ata: Add iMX pata support

Add basic support for pata on iMX. It has been tested only on imx51.
SDMA support will probably be added later so this version supports only
PIO.

v2:
  - enable only when needed IORDY
  - use dev_get_drvdata
v3:
  - add missing clk_put() calls
  - use platform_get_irq()
  - fix resume code to avoid disabling IORDY on resume
v4:
  - Remove EXPERIMENTAL and switch to depends on ARCH_MXC
  - Use devm_kzalloc()
  - make clock a must-have
  - Use only 1 ioremap

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

3 files changed, 263 insertions, 0 deletions

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index ca3e6be44a0..5987e0ba8c2 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -468,6 +468,15 @@ config PATA_ICSIDE
 	  interface card.  This is not required for ICS partition support.
 	  If you are unsure, say N to this.
 
+config PATA_IMX
+	tristate "PATA support for Freescale iMX"
+	depends on ARCH_MXC
+	help
+	  This option enables support for the PATA host available on Freescale
+          iMX SoCs.
+
+	  If unsure, say N.
+
 config PATA_IT8213
 	tristate "IT8213 PATA support (Experimental)"
 	depends on PCI && EXPERIMENTAL
diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index 8ac64e1aa05..9550d691fd1 100644
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_PATA_HPT37X)	+= pata_hpt37x.o
 obj-$(CONFIG_PATA_HPT3X2N)	+= pata_hpt3x2n.o
 obj-$(CONFIG_PATA_HPT3X3)	+= pata_hpt3x3.o
 obj-$(CONFIG_PATA_ICSIDE)	+= pata_icside.o
+obj-$(CONFIG_PATA_IMX)		+= pata_imx.o
 obj-$(CONFIG_PATA_IT8213)	+= pata_it8213.o
 obj-$(CONFIG_PATA_IT821X)	+= pata_it821x.o
 obj-$(CONFIG_PATA_JMICRON)	+= pata_jmicron.o
diff --git a/drivers/ata/pata_imx.c b/drivers/ata/pata_imx.c
new file mode 100644
index 00000000000..ca9d9caedfa
--- /dev/null
+++ b/drivers/ata/pata_imx.c
@@ -0,0 +1,253 @@
+/*
+ * Freescale iMX PATA driver
+ *
+ * Copyright (C) 2011 Arnaud Patard <arnaud.patard@rtp-net.org>
+ *
+ * Based on pata_platform - Copyright (C) 2006 - 2007  Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * TODO:
+ * - dmaengine support
+ * - check if timing stuff needed
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <scsi/scsi_host.h>
+#include <linux/ata.h>
+#include <linux/libata.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+
+#define DRV_NAME "pata_imx"
+
+#define PATA_IMX_ATA_CONTROL		0x24
+#define PATA_IMX_ATA_CTRL_FIFO_RST_B	(1<<7)
+#define PATA_IMX_ATA_CTRL_ATA_RST_B	(1<<6)
+#define PATA_IMX_ATA_CTRL_IORDY_EN	(1<<0)
+#define PATA_IMX_ATA_INT_EN		0x2C
+#define PATA_IMX_ATA_INTR_ATA_INTRQ2	(1<<3)
+#define PATA_IMX_DRIVE_DATA		0xA0
+#define PATA_IMX_DRIVE_CONTROL		0xD8
+
+struct pata_imx_priv {
+	struct clk *clk;
+	/* timings/interrupt/control regs */
+	u8 *host_regs;
+	u32 ata_ctl;
+};
+
+static int pata_imx_set_mode(struct ata_link *link, struct ata_device **unused)
+{
+	struct ata_device *dev;
+	struct ata_port *ap = link->ap;
+	struct pata_imx_priv *priv = ap->host->private_data;
+	u32 val;
+
+	ata_for_each_dev(dev, link, ENABLED) {
+		dev->pio_mode = dev->xfer_mode = XFER_PIO_0;
+		dev->xfer_shift = ATA_SHIFT_PIO;
+		dev->flags |= ATA_DFLAG_PIO;
+
+		val = __raw_readl(priv->host_regs + PATA_IMX_ATA_CONTROL);
+		if (ata_pio_need_iordy(dev))
+			val |= PATA_IMX_ATA_CTRL_IORDY_EN;
+		else
+			val &= ~PATA_IMX_ATA_CTRL_IORDY_EN;
+		__raw_writel(val, priv->host_regs + PATA_IMX_ATA_CONTROL);
+
+		ata_dev_printk(dev, KERN_INFO, "configured for PIO\n");
+	}
+	return 0;
+}
+
+static struct scsi_host_template pata_imx_sht = {
+	ATA_PIO_SHT(DRV_NAME),
+};
+
+static struct ata_port_operations pata_imx_port_ops = {
+	.inherits		= &ata_sff_port_ops,
+	.sff_data_xfer		= ata_sff_data_xfer_noirq,
+	.cable_detect		= ata_cable_unknown,
+	.set_mode		= pata_imx_set_mode,
+};
+
+static void pata_imx_setup_port(struct ata_ioports *ioaddr)
+{
+	/* Fixup the port shift for platforms that need it */
+	ioaddr->data_addr	= ioaddr->cmd_addr + (ATA_REG_DATA    << 2);
+	ioaddr->error_addr	= ioaddr->cmd_addr + (ATA_REG_ERR     << 2);
+	ioaddr->feature_addr	= ioaddr->cmd_addr + (ATA_REG_FEATURE << 2);
+	ioaddr->nsect_addr	= ioaddr->cmd_addr + (ATA_REG_NSECT   << 2);
+	ioaddr->lbal_addr	= ioaddr->cmd_addr + (ATA_REG_LBAL    << 2);
+	ioaddr->lbam_addr	= ioaddr->cmd_addr + (ATA_REG_LBAM    << 2);
+	ioaddr->lbah_addr	= ioaddr->cmd_addr + (ATA_REG_LBAH    << 2);
+	ioaddr->device_addr	= ioaddr->cmd_addr + (ATA_REG_DEVICE  << 2);
+	ioaddr->status_addr	= ioaddr->cmd_addr + (ATA_REG_STATUS  << 2);
+	ioaddr->command_addr	= ioaddr->cmd_addr + (ATA_REG_CMD     << 2);
+}
+
+static int __devinit pata_imx_probe(struct platform_device *pdev)
+{
+	struct ata_host *host;
+	struct ata_port *ap;
+	struct pata_imx_priv *priv;
+	int irq = 0;
+	struct resource *io_res;
+
+	io_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (io_res == NULL)
+		return -EINVAL;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0)
+		return -EINVAL;
+
+	priv = devm_kzalloc(&pdev->dev,
+				sizeof(struct pata_imx_priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(&pdev->dev, "Failed to get clock\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	clk_enable(priv->clk);
+
+	host = ata_host_alloc(&pdev->dev, 1);
+	if (!host)
+		goto free_priv;
+
+	host->private_data = priv;
+	ap = host->ports[0];
+
+	ap->ops = &pata_imx_port_ops;
+	ap->pio_mask = ATA_PIO0;
+	ap->flags |= ATA_FLAG_SLAVE_POSS;
+
+	priv->host_regs = devm_ioremap(&pdev->dev, io_res->start,
+		resource_size(io_res));
+	if (!priv->host_regs) {
+		dev_err(&pdev->dev, "failed to map IO/CTL base\n");
+		goto free_priv;
+	}
+
+	ap->ioaddr.cmd_addr = priv->host_regs + PATA_IMX_DRIVE_DATA;
+	ap->ioaddr.ctl_addr = priv->host_regs + PATA_IMX_DRIVE_CONTROL;
+
+	ap->ioaddr.altstatus_addr = ap->ioaddr.ctl_addr;
+
+	pata_imx_setup_port(&ap->ioaddr);
+
+	ata_port_desc(ap, "cmd 0x%llx ctl 0x%llx",
+		(unsigned long long)io_res->start + PATA_IMX_DRIVE_DATA,
+		(unsigned long long)io_res->start + PATA_IMX_DRIVE_CONTROL);
+
+	/* deassert resets */
+	__raw_writel(PATA_IMX_ATA_CTRL_FIFO_RST_B |
+			PATA_IMX_ATA_CTRL_ATA_RST_B,
+			priv->host_regs + PATA_IMX_ATA_CONTROL);
+	/* enable interrupts */
+	__raw_writel(PATA_IMX_ATA_INTR_ATA_INTRQ2,
+			priv->host_regs + PATA_IMX_ATA_INT_EN);
+
+	/* activate */
+	return ata_host_activate(host, irq, ata_sff_interrupt, 0,
+				&pata_imx_sht);
+
+free_priv:
+	clk_disable(priv->clk);
+	clk_put(priv->clk);
+	return -ENOMEM;
+}
+
+static int __devexit pata_imx_remove(struct platform_device *pdev)
+{
+	struct ata_host *host = dev_get_drvdata(&pdev->dev);
+	struct pata_imx_priv *priv = host->private_data;
+
+	ata_host_detach(host);
+
+	__raw_writel(0, priv->host_regs + PATA_IMX_ATA_INT_EN);
+
+	clk_disable(priv->clk);
+	clk_put(priv->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int pata_imx_suspend(struct device *dev)
+{
+	struct ata_host *host = dev_get_drvdata(dev);
+	struct pata_imx_priv *priv = host->private_data;
+	int ret;
+
+	ret = ata_host_suspend(host, PMSG_SUSPEND);
+	if (!ret) {
+		__raw_writel(0, priv->host_regs + PATA_IMX_ATA_INT_EN);
+		priv->ata_ctl =
+			__raw_readl(priv->host_regs + PATA_IMX_ATA_CONTROL);
+		clk_disable(priv->clk);
+	}
+
+	return ret;
+}
+
+static int pata_imx_resume(struct device *dev)
+{
+	struct ata_host *host = dev_get_drvdata(dev);
+	struct pata_imx_priv *priv = host->private_data;
+
+	clk_enable(priv->clk);
+
+	__raw_writel(priv->ata_ctl, priv->host_regs + PATA_IMX_ATA_CONTROL);
+
+	__raw_writel(PATA_IMX_ATA_INTR_ATA_INTRQ2,
+			priv->host_regs + PATA_IMX_ATA_INT_EN);
+
+	ata_host_resume(host);
+
+	return 0;
+}
+
+static const struct dev_pm_ops pata_imx_pm_ops = {
+	.suspend	= pata_imx_suspend,
+	.resume		= pata_imx_resume,
+};
+#endif
+
+static struct platform_driver pata_imx_driver = {
+	.probe		= pata_imx_probe,
+	.remove		= __devexit_p(pata_imx_remove),
+	.driver = {
+		.name		= DRV_NAME,
+		.owner		= THIS_MODULE,
+#ifdef CONFIG_PM
+		.pm		= &pata_imx_pm_ops,
+#endif
+	},
+};
+
+static int __init pata_imx_init(void)
+{
+	return platform_driver_register(&pata_imx_driver);
+}
+
+static void __exit pata_imx_exit(void)
+{
+	platform_driver_unregister(&pata_imx_driver);
+}
+module_init(pata_imx_init);
+module_exit(pata_imx_exit);
+
+MODULE_AUTHOR("Arnaud Patard <arnaud.patard@rtp-net.org>");
+MODULE_DESCRIPTION("low-level driver for iMX PATA");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);