PATA host controller driver for ep93xx

Add PATA host controller driver for ep93xx.

Signed-off-by: Rafal Prylowski <prylowski@metasoft.pl>
Cc: Joao Ramos <joao.ramos@inov.pt>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

3 files changed, 1054 insertions, 0 deletions

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 6bdedd7..2be8ef1 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -416,6 +416,15 @@ config PATA_EFAR
 
 	  If unsure, say N.
 
+config PATA_EP93XX
+	tristate "Cirrus Logic EP93xx PATA support"
+	depends on ARCH_EP93XX
+	help
+	  This option enables support for the PATA controller in
+	  the Cirrus Logic EP9312 and EP9315 ARM CPU.
+
+	  If unsure, say N.
+
 config PATA_HPT366
 	tristate "HPT 366/368 PATA support"
 	depends on PCI
diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index 6ece5b7..a454a13 100644
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_PATA_CS5535)	+= pata_cs5535.o
 obj-$(CONFIG_PATA_CS5536)	+= pata_cs5536.o
 obj-$(CONFIG_PATA_CYPRESS)	+= pata_cypress.o
 obj-$(CONFIG_PATA_EFAR)		+= pata_efar.o
+obj-$(CONFIG_PATA_EP93XX)	+= pata_ep93xx.o
 obj-$(CONFIG_PATA_HPT366)	+= pata_hpt366.o
 obj-$(CONFIG_PATA_HPT37X)	+= pata_hpt37x.o
 obj-$(CONFIG_PATA_HPT3X2N)	+= pata_hpt3x2n.o
diff --git a/drivers/ata/pata_ep93xx.c b/drivers/ata/pata_ep93xx.c
new file mode 100644
index 0000000..6ef2e37
--- /dev/null
+++ b/drivers/ata/pata_ep93xx.c
@@ -0,0 +1,1044 @@
+/*
+ * EP93XX PATA controller driver.
+ *
+ * Copyright (c) 2012, Metasoft s.c.
+ *	Rafal Prylowski <prylowski@metasoft.pl>
+ *
+ * Based on pata_scc.c, pata_icside.c and on earlier version of EP93XX
+ * PATA driver by Lennert Buytenhek and Alessandro Zummo.
+ * Read/Write timings, resource management and other improvements
+ * from driver by Joao Ramos and Bartlomiej Zolnierkiewicz.
+ * DMA engine support based on spi-ep93xx.c by Mika Westerberg.
+ *
+ * Original copyrights:
+ *
+ * Support for Cirrus Logic's EP93xx (EP9312, EP9315) CPUs
+ * PATA host controller driver.
+ *
+ * Copyright (c) 2009, Bartlomiej Zolnierkiewicz
+ *
+ * Heavily based on the ep93xx-ide.c driver:
+ *
+ * Copyright (c) 2009, Joao Ramos <joao.ramos@inov.pt>
+ *		      INESC Inovacao (INOV)
+ *
+ * EP93XX PATA controller driver.
+ * Copyright (C) 2007 Lennert Buytenhek <buytenh@wantstofly.org>
+ *
+ * An ATA driver for the Cirrus Logic EP93xx PATA controller.
+ *
+ * Based on an earlier version by Alessandro Zummo, which is:
+ *   Copyright (C) 2006 Tower Technologies
+ */
+
+#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/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/ktime.h>
+
+#include <mach/dma.h>
+#include <mach/platform.h>
+
+#define DRV_NAME	"ep93xx-ide"
+#define DRV_VERSION	"1.0"
+
+enum {
+	/* IDE Control Register */
+	IDECTRL				= 0x00,
+	IDECTRL_CS0N			= (1 << 0),
+	IDECTRL_CS1N			= (1 << 1),
+	IDECTRL_DIORN			= (1 << 5),
+	IDECTRL_DIOWN			= (1 << 6),
+	IDECTRL_INTRQ			= (1 << 9),
+	IDECTRL_IORDY			= (1 << 10),
+	/*
+	 * the device IDE register to be accessed is selected through
+	 * IDECTRL register's specific bitfields 'DA', 'CS1N' and 'CS0N':
+	 *   b4   b3   b2    b1     b0
+	 *   A2   A1   A0   CS1N   CS0N
+	 * the values filled in this structure allows the value to be directly
+	 * ORed to the IDECTRL register, hence giving directly the A[2:0] and
+	 * CS1N/CS0N values for each IDE register.
+	 * The values correspond to the transformation:
+	 *   ((real IDE address) << 2) | CS1N value << 1 | CS0N value
+	 */
+	IDECTRL_ADDR_CMD		= 0 + 2, /* CS1 */
+	IDECTRL_ADDR_DATA		= (ATA_REG_DATA << 2) + 2,
+	IDECTRL_ADDR_ERROR		= (ATA_REG_ERR << 2) + 2,
+	IDECTRL_ADDR_FEATURE		= (ATA_REG_FEATURE << 2) + 2,
+	IDECTRL_ADDR_NSECT		= (ATA_REG_NSECT << 2) + 2,
+	IDECTRL_ADDR_LBAL		= (ATA_REG_LBAL << 2) + 2,
+	IDECTRL_ADDR_LBAM		= (ATA_REG_LBAM << 2) + 2,
+	IDECTRL_ADDR_LBAH		= (ATA_REG_LBAH << 2) + 2,
+	IDECTRL_ADDR_DEVICE		= (ATA_REG_DEVICE << 2) + 2,
+	IDECTRL_ADDR_STATUS		= (ATA_REG_STATUS << 2) + 2,
+	IDECTRL_ADDR_COMMAND		= (ATA_REG_CMD << 2) + 2,
+	IDECTRL_ADDR_ALTSTATUS		= (0x06 << 2) + 1, /* CS0 */
+	IDECTRL_ADDR_CTL		= (0x06 << 2) + 1, /* CS0 */
+
+	/* IDE Configuration Register */
+	IDECFG				= 0x04,
+	IDECFG_IDEEN			= (1 << 0),
+	IDECFG_PIO			= (1 << 1),
+	IDECFG_MDMA			= (1 << 2),
+	IDECFG_UDMA			= (1 << 3),
+	IDECFG_MODE_SHIFT		= 4,
+	IDECFG_MODE_MASK		= (0xf << 4),
+	IDECFG_WST_SHIFT		= 8,
+	IDECFG_WST_MASK			= (0x3 << 8),
+
+	/* MDMA Operation Register */
+	IDEMDMAOP			= 0x08,
+
+	/* UDMA Operation Register */
+	IDEUDMAOP			= 0x0c,
+	IDEUDMAOP_UEN			= (1 << 0),
+	IDEUDMAOP_RWOP			= (1 << 1),
+
+	/* PIO/MDMA/UDMA Data Registers */
+	IDEDATAOUT			= 0x10,
+	IDEDATAIN			= 0x14,
+	IDEMDMADATAOUT			= 0x18,
+	IDEMDMADATAIN			= 0x1c,
+	IDEUDMADATAOUT			= 0x20,
+	IDEUDMADATAIN			= 0x24,
+
+	/* UDMA Status Register */
+	IDEUDMASTS			= 0x28,
+	IDEUDMASTS_DMAIDE		= (1 << 16),
+	IDEUDMASTS_INTIDE		= (1 << 17),
+	IDEUDMASTS_SBUSY		= (1 << 18),
+	IDEUDMASTS_NDO			= (1 << 24),
+	IDEUDMASTS_NDI			= (1 << 25),
+	IDEUDMASTS_N4X			= (1 << 26),
+
+	/* UDMA Debug Status Register */
+	IDEUDMADEBUG			= 0x2c,
+};
+
+struct ep93xx_pata_data {
+	const struct platform_device *pdev;
+	void __iomem *ide_base;
+	struct ata_timing t;
+	bool iordy;
+
+	unsigned long udma_in_phys;
+	unsigned long udma_out_phys;
+
+	struct dma_chan *dma_rx_channel;
+	struct ep93xx_dma_data dma_rx_data;
+	struct dma_chan *dma_tx_channel;
+	struct ep93xx_dma_data dma_tx_data;
+};
+
+static void ep93xx_pata_clear_regs(void __iomem *base)
+{
+	writel(IDECTRL_CS0N | IDECTRL_CS1N | IDECTRL_DIORN |
+		IDECTRL_DIOWN, base + IDECTRL);
+
+	writel(0, base + IDECFG);
+	writel(0, base + IDEMDMAOP);
+	writel(0, base + IDEUDMAOP);
+	writel(0, base + IDEDATAOUT);
+	writel(0, base + IDEDATAIN);
+	writel(0, base + IDEMDMADATAOUT);
+	writel(0, base + IDEMDMADATAIN);
+	writel(0, base + IDEUDMADATAOUT);
+	writel(0, base + IDEUDMADATAIN);
+	writel(0, base + IDEUDMADEBUG);
+}
+
+static bool ep93xx_pata_check_iordy(void __iomem *base)
+{
+	return !!(readl(base + IDECTRL) & IDECTRL_IORDY);
+}
+
+/*
+ * According to EP93xx User's Guide, WST field of IDECFG specifies number
+ * of HCLK cycles to hold the data bus after a PIO write operation.
+ * It should be programmed to guarantee following delays:
+ *
+ * PIO Mode   [ns]
+ * 0          30
+ * 1          20
+ * 2          15
+ * 3          10
+ * 4          5
+ *
+ * Maximum possible value for HCLK is 100MHz.
+ */
+static int ep93xx_pata_get_wst(int pio_mode)
+{
+	int val;
+
+	if (pio_mode == 0)
+		val = 3;
+	else if (pio_mode < 3)
+		val = 2;
+	else
+		val = 1;
+
+	return val << IDECFG_WST_SHIFT;
+}
+
+static void ep93xx_pata_enable_pio(void __iomem *base, int pio_mode)
+{
+	writel(IDECFG_IDEEN | IDECFG_PIO |
+		ep93xx_pata_get_wst(pio_mode) |
+		(pio_mode << IDECFG_MODE_SHIFT), base + IDECFG);
+}
+
+/*
+ * Based on delay loop found in mach-pxa/mp900.c.
+ *
+ * Single iteration should take 5 cpu cycles. This is 25ns assuming the
+ * fastest ep93xx cpu speed (200MHz) and is better optimized for PIO4 timings
+ * than eg. 20ns.
+ */
+static void ep93xx_pata_delay(unsigned long count)
+{
+	__asm__ volatile (
+		"0:\n"
+		"mov r0, r0\n"
+		"subs %0, %1, #1\n"
+		"bge 0b\n"
+		: "=r" (count)
+		: "0" (count)
+	);
+}
+
+static unsigned long ep93xx_pata_wait_for_iordy(void __iomem *base,
+						unsigned long t2)
+{
+	/*
+	 * According to ATA specification, IORDY pin can be first sampled
+	 * tA = 35ns after activation of DIOR-/DIOW-. Maximum IORDY pulse
+	 * width is tB = 1250ns.
+	 *
+	 * We are already t2 delay loop iterations after activation of
+	 * DIOR-/DIOW-, so we set timeout to (1250 + 35) / 25 - t2 additional
+	 * delay loop iterations.
+	 */
+	unsigned long start = (1250 + 35) / 25 - t2;
+	unsigned long counter = start;
+
+	while (!ep93xx_pata_check_iordy(base) && counter--)
+		ep93xx_pata_delay(1);
+	return start - counter;
+}
+
+/* common part at start of ep93xx_pata_read/write() */
+static void ep93xx_pata_rw_begin(void __iomem *base, unsigned long addr,
+				 unsigned long t1)
+{
+	writel(IDECTRL_DIOWN | IDECTRL_DIORN | addr, base + IDECTRL);
+	ep93xx_pata_delay(t1);
+}
+
+/* common part at end of ep93xx_pata_read/write() */
+static void ep93xx_pata_rw_end(void __iomem *base, unsigned long addr,
+			       bool iordy, unsigned long t0, unsigned long t2,
+			       unsigned long t2i)
+{
+	ep93xx_pata_delay(t2);
+	/* lengthen t2 if needed */
+	if (iordy)
+		t2 += ep93xx_pata_wait_for_iordy(base, t2);
+	writel(IDECTRL_DIOWN | IDECTRL_DIORN | addr, base + IDECTRL);
+	if (t0 > t2 && t0 - t2 > t2i)
+		ep93xx_pata_delay(t0 - t2);
+	else
+		ep93xx_pata_delay(t2i);
+}
+
+static u16 ep93xx_pata_read(struct ep93xx_pata_data *drv_data,
+			    unsigned long addr,
+			    bool reg)
+{
+	void __iomem *base = drv_data->ide_base;
+	const struct ata_timing *t = &drv_data->t;
+	unsigned long t0 = reg ? t->cyc8b : t->cycle;
+	unsigned long t2 = reg ? t->act8b : t->active;
+	unsigned long t2i = reg ? t->rec8b : t->recover;
+
+	ep93xx_pata_rw_begin(base, addr, t->setup);
+	writel(IDECTRL_DIOWN | addr, base + IDECTRL);
+	/*
+	 * The IDEDATAIN register is loaded from the DD pins at the positive
+	 * edge of the DIORN signal. (EP93xx UG p27-14)
+	 */
+	ep93xx_pata_rw_end(base, addr, drv_data->iordy, t0, t2, t2i);
+	return readl(base + IDEDATAIN);
+}
+
+/* IDE register read */
+static u16 ep93xx_pata_read_reg(struct ep93xx_pata_data *drv_data,
+				unsigned long addr)
+{
+	return ep93xx_pata_read(drv_data, addr, true);
+}
+
+/* PIO data read */
+static u16 ep93xx_pata_read_data(struct ep93xx_pata_data *drv_data,
+				 unsigned long addr)
+{
+	return ep93xx_pata_read(drv_data, addr, false);
+}
+
+static void ep93xx_pata_write(struct ep93xx_pata_data *drv_data,
+			      u16 value, unsigned long addr,
+			      bool reg)
+{
+	void __iomem *base = drv_data->ide_base;
+	const struct ata_timing *t = &drv_data->t;
+	unsigned long t0 = reg ? t->cyc8b : t->cycle;
+	unsigned long t2 = reg ? t->act8b : t->active;
+	unsigned long t2i = reg ? t->rec8b : t->recover;
+
+	ep93xx_pata_rw_begin(base, addr, t->setup);
+	/*
+	 * Value from IDEDATAOUT register is driven onto the DD pins when
+	 * DIOWN is low. (EP93xx UG p27-13)
+	 */
+	writel(value, base + IDEDATAOUT);
+	writel(IDECTRL_DIORN | addr, base + IDECTRL);
+	ep93xx_pata_rw_end(base, addr, drv_data->iordy, t0, t2, t2i);
+}
+
+/* IDE register write */
+static void ep93xx_pata_write_reg(struct ep93xx_pata_data *drv_data,
+				  u16 value, unsigned long addr)
+{
+	ep93xx_pata_write(drv_data, value, addr, true);
+}
+
+/* PIO data write */
+static void ep93xx_pata_write_data(struct ep93xx_pata_data *drv_data,
+				   u16 value, unsigned long addr)
+{
+	ep93xx_pata_write(drv_data, value, addr, false);
+}
+
+static void ep93xx_pata_set_piomode(struct ata_port *ap,
+				    struct ata_device *adev)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+	struct ata_device *pair = ata_dev_pair(adev);
+	/*
+	 * Calculate timings for the delay loop, assuming ep93xx cpu speed
+	 * is 200MHz (maximum possible for ep93xx). If actual cpu speed is
+	 * slower, we will wait a bit longer in each delay.
+	 * Additional division of cpu speed by 5, because single iteration
+	 * of our delay loop takes 5 cpu cycles (25ns).
+	 */
+	unsigned long T = 1000000 / (200 / 5);
+
+	ata_timing_compute(adev, adev->pio_mode, &drv_data->t, T, 0);
+	if (pair && pair->pio_mode) {
+		struct ata_timing t;
+		ata_timing_compute(pair, pair->pio_mode, &t, T, 0);
+		ata_timing_merge(&t, &drv_data->t, &drv_data->t,
+			ATA_TIMING_SETUP | ATA_TIMING_8BIT);
+	}
+	drv_data->iordy = ata_pio_need_iordy(adev);
+
+	ep93xx_pata_enable_pio(drv_data->ide_base,
+			       adev->pio_mode - XFER_PIO_0);
+}
+
+/* Note: original code is ata_sff_check_status */
+static u8 ep93xx_pata_check_status(struct ata_port *ap)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+
+	return ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_STATUS);
+}
+
+static u8 ep93xx_pata_check_altstatus(struct ata_port *ap)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+
+	return ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_ALTSTATUS);
+}
+
+/* Note: original code is ata_sff_tf_load */
+static void ep93xx_pata_tf_load(struct ata_port *ap,
+				const struct ata_taskfile *tf)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+	unsigned int is_addr = tf->flags & ATA_TFLAG_ISADDR;
+
+	if (tf->ctl != ap->last_ctl) {
+		ep93xx_pata_write_reg(drv_data, tf->ctl, IDECTRL_ADDR_CTL);
+		ap->last_ctl = tf->ctl;
+		ata_wait_idle(ap);
+	}
+
+	if (is_addr && (tf->flags & ATA_TFLAG_LBA48)) {
+		ep93xx_pata_write_reg(drv_data, tf->hob_feature,
+			IDECTRL_ADDR_FEATURE);
+		ep93xx_pata_write_reg(drv_data, tf->hob_nsect,
+			IDECTRL_ADDR_NSECT);
+		ep93xx_pata_write_reg(drv_data, tf->hob_lbal,
+			IDECTRL_ADDR_LBAL);
+		ep93xx_pata_write_reg(drv_data, tf->hob_lbam,
+			IDECTRL_ADDR_LBAM);
+		ep93xx_pata_write_reg(drv_data, tf->hob_lbah,
+			IDECTRL_ADDR_LBAH);
+	}
+
+	if (is_addr) {
+		ep93xx_pata_write_reg(drv_data, tf->feature,
+			IDECTRL_ADDR_FEATURE);
+		ep93xx_pata_write_reg(drv_data, tf->nsect, IDECTRL_ADDR_NSECT);
+		ep93xx_pata_write_reg(drv_data, tf->lbal, IDECTRL_ADDR_LBAL);
+		ep93xx_pata_write_reg(drv_data, tf->lbam, IDECTRL_ADDR_LBAM);
+		ep93xx_pata_write_reg(drv_data, tf->lbah, IDECTRL_ADDR_LBAH);
+	}
+
+	if (tf->flags & ATA_TFLAG_DEVICE)
+		ep93xx_pata_write_reg(drv_data, tf->device,
+			IDECTRL_ADDR_DEVICE);
+
+	ata_wait_idle(ap);
+}
+
+/* Note: original code is ata_sff_tf_read */
+static void ep93xx_pata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+
+	tf->command = ep93xx_pata_check_status(ap);
+	tf->feature = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_FEATURE);
+	tf->nsect = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_NSECT);
+	tf->lbal = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAL);
+	tf->lbam = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAM);
+	tf->lbah = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAH);
+	tf->device = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_DEVICE);
+
+	if (tf->flags & ATA_TFLAG_LBA48) {
+		ep93xx_pata_write_reg(drv_data, tf->ctl | ATA_HOB,
+			IDECTRL_ADDR_CTL);
+		tf->hob_feature = ep93xx_pata_read_reg(drv_data,
+			IDECTRL_ADDR_FEATURE);
+		tf->hob_nsect = ep93xx_pata_read_reg(drv_data,
+			IDECTRL_ADDR_NSECT);
+		tf->hob_lbal = ep93xx_pata_read_reg(drv_data,
+			IDECTRL_ADDR_LBAL);
+		tf->hob_lbam = ep93xx_pata_read_reg(drv_data,
+			IDECTRL_ADDR_LBAM);
+		tf->hob_lbah = ep93xx_pata_read_reg(drv_data,
+			IDECTRL_ADDR_LBAH);
+		ep93xx_pata_write_reg(drv_data, tf->ctl, IDECTRL_ADDR_CTL);
+		ap->last_ctl = tf->ctl;
+	}
+}
+
+/* Note: original code is ata_sff_exec_command */
+static void ep93xx_pata_exec_command(struct ata_port *ap,
+				     const struct ata_taskfile *tf)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+
+	ep93xx_pata_write_reg(drv_data, tf->command,
+			  IDECTRL_ADDR_COMMAND);
+	ata_sff_pause(ap);
+}
+
+/* Note: original code is ata_sff_dev_select */
+static void ep93xx_pata_dev_select(struct ata_port *ap, unsigned int device)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+	u8 tmp = ATA_DEVICE_OBS;
+
+	if (device != 0)
+		tmp |= ATA_DEV1;
+
+	ep93xx_pata_write_reg(drv_data, tmp, IDECTRL_ADDR_DEVICE);
+	ata_sff_pause(ap);	/* needed; also flushes, for mmio */
+}
+
+/* Note: original code is ata_sff_set_devctl */
+static void ep93xx_pata_set_devctl(struct ata_port *ap, u8 ctl)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+
+	ep93xx_pata_write_reg(drv_data, ctl, IDECTRL_ADDR_CTL);
+}
+
+/* Note: original code is ata_sff_data_xfer */
+static unsigned int ep93xx_pata_data_xfer(struct ata_device *adev,
+					  unsigned char *buf,
+					  unsigned int buflen, int rw)
+{
+	struct ata_port *ap = adev->link->ap;
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+	u16 *data = (u16 *)buf;
+	unsigned int words = buflen >> 1;
+
+	/* Transfer multiple of 2 bytes */
+	while (words--)
+		if (rw == READ)
+			*data++ = cpu_to_le16(
+				ep93xx_pata_read_data(
+					drv_data, IDECTRL_ADDR_DATA));
+		else
+			ep93xx_pata_write_data(drv_data, le16_to_cpu(*data++),
+				IDECTRL_ADDR_DATA);
+
+	/* Transfer trailing 1 byte, if any. */
+	if (unlikely(buflen & 0x01)) {
+		unsigned char pad[2] = { };
+
+		buf += buflen - 1;
+
+		if (rw == READ) {
+			*pad = cpu_to_le16(
+				ep93xx_pata_read_data(
+					drv_data, IDECTRL_ADDR_DATA));
+			*buf = pad[0];
+		} else {
+			pad[0] = *buf;
+			ep93xx_pata_write_data(drv_data, le16_to_cpu(*pad),
+					  IDECTRL_ADDR_DATA);
+		}
+		words++;
+	}
+
+	return words << 1;
+}
+
+/* Note: original code is ata_devchk */
+static bool ep93xx_pata_device_is_present(struct ata_port *ap,
+					  unsigned int device)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+	u8 nsect, lbal;
+
+	ap->ops->sff_dev_select(ap, device);
+
+	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_NSECT);
+	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_LBAL);
+
+	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_NSECT);
+	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_LBAL);
+
+	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_NSECT);
+	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_LBAL);
+
+	nsect = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_NSECT);
+	lbal = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAL);
+
+	if ((nsect == 0x55) && (lbal == 0xaa))
+		return true;
+
+	return false;
+}
+
+/* Note: original code is ata_sff_wait_after_reset */
+static int ep93xx_pata_wait_after_reset(struct ata_link *link,
+					unsigned int devmask,
+					unsigned long deadline)
+{
+	struct ata_port *ap = link->ap;
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+	unsigned int dev0 = devmask & (1 << 0);
+	unsigned int dev1 = devmask & (1 << 1);
+	int rc, ret = 0;
+
+	ata_msleep(ap, ATA_WAIT_AFTER_RESET);
+
+	/* always check readiness of the master device */
+	rc = ata_sff_wait_ready(link, deadline);
+	/*
+	 * -ENODEV means the odd clown forgot the D7 pulldown resistor
+	 * and TF status is 0xff, bail out on it too.
+	 */
+	if (rc)
+		return rc;
+
+	/*
+	 * if device 1 was found in ata_devchk, wait for register
+	 * access briefly, then wait for BSY to clear.
+	 */
+	if (dev1) {
+		int i;
+
+		ap->ops->sff_dev_select(ap, 1);
+
+		/*
+		 * Wait for register access.  Some ATAPI devices fail
+		 * to set nsect/lbal after reset, so don't waste too
+		 * much time on it.  We're gonna wait for !BSY anyway.
+		 */
+		for (i = 0; i < 2; i++) {
+			u8 nsect, lbal;
+
+			nsect = ep93xx_pata_read_reg(drv_data,
+				IDECTRL_ADDR_NSECT);
+			lbal = ep93xx_pata_read_reg(drv_data,
+				IDECTRL_ADDR_LBAL);
+			if (nsect == 1 && lbal == 1)
+				break;
+			msleep(50);	/* give drive a breather */
+		}
+
+		rc = ata_sff_wait_ready(link, deadline);
+		if (rc) {
+			if (rc != -ENODEV)
+				return rc;
+			ret = rc;
+		}
+	}
+	/* is all this really necessary? */
+	ap->ops->sff_dev_select(ap, 0);
+	if (dev1)
+		ap->ops->sff_dev_select(ap, 1);
+	if (dev0)
+		ap->ops->sff_dev_select(ap, 0);
+
+	return ret;
+}
+
+/* Note: original code is ata_bus_softreset */
+static int ep93xx_pata_bus_softreset(struct ata_port *ap, unsigned int devmask,
+				     unsigned long deadline)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+
+	ep93xx_pata_write_reg(drv_data, ap->ctl, IDECTRL_ADDR_CTL);
+	udelay(20);		/* FIXME: flush */
+	ep93xx_pata_write_reg(drv_data, ap->ctl | ATA_SRST, IDECTRL_ADDR_CTL);
+	udelay(20);		/* FIXME: flush */
+	ep93xx_pata_write_reg(drv_data, ap->ctl, IDECTRL_ADDR_CTL);
+	ap->last_ctl = ap->ctl;
+
+	return ep93xx_pata_wait_after_reset(&ap->link, devmask, deadline);
+}
+
+static void ep93xx_pata_release_dma(struct ep93xx_pata_data *drv_data)
+{
+	if (drv_data->dma_rx_channel) {
+		dma_release_channel(drv_data->dma_rx_channel);
+		drv_data->dma_rx_channel = NULL;
+	}
+	if (drv_data->dma_tx_channel) {
+		dma_release_channel(drv_data->dma_tx_channel);
+		drv_data->dma_tx_channel = NULL;
+	}
+}
+
+static bool ep93xx_pata_dma_filter(struct dma_chan *chan, void *filter_param)
+{
+	if (ep93xx_dma_chan_is_m2p(chan))
+		return false;
+
+	chan->private = filter_param;
+	return true;
+}
+
+static void ep93xx_pata_dma_init(struct ep93xx_pata_data *drv_data)
+{
+	const struct platform_device *pdev = drv_data->pdev;
+	dma_cap_mask_t mask;
+	struct dma_slave_config conf;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	/*
+	 * Request two channels for IDE. Another possibility would be
+	 * to request only one channel, and reprogram it's direction at
+	 * start of new transfer.
+	 */
+	drv_data->dma_rx_data.port = EP93XX_DMA_IDE;
+	drv_data->dma_rx_data.direction = DMA_FROM_DEVICE;
+	drv_data->dma_rx_data.name = "ep93xx-pata-rx";
+	drv_data->dma_rx_channel = dma_request_channel(mask,
+		ep93xx_pata_dma_filter, &drv_data->dma_rx_data);
+	if (!drv_data->dma_rx_channel)
+		return;
+
+	drv_data->dma_tx_data.port = EP93XX_DMA_IDE;
+	drv_data->dma_tx_data.direction = DMA_TO_DEVICE;
+	drv_data->dma_tx_data.name = "ep93xx-pata-tx";
+	drv_data->dma_tx_channel = dma_request_channel(mask,
+		ep93xx_pata_dma_filter, &drv_data->dma_tx_data);
+	if (!drv_data->dma_tx_channel) {
+		dma_release_channel(drv_data->dma_rx_channel);
+		return;
+	}
+
+	/* Configure receive channel direction and source address */
+	memset(&conf, 0, sizeof(conf));
+	conf.direction = DMA_FROM_DEVICE;
+	conf.src_addr = drv_data->udma_in_phys;
+	conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	if (dmaengine_slave_config(drv_data->dma_rx_channel, &conf)) {
+		dev_err(&pdev->dev, "failed to configure rx dma channel\n");
+		ep93xx_pata_release_dma(drv_data);
+		return;
+	}
+
+	/* Configure transmit channel direction and destination address */
+	memset(&conf, 0, sizeof(conf));
+	conf.direction = DMA_TO_DEVICE;
+	conf.dst_addr = drv_data->udma_out_phys;
+	conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	if (dmaengine_slave_config(drv_data->dma_tx_channel, &conf)) {
+		dev_err(&pdev->dev, "failed to configure tx dma channel\n");
+		ep93xx_pata_release_dma(drv_data);
+	}
+}
+
+static void ep93xx_pata_dma_start(struct ata_queued_cmd *qc)
+{
+	struct dma_async_tx_descriptor *txd;
+	struct ep93xx_pata_data *drv_data = qc->ap->host->private_data;
+	void __iomem *base = drv_data->ide_base;
+	struct ata_device *adev = qc->dev;
+	u32 v = qc->dma_dir == DMA_TO_DEVICE ? IDEUDMAOP_RWOP : 0;
+	struct dma_chan *channel = qc->dma_dir == DMA_TO_DEVICE
+		? drv_data->dma_tx_channel : drv_data->dma_rx_channel;
+
+	txd = channel->device->device_prep_slave_sg(channel, qc->sg,
+		 qc->n_elem, qc->dma_dir, DMA_CTRL_ACK, NULL);
+	if (!txd) {
+		dev_err(qc->ap->dev, "failed to prepare slave for sg dma\n");
+		return;
+	}
+	txd->callback = NULL;
+	txd->callback_param = NULL;
+
+	if (dmaengine_submit(txd) < 0) {
+		dev_err(qc->ap->dev, "failed to submit dma transfer\n");
+		return;
+	}
+	dma_async_issue_pending(channel);
+
+	/*
+	 * When enabling UDMA operation, IDEUDMAOP register needs to be
+	 * programmed in three step sequence:
+	 * 1) set or clear the RWOP bit,
+	 * 2) perform dummy read of the register,
+	 * 3) set the UEN bit.
+	 */
+	writel(v, base + IDEUDMAOP);
+	readl(base + IDEUDMAOP);
+	writel(v | IDEUDMAOP_UEN, base + IDEUDMAOP);
+
+	writel(IDECFG_IDEEN | IDECFG_UDMA |
+		((adev->xfer_mode - XFER_UDMA_0) << IDECFG_MODE_SHIFT),
+		base + IDECFG);
+}
+
+static void ep93xx_pata_dma_stop(struct ata_queued_cmd *qc)
+{
+	struct ep93xx_pata_data *drv_data = qc->ap->host->private_data;
+	void __iomem *base = drv_data->ide_base;
+
+	/* terminate all dma transfers, if not yet finished */
+	dmaengine_terminate_all(drv_data->dma_rx_channel);
+	dmaengine_terminate_all(drv_data->dma_tx_channel);
+
+	/*
+	 * To properly stop IDE-DMA, IDEUDMAOP register must to be cleared
+	 * and IDECTRL register must be set to default value.
+	 */
+	writel(0, base + IDEUDMAOP);
+	writel(readl(base + IDECTRL) | IDECTRL_DIOWN | IDECTRL_DIORN |
+		IDECTRL_CS0N | IDECTRL_CS1N, base + IDECTRL);
+
+	ep93xx_pata_enable_pio(drv_data->ide_base,
+		qc->dev->pio_mode - XFER_PIO_0);
+
+	ata_sff_dma_pause(qc->ap);
+}
+
+static void ep93xx_pata_dma_setup(struct ata_queued_cmd *qc)
+{
+	qc->ap->ops->sff_exec_command(qc->ap, &qc->tf);
+}
+
+static u8 ep93xx_pata_dma_status(struct ata_port *ap)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+	u32 val = readl(drv_data->ide_base + IDEUDMASTS);
+
+	/*
+	 * UDMA Status Register bits:
+	 *
+	 * DMAIDE - DMA request signal from UDMA state machine,
+	 * INTIDE - INT line generated by UDMA because of errors in the
+	 *          state machine,
+	 * SBUSY - UDMA state machine busy, not in idle state,
+	 * NDO   - error for data-out not completed,
+	 * NDI   - error for data-in not completed,
+	 * N4X   - error for data transferred not multiplies of four
+	 *         32-bit words.
+	 * (EP93xx UG p27-17)
+	 */
+	if (val & IDEUDMASTS_NDO || val & IDEUDMASTS_NDI ||
+	    val & IDEUDMASTS_N4X || val & IDEUDMASTS_INTIDE)
+		return ATA_DMA_ERR;
+
+	/* read INTRQ (INT[3]) pin input state */
+	if (readl(drv_data->ide_base + IDECTRL) & IDECTRL_INTRQ)
+		return ATA_DMA_INTR;
+
+	if (val & IDEUDMASTS_SBUSY || val & IDEUDMASTS_DMAIDE)
+		return ATA_DMA_ACTIVE;
+
+	return 0;
+}
+
+/* Note: original code is ata_sff_softreset */
+static int ep93xx_pata_softreset(struct ata_link *al, unsigned int *classes,
+				 unsigned long deadline)
+{
+	struct ata_port *ap = al->ap;
+	unsigned int slave_possible = ap->flags & ATA_FLAG_SLAVE_POSS;
+	unsigned int devmask = 0;
+	int rc;
+	u8 err;
+
+	/* determine if device 0/1 are present */
+	if (ep93xx_pata_device_is_present(ap, 0))
+		devmask |= (1 << 0);
+	if (slave_possible && ep93xx_pata_device_is_present(ap, 1))
+		devmask |= (1 << 1);
+
+	/* select device 0 again */
+	ap->ops->sff_dev_select(al->ap, 0);
+
+	/* issue bus reset */
+	rc = ep93xx_pata_bus_softreset(ap, devmask, deadline);
+	/* if link is ocuppied, -ENODEV too is an error */
+	if (rc && (rc != -ENODEV || sata_scr_valid(al))) {
+		ata_link_printk(al, KERN_ERR, "SRST failed (errno=%d)\n",
+				rc);
+		return rc;
+	}
+
+	/* determine by signature whether we have ATA or ATAPI devices */
+	classes[0] = ata_sff_dev_classify(&al->device[0], devmask & (1 << 0),
+					  &err);
+	if (slave_possible && err != 0x81)
+		classes[1] = ata_sff_dev_classify(&al->device[1],
+						  devmask & (1 << 1), &err);
+
+	return 0;
+}
+
+/* Note: original code is ata_sff_drain_fifo */
+static void ep93xx_pata_drain_fifo(struct ata_queued_cmd *qc)
+{
+	int count;
+	struct ata_port *ap;
+	struct ep93xx_pata_data *drv_data;
+
+	/* We only need to flush incoming data when a command was running */
+	if (qc == NULL || qc->dma_dir == DMA_TO_DEVICE)
+		return;
+
+	ap = qc->ap;
+	drv_data = ap->host->private_data;
+	/* Drain up to 64K of data before we give up this recovery method */
+	for (count = 0; (ap->ops->sff_check_status(ap) & ATA_DRQ)
+		     && count < 65536; count += 2)
+		ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_DATA);
+
+	/* Can become DEBUG later */
+	if (count)
+		ata_port_printk(ap, KERN_DEBUG,
+				"drained %d bytes to clear DRQ.\n", count);
+
+}
+
+static int ep93xx_pata_port_start(struct ata_port *ap)
+{
+	struct ep93xx_pata_data *drv_data = ap->host->private_data;
+
+	/*
+	 * Set timings to safe values at startup (= number of ns from ATA
+	 * specification), we'll switch to properly calculated values later.
+	 */
+	drv_data->t = *ata_timing_find_mode(XFER_PIO_0);
+	return 0;
+}
+
+static struct scsi_host_template ep93xx_pata_sht = {
+	ATA_BASE_SHT(DRV_NAME),
+	/* ep93xx dma implementation limit */
+	.sg_tablesize		= 32,
+	/* ep93xx dma can't transfer 65536 bytes at once */
+	.dma_boundary		= 0x7fff,
+};
+
+static struct ata_port_operations ep93xx_pata_port_ops = {
+	.inherits		= &ata_bmdma_port_ops,
+
+	.qc_prep		= ata_noop_qc_prep,
+
+	.softreset		= ep93xx_pata_softreset,
+	.hardreset		= ATA_OP_NULL,
+
+	.sff_dev_select		= ep93xx_pata_dev_select,
+	.sff_set_devctl		= ep93xx_pata_set_devctl,
+	.sff_check_status	= ep93xx_pata_check_status,
+	.sff_check_altstatus	= ep93xx_pata_check_altstatus,
+	.sff_tf_load		= ep93xx_pata_tf_load,
+	.sff_tf_read		= ep93xx_pata_tf_read,
+	.sff_exec_command	= ep93xx_pata_exec_command,
+	.sff_data_xfer		= ep93xx_pata_data_xfer,
+	.sff_drain_fifo		= ep93xx_pata_drain_fifo,
+	.sff_irq_clear		= ATA_OP_NULL,
+
+	.set_piomode		= ep93xx_pata_set_piomode,
+
+	.bmdma_setup		= ep93xx_pata_dma_setup,
+	.bmdma_start		= ep93xx_pata_dma_start,
+	.bmdma_stop		= ep93xx_pata_dma_stop,
+	.bmdma_status		= ep93xx_pata_dma_status,
+
+	.cable_detect		= ata_cable_unknown,
+	.port_start		= ep93xx_pata_port_start,
+};
+
+static int __devinit ep93xx_pata_probe(struct platform_device *pdev)
+{
+	struct ep93xx_pata_data *drv_data;
+	struct ata_host *host;
+	struct ata_port *ap;
+	unsigned int irq;
+	struct resource *mem_res;
+	void __iomem *ide_base;
+	int err;
+
+	err = ep93xx_ide_acquire_gpio(pdev);
+	if (err)
+		return err;
+
+	/* INT[3] (IRQ_EP93XX_EXT3) line connected as pull down */
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		err = -ENXIO;
+		goto err_rel_gpio;
+	}
+
+	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem_res) {
+		err = -ENXIO;
+		goto err_rel_gpio;
+	}
+
+	ide_base = devm_request_and_ioremap(&pdev->dev, mem_res);
+	if (!ide_base) {
+		err = -ENXIO;
+		goto err_rel_gpio;
+	}
+
+	drv_data = devm_kzalloc(&pdev->dev, sizeof(*drv_data), GFP_KERNEL);
+	if (!drv_data) {
+		err = -ENXIO;
+		goto err_rel_gpio;
+	}
+
+	platform_set_drvdata(pdev, drv_data);
+	drv_data->pdev = pdev;
+	drv_data->ide_base = ide_base;
+	drv_data->udma_in_phys = mem_res->start + IDEUDMADATAIN;
+	drv_data->udma_out_phys = mem_res->start + IDEUDMADATAOUT;
+	ep93xx_pata_dma_init(drv_data);
+
+	/* allocate host */
+	host = ata_host_alloc(&pdev->dev, 1);
+	if (!host) {
+		err = -ENXIO;
+		goto err_rel_dma;
+	}
+
+	ep93xx_pata_clear_regs(ide_base);
+
+	host->private_data = drv_data;
+
+	ap = host->ports[0];
+	ap->dev = &pdev->dev;
+	ap->ops = &ep93xx_pata_port_ops;
+	ap->flags |= ATA_FLAG_SLAVE_POSS;
+	ap->pio_mask = ATA_PIO4;
+
+	/*
+	 * Maximum UDMA modes:
+	 * EP931x rev.E0 - UDMA2
+	 * EP931x rev.E1 - UDMA3
+	 * EP931x rev.E2 - UDMA4
+	 *
+	 * MWDMA support was removed from EP931x rev.E2,
+	 * so this driver supports only UDMA modes.
+	 */
+	if (drv_data->dma_rx_channel && drv_data->dma_tx_channel) {
+		int chip_rev = ep93xx_chip_revision();
+
+		if (chip_rev == EP93XX_CHIP_REV_E1)
+			ap->udma_mask = ATA_UDMA3;
+		else if (chip_rev == EP93XX_CHIP_REV_E2)
+			ap->udma_mask = ATA_UDMA4;
+		else
+			ap->udma_mask = ATA_UDMA2;
+	}
+
+	/* defaults, pio 0 */
+	ep93xx_pata_enable_pio(ide_base, 0);
+
+	dev_info(&pdev->dev, "version " DRV_VERSION "\n");
+
+	/* activate host */
+	err = ata_host_activate(host, irq, ata_bmdma_interrupt, 0,
+		&ep93xx_pata_sht);
+	if (err == 0)
+		return 0;
+
+err_rel_dma:
+	ep93xx_pata_release_dma(drv_data);
+err_rel_gpio:
+	ep93xx_ide_release_gpio(pdev);
+	return err;
+}
+
+static int __devexit ep93xx_pata_remove(struct platform_device *pdev)
+{
+	struct ata_host *host = platform_get_drvdata(pdev);
+	struct ep93xx_pata_data *drv_data = host->private_data;
+
+	ata_host_detach(host);
+	ep93xx_pata_release_dma(drv_data);
+	ep93xx_pata_clear_regs(drv_data->ide_base);
+	ep93xx_ide_release_gpio(pdev);
+	return 0;
+}
+
+static struct platform_driver ep93xx_pata_platform_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.owner = THIS_MODULE,
+	},
+	.probe = ep93xx_pata_probe,
+	.remove = __devexit_p(ep93xx_pata_remove),
+};
+
+module_platform_driver(ep93xx_pata_platform_driver);
+
+MODULE_AUTHOR("Alessandro Zummo, Lennert Buytenhek, Joao Ramos, "
+		"Bartlomiej Zolnierkiewicz, Rafal Prylowski");
+MODULE_DESCRIPTION("low-level driver for cirrus ep93xx IDE controller");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+MODULE_ALIAS("platform:pata_ep93xx");