/*
   * APEI Hardware Error Souce Table support
   *
   * HEST describes error sources in detail; communicates operational
   * parameters (i.e. severity levels, masking bits, and threshold
   * values) to Linux as necessary. It also allows the BIOS to report
   * non-standard error sources to Linux (for example, chipset-specific
   * error registers).
   *
   * For more information about HEST, please refer to ACPI Specification
   * version 4.0, section 17.3.2.
   *
   * Copyright 2009 Intel Corp.
   *   Author: Huang Ying <ying.huang@intel.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License version
   * 2 as published by the Free Software Foundation;
   *
   * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/acpi.h>
  #include <linux/kdebug.h>
  #include <linux/highmem.h>
  #include <linux/io.h>
  #include <linux/platform_device.h>
  #include <acpi/apei.h>
  #include <asm/mce.h>
  
  #include "apei-internal.h"
  
  #define HEST_PFX "HEST: "
  
  bool hest_disable;
  EXPORT_SYMBOL_GPL(hest_disable);
  
  /* HEST table parsing */
  
  static struct acpi_table_hest *__read_mostly hest_tab;
  
  static const int hest_esrc_len_tab[ACPI_HEST_TYPE_RESERVED] = {
  	[ACPI_HEST_TYPE_IA32_CHECK] = -1,	/* need further calculation */
  	[ACPI_HEST_TYPE_IA32_CORRECTED_CHECK] = -1,
  	[ACPI_HEST_TYPE_IA32_NMI] = sizeof(struct acpi_hest_ia_nmi),
  	[ACPI_HEST_TYPE_AER_ROOT_PORT] = sizeof(struct acpi_hest_aer_root),
  	[ACPI_HEST_TYPE_AER_ENDPOINT] = sizeof(struct acpi_hest_aer),
  	[ACPI_HEST_TYPE_AER_BRIDGE] = sizeof(struct acpi_hest_aer_bridge),
  	[ACPI_HEST_TYPE_GENERIC_ERROR] = sizeof(struct acpi_hest_generic),
  };
  
  static int hest_esrc_len(struct acpi_hest_header *hest_hdr)
  {
  	u16 hest_type = hest_hdr->type;
  	int len;
  
  	if (hest_type >= ACPI_HEST_TYPE_RESERVED)
  		return 0;
  
  	len = hest_esrc_len_tab[hest_type];
  
  	if (hest_type == ACPI_HEST_TYPE_IA32_CORRECTED_CHECK) {
  		struct acpi_hest_ia_corrected *cmc;
  		cmc = (struct acpi_hest_ia_corrected *)hest_hdr;
  		len = sizeof(*cmc) + cmc->num_hardware_banks *
  			sizeof(struct acpi_hest_ia_error_bank);
  	} else if (hest_type == ACPI_HEST_TYPE_IA32_CHECK) {
  		struct acpi_hest_ia_machine_check *mc;
  		mc = (struct acpi_hest_ia_machine_check *)hest_hdr;
  		len = sizeof(*mc) + mc->num_hardware_banks *
  			sizeof(struct acpi_hest_ia_error_bank);
  	}
  	BUG_ON(len == -1);
  
  	return len;
  };
  
  int apei_hest_parse(apei_hest_func_t func, void *data)
  {
  	struct acpi_hest_header *hest_hdr;
  	int i, rc, len;
  
  	if (hest_disable || !hest_tab)
  		return -EINVAL;
  
  	hest_hdr = (struct acpi_hest_header *)(hest_tab + 1);
  	for (i = 0; i < hest_tab->error_source_count; i++) {
  		len = hest_esrc_len(hest_hdr);
  		if (!len) {
  			pr_warning(FW_WARN HEST_PFX
  				   "Unknown or unused hardware error source "
  				   "type: %d for hardware error source: %d.
  ",
  				   hest_hdr->type, hest_hdr->source_id);
  			return -EINVAL;
  		}
  		if ((void *)hest_hdr + len >
  		    (void *)hest_tab + hest_tab->header.length) {
  			pr_warning(FW_BUG HEST_PFX
  		"Table contents overflow for hardware error source: %d.
  ",
  				hest_hdr->source_id);
  			return -EINVAL;
  		}
  
  		rc = func(hest_hdr, data);
  		if (rc)
  			return rc;
  
  		hest_hdr = (void *)hest_hdr + len;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(apei_hest_parse);
  
  /*
   * Check if firmware advertises firmware first mode. We need FF bit to be set
   * along with a set of MC banks which work in FF mode.
   */
  static int __init hest_parse_cmc(struct acpi_hest_header *hest_hdr, void *data)
  {
  #ifdef CONFIG_X86_MCE
  	int i;
  	struct acpi_hest_ia_corrected *cmc;
  	struct acpi_hest_ia_error_bank *mc_bank;
  
  	if (hest_hdr->type != ACPI_HEST_TYPE_IA32_CORRECTED_CHECK)
  		return 0;
  
  	cmc = (struct acpi_hest_ia_corrected *)hest_hdr;
  	if (!cmc->enabled)
  		return 0;
  
  	/*
  	 * We expect HEST to provide a list of MC banks that report errors
  	 * in firmware first mode. Otherwise, return non-zero value to
  	 * indicate that we are done parsing HEST.
  	 */
  	if (!(cmc->flags & ACPI_HEST_FIRMWARE_FIRST) || !cmc->num_hardware_banks)
  		return 1;
  
  	pr_info(HEST_PFX "Enabling Firmware First mode for corrected errors.
  ");
  
  	mc_bank = (struct acpi_hest_ia_error_bank *)(cmc + 1);
  	for (i = 0; i < cmc->num_hardware_banks; i++, mc_bank++)
  		mce_disable_bank(mc_bank->bank_number);
  #endif
  	return 1;
  }
  
  struct ghes_arr {
  	struct platform_device **ghes_devs;
  	unsigned int count;
  };
  
  static int __init hest_parse_ghes_count(struct acpi_hest_header *hest_hdr, void *data)
  {
  	int *count = data;
  
  	if (hest_hdr->type == ACPI_HEST_TYPE_GENERIC_ERROR)
  		(*count)++;
  	return 0;
  }
  
  static int __init hest_parse_ghes(struct acpi_hest_header *hest_hdr, void *data)
  {
  	struct platform_device *ghes_dev;
  	struct ghes_arr *ghes_arr = data;
  	int rc, i;
  
  	if (hest_hdr->type != ACPI_HEST_TYPE_GENERIC_ERROR)
  		return 0;
  
  	if (!((struct acpi_hest_generic *)hest_hdr)->enabled)
  		return 0;
  	for (i = 0; i < ghes_arr->count; i++) {
  		struct acpi_hest_header *hdr;
  		ghes_dev = ghes_arr->ghes_devs[i];
  		hdr = *(struct acpi_hest_header **)ghes_dev->dev.platform_data;
  		if (hdr->source_id == hest_hdr->source_id) {
  			pr_warning(FW_WARN HEST_PFX "Duplicated hardware error source ID: %d.
  ",
  				   hdr->source_id);
  			return -EIO;
  		}
  	}
  	ghes_dev = platform_device_alloc("GHES", hest_hdr->source_id);
  	if (!ghes_dev)
  		return -ENOMEM;
  
  	rc = platform_device_add_data(ghes_dev, &hest_hdr, sizeof(void *));
  	if (rc)
  		goto err;
  
  	rc = platform_device_add(ghes_dev);
  	if (rc)
  		goto err;
  	ghes_arr->ghes_devs[ghes_arr->count++] = ghes_dev;
  
  	return 0;
  err:
  	platform_device_put(ghes_dev);
  	return rc;
  }
  
  static int __init hest_ghes_dev_register(unsigned int ghes_count)
  {
  	int rc, i;
  	struct ghes_arr ghes_arr;
  
  	ghes_arr.count = 0;
  	ghes_arr.ghes_devs = kmalloc(sizeof(void *) * ghes_count, GFP_KERNEL);
  	if (!ghes_arr.ghes_devs)
  		return -ENOMEM;
  
  	rc = apei_hest_parse(hest_parse_ghes, &ghes_arr);
  	if (rc)
  		goto err;
  out:
  	kfree(ghes_arr.ghes_devs);
  	return rc;
  err:
  	for (i = 0; i < ghes_arr.count; i++)
  		platform_device_unregister(ghes_arr.ghes_devs[i]);
  	goto out;
  }
  
  static int __init setup_hest_disable(char *str)
  {
  	hest_disable = 1;
  	return 0;
  }
  
  __setup("hest_disable", setup_hest_disable);
  
  void __init acpi_hest_init(void)
  {
  	acpi_status status;
  	int rc = -ENODEV;
  	unsigned int ghes_count = 0;
  
  	if (hest_disable) {
  		pr_info(HEST_PFX "Table parsing disabled.
  ");
  		return;
  	}
  
  	status = acpi_get_table(ACPI_SIG_HEST, 0,
  				(struct acpi_table_header **)&hest_tab);
  	if (status == AE_NOT_FOUND)
  		goto err;
  	else if (ACPI_FAILURE(status)) {
  		const char *msg = acpi_format_exception(status);
  		pr_err(HEST_PFX "Failed to get table, %s
  ", msg);
  		rc = -EINVAL;
  		goto err;
  	}
  
  	if (!acpi_disable_cmcff)
  		apei_hest_parse(hest_parse_cmc, NULL);
  
  	if (!ghes_disable) {
  		rc = apei_hest_parse(hest_parse_ghes_count, &ghes_count);
  		if (rc)
  			goto err;
  		rc = hest_ghes_dev_register(ghes_count);
  		if (rc)
  			goto err;
  	}
  
  	pr_info(HEST_PFX "Table parsing has been initialized.
  ");
  	return;
  err:
  	hest_disable = 1;
  }