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>
28 #include <linux/interrupt.h>
30 #include "pcie-designware.h"
32 #define to_imx6_pcie(x) container_of(x, struct imx6_pcie, pp)
40 struct regmap *iomuxc_gpr;
41 void __iomem *mem_base;
44 /* PCIe Root Complex registers (memory-mapped) */
45 #define PCIE_RC_LCR 0x7c
46 #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1 0x1
47 #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2 0x2
48 #define PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK 0xf
50 /* PCIe Port Logic registers (memory-mapped) */
51 #define PL_OFFSET 0x700
52 #define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
53 #define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
54 #define PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING (1 << 29)
55 #define PCIE_PHY_DEBUG_R1_XMLH_LINK_UP (1 << 4)
57 #define PCIE_PHY_CTRL (PL_OFFSET + 0x114)
58 #define PCIE_PHY_CTRL_DATA_LOC 0
59 #define PCIE_PHY_CTRL_CAP_ADR_LOC 16
60 #define PCIE_PHY_CTRL_CAP_DAT_LOC 17
61 #define PCIE_PHY_CTRL_WR_LOC 18
62 #define PCIE_PHY_CTRL_RD_LOC 19
64 #define PCIE_PHY_STAT (PL_OFFSET + 0x110)
65 #define PCIE_PHY_STAT_ACK_LOC 16
67 #define PCIE_LINK_WIDTH_SPEED_CONTROL 0x80C
68 #define PORT_LOGIC_SPEED_CHANGE (0x1 << 17)
70 /* PHY registers (not memory-mapped) */
71 #define PCIE_PHY_RX_ASIC_OUT 0x100D
73 #define PHY_RX_OVRD_IN_LO 0x1005
74 #define PHY_RX_OVRD_IN_LO_RX_DATA_EN (1 << 5)
75 #define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1 << 3)
77 static int pcie_phy_poll_ack(void __iomem *dbi_base, int exp_val)
80 u32 max_iterations = 10;
84 val = readl(dbi_base + PCIE_PHY_STAT);
85 val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1;
92 } while (wait_counter < max_iterations);
97 static int pcie_phy_wait_ack(void __iomem *dbi_base, int addr)
102 val = addr << PCIE_PHY_CTRL_DATA_LOC;
103 writel(val, dbi_base + PCIE_PHY_CTRL);
105 val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC);
106 writel(val, dbi_base + PCIE_PHY_CTRL);
108 ret = pcie_phy_poll_ack(dbi_base, 1);
112 val = addr << PCIE_PHY_CTRL_DATA_LOC;
113 writel(val, dbi_base + PCIE_PHY_CTRL);
115 ret = pcie_phy_poll_ack(dbi_base, 0);
122 /* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */
123 static int pcie_phy_read(void __iomem *dbi_base, int addr , int *data)
128 ret = pcie_phy_wait_ack(dbi_base, addr);
132 /* assert Read signal */
133 phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC;
134 writel(phy_ctl, dbi_base + PCIE_PHY_CTRL);
136 ret = pcie_phy_poll_ack(dbi_base, 1);
140 val = readl(dbi_base + PCIE_PHY_STAT);
141 *data = val & 0xffff;
143 /* deassert Read signal */
144 writel(0x00, dbi_base + PCIE_PHY_CTRL);
146 ret = pcie_phy_poll_ack(dbi_base, 0);
153 static int pcie_phy_write(void __iomem *dbi_base, int addr, int data)
160 ret = pcie_phy_wait_ack(dbi_base, addr);
164 var = data << PCIE_PHY_CTRL_DATA_LOC;
165 writel(var, dbi_base + PCIE_PHY_CTRL);
168 var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC);
169 writel(var, dbi_base + PCIE_PHY_CTRL);
171 ret = pcie_phy_poll_ack(dbi_base, 1);
175 /* deassert cap data */
176 var = data << PCIE_PHY_CTRL_DATA_LOC;
177 writel(var, dbi_base + PCIE_PHY_CTRL);
179 /* wait for ack de-assertion */
180 ret = pcie_phy_poll_ack(dbi_base, 0);
184 /* assert wr signal */
185 var = 0x1 << PCIE_PHY_CTRL_WR_LOC;
186 writel(var, dbi_base + PCIE_PHY_CTRL);
189 ret = pcie_phy_poll_ack(dbi_base, 1);
193 /* deassert wr signal */
194 var = data << PCIE_PHY_CTRL_DATA_LOC;
195 writel(var, dbi_base + PCIE_PHY_CTRL);
197 /* wait for ack de-assertion */
198 ret = pcie_phy_poll_ack(dbi_base, 0);
202 writel(0x0, dbi_base + PCIE_PHY_CTRL);
207 /* Added for PCI abort handling */
208 static int imx6q_pcie_abort_handler(unsigned long addr,
209 unsigned int fsr, struct pt_regs *regs)
214 static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
216 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
218 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
219 IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18);
220 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
221 IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
226 static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
228 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
231 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
232 IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18);
233 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
234 IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16);
236 ret = clk_prepare_enable(imx6_pcie->pcie_phy);
238 dev_err(pp->dev, "unable to enable pcie_phy clock\n");
242 ret = clk_prepare_enable(imx6_pcie->pcie_bus);
244 dev_err(pp->dev, "unable to enable pcie_bus clock\n");
248 ret = clk_prepare_enable(imx6_pcie->pcie);
250 dev_err(pp->dev, "unable to enable pcie clock\n");
254 /* allow the clocks to stabilize */
255 usleep_range(200, 500);
257 /* Some boards don't have PCIe reset GPIO. */
258 if (gpio_is_valid(imx6_pcie->reset_gpio)) {
259 gpio_set_value(imx6_pcie->reset_gpio, 0);
261 gpio_set_value(imx6_pcie->reset_gpio, 1);
266 clk_disable_unprepare(imx6_pcie->pcie_bus);
268 clk_disable_unprepare(imx6_pcie->pcie_phy);
274 static void imx6_pcie_init_phy(struct pcie_port *pp)
276 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
278 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
279 IMX6Q_GPR12_PCIE_CTL_2, 0 << 10);
281 /* configure constant input signal to the pcie ctrl and phy */
282 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
283 IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
284 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
285 IMX6Q_GPR12_LOS_LEVEL, 9 << 4);
287 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
288 IMX6Q_GPR8_TX_DEEMPH_GEN1, 0 << 0);
289 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
290 IMX6Q_GPR8_TX_DEEMPH_GEN2_3P5DB, 0 << 6);
291 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
292 IMX6Q_GPR8_TX_DEEMPH_GEN2_6DB, 20 << 12);
293 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
294 IMX6Q_GPR8_TX_SWING_FULL, 127 << 18);
295 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
296 IMX6Q_GPR8_TX_SWING_LOW, 127 << 25);
299 static int imx6_pcie_wait_for_link(struct pcie_port *pp)
303 while (!dw_pcie_link_up(pp)) {
304 usleep_range(100, 1000);
308 dev_err(pp->dev, "phy link never came up\n");
309 dev_dbg(pp->dev, "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
310 readl(pp->dbi_base + PCIE_PHY_DEBUG_R0),
311 readl(pp->dbi_base + PCIE_PHY_DEBUG_R1));
318 static irqreturn_t imx6_pcie_msi_handler(int irq, void *arg)
320 struct pcie_port *pp = arg;
322 return dw_handle_msi_irq(pp);
325 static int imx6_pcie_start_link(struct pcie_port *pp)
327 struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
332 * Force Gen1 operation when starting the link. In case the link is
333 * started in Gen2 mode, there is a possibility the devices on the
334 * bus will not be detected at all. This happens with PCIe switches.
336 tmp = readl(pp->dbi_base + PCIE_RC_LCR);
337 tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK;
338 tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1;
339 writel(tmp, pp->dbi_base + PCIE_RC_LCR);
342 regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
343 IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);
345 ret = imx6_pcie_wait_for_link(pp);
349 /* Allow Gen2 mode after the link is up. */
350 tmp = readl(pp->dbi_base + PCIE_RC_LCR);
351 tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK;
352 tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2;
353 writel(tmp, pp->dbi_base + PCIE_RC_LCR);
356 * Start Directed Speed Change so the best possible speed both link
357 * partners support can be negotiated.
359 tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL);
360 tmp |= PORT_LOGIC_SPEED_CHANGE;
361 writel(tmp, pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL);
365 tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL);
366 /* Test if the speed change finished. */
367 if (!(tmp & PORT_LOGIC_SPEED_CHANGE))
369 usleep_range(100, 1000);
372 /* Make sure link training is finished as well! */
374 ret = imx6_pcie_wait_for_link(pp);
379 dev_err(pp->dev, "Failed to bring link up!\n");
381 tmp = readl(pp->dbi_base + 0x80);
382 dev_dbg(pp->dev, "Link up, Gen=%i\n", (tmp >> 16) & 0xf);
388 static void imx6_pcie_host_init(struct pcie_port *pp)
390 imx6_pcie_assert_core_reset(pp);
392 imx6_pcie_init_phy(pp);
394 imx6_pcie_deassert_core_reset(pp);
396 dw_pcie_setup_rc(pp);
398 imx6_pcie_start_link(pp);
400 if (IS_ENABLED(CONFIG_PCI_MSI))
401 dw_pcie_msi_init(pp);
404 static void imx6_pcie_reset_phy(struct pcie_port *pp)
408 pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &temp);
409 temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN |
410 PHY_RX_OVRD_IN_LO_RX_PLL_EN);
411 pcie_phy_write(pp->dbi_base, PHY_RX_OVRD_IN_LO, temp);
413 usleep_range(2000, 3000);
415 pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &temp);
416 temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN |
417 PHY_RX_OVRD_IN_LO_RX_PLL_EN);
418 pcie_phy_write(pp->dbi_base, PHY_RX_OVRD_IN_LO, temp);
421 static int imx6_pcie_link_up(struct pcie_port *pp)
423 u32 rc, debug_r0, rx_valid;
427 * Test if the PHY reports that the link is up and also that the LTSSM
428 * training finished. There are three possible states of the link when
429 * this code is called:
430 * 1) The link is DOWN (unlikely)
431 * The link didn't come up yet for some reason. This usually means
432 * we have a real problem somewhere. Reset the PHY and exit. This
433 * state calls for inspection of the DEBUG registers.
434 * 2) The link is UP, but still in LTSSM training
435 * Wait for the training to finish, which should take a very short
436 * time. If the training does not finish, we have a problem and we
437 * need to inspect the DEBUG registers. If the training does finish,
438 * the link is up and operating correctly.
439 * 3) The link is UP and no longer in LTSSM training
440 * The link is up and operating correctly.
443 rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1);
444 if (!(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP))
446 if (!(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING))
450 dev_dbg(pp->dev, "Link is up, but still in training\n");
452 * Wait a little bit, then re-check if the link finished
455 usleep_range(1000, 2000);
458 * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
459 * Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2).
460 * If (MAC/LTSSM.state == Recovery.RcvrLock)
461 * && (PHY/rx_valid==0) then pulse PHY/rx_reset. Transition
464 pcie_phy_read(pp->dbi_base, PCIE_PHY_RX_ASIC_OUT, &rx_valid);
465 debug_r0 = readl(pp->dbi_base + PCIE_PHY_DEBUG_R0);
470 if ((debug_r0 & 0x3f) != 0x0d)
473 dev_err(pp->dev, "transition to gen2 is stuck, reset PHY!\n");
474 dev_dbg(pp->dev, "debug_r0=%08x debug_r1=%08x\n", debug_r0, rc);
476 imx6_pcie_reset_phy(pp);
481 static struct pcie_host_ops imx6_pcie_host_ops = {
482 .link_up = imx6_pcie_link_up,
483 .host_init = imx6_pcie_host_init,
486 static int __init imx6_add_pcie_port(struct pcie_port *pp,
487 struct platform_device *pdev)
491 if (IS_ENABLED(CONFIG_PCI_MSI)) {
492 pp->msi_irq = platform_get_irq_byname(pdev, "msi");
493 if (pp->msi_irq <= 0) {
494 dev_err(&pdev->dev, "failed to get MSI irq\n");
498 ret = devm_request_irq(&pdev->dev, pp->msi_irq,
499 imx6_pcie_msi_handler,
500 IRQF_SHARED, "mx6-pcie-msi", pp);
502 dev_err(&pdev->dev, "failed to request MSI irq\n");
507 pp->root_bus_nr = -1;
508 pp->ops = &imx6_pcie_host_ops;
510 ret = dw_pcie_host_init(pp);
512 dev_err(&pdev->dev, "failed to initialize host\n");
519 static int __init imx6_pcie_probe(struct platform_device *pdev)
521 struct imx6_pcie *imx6_pcie;
522 struct pcie_port *pp;
523 struct device_node *np = pdev->dev.of_node;
524 struct resource *dbi_base;
527 imx6_pcie = devm_kzalloc(&pdev->dev, sizeof(*imx6_pcie), GFP_KERNEL);
532 pp->dev = &pdev->dev;
534 /* Added for PCI abort handling */
535 hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
536 "imprecise external abort");
538 dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
539 pp->dbi_base = devm_ioremap_resource(&pdev->dev, dbi_base);
540 if (IS_ERR(pp->dbi_base))
541 return PTR_ERR(pp->dbi_base);
544 imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
545 if (gpio_is_valid(imx6_pcie->reset_gpio)) {
546 ret = devm_gpio_request_one(&pdev->dev, imx6_pcie->reset_gpio,
547 GPIOF_OUT_INIT_LOW, "PCIe reset");
549 dev_err(&pdev->dev, "unable to get reset gpio\n");
555 imx6_pcie->pcie_phy = devm_clk_get(&pdev->dev, "pcie_phy");
556 if (IS_ERR(imx6_pcie->pcie_phy)) {
558 "pcie_phy clock source missing or invalid\n");
559 return PTR_ERR(imx6_pcie->pcie_phy);
562 imx6_pcie->pcie_bus = devm_clk_get(&pdev->dev, "pcie_bus");
563 if (IS_ERR(imx6_pcie->pcie_bus)) {
565 "pcie_bus clock source missing or invalid\n");
566 return PTR_ERR(imx6_pcie->pcie_bus);
569 imx6_pcie->pcie = devm_clk_get(&pdev->dev, "pcie");
570 if (IS_ERR(imx6_pcie->pcie)) {
572 "pcie clock source missing or invalid\n");
573 return PTR_ERR(imx6_pcie->pcie);
576 /* Grab GPR config register range */
577 imx6_pcie->iomuxc_gpr =
578 syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
579 if (IS_ERR(imx6_pcie->iomuxc_gpr)) {
580 dev_err(&pdev->dev, "unable to find iomuxc registers\n");
581 return PTR_ERR(imx6_pcie->iomuxc_gpr);
584 ret = imx6_add_pcie_port(pp, pdev);
588 platform_set_drvdata(pdev, imx6_pcie);
592 static const struct of_device_id imx6_pcie_of_match[] = {
593 { .compatible = "fsl,imx6q-pcie", },
596 MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);
598 static struct platform_driver imx6_pcie_driver = {
600 .name = "imx6q-pcie",
601 .owner = THIS_MODULE,
602 .of_match_table = imx6_pcie_of_match,
606 /* Freescale PCIe driver does not allow module unload */
608 static int __init imx6_pcie_init(void)
610 return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
612 fs_initcall(imx6_pcie_init);
614 MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
615 MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver");
616 MODULE_LICENSE("GPL v2");