/*
   * UIO driver fo Humusoft MF624 DAQ card.
   * Copyright (C) 2011 Rostislav Lisovy <lisovy@gmail.com>,
   *                    Czech Technical University in Prague
   *
   * 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 of the License, 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; if not, write to the Free Software
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/device.h>
  #include <linux/pci.h>
  #include <linux/slab.h>
  #include <linux/io.h>
  #include <linux/kernel.h>
  #include <linux/uio_driver.h>
  
  #define PCI_VENDOR_ID_HUMUSOFT		0x186c
  #define PCI_DEVICE_ID_MF624		0x0624
  #define PCI_SUBVENDOR_ID_HUMUSOFT	0x186c
  #define PCI_SUBDEVICE_DEVICE		0x0624
  
  /* BAR0 Interrupt control/status register */
  #define INTCSR				0x4C
  #define INTCSR_ADINT_ENABLE		(1 << 0)
  #define INTCSR_CTR4INT_ENABLE		(1 << 3)
  #define INTCSR_PCIINT_ENABLE		(1 << 6)
  #define INTCSR_ADINT_STATUS		(1 << 2)
  #define INTCSR_CTR4INT_STATUS		(1 << 5)
  
  enum mf624_interrupt_source {ADC, CTR4, ALL};
  
  static void mf624_disable_interrupt(enum mf624_interrupt_source source,
  			     struct uio_info *info)
  {
  	void __iomem *INTCSR_reg = info->mem[0].internal_addr + INTCSR;
  
  	switch (source) {
  	case ADC:
  		iowrite32(ioread32(INTCSR_reg)
  			& ~(INTCSR_ADINT_ENABLE | INTCSR_PCIINT_ENABLE),
  			INTCSR_reg);
  		break;
  
  	case CTR4:
  		iowrite32(ioread32(INTCSR_reg)
  			& ~(INTCSR_CTR4INT_ENABLE | INTCSR_PCIINT_ENABLE),
  			INTCSR_reg);
  		break;
  
  	case ALL:
  	default:
  		iowrite32(ioread32(INTCSR_reg)
  			& ~(INTCSR_ADINT_ENABLE | INTCSR_CTR4INT_ENABLE
  			    | INTCSR_PCIINT_ENABLE),
  			INTCSR_reg);
  		break;
  	}
  }
  
  static void mf624_enable_interrupt(enum mf624_interrupt_source source,
  			    struct uio_info *info)
  {
  	void __iomem *INTCSR_reg = info->mem[0].internal_addr + INTCSR;
  
  	switch (source) {
  	case ADC:
  		iowrite32(ioread32(INTCSR_reg)
  			| INTCSR_ADINT_ENABLE | INTCSR_PCIINT_ENABLE,
  			INTCSR_reg);
  		break;
  
  	case CTR4:
  		iowrite32(ioread32(INTCSR_reg)
  			| INTCSR_CTR4INT_ENABLE | INTCSR_PCIINT_ENABLE,
  			INTCSR_reg);
  		break;
  
  	case ALL:
  	default:
  		iowrite32(ioread32(INTCSR_reg)
  			| INTCSR_ADINT_ENABLE | INTCSR_CTR4INT_ENABLE
  			| INTCSR_PCIINT_ENABLE,
  			INTCSR_reg);
  		break;
  	}
  }
  
  static irqreturn_t mf624_irq_handler(int irq, struct uio_info *info)
  {
  	void __iomem *INTCSR_reg = info->mem[0].internal_addr + INTCSR;
  
  	if ((ioread32(INTCSR_reg) & INTCSR_ADINT_ENABLE)
  	    && (ioread32(INTCSR_reg) & INTCSR_ADINT_STATUS)) {
  		mf624_disable_interrupt(ADC, info);
  		return IRQ_HANDLED;
  	}
  
  	if ((ioread32(INTCSR_reg) & INTCSR_CTR4INT_ENABLE)
  	    && (ioread32(INTCSR_reg) & INTCSR_CTR4INT_STATUS)) {
  		mf624_disable_interrupt(CTR4, info);
  		return IRQ_HANDLED;
  	}
  
  	return IRQ_NONE;
  }
  
  static int mf624_irqcontrol(struct uio_info *info, s32 irq_on)
  {
  	if (irq_on == 0)
  		mf624_disable_interrupt(ALL, info);
  	else if (irq_on == 1)
  		mf624_enable_interrupt(ALL, info);
  
  	return 0;
  }
  
  static int mf624_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
  {
  	struct uio_info *info;
  
  	info = kzalloc(sizeof(struct uio_info), GFP_KERNEL);
  	if (!info)
  		return -ENOMEM;
  
  	if (pci_enable_device(dev))
  		goto out_free;
  
  	if (pci_request_regions(dev, "mf624"))
  		goto out_disable;
  
  	info->name = "mf624";
  	info->version = "0.0.1";
  
  	/* Note: Datasheet says device uses BAR0, BAR1, BAR2 -- do not trust it */
  
  	/* BAR0 */
  	info->mem[0].name = "PCI chipset, interrupts, status "
  			"bits, special functions";
  	info->mem[0].addr = pci_resource_start(dev, 0);
  	if (!info->mem[0].addr)
  		goto out_release;
  	info->mem[0].size = pci_resource_len(dev, 0);
  	info->mem[0].memtype = UIO_MEM_PHYS;
  	info->mem[0].internal_addr = pci_ioremap_bar(dev, 0);
  	if (!info->mem[0].internal_addr)
  		goto out_release;
  
  	/* BAR2 */
  	info->mem[1].name = "ADC, DAC, DIO";
  	info->mem[1].addr = pci_resource_start(dev, 2);
  	if (!info->mem[1].addr)
  		goto out_unmap0;
  	info->mem[1].size = pci_resource_len(dev, 2);
  	info->mem[1].memtype = UIO_MEM_PHYS;
  	info->mem[1].internal_addr = pci_ioremap_bar(dev, 2);
  	if (!info->mem[1].internal_addr)
  		goto out_unmap0;
  
  	/* BAR4 */
  	info->mem[2].name = "Counter/timer chip";
  	info->mem[2].addr = pci_resource_start(dev, 4);
  	if (!info->mem[2].addr)
  		goto out_unmap1;
  	info->mem[2].size = pci_resource_len(dev, 4);
  	info->mem[2].memtype = UIO_MEM_PHYS;
  	info->mem[2].internal_addr = pci_ioremap_bar(dev, 4);
  	if (!info->mem[2].internal_addr)
  		goto out_unmap1;
  
  	info->irq = dev->irq;
  	info->irq_flags = IRQF_SHARED;
  	info->handler = mf624_irq_handler;
  
  	info->irqcontrol = mf624_irqcontrol;
  
  	if (uio_register_device(&dev->dev, info))
  		goto out_unmap2;
  
  	pci_set_drvdata(dev, info);
  
  	return 0;
  
  out_unmap2:
  	iounmap(info->mem[2].internal_addr);
  out_unmap1:
  	iounmap(info->mem[1].internal_addr);
  out_unmap0:
  	iounmap(info->mem[0].internal_addr);
  
  out_release:
  	pci_release_regions(dev);
  
  out_disable:
  	pci_disable_device(dev);
  
  out_free:
  	kfree(info);
  	return -ENODEV;
  }
  
  static void mf624_pci_remove(struct pci_dev *dev)
  {
  	struct uio_info *info = pci_get_drvdata(dev);
  
  	mf624_disable_interrupt(ALL, info);
  
  	uio_unregister_device(info);
  	pci_release_regions(dev);
  	pci_disable_device(dev);
  
  	iounmap(info->mem[0].internal_addr);
  	iounmap(info->mem[1].internal_addr);
  	iounmap(info->mem[2].internal_addr);
  
  	kfree(info);
  }
  
  static const struct pci_device_id mf624_pci_id[] = {
  	{ PCI_DEVICE(PCI_VENDOR_ID_HUMUSOFT, PCI_DEVICE_ID_MF624) },
  	{ 0, }
  };
  
  static struct pci_driver mf624_pci_driver = {
  	.name = "mf624",
  	.id_table = mf624_pci_id,
  	.probe = mf624_pci_probe,
  	.remove = mf624_pci_remove,
  };
  MODULE_DEVICE_TABLE(pci, mf624_pci_id);
  
  module_pci_driver(mf624_pci_driver);
  MODULE_LICENSE("GPL v2");
  MODULE_AUTHOR("Rostislav Lisovy <lisovy@gmail.com>");