/* * PCIe host controller driver for Freescale i.MX6 SoCs * * Copyright (C) 2013 Kosagi * http://www.kosagi.com * * Author: Sean Cross <xobs@kosagi.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/clk.h> #include <linux/delay.h> #include <linux/gpio.h> #include <linux/kernel.h> #include <linux/mfd/syscon.h> #include <linux/mfd/syscon/imx6q-iomuxc-gpr.h> #include <linux/module.h> #include <linux/of_gpio.h> #include <linux/pci.h> #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/resource.h> #include <linux/signal.h> #include <linux/types.h> #include <linux/interrupt.h> #include "pcie-designware.h" #define to_imx6_pcie(x) container_of(x, struct imx6_pcie, pp) struct imx6_pcie { int reset_gpio; struct clk *pcie_bus; struct clk *pcie_phy; struct clk *pcie; struct pcie_port pp; struct regmap *iomuxc_gpr; void __iomem *mem_base; }; /* PCIe Root Complex registers (memory-mapped) */ #define PCIE_RC_LCR 0x7c #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1 0x1 #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2 0x2 #define PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK 0xf #define PCIE_RC_LCSR 0x80 /* PCIe Port Logic registers (memory-mapped) */ #define PL_OFFSET 0x700 #define PCIE_PL_PFLR (PL_OFFSET + 0x08) #define PCIE_PL_PFLR_LINK_STATE_MASK (0x3f << 16) #define PCIE_PL_PFLR_FORCE_LINK (1 << 15) #define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28) #define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c) #define PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING (1 << 29) #define PCIE_PHY_DEBUG_R1_XMLH_LINK_UP (1 << 4) #define PCIE_PHY_CTRL (PL_OFFSET + 0x114) #define PCIE_PHY_CTRL_DATA_LOC 0 #define PCIE_PHY_CTRL_CAP_ADR_LOC 16 #define PCIE_PHY_CTRL_CAP_DAT_LOC 17 #define PCIE_PHY_CTRL_WR_LOC 18 #define PCIE_PHY_CTRL_RD_LOC 19 #define PCIE_PHY_STAT (PL_OFFSET + 0x110) #define PCIE_PHY_STAT_ACK_LOC 16 #define PCIE_LINK_WIDTH_SPEED_CONTROL 0x80C #define PORT_LOGIC_SPEED_CHANGE (0x1 << 17) /* PHY registers (not memory-mapped) */ #define PCIE_PHY_RX_ASIC_OUT 0x100D #define PCIE_PHY_RX_ASIC_OUT_VALID (1 << 0) #define PHY_RX_OVRD_IN_LO 0x1005 #define PHY_RX_OVRD_IN_LO_RX_DATA_EN (1 << 5) #define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1 << 3) static int pcie_phy_poll_ack(void __iomem *dbi_base, int exp_val) { u32 val; u32 max_iterations = 10; u32 wait_counter = 0; do { val = readl(dbi_base + PCIE_PHY_STAT); val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1; wait_counter++; if (val == exp_val) return 0; udelay(1); } while (wait_counter < max_iterations); return -ETIMEDOUT; } static int pcie_phy_wait_ack(void __iomem *dbi_base, int addr) { u32 val; int ret; val = addr << PCIE_PHY_CTRL_DATA_LOC; writel(val, dbi_base + PCIE_PHY_CTRL); val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC); writel(val, dbi_base + PCIE_PHY_CTRL); ret = pcie_phy_poll_ack(dbi_base, 1); if (ret) return ret; val = addr << PCIE_PHY_CTRL_DATA_LOC; writel(val, dbi_base + PCIE_PHY_CTRL); return pcie_phy_poll_ack(dbi_base, 0); } /* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */ static int pcie_phy_read(void __iomem *dbi_base, int addr , int *data) { u32 val, phy_ctl; int ret; ret = pcie_phy_wait_ack(dbi_base, addr); if (ret) return ret; /* assert Read signal */ phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC; writel(phy_ctl, dbi_base + PCIE_PHY_CTRL); ret = pcie_phy_poll_ack(dbi_base, 1); if (ret) return ret; val = readl(dbi_base + PCIE_PHY_STAT); *data = val & 0xffff; /* deassert Read signal */ writel(0x00, dbi_base + PCIE_PHY_CTRL); return pcie_phy_poll_ack(dbi_base, 0); } static int pcie_phy_write(void __iomem *dbi_base, int addr, int data) { u32 var; int ret; /* write addr */ /* cap addr */ ret = pcie_phy_wait_ack(dbi_base, addr); if (ret) return ret; var = data << PCIE_PHY_CTRL_DATA_LOC; writel(var, dbi_base + PCIE_PHY_CTRL); /* capture data */ var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC); writel(var, dbi_base + PCIE_PHY_CTRL); ret = pcie_phy_poll_ack(dbi_base, 1); if (ret) return ret; /* deassert cap data */ var = data << PCIE_PHY_CTRL_DATA_LOC; writel(var, dbi_base + PCIE_PHY_CTRL); /* wait for ack de-assertion */ ret = pcie_phy_poll_ack(dbi_base, 0); if (ret) return ret; /* assert wr signal */ var = 0x1 << PCIE_PHY_CTRL_WR_LOC; writel(var, dbi_base + PCIE_PHY_CTRL); /* wait for ack */ ret = pcie_phy_poll_ack(dbi_base, 1); if (ret) return ret; /* deassert wr signal */ var = data << PCIE_PHY_CTRL_DATA_LOC; writel(var, dbi_base + PCIE_PHY_CTRL); /* wait for ack de-assertion */ ret = pcie_phy_poll_ack(dbi_base, 0); if (ret) return ret; writel(0x0, dbi_base + PCIE_PHY_CTRL); return 0; } /* Added for PCI abort handling */ static int imx6q_pcie_abort_handler(unsigned long addr, unsigned int fsr, struct pt_regs *regs) { return 0; } static int imx6_pcie_assert_core_reset(struct pcie_port *pp) { struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); u32 val, gpr1, gpr12; /* * If the bootloader already enabled the link we need some special * handling to get the core back into a state where it is safe to * touch it for configuration. As there is no dedicated reset signal * wired up for MX6QDL, we need to manually force LTSSM into "detect" * state before completely disabling LTSSM, which is a prerequisite * for core configuration. * * If both LTSSM_ENABLE and REF_SSP_ENABLE are active we have a strong * indication that the bootloader activated the link. */ regmap_read(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, &gpr1); regmap_read(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, &gpr12); if ((gpr1 & IMX6Q_GPR1_PCIE_REF_CLK_EN) && (gpr12 & IMX6Q_GPR12_PCIE_CTL_2)) { val = readl(pp->dbi_base + PCIE_PL_PFLR); val &= ~PCIE_PL_PFLR_LINK_STATE_MASK; val |= PCIE_PL_PFLR_FORCE_LINK; writel(val, pp->dbi_base + PCIE_PL_PFLR); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6Q_GPR12_PCIE_CTL_2, 0 << 10); } regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16); return 0; } static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) { struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); int ret; ret = clk_prepare_enable(imx6_pcie->pcie_phy); if (ret) { dev_err(pp->dev, "unable to enable pcie_phy clock\n"); goto err_pcie_phy; } ret = clk_prepare_enable(imx6_pcie->pcie_bus); if (ret) { dev_err(pp->dev, "unable to enable pcie_bus clock\n"); goto err_pcie_bus; } ret = clk_prepare_enable(imx6_pcie->pcie); if (ret) { dev_err(pp->dev, "unable to enable pcie clock\n"); goto err_pcie; } /* power up core phy and enable ref clock */ regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); /* * the async reset input need ref clock to sync internally, * when the ref clock comes after reset, internal synced * reset time is too short, cannot meet the requirement. * add one ~10us delay here. */ udelay(10); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); /* allow the clocks to stabilize */ usleep_range(200, 500); /* Some boards don't have PCIe reset GPIO. */ if (gpio_is_valid(imx6_pcie->reset_gpio)) { gpio_set_value(imx6_pcie->reset_gpio, 0); msleep(100); gpio_set_value(imx6_pcie->reset_gpio, 1); } return 0; err_pcie: clk_disable_unprepare(imx6_pcie->pcie_bus); err_pcie_bus: clk_disable_unprepare(imx6_pcie->pcie_phy); err_pcie_phy: return ret; } static void imx6_pcie_init_phy(struct pcie_port *pp) { struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6Q_GPR12_PCIE_CTL_2, 0 << 10); /* configure constant input signal to the pcie ctrl and phy */ regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6Q_GPR12_LOS_LEVEL, 9 << 4); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, IMX6Q_GPR8_TX_DEEMPH_GEN1, 0 << 0); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, IMX6Q_GPR8_TX_DEEMPH_GEN2_3P5DB, 0 << 6); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, IMX6Q_GPR8_TX_DEEMPH_GEN2_6DB, 20 << 12); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, IMX6Q_GPR8_TX_SWING_FULL, 127 << 18); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, IMX6Q_GPR8_TX_SWING_LOW, 127 << 25); } static int imx6_pcie_wait_for_link(struct pcie_port *pp) { unsigned int retries; for (retries = 0; retries < 200; retries++) { if (dw_pcie_link_up(pp)) return 0; usleep_range(100, 1000); } dev_err(pp->dev, "phy link never came up\n"); dev_dbg(pp->dev, "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n", readl(pp->dbi_base + PCIE_PHY_DEBUG_R0), readl(pp->dbi_base + PCIE_PHY_DEBUG_R1)); return -EINVAL; } static int imx6_pcie_wait_for_speed_change(struct pcie_port *pp) { u32 tmp; unsigned int retries; for (retries = 0; retries < 200; retries++) { tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); /* Test if the speed change finished. */ if (!(tmp & PORT_LOGIC_SPEED_CHANGE)) return 0; usleep_range(100, 1000); } dev_err(pp->dev, "Speed change timeout\n"); return -EINVAL; } static irqreturn_t imx6_pcie_msi_handler(int irq, void *arg) { struct pcie_port *pp = arg; return dw_handle_msi_irq(pp); } static int imx6_pcie_establish_link(struct pcie_port *pp) { struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); u32 tmp; int ret; /* * Force Gen1 operation when starting the link. In case the link is * started in Gen2 mode, there is a possibility the devices on the * bus will not be detected at all. This happens with PCIe switches. */ tmp = readl(pp->dbi_base + PCIE_RC_LCR); tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK; tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1; writel(tmp, pp->dbi_base + PCIE_RC_LCR); /* Start LTSSM. */ regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6Q_GPR12_PCIE_CTL_2, 1 << 10); ret = imx6_pcie_wait_for_link(pp); if (ret) return ret; /* Allow Gen2 mode after the link is up. */ tmp = readl(pp->dbi_base + PCIE_RC_LCR); tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK; tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2; writel(tmp, pp->dbi_base + PCIE_RC_LCR); /* * Start Directed Speed Change so the best possible speed both link * partners support can be negotiated. */ tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); tmp |= PORT_LOGIC_SPEED_CHANGE; writel(tmp, pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); ret = imx6_pcie_wait_for_speed_change(pp); if (ret) { dev_err(pp->dev, "Failed to bring link up!\n"); return ret; } /* Make sure link training is finished as well! */ ret = imx6_pcie_wait_for_link(pp); if (ret) { dev_err(pp->dev, "Failed to bring link up!\n"); return ret; } tmp = readl(pp->dbi_base + PCIE_RC_LCSR); dev_dbg(pp->dev, "Link up, Gen=%i\n", (tmp >> 16) & 0xf); return 0; } static void imx6_pcie_host_init(struct pcie_port *pp) { imx6_pcie_assert_core_reset(pp); imx6_pcie_init_phy(pp); imx6_pcie_deassert_core_reset(pp); dw_pcie_setup_rc(pp); imx6_pcie_establish_link(pp); if (IS_ENABLED(CONFIG_PCI_MSI)) dw_pcie_msi_init(pp); } static void imx6_pcie_reset_phy(struct pcie_port *pp) { u32 tmp; pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &tmp); tmp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN | PHY_RX_OVRD_IN_LO_RX_PLL_EN); pcie_phy_write(pp->dbi_base, PHY_RX_OVRD_IN_LO, tmp); usleep_range(2000, 3000); pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &tmp); tmp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN | PHY_RX_OVRD_IN_LO_RX_PLL_EN); pcie_phy_write(pp->dbi_base, PHY_RX_OVRD_IN_LO, tmp); } static int imx6_pcie_link_up(struct pcie_port *pp) { u32 rc, debug_r0, rx_valid; int count = 5; /* * Test if the PHY reports that the link is up and also that the LTSSM * training finished. There are three possible states of the link when * this code is called: * 1) The link is DOWN (unlikely) * The link didn't come up yet for some reason. This usually means * we have a real problem somewhere. Reset the PHY and exit. This * state calls for inspection of the DEBUG registers. * 2) The link is UP, but still in LTSSM training * Wait for the training to finish, which should take a very short * time. If the training does not finish, we have a problem and we * need to inspect the DEBUG registers. If the training does finish, * the link is up and operating correctly. * 3) The link is UP and no longer in LTSSM training * The link is up and operating correctly. */ while (1) { rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1); if (!(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP)) break; if (!(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING)) return 1; if (!count--) break; dev_dbg(pp->dev, "Link is up, but still in training\n"); /* * Wait a little bit, then re-check if the link finished * the training. */ usleep_range(1000, 2000); } /* * From L0, initiate MAC entry to gen2 if EP/RC supports gen2. * Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2). * If (MAC/LTSSM.state == Recovery.RcvrLock) * && (PHY/rx_valid==0) then pulse PHY/rx_reset. Transition * to gen2 is stuck */ pcie_phy_read(pp->dbi_base, PCIE_PHY_RX_ASIC_OUT, &rx_valid); debug_r0 = readl(pp->dbi_base + PCIE_PHY_DEBUG_R0); if (rx_valid & PCIE_PHY_RX_ASIC_OUT_VALID) return 0; if ((debug_r0 & 0x3f) != 0x0d) return 0; dev_err(pp->dev, "transition to gen2 is stuck, reset PHY!\n"); dev_dbg(pp->dev, "debug_r0=%08x debug_r1=%08x\n", debug_r0, rc); imx6_pcie_reset_phy(pp); return 0; } static struct pcie_host_ops imx6_pcie_host_ops = { .link_up = imx6_pcie_link_up, .host_init = imx6_pcie_host_init, }; static int __init imx6_add_pcie_port(struct pcie_port *pp, struct platform_device *pdev) { int ret; if (IS_ENABLED(CONFIG_PCI_MSI)) { pp->msi_irq = platform_get_irq_byname(pdev, "msi"); if (pp->msi_irq <= 0) { dev_err(&pdev->dev, "failed to get MSI irq\n"); return -ENODEV; } ret = devm_request_irq(&pdev->dev, pp->msi_irq, imx6_pcie_msi_handler, IRQF_SHARED, "mx6-pcie-msi", pp); if (ret) { dev_err(&pdev->dev, "failed to request MSI irq\n"); return ret; } } pp->root_bus_nr = -1; pp->ops = &imx6_pcie_host_ops; ret = dw_pcie_host_init(pp); if (ret) { dev_err(&pdev->dev, "failed to initialize host\n"); return ret; } return 0; } static int __init imx6_pcie_probe(struct platform_device *pdev) { struct imx6_pcie *imx6_pcie; struct pcie_port *pp; struct device_node *np = pdev->dev.of_node; struct resource *dbi_base; int ret; imx6_pcie = devm_kzalloc(&pdev->dev, sizeof(*imx6_pcie), GFP_KERNEL); if (!imx6_pcie) return -ENOMEM; pp = &imx6_pcie->pp; pp->dev = &pdev->dev; /* Added for PCI abort handling */ hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0, "imprecise external abort"); dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0); pp->dbi_base = devm_ioremap_resource(&pdev->dev, dbi_base); if (IS_ERR(pp->dbi_base)) return PTR_ERR(pp->dbi_base); /* Fetch GPIOs */ imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0); if (gpio_is_valid(imx6_pcie->reset_gpio)) { ret = devm_gpio_request_one(&pdev->dev, imx6_pcie->reset_gpio, GPIOF_OUT_INIT_LOW, "PCIe reset"); if (ret) { dev_err(&pdev->dev, "unable to get reset gpio\n"); return ret; } } /* Fetch clocks */ imx6_pcie->pcie_phy = devm_clk_get(&pdev->dev, "pcie_phy"); if (IS_ERR(imx6_pcie->pcie_phy)) { dev_err(&pdev->dev, "pcie_phy clock source missing or invalid\n"); return PTR_ERR(imx6_pcie->pcie_phy); } imx6_pcie->pcie_bus = devm_clk_get(&pdev->dev, "pcie_bus"); if (IS_ERR(imx6_pcie->pcie_bus)) { dev_err(&pdev->dev, "pcie_bus clock source missing or invalid\n"); return PTR_ERR(imx6_pcie->pcie_bus); } imx6_pcie->pcie = devm_clk_get(&pdev->dev, "pcie"); if (IS_ERR(imx6_pcie->pcie)) { dev_err(&pdev->dev, "pcie clock source missing or invalid\n"); return PTR_ERR(imx6_pcie->pcie); } /* Grab GPR config register range */ imx6_pcie->iomuxc_gpr = syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr"); if (IS_ERR(imx6_pcie->iomuxc_gpr)) { dev_err(&pdev->dev, "unable to find iomuxc registers\n"); return PTR_ERR(imx6_pcie->iomuxc_gpr); } ret = imx6_add_pcie_port(pp, pdev); if (ret < 0) return ret; platform_set_drvdata(pdev, imx6_pcie); return 0; } static void imx6_pcie_shutdown(struct platform_device *pdev) { struct imx6_pcie *imx6_pcie = platform_get_drvdata(pdev); /* bring down link, so bootloader gets clean state in case of reboot */ imx6_pcie_assert_core_reset(&imx6_pcie->pp); } static const struct of_device_id imx6_pcie_of_match[] = { { .compatible = "fsl,imx6q-pcie", }, {}, }; MODULE_DEVICE_TABLE(of, imx6_pcie_of_match); static struct platform_driver imx6_pcie_driver = { .driver = { .name = "imx6q-pcie", .of_match_table = imx6_pcie_of_match, }, .shutdown = imx6_pcie_shutdown, }; /* Freescale PCIe driver does not allow module unload */ static int __init imx6_pcie_init(void) { return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe); } module_init(imx6_pcie_init); MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>"); MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver"); MODULE_LICENSE("GPL v2");