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Commit 4bd70bc9 authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

Merge branch 'pci/host-imx6' into next 

* pci/host-imx6:
  PCI: imx6: Fix bugs in PCIe startup code
  PCI: imx6: Start link in Gen1 before negotiating for Gen2 mode
  PCI: imx6: Factor out link up wait loop
  PCI: imx6: Factor out PHY reset
  PCI: imx6: Report "link up" only after link training completes
  PCI: imx6: Make reset-gpio optional
parents 608235a3 bc9ef770

Documentation/devicetree/bindings/pci/designware-pcie.txt

+2 −0
Original line number Diff line number Diff line
@@ -19,6 +19,8 @@ Required properties: 
	to define the mapping of the PCIe interface to interrupt

	numbers.

- num-lanes: number of lanes to use



Optional properties:

- reset-gpio: gpio pin number of power good signal



Optional properties for fsl,imx6q-pcie

drivers/pci/host/pci-imx6.c

+134 −54
Original line number Diff line number Diff line
@@ -44,10 +44,18 @@ struct imx6_pcie { 
	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
@@ -59,6 +67,9 @@ struct imx6_pcie { 
#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
@@ -209,15 +220,9 @@ static int imx6_pcie_assert_core_reset(struct pcie_port *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_GPR12,

			IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);

	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,

			IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);



	gpio_set_value(imx6_pcie->reset_gpio, 0);

	msleep(100);

	gpio_set_value(imx6_pcie->reset_gpio, 1);



	return 0;

}
@@ -261,6 +266,12 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) 
	/* 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_axi:
@@ -299,46 +310,133 @@ static void imx6_pcie_init_phy(struct pcie_port *pp) 
			IMX6Q_GPR8_TX_SWING_LOW, 127 << 25);

}



static void imx6_pcie_host_init(struct pcie_port *pp)

static int imx6_pcie_wait_for_link(struct pcie_port *pp)

{

	int count = 0;

	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);

	int count = 200;



	imx6_pcie_assert_core_reset(pp);

	while (!dw_pcie_link_up(pp)) {

		usleep_range(100, 1000);

		if (--count)

			continue;



	imx6_pcie_init_phy(pp);

		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;

	}



	imx6_pcie_deassert_core_reset(pp);

	return 0;

}



	dw_pcie_setup_rc(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);



	while (!dw_pcie_link_up(pp)) {

		usleep_range(100, 1000);

		count++;

		if (count >= 200) {

			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));

	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;

	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);

}



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, ltssm, rx_valid, temp;

	u32 rc, ltssm, rx_valid;



	/* link is debug bit 36, debug register 1 starts at bit 32 */

	rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) & (0x1 << (36 - 32));

	if (rc)

		return -EAGAIN;

	/*

	 * Test if the PHY reports that the link is up and also that

	 * the link training finished.  It might happen that the PHY

	 * reports the link is already up, but the link training bit

	 * is still set, so make sure to check the training is done

	 * as well here.

	 */

	rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1);

	if ((rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP) &&

	    !(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING))

		return 1;



	/*

	 * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
@@ -358,21 +456,7 @@ static int imx6_pcie_link_up(struct pcie_port *pp) 


	dev_err(pp->dev, "transition to gen2 is stuck, reset PHY!\n");



	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);

	imx6_pcie_reset_phy(pp);



	return 0;

}
@@ -432,18 +516,14 @@ static int __init imx6_pcie_probe(struct platform_device *pdev) 


	/* Fetch GPIOs */

	imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);

	if (!gpio_is_valid(imx6_pcie->reset_gpio)) {

		dev_err(&pdev->dev, "no reset-gpio defined\n");

		ret = -ENODEV;

	}

	ret = devm_gpio_request_one(&pdev->dev,

				imx6_pcie->reset_gpio,

				GPIOF_OUT_INIT_LOW,

				"PCIe reset");

	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;

		}

	}



	imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0);

	if (gpio_is_valid(imx6_pcie->power_on_gpio)) {