ahci: imx: add the imx8qm ahci sata support

- There are three PHY lanes on iMX8QM, and can be
  used in the following three cases
    1. a two lanes PCIE_A, and a single lane SATA.
    2. a single lane PCIE_A, a single lane PCIE_B
    and a single lane SATA.
    3. a two lanes PCIE_A, and a single lane PCIE_B.
  The configuration of the iMX8QM AHCI SATA is relied
  on the usage of PCIE ports in the case 1 and 2.
  Use standalone iMX8 AHCI SATA probe and enable
  functions to enable iMX8QM AHCI SATA support.
- To save power consumption, PHY CLKs can be gated
  off after the configurations are done.
- The impedance ratio should be configured refer to
  differnet REXT values.
  0x6c <--> REXT value is 85Ohms
  0x80 (default value) <--> REXT value is 100Ohms.
  In general, REXT value should be 85ohms in standalone
  PCIE HW board design, and 100ohms in SATA standalone
  HW board design.
  When the PCIE and the SATA are enabled simultaneously
  in the HW board design. The REXT value would be set
  to 85ohms.
  Configure the SATA PHY impedance ratio to 0x6c in
  default.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/ahci_imx.c

@@ -23,6 +23,7 @@
 #include <linux/regmap.h>
 #include <linux/ahci_platform.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 #include <linux/mfd/syscon.h>
 #include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
 #include <linux/libata.h>
@@ -53,12 +54,49 @@ enum {
 	/* Clock Reset Register */
 	IMX_CLOCK_RESET				= 0x7f3f,
 	IMX_CLOCK_RESET_RESET			= 1 << 0,
+	/* IMX8QM HSIO AHCI definitions */
+	IMX8QM_SATA_PHY_RX_IMPED_RATIO_OFFSET	= 0x03,
+	IMX8QM_SATA_PHY_TX_IMPED_RATIO_OFFSET	= 0x09,
+	IMX8QM_SATA_PHY_IMPED_RATIO_85OHM	= 0x6c,
+	IMX8QM_LPCG_PHYX2_OFFSET		= 0x00000,
+	IMX8QM_CSR_PHYX2_OFFSET			= 0x90000,
+	IMX8QM_CSR_PHYX1_OFFSET			= 0xa0000,
+	IMX8QM_CSR_PHYX_STTS0_OFFSET		= 0x4,
+	IMX8QM_CSR_PCIEA_OFFSET			= 0xb0000,
+	IMX8QM_CSR_PCIEB_OFFSET			= 0xc0000,
+	IMX8QM_CSR_SATA_OFFSET			= 0xd0000,
+	IMX8QM_CSR_PCIE_CTRL2_OFFSET		= 0x8,
+	IMX8QM_CSR_MISC_OFFSET			= 0xe0000,
+
+	IMX8QM_LPCG_PHYX2_PCLK0_MASK		= (0x3 << 16),
+	IMX8QM_LPCG_PHYX2_PCLK1_MASK		= (0x3 << 20),
+	IMX8QM_PHY_APB_RSTN_0			= BIT(0),
+	IMX8QM_PHY_MODE_SATA			= BIT(19),
+	IMX8QM_PHY_MODE_MASK			= (0xf << 17),
+	IMX8QM_PHY_PIPE_RSTN_0			= BIT(24),
+	IMX8QM_PHY_PIPE_RSTN_OVERRIDE_0		= BIT(25),
+	IMX8QM_PHY_PIPE_RSTN_1			= BIT(26),
+	IMX8QM_PHY_PIPE_RSTN_OVERRIDE_1		= BIT(27),
+	IMX8QM_STTS0_LANE0_TX_PLL_LOCK		= BIT(4),
+	IMX8QM_MISC_IOB_RXENA			= BIT(0),
+	IMX8QM_MISC_IOB_TXENA			= BIT(1),
+	IMX8QM_MISC_PHYX1_EPCS_SEL		= BIT(12),
+	IMX8QM_MISC_CLKREQN_OUT_OVERRIDE_1	= BIT(24),
+	IMX8QM_MISC_CLKREQN_OUT_OVERRIDE_0	= BIT(25),
+	IMX8QM_MISC_CLKREQN_IN_OVERRIDE_1	= BIT(28),
+	IMX8QM_MISC_CLKREQN_IN_OVERRIDE_0	= BIT(29),
+	IMX8QM_SATA_CTRL_RESET_N		= BIT(12),
+	IMX8QM_SATA_CTRL_EPCS_PHYRESET_N	= BIT(7),
+	IMX8QM_CTRL_BUTTON_RST_N		= BIT(21),
+	IMX8QM_CTRL_POWER_UP_RST_N		= BIT(23),
+	IMX8QM_CTRL_LTSSM_ENABLE		= BIT(4),
 };
 
 enum ahci_imx_type {
 	AHCI_IMX53,
 	AHCI_IMX6Q,
 	AHCI_IMX6QP,
+	AHCI_IMX8QM,
 };
 
 struct imx_ahci_priv {
@@ -67,10 +105,18 @@ struct imx_ahci_priv {
 	struct clk *sata_clk;
 	struct clk *sata_ref_clk;
 	struct clk *ahb_clk;
+	struct clk *epcs_tx_clk;
+	struct clk *epcs_rx_clk;
+	struct clk *phy_apbclk;
+	struct clk *phy_pclk0;
+	struct clk *phy_pclk1;
+	void __iomem *phy_base;
+	int clkreq_gpio;
 	struct regmap *gpr;
 	bool no_device;
 	bool first_time;
 	u32 phy_params;
+	u32 imped_ratio;
 };
 
 static int ahci_imx_hotplug;
@@ -407,6 +453,207 @@ static struct attribute *fsl_sata_ahci_attrs[] = {
 };
 ATTRIBUTE_GROUPS(fsl_sata_ahci);
 
+static int imx8_sata_enable(struct ahci_host_priv *hpriv)
+{
+	u32 val, reg;
+	int i, ret;
+	struct imx_ahci_priv *imxpriv = hpriv->plat_data;
+	struct device *dev = &imxpriv->ahci_pdev->dev;
+
+	/* configure the hsio for sata */
+	ret = clk_prepare_enable(imxpriv->phy_pclk0);
+	if (ret < 0) {
+		dev_err(dev, "can't enable phy_pclk0.\n");
+		return ret;
+	}
+	ret = clk_prepare_enable(imxpriv->phy_pclk1);
+	if (ret < 0) {
+		dev_err(dev, "can't enable phy_pclk1.\n");
+		goto disable_phy_pclk0;
+	}
+	ret = clk_prepare_enable(imxpriv->epcs_tx_clk);
+	if (ret < 0) {
+		dev_err(dev, "can't enable epcs_tx_clk.\n");
+		goto disable_phy_pclk1;
+	}
+	ret = clk_prepare_enable(imxpriv->epcs_rx_clk);
+	if (ret < 0) {
+		dev_err(dev, "can't enable epcs_rx_clk.\n");
+		goto disable_epcs_tx_clk;
+	}
+	ret = clk_prepare_enable(imxpriv->phy_apbclk);
+	if (ret < 0) {
+		dev_err(dev, "can't enable phy_apbclk.\n");
+		goto disable_epcs_rx_clk;
+	}
+	/* Configure PHYx2 PIPE_RSTN */
+	regmap_read(imxpriv->gpr, IMX8QM_CSR_PCIEA_OFFSET +
+			IMX8QM_CSR_PCIE_CTRL2_OFFSET, &val);
+	if ((val & IMX8QM_CTRL_LTSSM_ENABLE) == 0) {
+		/* The link of the PCIEA of HSIO is down */
+		regmap_update_bits(imxpriv->gpr,
+				IMX8QM_CSR_PHYX2_OFFSET,
+				IMX8QM_PHY_PIPE_RSTN_0 |
+				IMX8QM_PHY_PIPE_RSTN_OVERRIDE_0,
+				IMX8QM_PHY_PIPE_RSTN_0 |
+				IMX8QM_PHY_PIPE_RSTN_OVERRIDE_0);
+	}
+	regmap_read(imxpriv->gpr, IMX8QM_CSR_PCIEB_OFFSET +
+			IMX8QM_CSR_PCIE_CTRL2_OFFSET, &reg);
+	if ((reg & IMX8QM_CTRL_LTSSM_ENABLE) == 0) {
+		/* The link of the PCIEB of HSIO is down */
+		regmap_update_bits(imxpriv->gpr,
+				IMX8QM_CSR_PHYX2_OFFSET,
+				IMX8QM_PHY_PIPE_RSTN_1 |
+				IMX8QM_PHY_PIPE_RSTN_OVERRIDE_1,
+				IMX8QM_PHY_PIPE_RSTN_1 |
+				IMX8QM_PHY_PIPE_RSTN_OVERRIDE_1);
+	}
+	if (((reg | val) & IMX8QM_CTRL_LTSSM_ENABLE) == 0) {
+		/* The links of both PCIA and PCIEB of HSIO are down */
+		regmap_update_bits(imxpriv->gpr,
+				IMX8QM_LPCG_PHYX2_OFFSET,
+				IMX8QM_LPCG_PHYX2_PCLK0_MASK |
+				IMX8QM_LPCG_PHYX2_PCLK1_MASK,
+				0);
+	}
+
+	/* set PWR_RST and BT_RST of csr_pciea */
+	val = IMX8QM_CSR_PCIEA_OFFSET + IMX8QM_CSR_PCIE_CTRL2_OFFSET;
+	regmap_update_bits(imxpriv->gpr,
+			val,
+			IMX8QM_CTRL_BUTTON_RST_N,
+			IMX8QM_CTRL_BUTTON_RST_N);
+	regmap_update_bits(imxpriv->gpr,
+			val,
+			IMX8QM_CTRL_POWER_UP_RST_N,
+			IMX8QM_CTRL_POWER_UP_RST_N);
+
+	/* PHYX1_MODE to SATA */
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_PHYX1_OFFSET,
+			IMX8QM_PHY_MODE_MASK,
+			IMX8QM_PHY_MODE_SATA);
+
+	/*
+	 * BIT0 RXENA 1, BIT1 TXENA 0
+	 * BIT12 PHY_X1_EPCS_SEL 1.
+	 */
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_MISC_OFFSET,
+			IMX8QM_MISC_IOB_RXENA,
+			IMX8QM_MISC_IOB_RXENA);
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_MISC_OFFSET,
+			IMX8QM_MISC_IOB_TXENA,
+			0);
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_MISC_OFFSET,
+			IMX8QM_MISC_PHYX1_EPCS_SEL,
+			IMX8QM_MISC_PHYX1_EPCS_SEL);
+	/*
+	 * It is possible, for PCIe and SATA are sharing
+	 * the same clock source, HPLL or external oscillator.
+	 * When PCIe is in low power modes (L1.X or L2 etc),
+	 * the clock source can be turned off. In this case,
+	 * if this clock source is required to be toggling by
+	 * SATA, then SATA functions will be abnormal.
+	 * Set the override here to avoid it.
+	 */
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_MISC_OFFSET,
+			IMX8QM_MISC_CLKREQN_OUT_OVERRIDE_1 |
+			IMX8QM_MISC_CLKREQN_OUT_OVERRIDE_0 |
+			IMX8QM_MISC_CLKREQN_IN_OVERRIDE_1 |
+			IMX8QM_MISC_CLKREQN_IN_OVERRIDE_0,
+			IMX8QM_MISC_CLKREQN_OUT_OVERRIDE_1 |
+			IMX8QM_MISC_CLKREQN_OUT_OVERRIDE_0 |
+			IMX8QM_MISC_CLKREQN_IN_OVERRIDE_1 |
+			IMX8QM_MISC_CLKREQN_IN_OVERRIDE_0);
+
+	/* clear PHY RST, then set it */
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_SATA_OFFSET,
+			IMX8QM_SATA_CTRL_EPCS_PHYRESET_N,
+			0);
+
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_SATA_OFFSET,
+			IMX8QM_SATA_CTRL_EPCS_PHYRESET_N,
+			IMX8QM_SATA_CTRL_EPCS_PHYRESET_N);
+
+	/* CTRL RST: SET -> delay 1 us -> CLEAR -> SET */
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_SATA_OFFSET,
+			IMX8QM_SATA_CTRL_RESET_N,
+			IMX8QM_SATA_CTRL_RESET_N);
+	udelay(1);
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_SATA_OFFSET,
+			IMX8QM_SATA_CTRL_RESET_N,
+			0);
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_SATA_OFFSET,
+			IMX8QM_SATA_CTRL_RESET_N,
+			IMX8QM_SATA_CTRL_RESET_N);
+
+	/* APB reset */
+	regmap_update_bits(imxpriv->gpr,
+			IMX8QM_CSR_PHYX1_OFFSET,
+			IMX8QM_PHY_APB_RSTN_0,
+			IMX8QM_PHY_APB_RSTN_0);
+
+	for (i = 0; i < 100; i++) {
+		reg = IMX8QM_CSR_PHYX1_OFFSET +
+			IMX8QM_CSR_PHYX_STTS0_OFFSET;
+		regmap_read(imxpriv->gpr, reg, &val);
+		val &= IMX8QM_STTS0_LANE0_TX_PLL_LOCK;
+		if (val == IMX8QM_STTS0_LANE0_TX_PLL_LOCK)
+			break;
+		udelay(1);
+	}
+
+	if (val != IMX8QM_STTS0_LANE0_TX_PLL_LOCK) {
+		dev_err(dev, "TX PLL of the PHY is not locked\n");
+		ret = -ENODEV;
+	} else {
+		writeb(imxpriv->imped_ratio, imxpriv->phy_base +
+				IMX8QM_SATA_PHY_RX_IMPED_RATIO_OFFSET);
+		writeb(imxpriv->imped_ratio, imxpriv->phy_base +
+				IMX8QM_SATA_PHY_TX_IMPED_RATIO_OFFSET);
+		reg = readb(imxpriv->phy_base +
+				IMX8QM_SATA_PHY_RX_IMPED_RATIO_OFFSET);
+		if (unlikely(reg != imxpriv->imped_ratio))
+			dev_info(dev, "Can't set PHY RX impedance ratio.\n");
+		reg = readb(imxpriv->phy_base +
+				IMX8QM_SATA_PHY_TX_IMPED_RATIO_OFFSET);
+		if (unlikely(reg != imxpriv->imped_ratio))
+			dev_info(dev, "Can't set PHY TX impedance ratio.\n");
+		usleep_range(50, 100);
+
+		/*
+		 * To reduce the power consumption, gate off
+		 * the PHY clks
+		 */
+		clk_disable_unprepare(imxpriv->phy_apbclk);
+		clk_disable_unprepare(imxpriv->phy_pclk1);
+		clk_disable_unprepare(imxpriv->phy_pclk0);
+		return ret;
+	}
+
+	clk_disable_unprepare(imxpriv->phy_apbclk);
+disable_epcs_rx_clk:
+	clk_disable_unprepare(imxpriv->epcs_rx_clk);
+disable_epcs_tx_clk:
+	clk_disable_unprepare(imxpriv->epcs_tx_clk);
+disable_phy_pclk1:
+	clk_disable_unprepare(imxpriv->phy_pclk1);
+disable_phy_pclk0:
+	clk_disable_unprepare(imxpriv->phy_pclk0);
+
+	return ret;
+}
+
 static int imx_sata_enable(struct ahci_host_priv *hpriv)
 {
 	struct imx_ahci_priv *imxpriv = hpriv->plat_data;
@@ -454,6 +701,8 @@ static int imx_sata_enable(struct ahci_host_priv *hpriv)
 			dev_err(dev, "failed to reset phy: %d\n", ret);
 			goto disable_clk;
 		}
+	} else if (imxpriv->type == AHCI_IMX8QM) {
+		ret = imx8_sata_enable(hpriv);
 	}
 
 	usleep_range(1000, 2000);
@@ -491,6 +740,11 @@ static void imx_sata_disable(struct ahci_host_priv *hpriv)
 				   !IMX6Q_GPR13_SATA_MPLL_CLK_EN);
 		break;
 
+	case AHCI_IMX8QM:
+		clk_disable_unprepare(imxpriv->epcs_rx_clk);
+		clk_disable_unprepare(imxpriv->epcs_tx_clk);
+		break;
+
 	default:
 		break;
 	}
@@ -567,6 +821,7 @@ static const struct of_device_id imx_ahci_of_match[] = {
 	{ .compatible = "fsl,imx53-ahci", .data = (void *)AHCI_IMX53 },
 	{ .compatible = "fsl,imx6q-ahci", .data = (void *)AHCI_IMX6Q },
 	{ .compatible = "fsl,imx6qp-ahci", .data = (void *)AHCI_IMX6QP },
+	{ .compatible = "fsl,imx8qm-ahci", .data = (void *)AHCI_IMX8QM },
 	{},
 };
 MODULE_DEVICE_TABLE(of, imx_ahci_of_match);
@@ -734,6 +989,79 @@ static struct scsi_host_template ahci_platform_sht = {
 	AHCI_SHT(DRV_NAME),
 };
 
+static int imx8_sata_probe(struct device *dev, struct imx_ahci_priv *imxpriv)
+{
+	int ret;
+	struct resource *phy_res;
+	struct platform_device *pdev = imxpriv->ahci_pdev;
+	struct device_node *np = dev->of_node;
+
+	if (of_property_read_u32(np, "fsl,phy-imp", &imxpriv->imped_ratio))
+		imxpriv->imped_ratio = IMX8QM_SATA_PHY_IMPED_RATIO_85OHM;
+	phy_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "phy");
+	if (phy_res) {
+		imxpriv->phy_base = devm_ioremap(dev, phy_res->start,
+					resource_size(phy_res));
+		if (!imxpriv->phy_base) {
+			dev_err(dev, "error with ioremap\n");
+			return -ENOMEM;
+		}
+	} else {
+		dev_err(dev, "missing *phy* reg region.\n");
+		return -ENOMEM;
+	}
+	imxpriv->gpr =
+		 syscon_regmap_lookup_by_phandle(np, "hsio");
+	if (IS_ERR(imxpriv->gpr)) {
+		dev_err(dev, "unable to find gpr registers\n");
+		return PTR_ERR(imxpriv->gpr);
+	}
+
+	imxpriv->epcs_tx_clk = devm_clk_get(dev, "epcs_tx");
+	if (IS_ERR(imxpriv->epcs_tx_clk)) {
+		dev_err(dev, "can't get epcs_tx_clk clock.\n");
+		return PTR_ERR(imxpriv->epcs_tx_clk);
+	}
+	imxpriv->epcs_rx_clk = devm_clk_get(dev, "epcs_rx");
+	if (IS_ERR(imxpriv->epcs_rx_clk)) {
+		dev_err(dev, "can't get epcs_rx_clk clock.\n");
+		return PTR_ERR(imxpriv->epcs_rx_clk);
+	}
+	imxpriv->phy_pclk0 = devm_clk_get(dev, "phy_pclk0");
+	if (IS_ERR(imxpriv->phy_pclk0)) {
+		dev_err(dev, "can't get phy_pclk0 clock.\n");
+		return PTR_ERR(imxpriv->phy_pclk0);
+	}
+	imxpriv->phy_pclk1 = devm_clk_get(dev, "phy_pclk1");
+	if (IS_ERR(imxpriv->phy_pclk1)) {
+		dev_err(dev, "can't get phy_pclk1 clock.\n");
+		return PTR_ERR(imxpriv->phy_pclk1);
+	}
+	imxpriv->phy_apbclk = devm_clk_get(dev, "phy_apbclk");
+	if (IS_ERR(imxpriv->phy_apbclk)) {
+		dev_err(dev, "can't get phy_apbclk clock.\n");
+		return PTR_ERR(imxpriv->phy_apbclk);
+	}
+
+	/* Fetch GPIO, then enable the external OSC */
+	imxpriv->clkreq_gpio = of_get_named_gpio(np, "clkreq-gpio", 0);
+	if (gpio_is_valid(imxpriv->clkreq_gpio)) {
+		ret = devm_gpio_request_one(dev, imxpriv->clkreq_gpio,
+					    GPIOF_OUT_INIT_LOW,
+					    "SATA CLKREQ");
+		if (ret == -EBUSY) {
+			dev_info(dev, "clkreq had been initialized.\n");
+		} else if (ret) {
+			dev_err(dev, "%d unable to get clkreq.\n", ret);
+			return ret;
+		}
+	} else if (imxpriv->clkreq_gpio == -EPROBE_DEFER) {
+		return imxpriv->clkreq_gpio;
+	}
+
+	return 0;
+}
+
 static int imx_ahci_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -793,6 +1121,10 @@ static int imx_ahci_probe(struct platform_device *pdev)
 				   IMX6Q_GPR13_SATA_RX_DPLL_MODE_2P_4F |
 				   IMX6Q_GPR13_SATA_SPD_MODE_3P0G |
 				   reg_value;
+	} else if (imxpriv->type == AHCI_IMX8QM) {
+		ret =  imx8_sata_probe(dev, imxpriv);
+		if (ret)
+			return ret;
 	}
 
 	hpriv = ahci_platform_get_resources(pdev);