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  • /*
     * Freescale i.MX6 PCI Express Root-Complex driver
     *
     * Copyright (C) 2013 Marek Vasut <marex@denx.de>
     *
     * Based on upstream Linux kernel driver:
     * pci-imx6.c:		Sean Cross <xobs@kosagi.com>
     * pcie-designware.c:	Jingoo Han <jg1.han@samsung.com>
     *
     * SPDX-License-Identifier:	GPL-2.0
     */
    
    #include <common.h>
    #include <pci.h>
    #include <asm/arch/clock.h>
    #include <asm/arch/iomux.h>
    #include <asm/arch/crm_regs.h>
    
    #include <asm/gpio.h>
    
    #include <asm/io.h>
    
    #include <linux/sizes.h>
    
    #include <errno.h>
    
    #include <asm/arch/sys_proto.h>
    
    
    #define PCI_ACCESS_READ  0
    #define PCI_ACCESS_WRITE 1
    
    
    #ifdef CONFIG_MX6SX
    #define MX6_DBI_ADDR	0x08ffc000
    #define MX6_IO_ADDR	0x08000000
    #define MX6_MEM_ADDR	0x08100000
    #define MX6_ROOT_ADDR	0x08f00000
    #else
    
    #define MX6_DBI_ADDR	0x01ffc000
    #define MX6_IO_ADDR	0x01000000
    #define MX6_MEM_ADDR	0x01100000
    #define MX6_ROOT_ADDR	0x01f00000
    
    #endif
    #define MX6_DBI_SIZE	0x4000
    #define MX6_IO_SIZE	0x100000
    #define MX6_MEM_SIZE	0xe00000
    
    #define MX6_ROOT_SIZE	0xfc000
    
    /* 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_LINK_UP		(1 << 4)
    #define PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING	(1 << 29)
    
    #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_DATA_LOC 0
    #define PCIE_PHY_STAT_ACK_LOC 16
    
    /* 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)
    
    
    #define PCIE_PHY_PUP_REQ		(1 << 7)
    
    
    /* iATU registers */
    #define PCIE_ATU_VIEWPORT		0x900
    #define PCIE_ATU_REGION_INBOUND		(0x1 << 31)
    #define PCIE_ATU_REGION_OUTBOUND	(0x0 << 31)
    #define PCIE_ATU_REGION_INDEX1		(0x1 << 0)
    #define PCIE_ATU_REGION_INDEX0		(0x0 << 0)
    #define PCIE_ATU_CR1			0x904
    #define PCIE_ATU_TYPE_MEM		(0x0 << 0)
    #define PCIE_ATU_TYPE_IO		(0x2 << 0)
    #define PCIE_ATU_TYPE_CFG0		(0x4 << 0)
    #define PCIE_ATU_TYPE_CFG1		(0x5 << 0)
    #define PCIE_ATU_CR2			0x908
    #define PCIE_ATU_ENABLE			(0x1 << 31)
    #define PCIE_ATU_BAR_MODE_ENABLE	(0x1 << 30)
    #define PCIE_ATU_LOWER_BASE		0x90C
    #define PCIE_ATU_UPPER_BASE		0x910
    #define PCIE_ATU_LIMIT			0x914
    #define PCIE_ATU_LOWER_TARGET		0x918
    #define PCIE_ATU_BUS(x)			(((x) & 0xff) << 24)
    #define PCIE_ATU_DEV(x)			(((x) & 0x1f) << 19)
    #define PCIE_ATU_FUNC(x)		(((x) & 0x7) << 16)
    #define PCIE_ATU_UPPER_TARGET		0x91C
    
    /*
     * PHY access functions
     */
    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;
    }
    
    static int imx6_pcie_link_up(void)
    {
    	u32 rc, ltssm;
    	int rx_valid, temp;
    
    	/* link is debug bit 36, debug register 1 starts at bit 32 */
    	rc = readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R1);
    	if ((rc & PCIE_PHY_DEBUG_R1_LINK_UP) &&
    	    !(rc & PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING))
    		return -EAGAIN;
    
    	/*
    	 * 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((void *)MX6_DBI_ADDR, PCIE_PHY_RX_ASIC_OUT, &rx_valid);
    	ltssm = readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R0) & 0x3F;
    
    	if (rx_valid & 0x01)
    		return 0;
    
    	if (ltssm != 0x0d)
    		return 0;
    
    	printf("transition to gen2 is stuck, reset PHY!\n");
    
    	pcie_phy_read((void *)MX6_DBI_ADDR, 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((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, temp);
    
    	udelay(3000);
    
    	pcie_phy_read((void *)MX6_DBI_ADDR, 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((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, temp);
    
    	return 0;
    }
    
    /*
     * iATU region setup
     */
    static int imx_pcie_regions_setup(void)
    {
    	/*
    	 * i.MX6 defines 16MB in the AXI address map for PCIe.
    	 *
    	 * That address space excepted the pcie registers is
    	 * split and defined into different regions by iATU,
    	 * with sizes and offsets as follows:
    	 *
    	 * 0x0100_0000 --- 0x010F_FFFF 1MB IORESOURCE_IO
    	 * 0x0110_0000 --- 0x01EF_FFFF 14MB IORESOURCE_MEM
    	 * 0x01F0_0000 --- 0x01FF_FFFF 1MB Cfg + Registers
    	 */
    
    	/* CMD reg:I/O space, MEM space, and Bus Master Enable */
    	setbits_le32(MX6_DBI_ADDR | PCI_COMMAND,
    		     PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);
    
    	/* Set the CLASS_REV of RC CFG header to PCI_CLASS_BRIDGE_PCI */
    	setbits_le32(MX6_DBI_ADDR + PCI_CLASS_REVISION,
    		     PCI_CLASS_BRIDGE_PCI << 16);
    
    	/* Region #0 is used for Outbound CFG space access. */
    	writel(0, MX6_DBI_ADDR + PCIE_ATU_VIEWPORT);
    
    	writel(MX6_ROOT_ADDR, MX6_DBI_ADDR + PCIE_ATU_LOWER_BASE);
    	writel(0, MX6_DBI_ADDR + PCIE_ATU_UPPER_BASE);
    	writel(MX6_ROOT_ADDR + MX6_ROOT_SIZE, MX6_DBI_ADDR + PCIE_ATU_LIMIT);
    
    	writel(0, MX6_DBI_ADDR + PCIE_ATU_LOWER_TARGET);
    	writel(0, MX6_DBI_ADDR + PCIE_ATU_UPPER_TARGET);
    	writel(PCIE_ATU_TYPE_CFG0, MX6_DBI_ADDR + PCIE_ATU_CR1);
    	writel(PCIE_ATU_ENABLE, MX6_DBI_ADDR + PCIE_ATU_CR2);
    
    	return 0;
    }
    
    /*
     * PCI Express accessors
     */
    static uint32_t get_bus_address(pci_dev_t d, int where)
    {
    	uint32_t va_address;
    
    	/* Reconfigure Region #0 */
    	writel(0, MX6_DBI_ADDR + PCIE_ATU_VIEWPORT);
    
    	if (PCI_BUS(d) < 2)
    		writel(PCIE_ATU_TYPE_CFG0, MX6_DBI_ADDR + PCIE_ATU_CR1);
    	else
    		writel(PCIE_ATU_TYPE_CFG1, MX6_DBI_ADDR + PCIE_ATU_CR1);
    
    	if (PCI_BUS(d) == 0) {
    		va_address = MX6_DBI_ADDR;
    	} else {
    		writel(d << 8, MX6_DBI_ADDR + PCIE_ATU_LOWER_TARGET);
    		va_address = MX6_IO_ADDR + SZ_16M - SZ_1M;
    	}
    
    	va_address += (where & ~0x3);
    
    	return va_address;
    }
    
    static int imx_pcie_addr_valid(pci_dev_t d)
    {
    	if ((PCI_BUS(d) == 0) && (PCI_DEV(d) > 1))
    		return -EINVAL;
    	if ((PCI_BUS(d) == 1) && (PCI_DEV(d) > 0))
    		return -EINVAL;
    	return 0;
    }
    
    /*
     * Replace the original ARM DABT handler with a simple jump-back one.
     *
     * The problem here is that if we have a PCIe bridge attached to this PCIe
     * controller, but no PCIe device is connected to the bridges' downstream
     * port, the attempt to read/write from/to the config space will produce
     * a DABT. This is a behavior of the controller and can not be disabled
     * unfortuatelly.
     *
     * To work around the problem, we backup the current DABT handler address
     * and replace it with our own DABT handler, which only bounces right back
     * into the code.
     */
    static void imx_pcie_fix_dabt_handler(bool set)
    {
    	extern uint32_t *_data_abort;
    	uint32_t *data_abort_addr = (uint32_t *)&_data_abort;
    
    	static const uint32_t data_abort_bounce_handler = 0xe25ef004;
    	uint32_t data_abort_bounce_addr = (uint32_t)&data_abort_bounce_handler;
    
    	static uint32_t data_abort_backup;
    
    	if (set) {
    		data_abort_backup = *data_abort_addr;
    		*data_abort_addr = data_abort_bounce_addr;
    	} else {
    		*data_abort_addr = data_abort_backup;
    	}
    }
    
    static int imx_pcie_read_config(struct pci_controller *hose, pci_dev_t d,
    				int where, u32 *val)
    {
    	uint32_t va_address;
    	int ret;
    
    	ret = imx_pcie_addr_valid(d);
    	if (ret) {
    		*val = 0xffffffff;
    
    	}
    
    	va_address = get_bus_address(d, where);
    
    	/*
    	 * Read the PCIe config space. We must replace the DABT handler
    	 * here in case we got data abort from the PCIe controller, see
    	 * imx_pcie_fix_dabt_handler() description. Note that writing the
    	 * "val" with valid value is also imperative here as in case we
    	 * did got DABT, the val would contain random value.
    	 */
    	imx_pcie_fix_dabt_handler(true);
    	writel(0xffffffff, val);
    	*val = readl(va_address);
    	imx_pcie_fix_dabt_handler(false);
    
    	return 0;
    }
    
    static int imx_pcie_write_config(struct pci_controller *hose, pci_dev_t d,
    			int where, u32 val)
    {
    	uint32_t va_address = 0;
    	int ret;
    
    	ret = imx_pcie_addr_valid(d);
    	if (ret)
    		return ret;
    
    	va_address = get_bus_address(d, where);
    
    	/*
    	 * Write the PCIe config space. We must replace the DABT handler
    	 * here in case we got data abort from the PCIe controller, see
    	 * imx_pcie_fix_dabt_handler() description.
    	 */
    	imx_pcie_fix_dabt_handler(true);
    	writel(val, va_address);
    	imx_pcie_fix_dabt_handler(false);
    
    	return 0;
    }
    
    /*
     * Initial bus setup
     */
    static int imx6_pcie_assert_core_reset(void)
    {
    	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
    
    
    	if (is_mx6dqp())
    		setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_PCIE_SW_RST);
    
    
    #if defined(CONFIG_MX6SX)
    	struct gpc *gpc_regs = (struct gpc *)GPC_BASE_ADDR;
    
    	/* SSP_EN is not used on MX6SX anymore */
    	setbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_TEST_POWERDOWN);
    	/* Force PCIe PHY reset */
    	setbits_le32(&iomuxc_regs->gpr[5], IOMUXC_GPR5_PCIE_BTNRST);
    	/* Power up PCIe PHY */
    	setbits_le32(&gpc_regs->cntr, PCIE_PHY_PUP_REQ);
    #else
    
    	setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_TEST_POWERDOWN);
    	clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_REF_SSP_EN);
    
    
    	return 0;
    }
    
    static int imx6_pcie_init_phy(void)
    {
    	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
    
    	clrbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_APPS_LTSSM_ENABLE);
    
    	clrsetbits_le32(&iomuxc_regs->gpr[12],
    			IOMUXC_GPR12_DEVICE_TYPE_MASK,
    			IOMUXC_GPR12_DEVICE_TYPE_RC);
    	clrsetbits_le32(&iomuxc_regs->gpr[12],
    			IOMUXC_GPR12_LOS_LEVEL_MASK,
    			IOMUXC_GPR12_LOS_LEVEL_9);
    
    
    #ifdef CONFIG_MX6SX
    	clrsetbits_le32(&iomuxc_regs->gpr[12],
    			IOMUXC_GPR12_RX_EQ_MASK,
    			IOMUXC_GPR12_RX_EQ_2);
    #endif
    
    
    	writel((0x0 << IOMUXC_GPR8_PCS_TX_DEEMPH_GEN1_OFFSET) |
    	       (0x0 << IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_3P5DB_OFFSET) |
    	       (20 << IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_6DB_OFFSET) |
    	       (127 << IOMUXC_GPR8_PCS_TX_SWING_FULL_OFFSET) |
    	       (127 << IOMUXC_GPR8_PCS_TX_SWING_LOW_OFFSET),
    	       &iomuxc_regs->gpr[8]);
    
    	return 0;
    }
    
    
    __weak int imx6_pcie_toggle_power(void)
    {
    #ifdef CONFIG_PCIE_IMX_POWER_GPIO
    	gpio_direction_output(CONFIG_PCIE_IMX_POWER_GPIO, 0);
    	mdelay(20);
    	gpio_set_value(CONFIG_PCIE_IMX_POWER_GPIO, 1);
    	mdelay(20);
    #endif
    	return 0;
    }
    
    
    __weak int imx6_pcie_toggle_reset(void)
    {
    	/*
    	 * See 'PCI EXPRESS BASE SPECIFICATION, REV 3.0, SECTION 6.6.1'
    	 * for detailed understanding of the PCIe CR reset logic.
    	 *
    	 * The PCIe #PERST reset line _MUST_ be connected, otherwise your
    	 * design does not conform to the specification. You must wait at
    
    	 * least 20 ms after de-asserting the #PERST so the EP device can
    
    	 * do self-initialisation.
    	 *
    	 * In case your #PERST pin is connected to a plain GPIO pin of the
    	 * CPU, you can define CONFIG_PCIE_IMX_PERST_GPIO in your board's
    	 * configuration file and the condition below will handle the rest
    	 * of the reset toggling.
    	 *
    	 * In case your #PERST toggling logic is more complex, for example
    	 * connected via CPLD or somesuch, you can override this function
    	 * in your board file and implement reset logic as needed. You must
    
    	 * not forget to wait at least 20 ms after de-asserting #PERST in
    
    	 * this case either though.
    	 *
    	 * In case your #PERST line of the PCIe EP device is not connected
    	 * at all, your design is broken and you should fix your design,
    	 * otherwise you will observe problems like for example the link
    	 * not coming up after rebooting the system back from running Linux
    	 * that uses the PCIe as well OR the PCIe link might not come up in
    	 * Linux at all in the first place since it's in some non-reset
    	 * state due to being previously used in U-Boot.
    	 */
    #ifdef CONFIG_PCIE_IMX_PERST_GPIO
    	gpio_direction_output(CONFIG_PCIE_IMX_PERST_GPIO, 0);
    	mdelay(20);
    	gpio_set_value(CONFIG_PCIE_IMX_PERST_GPIO, 1);
    	mdelay(20);
    #else
    	puts("WARNING: Make sure the PCIe #PERST line is connected!\n");
    #endif
    	return 0;
    }
    
    
    static int imx6_pcie_deassert_core_reset(void)
    {
    	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
    
    
    	imx6_pcie_toggle_power();
    
    
    	enable_pcie_clock();
    
    
    	if (is_mx6dqp())
    		clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_PCIE_SW_RST);
    
    
    	/*
    	 * Wait for the clock to settle a bit, when the clock are sourced
    
    	 * from the CPU, we need about 30 ms to settle.
    
    	mdelay(50);
    
    #if defined(CONFIG_MX6SX)
    	/* SSP_EN is not used on MX6SX anymore */
    	clrbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_TEST_POWERDOWN);
    	/* Clear PCIe PHY reset bit */
    	clrbits_le32(&iomuxc_regs->gpr[5], IOMUXC_GPR5_PCIE_BTNRST);
    #else
    
    	/* Enable PCIe */
    	clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_TEST_POWERDOWN);
    	setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_REF_SSP_EN);
    
    	imx6_pcie_toggle_reset();
    
    
    	return 0;
    }
    
    static int imx_pcie_link_up(void)
    {
    	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
    	uint32_t tmp;
    	int count = 0;
    
    	imx6_pcie_assert_core_reset();
    	imx6_pcie_init_phy();
    	imx6_pcie_deassert_core_reset();
    
    	imx_pcie_regions_setup();
    
    	/*
    	 * FIXME: Force the PCIe RC to Gen1 operation
    	 * The RC must be forced into Gen1 mode before bringing the link
    	 * up, otherwise no downstream devices are detected. After the
    	 * link is up, a managed Gen1->Gen2 transition can be initiated.
    	 */
    	tmp = readl(MX6_DBI_ADDR + 0x7c);
    	tmp &= ~0xf;
    	tmp |= 0x1;
    	writel(tmp, MX6_DBI_ADDR + 0x7c);
    
    	/* LTSSM enable, starting link. */
    	setbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_APPS_LTSSM_ENABLE);
    
    	while (!imx6_pcie_link_up()) {
    		udelay(10);
    		count++;
    
    		if (count >= 4000) {
    
    #ifdef CONFIG_PCI_SCAN_SHOW
    			puts("PCI:   pcie phy link never came up\n");
    #endif
    
    			debug("DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
    			      readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R0),
    			      readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R1));
    			return -EINVAL;
    		}
    	}
    
    	return 0;
    }
    
    void imx_pcie_init(void)
    {
    	/* Static instance of the controller. */
    	static struct pci_controller	pcc;
    	struct pci_controller		*hose = &pcc;
    	int ret;
    
    	memset(&pcc, 0, sizeof(pcc));
    
    	/* PCI I/O space */
    	pci_set_region(&hose->regions[0],
    		       MX6_IO_ADDR, MX6_IO_ADDR,
    		       MX6_IO_SIZE, PCI_REGION_IO);
    
    	/* PCI memory space */
    	pci_set_region(&hose->regions[1],
    		       MX6_MEM_ADDR, MX6_MEM_ADDR,
    		       MX6_MEM_SIZE, PCI_REGION_MEM);
    
    	/* System memory space */
    	pci_set_region(&hose->regions[2],
    		       MMDC0_ARB_BASE_ADDR, MMDC0_ARB_BASE_ADDR,
    		       0xefffffff, PCI_REGION_MEM | PCI_REGION_SYS_MEMORY);
    
    	hose->region_count = 3;
    
    	pci_set_ops(hose,
    		    pci_hose_read_config_byte_via_dword,
    		    pci_hose_read_config_word_via_dword,
    		    imx_pcie_read_config,
    		    pci_hose_write_config_byte_via_dword,
    		    pci_hose_write_config_word_via_dword,
    		    imx_pcie_write_config);
    
    	/* Start the controller. */
    	ret = imx_pcie_link_up();
    
    	if (!ret) {
    		pci_register_hose(hose);
    		hose->last_busno = pci_hose_scan(hose);
    	}
    }
    
    /* Probe function. */
    void pci_init_board(void)
    {
    	imx_pcie_init();
    }