diff options
Diffstat (limited to 'drivers/pci/host/pci-imx6.c')
| -rw-r--r-- | drivers/pci/host/pci-imx6.c | 616 |
1 files changed, 616 insertions, 0 deletions
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c new file mode 100644 index 00000000000..a568efaa331 --- /dev/null +++ b/drivers/pci/host/pci-imx6.c @@ -0,0 +1,616 @@ +/* + * 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 + +/* PCIe Port Logic registers (memory-mapped) */ +#define PL_OFFSET 0x700 +#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 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); + + ret = pcie_phy_poll_ack(dbi_base, 0); + if (ret) + return ret; + + return 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); + + ret = pcie_phy_poll_ack(dbi_base, 0); + if (ret) + return ret; + + return 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); + + 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; + + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, + IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, + IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); + + 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; + } + + /* 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) +{ + int count = 200; + + while (!dw_pcie_link_up(pp)) { + usleep_range(100, 1000); + if (--count) + continue; + + 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; + } + + return 0; +} + +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_start_link(struct pcie_port *pp) +{ + struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); + uint32_t tmp; + int ret, count; + + /* + * 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); + + count = 200; + while (count--) { + tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); + /* Test if the speed change finished. */ + if (!(tmp & PORT_LOGIC_SPEED_CHANGE)) + break; + usleep_range(100, 1000); + } + + /* Make sure link training is finished as well! */ + if (count) + ret = imx6_pcie_wait_for_link(pp); + else + ret = -EINVAL; + + if (ret) { + dev_err(pp->dev, "Failed to bring link up!\n"); + } else { + tmp = readl(pp->dbi_base + 0x80); + dev_dbg(pp->dev, "Link up, Gen=%i\n", (tmp >> 16) & 0xf); + } + + return ret; +} + +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_start_link(pp); + + if (IS_ENABLED(CONFIG_PCI_MSI)) + dw_pcie_msi_init(pp); +} + +static void imx6_pcie_reset_phy(struct pcie_port *pp) +{ + uint32_t temp; + + pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &temp); + temp |= (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, temp); + + usleep_range(2000, 3000); + + pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &temp); + temp &= ~(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, temp); +} + +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 & 0x01) + 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 -ENODEV; + } + } + + 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 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", + .owner = THIS_MODULE, + .of_match_table = imx6_pcie_of_match, + }, +}; + +/* 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); +} +fs_initcall(imx6_pcie_init); + +MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>"); +MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver"); +MODULE_LICENSE("GPL v2"); |