Subject: [PATCH] ahci_imx: add ahci sata support on imx platforms
From: Richard Zhu <[email-masked]>

imx6q contains one Synopsys AHCI SATA controller, But it can't share
ahci_platform driver with other controllers because there are some
misalignments of the generic AHCI controller - the bits definitions of
the HBA registers, the Vendor Specific registers, the AHCI PHY clock
and the AHCI signals adjustment window(GPR13 register).

 - CAP_SSS(bit20) of the HOST_CAP is writable, default value is '0',
   should be configured to be '1'

 - bit0 (only one AHCI SATA port on imx6q) of the HOST_PORTS_IMPL
   should be set to be '1'.(default 0)

 - One Vendor Specific register HOST_TIMER1MS(offset:0xe0) should be
   configured regarding to the frequency of AHB bus clock.

 - Configurations of the AHCI PHY clock, and the signal parameters of
   the GPR13

Setup its own ahci sata driver, contained the imx6q specific
initialized codes, re-use the generic ahci_platform driver, and keep
the generic ahci_platform driver clean as much as possible.

tj: patch description reformatted

Signed-off-by: Richard Zhu <[email-masked]>
Reviewed-by: Shawn Guo <[email-masked]>
Signed-off-by: Tejun Heo <[email-masked]>
---
 drivers/ata/Kconfig    |   9 ++
 drivers/ata/Makefile   |   1 +
 drivers/ata/ahci_imx.c | 236 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 246 insertions(+)
 create mode 100644 drivers/ata/ahci_imx.c

--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -97,6 +97,15 @@ config SATA_AHCI_PLATFORM
 
 	  If unsure, say N.
 
+config AHCI_IMX
+	tristate "Freescale i.MX AHCI SATA support"
+	depends on SATA_AHCI_PLATFORM
+	help
+	  This option enables support for the Freescale i.MX SoC's
+	  onboard AHCI SATA.
+
+	  If unsure, say N.
+
 config SATA_FSL
 	tristate "Freescale 3.0Gbps SATA support"
 	depends on FSL_SOC
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_SATA_INIC162X)	+= sata_inic
 obj-$(CONFIG_SATA_SIL24)	+= sata_sil24.o
 obj-$(CONFIG_SATA_DWC)		+= sata_dwc_460ex.o
 obj-$(CONFIG_SATA_HIGHBANK)	+= sata_highbank.o libahci.o
+obj-$(CONFIG_AHCI_IMX)		+= ahci_imx.o
 
 # SFF w/ custom DMA
 obj-$(CONFIG_PDC_ADMA)		+= pdc_adma.o
--- /dev/null
+++ b/drivers/ata/ahci_imx.c
@@ -0,0 +1,236 @@
+/*
+ * Freescale IMX AHCI SATA platform driver
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * based on the AHCI SATA platform driver by Jeff Garzik and Anton Vorontsov
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/ahci_platform.h>
+#include <linux/of_device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
+#include "ahci.h"
+
+enum {
+	HOST_TIMER1MS = 0xe0, /* Timer 1-ms */
+};
+
+struct imx_ahci_priv {
+	struct platform_device *ahci_pdev;
+	struct clk *sata_ref_clk;
+	struct clk *ahb_clk;
+	struct regmap *gpr;
+};
+
+static int imx6q_sata_init(struct device *dev, void __iomem *mmio)
+{
+	int ret = 0;
+	unsigned int reg_val;
+	struct imx_ahci_priv *imxpriv = dev_get_drvdata(dev->parent);
+
+	imxpriv->gpr =
+		syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
+	if (IS_ERR(imxpriv->gpr)) {
+		dev_err(dev, "failed to find fsl,imx6q-iomux-gpr regmap\n");
+		return PTR_ERR(imxpriv->gpr);
+	}
+
+	ret = clk_prepare_enable(imxpriv->sata_ref_clk);
+	if (ret < 0) {
+		dev_err(dev, "prepare-enable sata_ref clock err:%d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * set PHY Paremeters, two steps to configure the GPR13,
+	 * one write for rest of parameters, mask of first write
+	 * is 0x07fffffd, and the other one write for setting
+	 * the mpll_clk_en.
+	 */
+	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_RX_EQ_VAL_MASK
+			| IMX6Q_GPR13_SATA_RX_LOS_LVL_MASK
+			| IMX6Q_GPR13_SATA_RX_DPLL_MODE_MASK
+			| IMX6Q_GPR13_SATA_SPD_MODE_MASK
+			| IMX6Q_GPR13_SATA_MPLL_SS_EN
+			| IMX6Q_GPR13_SATA_TX_ATTEN_MASK
+			| IMX6Q_GPR13_SATA_TX_BOOST_MASK
+			| IMX6Q_GPR13_SATA_TX_LVL_MASK
+			| IMX6Q_GPR13_SATA_TX_EDGE_RATE
+			, IMX6Q_GPR13_SATA_RX_EQ_VAL_3_0_DB
+			| IMX6Q_GPR13_SATA_RX_LOS_LVL_SATA2M
+			| IMX6Q_GPR13_SATA_RX_DPLL_MODE_2P_4F
+			| IMX6Q_GPR13_SATA_SPD_MODE_3P0G
+			| IMX6Q_GPR13_SATA_MPLL_SS_EN
+			| IMX6Q_GPR13_SATA_TX_ATTEN_9_16
+			| IMX6Q_GPR13_SATA_TX_BOOST_3_33_DB
+			| IMX6Q_GPR13_SATA_TX_LVL_1_025_V);
+	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_MPLL_CLK_EN,
+			IMX6Q_GPR13_SATA_MPLL_CLK_EN);
+	usleep_range(100, 200);
+
+	/*
+	 * Configure the HWINIT bits of the HOST_CAP and HOST_PORTS_IMPL,
+	 * and IP vendor specific register HOST_TIMER1MS.
+	 * Configure CAP_SSS (support stagered spin up).
+	 * Implement the port0.
+	 * Get the ahb clock rate, and configure the TIMER1MS register.
+	 */
+	reg_val = readl(mmio + HOST_CAP);
+	if (!(reg_val & HOST_CAP_SSS)) {
+		reg_val |= HOST_CAP_SSS;
+		writel(reg_val, mmio + HOST_CAP);
+	}
+	reg_val = readl(mmio + HOST_PORTS_IMPL);
+	if (!(reg_val & 0x1)) {
+		reg_val |= 0x1;
+		writel(reg_val, mmio + HOST_PORTS_IMPL);
+	}
+
+	reg_val = clk_get_rate(imxpriv->ahb_clk) / 1000;
+	writel(reg_val, mmio + HOST_TIMER1MS);
+
+	return 0;
+}
+
+static void imx6q_sata_exit(struct device *dev)
+{
+	struct imx_ahci_priv *imxpriv =  dev_get_drvdata(dev->parent);
+
+	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_MPLL_CLK_EN,
+			!IMX6Q_GPR13_SATA_MPLL_CLK_EN);
+	clk_disable_unprepare(imxpriv->sata_ref_clk);
+}
+
+static struct ahci_platform_data imx6q_sata_pdata = {
+	.init = imx6q_sata_init,
+	.exit = imx6q_sata_exit,
+};
+
+static const struct of_device_id imx_ahci_of_match[] = {
+	{ .compatible = "fsl,imx6q-ahci", .data = &imx6q_sata_pdata},
+	{},
+};
+MODULE_DEVICE_TABLE(of, imx_ahci_of_match);
+
+static int imx_ahci_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *mem, *irq, res[2];
+	const struct of_device_id *of_id;
+	const struct ahci_platform_data *pdata = NULL;
+	struct imx_ahci_priv *imxpriv;
+	struct device *ahci_dev;
+	struct platform_device *ahci_pdev;
+	int ret;
+
+	imxpriv = devm_kzalloc(dev, sizeof(*imxpriv), GFP_KERNEL);
+	if (!imxpriv) {
+		dev_err(dev, "can't alloc ahci_host_priv\n");
+		return -ENOMEM;
+	}
+
+	ahci_pdev = platform_device_alloc("ahci", -1);
+	if (!ahci_pdev)
+		return -ENODEV;
+
+	ahci_dev = &ahci_pdev->dev;
+	ahci_dev->parent = dev;
+
+	imxpriv->ahb_clk = devm_clk_get(dev, "ahb");
+	if (IS_ERR(imxpriv->ahb_clk)) {
+		dev_err(dev, "can't get ahb clock.\n");
+		ret = PTR_ERR(imxpriv->ahb_clk);
+		goto err_out;
+	}
+
+	imxpriv->sata_ref_clk = devm_clk_get(dev, "sata_ref");
+	if (IS_ERR(imxpriv->sata_ref_clk)) {
+		dev_err(dev, "can't get sata_ref clock.\n");
+		ret = PTR_ERR(imxpriv->sata_ref_clk);
+		goto err_out;
+	}
+
+	imxpriv->ahci_pdev = ahci_pdev;
+	platform_set_drvdata(pdev, imxpriv);
+
+	of_id = of_match_device(imx_ahci_of_match, dev);
+	if (of_id) {
+		pdata = of_id->data;
+	} else {
+		ret = -EINVAL;
+		goto err_out;
+	}
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!mem || !irq) {
+		dev_err(dev, "no mmio/irq resource\n");
+		ret = -ENOMEM;
+		goto err_out;
+	}
+
+	res[0] = *mem;
+	res[1] = *irq;
+
+	ahci_dev->coherent_dma_mask = DMA_BIT_MASK(32);
+	ahci_dev->dma_mask = &ahci_dev->coherent_dma_mask;
+	ahci_dev->of_node = dev->of_node;
+
+	ret = platform_device_add_resources(ahci_pdev, res, 2);
+	if (ret)
+		goto err_out;
+
+	ret = platform_device_add_data(ahci_pdev, pdata, sizeof(*pdata));
+	if (ret)
+		goto err_out;
+
+	ret = platform_device_add(ahci_pdev);
+	if (ret) {
+err_out:
+		platform_device_put(ahci_pdev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int imx_ahci_remove(struct platform_device *pdev)
+{
+	struct imx_ahci_priv *imxpriv = platform_get_drvdata(pdev);
+	struct platform_device *ahci_pdev = imxpriv->ahci_pdev;
+
+	platform_device_unregister(ahci_pdev);
+	return 0;
+}
+
+static struct platform_driver imx_ahci_driver = {
+	.probe = imx_ahci_probe,
+	.remove = imx_ahci_remove,
+	.driver = {
+		.name = "ahci-imx",
+		.owner = THIS_MODULE,
+		.of_match_table = imx_ahci_of_match,
+	},
+};
+module_platform_driver(imx_ahci_driver);
+
+MODULE_DESCRIPTION("Freescale i.MX AHCI SATA platform driver");
+MODULE_AUTHOR("Richard Zhu <[email-masked]>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ahci:imx");