devm_clk_get(&pdev->dev, "pcie_axi");
506 if (IS_ERR(imx6_pcie->pcie_axi)) {
508 "pcie_axi clock source missing or invalid\n");
509 return PTR_ERR(imx6_pcie->pcie_axi);
512 /* Grab GPR config register range */
513 imx6_pcie->iomuxc_gpr =
514 syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
515 if (IS_ERR(imx6_pcie->iomuxc_gpr)) {
516 dev_err(&pdev->dev, "unable to find iomuxc registers\n");
517 return PTR_ERR(imx6_pcie->iomuxc_gpr);
520 ret = imx6_add_pcie_port(pp, pdev);
524 platform_set_drvdata(pdev, imx6_pcie);
528 static const struct of_device_id imx6_pcie_of_match[] = {
529 { .compatible = "fsl,imx6q-pcie", },
532 MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);
534 static struct platform_driver imx6_pcie_driver = {
536 .name = "imx6q-pcie",
537 .owner = THIS_MODULE,
538 .of_match_table = imx6_pcie_of_match,
542 /* Freescale PCIe driver does not allow module unload */
544 static int __init imx6_pcie_init(void)
546 return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
548 fs_initcall(imx6_pcie_init);
550 MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
551 MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver");
552 MODULE_LICENSE("GPL v2");