drivers/ata/pata_pxa.c - kernel/msm-4.9 - Gitiles

 /*
  * Generic PXA PATA driver
  *
  * Copyright (C) 2010 Marek Vasut <marek.vasut@gmail.com>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2, or (at your option)
  *  any later version.
  *
  *  This program is distributed in the hope that 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; see the file COPYING.  If not, write to
  *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/blkdev.h>
 #include <linux/ata.h>
 #include <linux/libata.h>
 #include <linux/platform_device.h>
 #include <linux/gpio.h>
 #include <linux/slab.h>
 #include <linux/completion.h>

 #include <scsi/scsi_host.h>

 #include <mach/pxa2xx-regs.h>
 #include <linux/platform_data/ata-pxa.h>
 #include <mach/dma.h>

 #define DRV_NAME	"pata_pxa"
 #define DRV_VERSION	"0.1"

 struct pata_pxa_data {
 	uint32_t		dma_channel;
 	struct pxa_dma_desc	*dma_desc;
 	dma_addr_t		dma_desc_addr;
 	uint32_t		dma_desc_id;

 	/* DMA IO physical address */
 	uint32_t		dma_io_addr;
 	/* PXA DREQ<0:2> pin selector */
 	uint32_t		dma_dreq;
 	/* DMA DCSR register value */
 	uint32_t		dma_dcsr;

 	struct completion	dma_done;
 };

 /*
  * Setup the DMA descriptors. The size is transfer capped at 4k per descriptor,
  * if the transfer is longer, it is split into multiple chained descriptors.
  */
 static void pxa_load_dmac(struct scatterlist *sg, struct ata_queued_cmd *qc)
 {
 	struct pata_pxa_data *pd = qc->ap->private_data;

 	uint32_t cpu_len, seg_len;
 	dma_addr_t cpu_addr;

 	cpu_addr = sg_dma_address(sg);
 	cpu_len = sg_dma_len(sg);

 	do {
 		seg_len = (cpu_len > 0x1000) ? 0x1000 : cpu_len;

 		pd->dma_desc[pd->dma_desc_id].ddadr = pd->dma_desc_addr +
 			((pd->dma_desc_id + 1) * sizeof(struct pxa_dma_desc));

 		pd->dma_desc[pd->dma_desc_id].dcmd = DCMD_BURST32 |
 					DCMD_WIDTH2 | (DCMD_LENGTH & seg_len);

 		if (qc->tf.flags & ATA_TFLAG_WRITE) {
 			pd->dma_desc[pd->dma_desc_id].dsadr = cpu_addr;
 			pd->dma_desc[pd->dma_desc_id].dtadr = pd->dma_io_addr;
 			pd->dma_desc[pd->dma_desc_id].dcmd |= DCMD_INCSRCADDR |
 						DCMD_FLOWTRG;
 		} else {
 			pd->dma_desc[pd->dma_desc_id].dsadr = pd->dma_io_addr;
 			pd->dma_desc[pd->dma_desc_id].dtadr = cpu_addr;
 			pd->dma_desc[pd->dma_desc_id].dcmd |= DCMD_INCTRGADDR |
 						DCMD_FLOWSRC;
 		}

 		cpu_len -= seg_len;
 		cpu_addr += seg_len;
 		pd->dma_desc_id++;

 	} while (cpu_len);

 	/* Should not happen */
 	if (seg_len & 0x1f)
 		DALGN |= (1 << pd->dma_dreq);
 }

 /*
  * Prepare taskfile for submission.
  */
 static void pxa_qc_prep(struct ata_queued_cmd *qc)
 {
 	struct pata_pxa_data *pd = qc->ap->private_data;
 	int si = 0;
 	struct scatterlist *sg;

 	if (!(qc->flags & ATA_QCFLAG_DMAMAP))
 		return;

 	pd->dma_desc_id = 0;

 	DCSR(pd->dma_channel) = 0;
 	DALGN &= ~(1 << pd->dma_dreq);

 	for_each_sg(qc->sg, sg, qc->n_elem, si)
 		pxa_load_dmac(sg, qc);

 	pd->dma_desc[pd->dma_desc_id - 1].ddadr = DDADR_STOP;

 	/* Fire IRQ only at the end of last block */
 	pd->dma_desc[pd->dma_desc_id - 1].dcmd |= DCMD_ENDIRQEN;

 	DDADR(pd->dma_channel) = pd->dma_desc_addr;
 	DRCMR(pd->dma_dreq) = DRCMR_MAPVLD | pd->dma_channel;

 }

 /*
  * Configure the DMA controller, load the DMA descriptors, but don't start the
  * DMA controller yet. Only issue the ATA command.
  */
 static void pxa_bmdma_setup(struct ata_queued_cmd *qc)
 {
 	qc->ap->ops->sff_exec_command(qc->ap, &qc->tf);
 }

 /*
  * Execute the DMA transfer.
  */
 static void pxa_bmdma_start(struct ata_queued_cmd *qc)
 {
 	struct pata_pxa_data *pd = qc->ap->private_data;
 	init_completion(&pd->dma_done);
 	DCSR(pd->dma_channel) = DCSR_RUN;
 }

 /*
  * Wait until the DMA transfer completes, then stop the DMA controller.
  */
 static void pxa_bmdma_stop(struct ata_queued_cmd *qc)
 {
 	struct pata_pxa_data *pd = qc->ap->private_data;

 	if ((DCSR(pd->dma_channel) & DCSR_RUN) &&
 		wait_for_completion_timeout(&pd->dma_done, HZ))
 		dev_err(qc->ap->dev, "Timeout waiting for DMA completion!");

 	DCSR(pd->dma_channel) = 0;
 }

 /*
  * Read DMA status. The bmdma_stop() will take care of properly finishing the
  * DMA transfer so we always have DMA-complete interrupt here.
  */
 static unsigned char pxa_bmdma_status(struct ata_port *ap)
 {
 	struct pata_pxa_data *pd = ap->private_data;
 	unsigned char ret = ATA_DMA_INTR;

 	if (pd->dma_dcsr & DCSR_BUSERR)
 		ret |= ATA_DMA_ERR;

 	return ret;
 }

 /*
  * No IRQ register present so we do nothing.
  */
 static void pxa_irq_clear(struct ata_port *ap)
 {
 }

 /*
  * Check for ATAPI DMA. ATAPI DMA is unsupported by this driver. It's still
  * unclear why ATAPI has DMA issues.
  */
 static int pxa_check_atapi_dma(struct ata_queued_cmd *qc)
 {
 	return -EOPNOTSUPP;
 }

 static struct scsi_host_template pxa_ata_sht = {
 	ATA_BMDMA_SHT(DRV_NAME),
 };

 static struct ata_port_operations pxa_ata_port_ops = {
 	.inherits		= &ata_bmdma_port_ops,
 	.cable_detect		= ata_cable_40wire,

 	.bmdma_setup		= pxa_bmdma_setup,
 	.bmdma_start		= pxa_bmdma_start,
 	.bmdma_stop		= pxa_bmdma_stop,
 	.bmdma_status		= pxa_bmdma_status,

 	.check_atapi_dma	= pxa_check_atapi_dma,

 	.sff_irq_clear		= pxa_irq_clear,

 	.qc_prep		= pxa_qc_prep,
 };

 /*
  * DMA interrupt handler.
  */
 static void pxa_ata_dma_irq(int dma, void *port)
 {
 	struct ata_port *ap = port;
 	struct pata_pxa_data *pd = ap->private_data;

 	pd->dma_dcsr = DCSR(dma);
 	DCSR(dma) = pd->dma_dcsr;

 	if (pd->dma_dcsr & DCSR_STOPSTATE)
 		complete(&pd->dma_done);
 }

 static int pxa_ata_probe(struct platform_device *pdev)
 {
 	struct ata_host *host;
 	struct ata_port *ap;
 	struct pata_pxa_data *data;
 	struct resource *cmd_res;
 	struct resource *ctl_res;
 	struct resource *dma_res;
 	struct resource *irq_res;
 	struct pata_pxa_pdata *pdata = dev_get_platdata(&pdev->dev);
 	int ret = 0;

 	/*
 	 * Resource validation, three resources are needed:
 	 *  - CMD port base address
 	 *  - CTL port base address
 	 *  - DMA port base address
 	 *  - IRQ pin
 	 */
 	if (pdev->num_resources != 4) {
 		dev_err(&pdev->dev, "invalid number of resources\n");
 		return -EINVAL;
 	}

 	/*
 	 * CMD port base address
 	 */
 	cmd_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (unlikely(cmd_res == NULL))
 		return -EINVAL;

 	/*
 	 * CTL port base address
 	 */
 	ctl_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 	if (unlikely(ctl_res == NULL))
 		return -EINVAL;

 	/*
 	 * DMA port base address
 	 */
 	dma_res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 	if (unlikely(dma_res == NULL))
 		return -EINVAL;

 	/*
 	 * IRQ pin
 	 */
 	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (unlikely(irq_res == NULL))
 		return -EINVAL;

 	/*
 	 * Allocate the host
 	 */
 	host = ata_host_alloc(&pdev->dev, 1);
 	if (!host)
 		return -ENOMEM;

 	ap		= host->ports[0];
 	ap->ops		= &pxa_ata_port_ops;
 	ap->pio_mask	= ATA_PIO4;
 	ap->mwdma_mask	= ATA_MWDMA2;

 	ap->ioaddr.cmd_addr	= devm_ioremap(&pdev->dev, cmd_res->start,
 						resource_size(cmd_res));
 	ap->ioaddr.ctl_addr	= devm_ioremap(&pdev->dev, ctl_res->start,
 						resource_size(ctl_res));
 	ap->ioaddr.bmdma_addr	= devm_ioremap(&pdev->dev, dma_res->start,
 						resource_size(dma_res));

 	/*
 	 * Adjust register offsets
 	 */
 	ap->ioaddr.altstatus_addr = ap->ioaddr.ctl_addr;
 	ap->ioaddr.data_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_DATA << pdata->reg_shift);
 	ap->ioaddr.error_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_ERR << pdata->reg_shift);
 	ap->ioaddr.feature_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_FEATURE << pdata->reg_shift);
 	ap->ioaddr.nsect_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_NSECT << pdata->reg_shift);
 	ap->ioaddr.lbal_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_LBAL << pdata->reg_shift);
 	ap->ioaddr.lbam_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_LBAM << pdata->reg_shift);
 	ap->ioaddr.lbah_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_LBAH << pdata->reg_shift);
 	ap->ioaddr.device_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_DEVICE << pdata->reg_shift);
 	ap->ioaddr.status_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_STATUS << pdata->reg_shift);
 	ap->ioaddr.command_addr	= ap->ioaddr.cmd_addr +
 					(ATA_REG_CMD << pdata->reg_shift);

 	/*
 	 * Allocate and load driver's internal data structure
 	 */
 	data = devm_kzalloc(&pdev->dev, sizeof(struct pata_pxa_data),
 								GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	ap->private_data = data;
 	data->dma_dreq = pdata->dma_dreq;
 	data->dma_io_addr = dma_res->start;

 	/*
 	 * Allocate space for the DMA descriptors
 	 */
 	data->dma_desc = dmam_alloc_coherent(&pdev->dev, PAGE_SIZE,
 					&data->dma_desc_addr, GFP_KERNEL);
 	if (!data->dma_desc)
 		return -EINVAL;

 	/*
 	 * Request the DMA channel
 	 */
 	data->dma_channel = pxa_request_dma(DRV_NAME, DMA_PRIO_LOW,
 						pxa_ata_dma_irq, ap);
 	if (data->dma_channel < 0)
 		return -EBUSY;

 	/*
 	 * Stop and clear the DMA channel
 	 */
 	DCSR(data->dma_channel) = 0;

 	/*
 	 * Activate the ATA host
 	 */
 	ret = ata_host_activate(host, irq_res->start, ata_sff_interrupt,
 				pdata->irq_flags, &pxa_ata_sht);
 	if (ret)
 		pxa_free_dma(data->dma_channel);

 	return ret;
 }

 static int pxa_ata_remove(struct platform_device *pdev)
 {
 	struct ata_host *host = platform_get_drvdata(pdev);
 	struct pata_pxa_data *data = host->ports[0]->private_data;

 	pxa_free_dma(data->dma_channel);

 	ata_host_detach(host);

 	return 0;
 }

 static struct platform_driver pxa_ata_driver = {
 	.probe		= pxa_ata_probe,
 	.remove		= pxa_ata_remove,
 	.driver		= {
 		.name		= DRV_NAME,
 		.owner		= THIS_MODULE,
 	},
 };

 module_platform_driver(pxa_ata_driver);

 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
 MODULE_DESCRIPTION("DMA-capable driver for PATA on PXA CPU");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(DRV_VERSION);
 MODULE_ALIAS("platform:" DRV_NAME);
	/*
	* Generic PXA PATA driver
	*
	* Copyright (C) 2010 Marek Vasut <marek.vasut@gmail.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2, or (at your option)
	* any later version.
	*
	* This program is distributed in the hope that 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; see the file COPYING. If not, write to
	* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/blkdev.h>
	#include <linux/ata.h>
	#include <linux/libata.h>
	#include <linux/platform_device.h>
	#include <linux/gpio.h>
	#include <linux/slab.h>
	#include <linux/completion.h>

	#include <scsi/scsi_host.h>

	#include <mach/pxa2xx-regs.h>
	#include <linux/platform_data/ata-pxa.h>
	#include <mach/dma.h>

	#define DRV_NAME "pata_pxa"
	#define DRV_VERSION "0.1"

	struct pata_pxa_data {
	uint32_t dma_channel;
	struct pxa_dma_desc *dma_desc;
	dma_addr_t dma_desc_addr;
	uint32_t dma_desc_id;

	/* DMA IO physical address */
	uint32_t dma_io_addr;
	/* PXA DREQ<0:2> pin selector */
	uint32_t dma_dreq;
	/* DMA DCSR register value */
	uint32_t dma_dcsr;

	struct completion dma_done;
	};

	/*
	* Setup the DMA descriptors. The size is transfer capped at 4k per descriptor,
	* if the transfer is longer, it is split into multiple chained descriptors.
	*/
	static void pxa_load_dmac(struct scatterlist sg, struct ata_queued_cmd qc)
	{
	struct pata_pxa_data *pd = qc->ap->private_data;

	uint32_t cpu_len, seg_len;
	dma_addr_t cpu_addr;

	cpu_addr = sg_dma_address(sg);
	cpu_len = sg_dma_len(sg);

	do {
	seg_len = (cpu_len > 0x1000) ? 0x1000 : cpu_len;

	pd->dma_desc[pd->dma_desc_id].ddadr = pd->dma_desc_addr +
	((pd->dma_desc_id + 1) * sizeof(struct pxa_dma_desc));

	pd->dma_desc[pd->dma_desc_id].dcmd = DCMD_BURST32 \|
	DCMD_WIDTH2 \| (DCMD_LENGTH & seg_len);

	if (qc->tf.flags & ATA_TFLAG_WRITE) {
	pd->dma_desc[pd->dma_desc_id].dsadr = cpu_addr;
	pd->dma_desc[pd->dma_desc_id].dtadr = pd->dma_io_addr;
	pd->dma_desc[pd->dma_desc_id].dcmd \|= DCMD_INCSRCADDR \|
	DCMD_FLOWTRG;
	} else {
	pd->dma_desc[pd->dma_desc_id].dsadr = pd->dma_io_addr;
	pd->dma_desc[pd->dma_desc_id].dtadr = cpu_addr;
	pd->dma_desc[pd->dma_desc_id].dcmd \|= DCMD_INCTRGADDR \|
	DCMD_FLOWSRC;
	}

	cpu_len -= seg_len;
	cpu_addr += seg_len;
	pd->dma_desc_id++;

	} while (cpu_len);

	/* Should not happen */
	if (seg_len & 0x1f)
	DALGN \|= (1 << pd->dma_dreq);
	}

	/*
	* Prepare taskfile for submission.
	*/
	static void pxa_qc_prep(struct ata_queued_cmd *qc)
	{
	struct pata_pxa_data *pd = qc->ap->private_data;
	int si = 0;
	struct scatterlist *sg;

	if (!(qc->flags & ATA_QCFLAG_DMAMAP))
	return;

	pd->dma_desc_id = 0;

	DCSR(pd->dma_channel) = 0;
	DALGN &= ~(1 << pd->dma_dreq);

	for_each_sg(qc->sg, sg, qc->n_elem, si)
	pxa_load_dmac(sg, qc);

	pd->dma_desc[pd->dma_desc_id - 1].ddadr = DDADR_STOP;

	/* Fire IRQ only at the end of last block */
	pd->dma_desc[pd->dma_desc_id - 1].dcmd \|= DCMD_ENDIRQEN;

	DDADR(pd->dma_channel) = pd->dma_desc_addr;
	DRCMR(pd->dma_dreq) = DRCMR_MAPVLD \| pd->dma_channel;

	}

	/*
	* Configure the DMA controller, load the DMA descriptors, but don't start the
	* DMA controller yet. Only issue the ATA command.
	*/
	static void pxa_bmdma_setup(struct ata_queued_cmd *qc)
	{
	qc->ap->ops->sff_exec_command(qc->ap, &qc->tf);
	}

	/*
	* Execute the DMA transfer.
	*/
	static void pxa_bmdma_start(struct ata_queued_cmd *qc)
	{
	struct pata_pxa_data *pd = qc->ap->private_data;
	init_completion(&pd->dma_done);
	DCSR(pd->dma_channel) = DCSR_RUN;
	}

	/*
	* Wait until the DMA transfer completes, then stop the DMA controller.
	*/
	static void pxa_bmdma_stop(struct ata_queued_cmd *qc)
	{
	struct pata_pxa_data *pd = qc->ap->private_data;

	if ((DCSR(pd->dma_channel) & DCSR_RUN) &&
	wait_for_completion_timeout(&pd->dma_done, HZ))
	dev_err(qc->ap->dev, "Timeout waiting for DMA completion!");

	DCSR(pd->dma_channel) = 0;
	}

	/*
	* Read DMA status. The bmdma_stop() will take care of properly finishing the
	* DMA transfer so we always have DMA-complete interrupt here.
	*/
	static unsigned char pxa_bmdma_status(struct ata_port *ap)
	{
	struct pata_pxa_data *pd = ap->private_data;
	unsigned char ret = ATA_DMA_INTR;

	if (pd->dma_dcsr & DCSR_BUSERR)
	ret \|= ATA_DMA_ERR;

	return ret;
	}

	/*
	* No IRQ register present so we do nothing.
	*/
	static void pxa_irq_clear(struct ata_port *ap)
	{
	}

	/*
	* Check for ATAPI DMA. ATAPI DMA is unsupported by this driver. It's still
	* unclear why ATAPI has DMA issues.
	*/
	static int pxa_check_atapi_dma(struct ata_queued_cmd *qc)
	{
	return -EOPNOTSUPP;
	}

	static struct scsi_host_template pxa_ata_sht = {
	ATA_BMDMA_SHT(DRV_NAME),
	};

	static struct ata_port_operations pxa_ata_port_ops = {
	.inherits = &ata_bmdma_port_ops,
	.cable_detect = ata_cable_40wire,

	.bmdma_setup = pxa_bmdma_setup,
	.bmdma_start = pxa_bmdma_start,
	.bmdma_stop = pxa_bmdma_stop,
	.bmdma_status = pxa_bmdma_status,

	.check_atapi_dma = pxa_check_atapi_dma,

	.sff_irq_clear = pxa_irq_clear,

	.qc_prep = pxa_qc_prep,
	};

	/*
	* DMA interrupt handler.
	*/
	static void pxa_ata_dma_irq(int dma, void *port)
	{
	struct ata_port *ap = port;
	struct pata_pxa_data *pd = ap->private_data;

	pd->dma_dcsr = DCSR(dma);
	DCSR(dma) = pd->dma_dcsr;

	if (pd->dma_dcsr & DCSR_STOPSTATE)
	complete(&pd->dma_done);
	}

	static int pxa_ata_probe(struct platform_device *pdev)
	{
	struct ata_host *host;
	struct ata_port *ap;
	struct pata_pxa_data *data;
	struct resource *cmd_res;
	struct resource *ctl_res;
	struct resource *dma_res;
	struct resource *irq_res;
	struct pata_pxa_pdata *pdata = dev_get_platdata(&pdev->dev);
	int ret = 0;

	/*
	* Resource validation, three resources are needed:
	* - CMD port base address
	* - CTL port base address
	* - DMA port base address
	* - IRQ pin
	*/
	if (pdev->num_resources != 4) {
	dev_err(&pdev->dev, "invalid number of resources\n");
	return -EINVAL;
	}

	/*
	* CMD port base address
	*/
	cmd_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (unlikely(cmd_res == NULL))
	return -EINVAL;

	/*
	* CTL port base address
	*/
	ctl_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	if (unlikely(ctl_res == NULL))
	return -EINVAL;

	/*
	* DMA port base address
	*/
	dma_res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
	if (unlikely(dma_res == NULL))
	return -EINVAL;

	/*
	* IRQ pin
	*/
	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (unlikely(irq_res == NULL))
	return -EINVAL;

	/*
	* Allocate the host
	*/
	host = ata_host_alloc(&pdev->dev, 1);
	if (!host)
	return -ENOMEM;

	ap = host->ports[0];
	ap->ops = &pxa_ata_port_ops;
	ap->pio_mask = ATA_PIO4;
	ap->mwdma_mask = ATA_MWDMA2;

	ap->ioaddr.cmd_addr = devm_ioremap(&pdev->dev, cmd_res->start,
	resource_size(cmd_res));
	ap->ioaddr.ctl_addr = devm_ioremap(&pdev->dev, ctl_res->start,
	resource_size(ctl_res));
	ap->ioaddr.bmdma_addr = devm_ioremap(&pdev->dev, dma_res->start,
	resource_size(dma_res));

	/*
	* Adjust register offsets
	*/
	ap->ioaddr.altstatus_addr = ap->ioaddr.ctl_addr;
	ap->ioaddr.data_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_DATA << pdata->reg_shift);
	ap->ioaddr.error_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_ERR << pdata->reg_shift);
	ap->ioaddr.feature_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_FEATURE << pdata->reg_shift);
	ap->ioaddr.nsect_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_NSECT << pdata->reg_shift);
	ap->ioaddr.lbal_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_LBAL << pdata->reg_shift);
	ap->ioaddr.lbam_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_LBAM << pdata->reg_shift);
	ap->ioaddr.lbah_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_LBAH << pdata->reg_shift);
	ap->ioaddr.device_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_DEVICE << pdata->reg_shift);
	ap->ioaddr.status_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_STATUS << pdata->reg_shift);
	ap->ioaddr.command_addr = ap->ioaddr.cmd_addr +
	(ATA_REG_CMD << pdata->reg_shift);

	/*
	* Allocate and load driver's internal data structure
	*/
	data = devm_kzalloc(&pdev->dev, sizeof(struct pata_pxa_data),
	GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	ap->private_data = data;
	data->dma_dreq = pdata->dma_dreq;
	data->dma_io_addr = dma_res->start;

	/*
	* Allocate space for the DMA descriptors
	*/
	data->dma_desc = dmam_alloc_coherent(&pdev->dev, PAGE_SIZE,
	&data->dma_desc_addr, GFP_KERNEL);
	if (!data->dma_desc)
	return -EINVAL;

	/*
	* Request the DMA channel
	*/
	data->dma_channel = pxa_request_dma(DRV_NAME, DMA_PRIO_LOW,
	pxa_ata_dma_irq, ap);
	if (data->dma_channel < 0)
	return -EBUSY;

	/*
	* Stop and clear the DMA channel
	*/
	DCSR(data->dma_channel) = 0;

	/*
	* Activate the ATA host
	*/
	ret = ata_host_activate(host, irq_res->start, ata_sff_interrupt,
	pdata->irq_flags, &pxa_ata_sht);
	if (ret)
	pxa_free_dma(data->dma_channel);

	return ret;
	}

	static int pxa_ata_remove(struct platform_device *pdev)
	{
	struct ata_host *host = platform_get_drvdata(pdev);
	struct pata_pxa_data *data = host->ports[0]->private_data;

	pxa_free_dma(data->dma_channel);

	ata_host_detach(host);

	return 0;
	}

	static struct platform_driver pxa_ata_driver = {
	.probe = pxa_ata_probe,
	.remove = pxa_ata_remove,
	.driver = {
	.name = DRV_NAME,
	.owner = THIS_MODULE,
	},
	};

	module_platform_driver(pxa_ata_driver);

	MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
	MODULE_DESCRIPTION("DMA-capable driver for PATA on PXA CPU");
	MODULE_LICENSE("GPL");
	MODULE_VERSION(DRV_VERSION);
	MODULE_ALIAS("platform:" DRV_NAME);