// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * Generic PXA PATA driver
   *
   * Copyright (C) 2010 Marek Vasut <marek.vasut@gmail.com>

   */
  
  #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/dmaengine.h>

  #include <linux/slab.h>
  #include <linux/completion.h>
  
  #include <scsi/scsi_host.h>

  #include <linux/platform_data/ata-pxa.h>

  
  #define DRV_NAME	"pata_pxa"
  #define DRV_VERSION	"0.1"
  
  struct pata_pxa_data {

  	struct dma_chan		*dma_chan;
  	dma_cookie_t		dma_cookie;

  	struct completion	dma_done;
  };
  
  /*

   * DMA interrupt handler.

   */

  static void pxa_ata_dma_irq(void *d)

  {

  	struct pata_pxa_data *pd = d;
  	enum dma_status status;

  	status = dmaengine_tx_status(pd->dma_chan, pd->dma_cookie, NULL);
  	if (status == DMA_ERROR || status == DMA_COMPLETE)
  		complete(&pd->dma_done);

  }
  
  /*
   * Prepare taskfile for submission.
   */

  static enum ata_completion_errors pxa_qc_prep(struct ata_queued_cmd *qc)

  {
  	struct pata_pxa_data *pd = qc->ap->private_data;

  	struct dma_async_tx_descriptor *tx;
  	enum dma_transfer_direction dir;

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

  		return AC_ERR_OK;

  	dir = (qc->dma_dir == DMA_TO_DEVICE ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
  	tx = dmaengine_prep_slave_sg(pd->dma_chan, qc->sg, qc->n_elem, dir,
  				     DMA_PREP_INTERRUPT);
  	if (!tx) {
  		ata_dev_err(qc->dev, "prep_slave_sg() failed
  ");

  		return AC_ERR_OK;

  	}
  	tx->callback = pxa_ata_dma_irq;
  	tx->callback_param = pd;
  	pd->dma_cookie = dmaengine_submit(tx);

  
  	return AC_ERR_OK;

  }
  
  /*
   * 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);

  	dma_async_issue_pending(pd->dma_chan);

  }
  
  /*
   * 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;

  	enum dma_status status;

  	status = dmaengine_tx_status(pd->dma_chan, pd->dma_cookie, NULL);
  	if (status != DMA_ERROR && status != DMA_COMPLETE &&
  	    wait_for_completion_timeout(&pd->dma_done, HZ))
  		ata_dev_err(qc->dev, "Timeout waiting for DMA completion!");

  	dmaengine_terminate_all(pd->dma_chan);

  }
  
  /*
   * 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;

  	struct dma_tx_state state;
  	enum dma_status status;

  	status = dmaengine_tx_status(pd->dma_chan, pd->dma_cookie, &state);
  	if (status != DMA_COMPLETE)

  		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,
  };

  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);

  	struct dma_slave_config	config;

  	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
  ");
  		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;

  	memset(&config, 0, sizeof(config));
  	config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
  	config.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
  	config.src_addr = dma_res->start;
  	config.dst_addr = dma_res->start;
  	config.src_maxburst = 32;
  	config.dst_maxburst = 32;

  
  	/*
  	 * Request the DMA channel
  	 */

  	data->dma_chan =

  		dma_request_slave_channel(&pdev->dev, "data");

  	if (!data->dma_chan)

  		return -EBUSY;

  	ret = dmaengine_slave_config(data->dma_chan, &config);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "dma configuration failed: %d
  ", ret);
  		return ret;
  	}

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

  		dma_release_channel(data->dma_chan);

  
  	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;

  	dma_release_channel(data->dma_chan);

  
  	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,

  	},
  };

  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);