/*
   * Copyright (C) 2012-2014 Intel Corporation
   *
   * Authors:
   * Xiaoyan Zhang <xiaoyan.zhang@intel.com>
   * Jiang Liu <jiang.liu@linux.intel.com>
   * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
   *
   * Maintained by: <tpmdd-devel@lists.sourceforge.net>
   *
   * This file contains implementation of the sysfs interface for PPI.
   *
   * 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; version 2
   * of the License.
   */
  
  
  #include <linux/acpi.h>
  #include "tpm.h"
  
  #define TPM_PPI_REVISION_ID	1
  #define TPM_PPI_FN_VERSION	1
  #define TPM_PPI_FN_SUBREQ	2
  #define TPM_PPI_FN_GETREQ	3
  #define TPM_PPI_FN_GETACT	4
  #define TPM_PPI_FN_GETRSP	5
  #define TPM_PPI_FN_SUBREQ2	7
  #define TPM_PPI_FN_GETOPR	8
  #define PPI_TPM_REQ_MAX		22
  #define PPI_VS_REQ_START	128
  #define PPI_VS_REQ_END		255
  
  static const u8 tpm_ppi_uuid[] = {
  	0xA6, 0xFA, 0xDD, 0x3D,
  	0x1B, 0x36,
  	0xB4, 0x4E,
  	0xA4, 0x24,
  	0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53
  };
  
  static inline union acpi_object *
  tpm_eval_dsm(acpi_handle ppi_handle, int func, acpi_object_type type,
  	     union acpi_object *argv4)
  {
  	BUG_ON(!ppi_handle);
  	return acpi_evaluate_dsm_typed(ppi_handle, tpm_ppi_uuid,
  				       TPM_PPI_REVISION_ID,
  				       func, argv4, type);
  }
  
  static ssize_t tpm_show_ppi_version(struct device *dev,
  				    struct device_attribute *attr, char *buf)
  {
  	struct tpm_chip *chip = to_tpm_chip(dev);
  
  	return scnprintf(buf, PAGE_SIZE, "%s
  ", chip->ppi_version);
  }
  
  static ssize_t tpm_show_ppi_request(struct device *dev,
  				    struct device_attribute *attr, char *buf)
  {
  	ssize_t size = -EINVAL;
  	union acpi_object *obj;
  	struct tpm_chip *chip = to_tpm_chip(dev);
  
  	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETREQ,
  			   ACPI_TYPE_PACKAGE, NULL);
  	if (!obj)
  		return -ENXIO;
  
  	/*
  	 * output.pointer should be of package type, including two integers.
  	 * The first is function return code, 0 means success and 1 means
  	 * error. The second is pending TPM operation requested by the OS, 0
  	 * means none and >0 means operation value.
  	 */
  	if (obj->package.count == 2 &&
  	    obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
  	    obj->package.elements[1].type == ACPI_TYPE_INTEGER) {
  		if (obj->package.elements[0].integer.value)
  			size = -EFAULT;
  		else
  			size = scnprintf(buf, PAGE_SIZE, "%llu
  ",
  				 obj->package.elements[1].integer.value);
  	}
  
  	ACPI_FREE(obj);
  
  	return size;
  }
  
  static ssize_t tpm_store_ppi_request(struct device *dev,
  				     struct device_attribute *attr,
  				     const char *buf, size_t count)
  {
  	u32 req;
  	u64 ret;
  	int func = TPM_PPI_FN_SUBREQ;
  	union acpi_object *obj, tmp;
  	union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(1, &tmp);
  	struct tpm_chip *chip = to_tpm_chip(dev);
  
  	/*
  	 * the function to submit TPM operation request to pre-os environment
  	 * is updated with function index from SUBREQ to SUBREQ2 since PPI
  	 * version 1.1
  	 */
  	if (acpi_check_dsm(chip->acpi_dev_handle, tpm_ppi_uuid,
  			   TPM_PPI_REVISION_ID, 1 << TPM_PPI_FN_SUBREQ2))
  		func = TPM_PPI_FN_SUBREQ2;
  
  	/*
  	 * PPI spec defines params[3].type as ACPI_TYPE_PACKAGE. Some BIOS
  	 * accept buffer/string/integer type, but some BIOS accept buffer/
  	 * string/package type. For PPI version 1.0 and 1.1, use buffer type
  	 * for compatibility, and use package type since 1.2 according to spec.
  	 */
  	if (strcmp(chip->ppi_version, "1.2") < 0) {
  		if (sscanf(buf, "%d", &req) != 1)
  			return -EINVAL;
  		argv4.type = ACPI_TYPE_BUFFER;
  		argv4.buffer.length = sizeof(req);
  		argv4.buffer.pointer = (u8 *)&req;
  	} else {
  		tmp.type = ACPI_TYPE_INTEGER;
  		if (sscanf(buf, "%llu", &tmp.integer.value) != 1)
  			return -EINVAL;
  	}
  
  	obj = tpm_eval_dsm(chip->acpi_dev_handle, func, ACPI_TYPE_INTEGER,
  			   &argv4);
  	if (!obj) {
  		return -ENXIO;
  	} else {
  		ret = obj->integer.value;
  		ACPI_FREE(obj);
  	}
  
  	if (ret == 0)
  		return (acpi_status)count;
  
  	return (ret == 1) ? -EPERM : -EFAULT;
  }
  
  static ssize_t tpm_show_ppi_transition_action(struct device *dev,
  					      struct device_attribute *attr,
  					      char *buf)
  {
  	u32 ret;
  	acpi_status status;
  	union acpi_object *obj = NULL;
  	union acpi_object tmp = {
  		.buffer.type = ACPI_TYPE_BUFFER,
  		.buffer.length = 0,
  		.buffer.pointer = NULL
  	};
  	struct tpm_chip *chip = to_tpm_chip(dev);
  
  	static char *info[] = {
  		"None",
  		"Shutdown",
  		"Reboot",
  		"OS Vendor-specific",
  		"Error",
  	};
  
  	/*
  	 * PPI spec defines params[3].type as empty package, but some platforms
  	 * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
  	 * compatibility, define params[3].type as buffer, if PPI version < 1.2
  	 */
  	if (strcmp(chip->ppi_version, "1.2") < 0)
  		obj = &tmp;
  	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETACT,
  			   ACPI_TYPE_INTEGER, obj);
  	if (!obj) {
  		return -ENXIO;
  	} else {
  		ret = obj->integer.value;
  		ACPI_FREE(obj);
  	}
  
  	if (ret < ARRAY_SIZE(info) - 1)
  		status = scnprintf(buf, PAGE_SIZE, "%d: %s
  ", ret, info[ret]);
  	else
  		status = scnprintf(buf, PAGE_SIZE, "%d: %s
  ", ret,
  				   info[ARRAY_SIZE(info)-1]);
  	return status;
  }
  
  static ssize_t tpm_show_ppi_response(struct device *dev,
  				     struct device_attribute *attr,
  				     char *buf)
  {
  	acpi_status status = -EINVAL;
  	union acpi_object *obj, *ret_obj;
  	u64 req, res;
  	struct tpm_chip *chip = to_tpm_chip(dev);
  
  	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETRSP,
  			   ACPI_TYPE_PACKAGE, NULL);
  	if (!obj)
  		return -ENXIO;
  
  	/*
  	 * parameter output.pointer should be of package type, including
  	 * 3 integers. The first means function return code, the second means
  	 * most recent TPM operation request, and the last means response to
  	 * the most recent TPM operation request. Only if the first is 0, and
  	 * the second integer is not 0, the response makes sense.
  	 */
  	ret_obj = obj->package.elements;
  	if (obj->package.count < 3 ||
  	    ret_obj[0].type != ACPI_TYPE_INTEGER ||
  	    ret_obj[1].type != ACPI_TYPE_INTEGER ||
  	    ret_obj[2].type != ACPI_TYPE_INTEGER)
  		goto cleanup;
  
  	if (ret_obj[0].integer.value) {
  		status = -EFAULT;
  		goto cleanup;
  	}
  
  	req = ret_obj[1].integer.value;
  	res = ret_obj[2].integer.value;
  	if (req) {
  		if (res == 0)
  			status = scnprintf(buf, PAGE_SIZE, "%llu %s
  ", req,
  					   "0: Success");
  		else if (res == 0xFFFFFFF0)
  			status = scnprintf(buf, PAGE_SIZE, "%llu %s
  ", req,
  					   "0xFFFFFFF0: User Abort");
  		else if (res == 0xFFFFFFF1)
  			status = scnprintf(buf, PAGE_SIZE, "%llu %s
  ", req,
  					   "0xFFFFFFF1: BIOS Failure");
  		else if (res >= 1 && res <= 0x00000FFF)
  			status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s
  ",
  					   req, res, "Corresponding TPM error");
  		else
  			status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s
  ",
  					   req, res, "Error");
  	} else {
  		status = scnprintf(buf, PAGE_SIZE, "%llu: %s
  ",
  				   req, "No Recent Request");
  	}
  
  cleanup:
  	ACPI_FREE(obj);
  	return status;
  }
  
  static ssize_t show_ppi_operations(acpi_handle dev_handle, char *buf, u32 start,
  				   u32 end)
  {
  	int i;
  	u32 ret;
  	char *str = buf;
  	union acpi_object *obj, tmp;
  	union acpi_object argv = ACPI_INIT_DSM_ARGV4(1, &tmp);
  
  	static char *info[] = {
  		"Not implemented",
  		"BIOS only",
  		"Blocked for OS by BIOS",
  		"User required",
  		"User not required",
  	};
  
  	if (!acpi_check_dsm(dev_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
  			    1 << TPM_PPI_FN_GETOPR))
  		return -EPERM;
  
  	tmp.integer.type = ACPI_TYPE_INTEGER;
  	for (i = start; i <= end; i++) {
  		tmp.integer.value = i;
  		obj = tpm_eval_dsm(dev_handle, TPM_PPI_FN_GETOPR,
  				   ACPI_TYPE_INTEGER, &argv);
  		if (!obj) {
  			return -ENOMEM;
  		} else {
  			ret = obj->integer.value;
  			ACPI_FREE(obj);
  		}
  
  		if (ret > 0 && ret < ARRAY_SIZE(info))
  			str += scnprintf(str, PAGE_SIZE, "%d %d: %s
  ",
  					 i, ret, info[ret]);
  	}
  
  	return str - buf;
  }
  
  static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
  					   struct device_attribute *attr,
  					   char *buf)
  {
  	struct tpm_chip *chip = to_tpm_chip(dev);
  
  	return show_ppi_operations(chip->acpi_dev_handle, buf, 0,
  				   PPI_TPM_REQ_MAX);
  }
  
  static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
  					  struct device_attribute *attr,
  					  char *buf)
  {
  	struct tpm_chip *chip = to_tpm_chip(dev);
  
  	return show_ppi_operations(chip->acpi_dev_handle, buf, PPI_VS_REQ_START,
  				   PPI_VS_REQ_END);
  }
  
  static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
  static DEVICE_ATTR(request, S_IRUGO | S_IWUSR | S_IWGRP,
  		   tpm_show_ppi_request, tpm_store_ppi_request);
  static DEVICE_ATTR(transition_action, S_IRUGO,
  		   tpm_show_ppi_transition_action, NULL);
  static DEVICE_ATTR(response, S_IRUGO, tpm_show_ppi_response, NULL);
  static DEVICE_ATTR(tcg_operations, S_IRUGO, tpm_show_ppi_tcg_operations, NULL);
  static DEVICE_ATTR(vs_operations, S_IRUGO, tpm_show_ppi_vs_operations, NULL);
  
  static struct attribute *ppi_attrs[] = {
  	&dev_attr_version.attr,
  	&dev_attr_request.attr,
  	&dev_attr_transition_action.attr,
  	&dev_attr_response.attr,
  	&dev_attr_tcg_operations.attr,
  	&dev_attr_vs_operations.attr, NULL,
  };
  static struct attribute_group ppi_attr_grp = {
  	.name = "ppi",
  	.attrs = ppi_attrs
  };
  
  void tpm_add_ppi(struct tpm_chip *chip)
  {
  	union acpi_object *obj;
  
  	if (!chip->acpi_dev_handle)
  		return;
  
  	if (!acpi_check_dsm(chip->acpi_dev_handle, tpm_ppi_uuid,
  			    TPM_PPI_REVISION_ID, 1 << TPM_PPI_FN_VERSION))
  		return;
  
  	/* Cache PPI version string. */
  	obj = acpi_evaluate_dsm_typed(chip->acpi_dev_handle, tpm_ppi_uuid,
  				      TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
  				      NULL, ACPI_TYPE_STRING);
  	if (obj) {
  		strlcpy(chip->ppi_version, obj->string.pointer,
  			sizeof(chip->ppi_version));
  		ACPI_FREE(obj);
  	}
  
  	chip->groups[chip->groups_cnt++] = &ppi_attr_grp;
  }