/*
   * 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.
   *

   * Copyright (C) 1996 David S. Miller (davem@davemloft.net)

   * Copyright (C) 1999 Andrew R. Baker (andrewb@uab.edu)
   * Copyright (C) 2001 Florian Lohoff (flo@rfc822.org)

   * Copyright (C) 2003, 07 Ralf Baechle (ralf@linux-mips.org)

   * 
   * (In all truth, Jed Schimmel wrote all this code.)
   */

  
  #undef DEBUG

  #include <linux/delay.h>
  #include <linux/dma-mapping.h>

  #include <linux/gfp.h>
  #include <linux/interrupt.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>

  #include <linux/spinlock.h>

  #include <asm/sgi/hpc3.h>
  #include <asm/sgi/ip22.h>

  #include <asm/sgi/wd.h>

  
  #include "scsi.h"

  #include "wd33c93.h"

  struct ip22_hostdata {
  	struct WD33C93_hostdata wh;

  	dma_addr_t dma;
  	void *cpu;
  	struct device *dev;

  };

  #define host_to_hostdata(host) ((struct ip22_hostdata *)((host)->hostdata))

  struct hpc_chunk {
  	struct hpc_dma_desc desc;
  	u32 _padding;	/* align to quadword boundary */
  };

  /* space for hpc dma descriptors */
  #define HPC_DMA_SIZE   PAGE_SIZE
  
  #define DMA_DIR(d)   ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE)

  static irqreturn_t sgiwd93_intr(int irq, void *dev_id)

  {

  	struct Scsi_Host * host = dev_id;

  	unsigned long flags;
  
  	spin_lock_irqsave(host->host_lock, flags);
  	wd33c93_intr(host);
  	spin_unlock_irqrestore(host->host_lock, flags);
  
  	return IRQ_HANDLED;
  }
  
  static inline

  void fill_hpc_entries(struct ip22_hostdata *hd, struct scsi_cmnd *cmd, int din)

  {
  	unsigned long len = cmd->SCp.this_residual;
  	void *addr = cmd->SCp.ptr;
  	dma_addr_t physaddr;
  	unsigned long count;

  	struct hpc_chunk *hcp;

  	physaddr = dma_map_single(hd->dev, addr, len, DMA_DIR(din));

  	cmd->SCp.dma_handle = physaddr;

  	hcp = hd->cpu;

  
  	while (len) {
  		/*
  		 * even cntinfo could be up to 16383, without
  		 * magic only 8192 works correctly
  		 */
  		count = len > 8192 ? 8192 : len;
  		hcp->desc.pbuf = physaddr;
  		hcp->desc.cntinfo = count;
  		hcp++;
  		len -= count;
  		physaddr += count;
  	}
  
  	/*
  	 * To make sure, if we trip an HPC bug, that we transfer every single
  	 * byte, we tag on an extra zero length dma descriptor at the end of
  	 * the chain.
  	 */
  	hcp->desc.pbuf = 0;
  	hcp->desc.cntinfo = HPCDMA_EOX;

  	dma_cache_sync(hd->dev, hd->cpu,
  		       (unsigned long)(hcp + 1) - (unsigned long)hd->cpu,
  		       DMA_TO_DEVICE);

  }

  static int dma_setup(struct scsi_cmnd *cmd, int datainp)

  {

  	struct ip22_hostdata *hdata = host_to_hostdata(cmd->device->host);

  	struct hpc3_scsiregs *hregs =
  		(struct hpc3_scsiregs *) cmd->device->host->base;

  	pr_debug("dma_setup: datainp<%d> hcp<%p> ", datainp, hdata->cpu);

  
  	hdata->wh.dma_dir = datainp;
  
  	/*
  	 * wd33c93 shouldn't pass us bogus dma_setups, but it does:-(  The
  	 * other wd33c93 drivers deal with it the same way (which isn't that
  	 * obvious).  IMHO a better fix would be, not to do these dma setups
  	 * in the first place.
  	 */
  	if (cmd->SCp.ptr == NULL || cmd->SCp.this_residual == 0)
  		return 1;

  	fill_hpc_entries(hdata, cmd, datainp);

  	pr_debug(" HPCGO
  ");

  
  	/* Start up the HPC. */

  	hregs->ndptr = hdata->dma;

  	if (datainp)
  		hregs->ctrl = HPC3_SCTRL_ACTIVE;
  	else
  		hregs->ctrl = HPC3_SCTRL_ACTIVE | HPC3_SCTRL_DIR;
  
  	return 0;
  }

  static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt,

  		     int status)
  {

  	struct ip22_hostdata *hdata = host_to_hostdata(instance);

  	struct hpc3_scsiregs *hregs;
  
  	if (!SCpnt)
  		return;

  	if (SCpnt->SCp.ptr == NULL || SCpnt->SCp.this_residual == 0)
  		return;

  	hregs = (struct hpc3_scsiregs *) SCpnt->device->host->base;

  	pr_debug("dma_stop: status<%d> ", status);

  
  	/* First stop the HPC and flush it's FIFO. */
  	if (hdata->wh.dma_dir) {
  		hregs->ctrl |= HPC3_SCTRL_FLUSH;
  		while (hregs->ctrl & HPC3_SCTRL_ACTIVE)
  			barrier();
  	}
  	hregs->ctrl = 0;

  	dma_unmap_single(hdata->dev, SCpnt->SCp.dma_handle,
  			 SCpnt->SCp.this_residual,
  			 DMA_DIR(hdata->wh.dma_dir));

  	pr_debug("
  ");

  }
  
  void sgiwd93_reset(unsigned long base)
  {
  	struct hpc3_scsiregs *hregs = (struct hpc3_scsiregs *) base;
  
  	hregs->ctrl = HPC3_SCTRL_CRESET;
  	udelay(50);
  	hregs->ctrl = 0;
  }

  EXPORT_SYMBOL_GPL(sgiwd93_reset);

  static inline void init_hpc_chain(struct ip22_hostdata *hdata)

  {

  	struct hpc_chunk *hcp = (struct hpc_chunk *)hdata->cpu;
  	dma_addr_t dma = hdata->dma;

  	unsigned long start, end;
  
  	start = (unsigned long) hcp;

  	end = start + HPC_DMA_SIZE;

  	while (start < end) {

  		hcp->desc.pnext = (u32) (dma + sizeof(struct hpc_chunk));

  		hcp->desc.cntinfo = HPCDMA_EOX;

  		hcp++;
  		dma += sizeof(struct hpc_chunk);

  		start += sizeof(struct hpc_chunk);
  	};
  	hcp--;

  	hcp->desc.pnext = hdata->dma;

  }

  static int sgiwd93_bus_reset(struct scsi_cmnd *cmd)
  {
  	/* FIXME perform bus-specific reset */
  
  	/* FIXME 2: kill this function, and let midlayer fallback
  	   to the same result, calling wd33c93_host_reset() */
  
  	spin_lock_irq(cmd->device->host->host_lock);
  	wd33c93_host_reset(cmd);
  	spin_unlock_irq(cmd->device->host->host_lock);
  
  	return SUCCESS;
  }
  
  /*
   * Kludge alert - the SCSI code calls the abort and reset method with int
   * arguments not with pointers.  So this is going to blow up beautyfully
   * on 64-bit systems with memory outside the compat address spaces.
   */
  static struct scsi_host_template sgiwd93_template = {
  	.module			= THIS_MODULE,
  	.proc_name		= "SGIWD93",
  	.name			= "SGI WD93",
  	.queuecommand		= wd33c93_queuecommand,
  	.eh_abort_handler	= wd33c93_abort,
  	.eh_bus_reset_handler	= sgiwd93_bus_reset,
  	.eh_host_reset_handler	= wd33c93_host_reset,
  	.can_queue		= 16,
  	.this_id		= 7,
  	.sg_tablesize		= SG_ALL,
  	.cmd_per_lun		= 8,
  	.use_clustering		= DISABLE_CLUSTERING,
  };

  static int __devinit sgiwd93_probe(struct platform_device *pdev)

  {

  	struct sgiwd93_platform_data *pd = pdev->dev.platform_data;
  	unsigned char *wdregs = pd->wdregs;
  	struct hpc3_scsiregs *hregs = pd->hregs;

  	struct ip22_hostdata *hdata;
  	struct Scsi_Host *host;
  	wd33c93_regs regs;

  	unsigned int unit = pd->unit;
  	unsigned int irq = pd->irq;
  	int err;
  
  	host = scsi_host_alloc(&sgiwd93_template, sizeof(struct ip22_hostdata));
  	if (!host) {
  		err = -ENOMEM;
  		goto out;
  	}

  
  	host->base = (unsigned long) hregs;
  	host->irq = irq;

  	hdata = host_to_hostdata(host);

  	hdata->dev = &pdev->dev;
  	hdata->cpu = dma_alloc_noncoherent(&pdev->dev, HPC_DMA_SIZE,
  					   &hdata->dma, GFP_KERNEL);
  	if (!hdata->cpu) {

  		printk(KERN_WARNING "sgiwd93: Could not allocate memory for "
  		       "host %d buffer.
  ", unit);

  		err = -ENOMEM;
  		goto out_put;

  	}

  	init_hpc_chain(hdata);

  
  	regs.SASR = wdregs + 3;
  	regs.SCMD = wdregs + 7;

  	hdata->wh.no_sync = 0;
  	hdata->wh.fast = 1;
  	hdata->wh.dma_mode = CTRL_BURST;

  	wd33c93_init(host, regs, dma_setup, dma_stop, WD33C93_FS_MHZ(20));

  	err = request_irq(irq, sgiwd93_intr, 0, "SGI WD93", host);
  	if (err) {

  		printk(KERN_WARNING "sgiwd93: Could not register irq %d "
  		       "for host %d.
  ", irq, unit);
  		goto out_free;
  	}

  	platform_set_drvdata(pdev, host);

  	err = scsi_add_host(host, NULL);
  	if (err)
  		goto out_irq;

  	scsi_scan_host(host);

  	return 0;

  out_irq:
  	free_irq(irq, host);
  out_free:

  	dma_free_noncoherent(&pdev->dev, HPC_DMA_SIZE, hdata->cpu, hdata->dma);

  out_put:
  	scsi_host_put(host);
  out:

  	return err;

  }

  static int __exit sgiwd93_remove(struct platform_device *pdev)

  {

  	struct Scsi_Host *host = platform_get_drvdata(pdev);
  	struct ip22_hostdata *hdata = (struct ip22_hostdata *) host->hostdata;
  	struct sgiwd93_platform_data *pd = pdev->dev.platform_data;
  
  	scsi_remove_host(host);
  	free_irq(pd->irq, host);

  	dma_free_noncoherent(&pdev->dev, HPC_DMA_SIZE, hdata->cpu, hdata->dma);

  	scsi_host_put(host);

  	return 0;

  }

  static struct platform_driver sgiwd93_driver = {
  	.probe  = sgiwd93_probe,
  	.remove = __devexit_p(sgiwd93_remove),
  	.driver = {

  		.name   = "sgiwd93",
  		.owner	= THIS_MODULE,

  	}
  };

  static int __init sgiwd93_module_init(void)
  {
  	return platform_driver_register(&sgiwd93_driver);
  }

  static void __exit sgiwd93_module_exit(void)
  {
  	return platform_driver_unregister(&sgiwd93_driver);

  }

  module_init(sgiwd93_module_init);
  module_exit(sgiwd93_module_exit);
  
  MODULE_DESCRIPTION("SGI WD33C93 driver");
  MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("platform:sgiwd93");