/*
   * Copyright (C) 2012 CERN (www.cern.ch)
   * Author: Alessandro Rubini <rubini@gnudd.com>
   *
   * Permission to use, copy, modify, and/or distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * The software is provided "as is"; the copyright holders disclaim
   * all warranties and liabilities, to the extent permitted by
   * applicable law.
   */
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/string.h>
  #include <linux/device.h>
  #include <linux/slab.h>
  #include <linux/firmware.h>
  #include <linux/workqueue.h>
  #include <linux/err.h>
  #include <linux/fmc.h>
  
  #define FF_EEPROM_SIZE		8192	/* The standard eeprom size */
  #define FF_MAX_MEZZANINES	4	/* Fakes a multi-mezzanine carrier */
  
  /* The user can pass up to 4 names of eeprom images to load */
  static char *ff_eeprom[FF_MAX_MEZZANINES];
  static int ff_nr_eeprom;
  module_param_array_named(eeprom, ff_eeprom, charp, &ff_nr_eeprom, 0444);
  
  /* The user can ask for a multi-mezzanine carrier, with the default eeprom */
  static int ff_nr_dev = 1;
  module_param_named(ndev, ff_nr_dev, int, 0444);
  
  
  /* Lazily, don't support the "standard" module parameters */
  
  /*
   * Eeprom built from these commands:
  
  	../fru-generator -v fake-vendor -n fake-design-for-testing \
  		-s 01234 -p none > IPMI-FRU
  
  	gensdbfs . ../fake-eeprom.bin
  */
  static char ff_eeimg[FF_MAX_MEZZANINES][FF_EEPROM_SIZE] = {
  	{
  	0x01, 0x00, 0x00, 0x01, 0x00, 0x0c, 0x00, 0xf2, 0x01, 0x0b, 0x00, 0xb2,
  	0x86, 0x87, 0xcb, 0x66, 0x61, 0x6b, 0x65, 0x2d, 0x76, 0x65, 0x6e, 0x64,
  	0x6f, 0x72, 0xd7, 0x66, 0x61, 0x6b, 0x65, 0x2d, 0x64, 0x65, 0x73, 0x69,
  	0x67, 0x6e, 0x2d, 0x66, 0x6f, 0x72, 0x2d, 0x74, 0x65, 0x73, 0x74, 0x69,
  	0x6e, 0x67, 0xc5, 0x30, 0x31, 0x32, 0x33, 0x34, 0xc4, 0x6e, 0x6f, 0x6e,
  	0x65, 0xda, 0x32, 0x30, 0x31, 0x32, 0x2d, 0x31, 0x31, 0x2d, 0x31, 0x39,
  	0x20, 0x32, 0x32, 0x3a, 0x34, 0x32, 0x3a, 0x33, 0x30, 0x2e, 0x30, 0x37,
  	0x34, 0x30, 0x35, 0x35, 0xc1, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x87,
  	0x02, 0x02, 0x0d, 0xf7, 0xf8, 0x02, 0xb0, 0x04, 0x74, 0x04, 0xec, 0x04,
  	0x00, 0x00, 0x00, 0x00, 0xe8, 0x03, 0x02, 0x02, 0x0d, 0x5c, 0x93, 0x01,
  	0x4a, 0x01, 0x39, 0x01, 0x5a, 0x01, 0x00, 0x00, 0x00, 0x00, 0xb8, 0x0b,
  	0x02, 0x02, 0x0d, 0x63, 0x8c, 0x00, 0xfa, 0x00, 0xed, 0x00, 0x06, 0x01,
  	0x00, 0x00, 0x00, 0x00, 0xa0, 0x0f, 0x01, 0x02, 0x0d, 0xfb, 0xf5, 0x05,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  	0x01, 0x02, 0x0d, 0xfc, 0xf4, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x0d, 0xfd, 0xf3, 0x03,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  	0xfa, 0x82, 0x0b, 0xea, 0x8f, 0xa2, 0x12, 0x00, 0x00, 0x1e, 0x44, 0x00,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  	0x00, 0x00, 0x00, 0x00, 0x53, 0x44, 0x42, 0x2d, 0x00, 0x03, 0x01, 0x01,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
  	0x00, 0x00, 0x01, 0xc4, 0x46, 0x69, 0x6c, 0x65, 0x44, 0x61, 0x74, 0x61,
  	0x2e, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
  	0x2e, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
  	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00,
  	0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xc0,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xc4, 0x46, 0x69, 0x6c, 0x65,
  	0x44, 0x61, 0x74, 0x61, 0x6e, 0x61, 0x6d, 0x65, 0x00, 0x00, 0x00, 0x01,
  	0x00, 0x00, 0x00, 0x00, 0x6e, 0x61, 0x6d, 0x65, 0x20, 0x20, 0x20, 0x20,
  	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x01,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00,
  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xdf,
  	0x46, 0x69, 0x6c, 0x65, 0x44, 0x61, 0x74, 0x61, 0x49, 0x50, 0x4d, 0x49,
  	0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x49, 0x50, 0x4d, 0x49,
  	0x2d, 0x46, 0x52, 0x55, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
  	0x20, 0x20, 0x20, 0x01, 0x66, 0x61, 0x6b, 0x65, 0x0a,
  	},
  };
  
  struct ff_dev {
  	struct fmc_device *fmc[FF_MAX_MEZZANINES];
  	struct device dev;
  };
  
  static struct ff_dev *ff_current_dev; /* We have 1 carrier, 1 slot */
  
  static int ff_reprogram(struct fmc_device *fmc, struct fmc_driver *drv,
  			  char *gw)
  {
  	const struct firmware *fw;
  	int ret;
  
  	if (!gw) {
  		/* program golden: success */
  		fmc->flags &= ~FMC_DEVICE_HAS_CUSTOM;
  		fmc->flags |= FMC_DEVICE_HAS_GOLDEN;
  		return 0;
  	}
  
  	dev_info(&fmc->dev, "reprogramming with %s
  ", gw);
  	ret = request_firmware(&fw, gw, &fmc->dev);
  	if (ret < 0) {
  		dev_warn(&fmc->dev, "request firmware \"%s\": error %i
  ",
  			 gw, ret);
  		goto out;
  	}
  	fmc->flags &= ~FMC_DEVICE_HAS_GOLDEN;
  	fmc->flags |= FMC_DEVICE_HAS_CUSTOM;
  
  out:
  	release_firmware(fw);
  	return ret;
  }
  
  static int ff_irq_request(struct fmc_device *fmc, irq_handler_t handler,
  			    char *name, int flags)
  {
  	return -EOPNOTSUPP;
  }
  
  /* FIXME: should also have some fake FMC GPIO mapping */
  
  
  /*
   * This work function is called when we changed the eeprom. It removes the
   * current fmc device and registers a new one, with different identifiers.
   */
  static struct ff_dev *ff_dev_create(void); /* defined later */
  
  static void ff_work_fn(struct work_struct *work)
  {
  	struct ff_dev *ff = ff_current_dev;
  	int ret;
  
  	fmc_device_unregister_n(ff->fmc, ff_nr_dev);
  	device_unregister(&ff->dev);
  	ff_current_dev = NULL;
  
  	ff = ff_dev_create();
  	if (IS_ERR(ff)) {
  		pr_warning("%s: can't re-create FMC devices
  ", __func__);
  		return;
  	}
  	ret = fmc_device_register_n(ff->fmc, ff_nr_dev);
  	if (ret < 0) {
  		dev_warn(&ff->dev, "can't re-register FMC devices
  ");
  		device_unregister(&ff->dev);
  		return;
  	}
  
  	ff_current_dev = ff;
  }
  
  static DECLARE_DELAYED_WORK(ff_work, ff_work_fn);
  
  
  /* low-level i2c */
  static int ff_eeprom_read(struct fmc_device *fmc, uint32_t offset,
  		void *buf, size_t size)
  {
  	if (offset > FF_EEPROM_SIZE)
  		return -EINVAL;
  	if (offset + size > FF_EEPROM_SIZE)
  		size = FF_EEPROM_SIZE - offset;
  	memcpy(buf, fmc->eeprom + offset, size);
  	return size;
  }
  
  static int ff_eeprom_write(struct fmc_device *fmc, uint32_t offset,
  		    const void *buf, size_t size)
  {
  	if (offset > FF_EEPROM_SIZE)
  		return -EINVAL;
  	if (offset + size > FF_EEPROM_SIZE)
  		size = FF_EEPROM_SIZE - offset;
  	dev_info(&fmc->dev, "write_eeprom: offset %i, size %zi
  ",
  		 (int)offset, size);
  	memcpy(fmc->eeprom + offset, buf, size);
  	schedule_delayed_work(&ff_work, HZ * 2); /* remove, replug, in 2s */
  	return size;
  }
  
  /* i2c operations for fmc */
  static int ff_read_ee(struct fmc_device *fmc, int pos, void *data, int len)
  {
  	if (!(fmc->flags & FMC_DEVICE_HAS_GOLDEN))
  		return -EOPNOTSUPP;
  	return ff_eeprom_read(fmc, pos, data, len);
  }
  
  static int ff_write_ee(struct fmc_device *fmc, int pos,
  			 const void *data, int len)
  {
  	if (!(fmc->flags & FMC_DEVICE_HAS_GOLDEN))
  		return -EOPNOTSUPP;
  	return ff_eeprom_write(fmc, pos, data, len);
  }
  
  /* readl and writel do not do anything. Don't waste RAM with "base" */
  static uint32_t ff_readl(struct fmc_device *fmc, int offset)
  {
  	return 0;
  }
  
  static void ff_writel(struct fmc_device *fmc, uint32_t value, int offset)
  {
  	return;
  }
  
  /* validate is useful so fmc-write-eeprom will not reprogram every 2 seconds */
  static int ff_validate(struct fmc_device *fmc, struct fmc_driver *drv)
  {
  	int i;
  
  	if (!drv->busid_n)
  		return 0; /* everyhing is valid */
  	for (i = 0; i < drv->busid_n; i++)
  		if (drv->busid_val[i] == fmc->device_id)
  			return i;
  	return -ENOENT;
  }
  
  
  
  static struct fmc_operations ff_fmc_operations = {
  	.read32 =		ff_readl,
  	.write32 =		ff_writel,
  	.reprogram =		ff_reprogram,
  	.irq_request =		ff_irq_request,
  	.read_ee =		ff_read_ee,
  	.write_ee =		ff_write_ee,
  	.validate =		ff_validate,
  };
  
  /* This device is kmalloced: release it */
  static void ff_dev_release(struct device *dev)
  {
  	struct ff_dev *ff = container_of(dev, struct ff_dev, dev);
  	kfree(ff);
  }
  
  static struct fmc_device ff_template_fmc = {
  	.version = FMC_VERSION,
  	.owner = THIS_MODULE,
  	.carrier_name = "fake-fmc-carrier",
  	.device_id = 0xf001, /* fool */
  	.eeprom_len = sizeof(ff_eeimg[0]),
  	.memlen = 0x1000, /* 4k, to show something */
  	.op = &ff_fmc_operations,
  	.hwdev = NULL, /* filled at creation time */
  	.flags = FMC_DEVICE_HAS_GOLDEN,
  };
  
  static struct ff_dev *ff_dev_create(void)
  {
  	struct ff_dev *ff;
  	struct fmc_device *fmc;
  	int i, ret;
  
  	ff = kzalloc(sizeof(*ff), GFP_KERNEL);
  	if (!ff)
  		return ERR_PTR(-ENOMEM);
  	dev_set_name(&ff->dev, "fake-fmc-carrier");
  	ff->dev.release = ff_dev_release;
  
  	ret = device_register(&ff->dev);
  	if (ret < 0) {
  		put_device(&ff->dev);
  		return ERR_PTR(ret);
  	}
  
  	/* Create fmc structures that refer to this new "hw" device */
  	for (i = 0; i < ff_nr_dev; i++) {
  		fmc = kmemdup(&ff_template_fmc, sizeof(ff_template_fmc),
  			      GFP_KERNEL);
  		fmc->hwdev = &ff->dev;
  		fmc->carrier_data = ff;
  		fmc->nr_slots = ff_nr_dev;
  		/* the following fields are different for each slot */
  		fmc->eeprom = ff_eeimg[i];
  		fmc->eeprom_addr = 0x50 + 2 * i;
  		fmc->slot_id = i;
  		ff->fmc[i] = fmc;
  		/* increment the identifier, each must be different */
  		ff_template_fmc.device_id++;
  	}
  	return ff;
  }
  
  /* init and exit */
  static int ff_init(void)
  {
  	struct ff_dev *ff;
  	const struct firmware *fw;
  	int i, len, ret = 0;
  
  	/* Replicate the default eeprom for the max number of mezzanines */
  	for (i = 1; i < FF_MAX_MEZZANINES; i++)
  		memcpy(ff_eeimg[i], ff_eeimg[0], sizeof(ff_eeimg[0]));
  
  	if (ff_nr_eeprom > ff_nr_dev)
  		ff_nr_dev = ff_nr_eeprom;
  
  	ff = ff_dev_create();
  	if (IS_ERR(ff))
  		return PTR_ERR(ff);
  
  	/* If the user passed "eeprom=" as a parameter, fetch them */
  	for (i = 0; i < ff_nr_eeprom; i++) {
  		if (!strlen(ff_eeprom[i]))
  			continue;
  		ret = request_firmware(&fw, ff_eeprom[i], &ff->dev);
  		if (ret < 0) {
  			dev_err(&ff->dev, "Mezzanine %i: can't load \"%s\" "
  				"(error %i)
  ", i, ff_eeprom[i], -ret);
  		} else {
  			len = min_t(size_t, fw->size, (size_t)FF_EEPROM_SIZE);
  			memcpy(ff_eeimg[i], fw->data, len);
  			release_firmware(fw);
  			dev_info(&ff->dev, "Mezzanine %i: eeprom \"%s\"
  ", i,
  				ff_eeprom[i]);
  		}
  	}
  
  	ret = fmc_device_register_n(ff->fmc, ff_nr_dev);
  	if (ret) {
  		device_unregister(&ff->dev);
  		return ret;
  	}
  	ff_current_dev = ff;
  	return ret;
  }
  
  static void ff_exit(void)
  {
  	if (ff_current_dev) {
  		fmc_device_unregister_n(ff_current_dev->fmc, ff_nr_dev);
  		device_unregister(&ff_current_dev->dev);
  	}
  	cancel_delayed_work_sync(&ff_work);
  }
  
  module_init(ff_init);
  module_exit(ff_exit);
  
  MODULE_LICENSE("Dual BSD/GPL");