[linux-2.6-block.git] / drivers / staging / rdma / hfi1 / efivar.c

/*
 * Copyright(c) 2015, 2016 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License 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.
 *
 * BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "efivar.h"

/* GUID for HFI1 variables in EFI */
#define HFI1_EFIVAR_GUID EFI_GUID(0xc50a953e, 0xa8b2, 0x42a6, \
		0xbf, 0x89, 0xd3, 0x33, 0xa6, 0xe9, 0xe6, 0xd4)
/* largest EFI data size we expect */
#define EFI_DATA_SIZE 4096

/*
 * Read the named EFI variable.  Return the size of the actual data in *size
 * and a kmalloc'ed buffer in *return_data.  The caller must free the
 * data.  It is guaranteed that *return_data will be NULL and *size = 0
 * if this routine fails.
 *
 * Return 0 on success, -errno on failure.
 */
static int read_efi_var(const char *name, unsigned long *size,
			void **return_data)
{
	efi_status_t status;
	efi_char16_t *uni_name;
	efi_guid_t guid;
	unsigned long temp_size;
	void *temp_buffer;
	void *data;
	int i;
	int ret;

	/* set failure return values */
	*size = 0;
	*return_data = NULL;

	if (!efi_enabled(EFI_RUNTIME_SERVICES))
		return -EOPNOTSUPP;

	uni_name = kcalloc(strlen(name) + 1, sizeof(efi_char16_t), GFP_KERNEL);
	temp_buffer = kzalloc(EFI_DATA_SIZE, GFP_KERNEL);

	if (!uni_name || !temp_buffer) {
		ret = -ENOMEM;
		goto fail;
	}

	/* input: the size of the buffer */
	temp_size = EFI_DATA_SIZE;

	/* convert ASCII to unicode - it is a 1:1 mapping */
	for (i = 0; name[i]; i++)
		uni_name[i] = name[i];

	/* need a variable for our GUID */
	guid = HFI1_EFIVAR_GUID;

	/* call into EFI runtime services */
	status = efi.get_variable(
			uni_name,
			&guid,
			NULL,
			&temp_size,
			temp_buffer);

	/*
	 * It would be nice to call efi_status_to_err() here, but that
	 * is in the EFIVAR_FS code and may not be compiled in.
	 * However, even that is insufficient since it does not cover
	 * EFI_BUFFER_TOO_SMALL which could be an important return.
	 * For now, just split out succces or not found.
	 */
	ret = status == EFI_SUCCESS   ? 0 :
	      status == EFI_NOT_FOUND ? -ENOENT :
					-EINVAL;
	if (ret)
		goto fail;

	/*
	 * We have successfully read the EFI variable into our
	 * temporary buffer.  Now allocate a correctly sized
	 * buffer.
	 */
	data = kmemdup(temp_buffer, temp_size, GFP_KERNEL);
	if (!data) {
		ret = -ENOMEM;
		goto fail;
	}

	*size = temp_size;
	*return_data = data;

fail:
	kfree(uni_name);
	kfree(temp_buffer);

	return ret;
}

/*
 * Read an HFI1 EFI variable of the form:
 *	<PCIe address>-<kind>
 * Return an kalloc'ed array and size of the data.
 *
 * Returns 0 on success, -errno on failure.
 */
int read_hfi1_efi_var(struct hfi1_devdata *dd, const char *kind,
		      unsigned long *size, void **return_data)
{
	char name[64];

	/* create a common prefix */
	snprintf(name, sizeof(name), "%04x:%02x:%02x.%x-%s",
		 pci_domain_nr(dd->pcidev->bus),
		 dd->pcidev->bus->number,
		 PCI_SLOT(dd->pcidev->devfn),
		 PCI_FUNC(dd->pcidev->devfn),
		 kind);

	return read_efi_var(name, size, return_data);
}
Commit	Line	Data
5d9157aa	1	/*
05d6ac1d	2	* Copyright(c) 2015, 2016 Intel Corporation.
5d9157aa DL	3	*
	4	* This file is provided under a dual BSD/GPLv2 license. When using or
	5	* redistributing this file, you may do so under either license.
	6	*
	7	* GPL LICENSE SUMMARY
	8	*
5d9157aa DL	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of version 2 of the GNU General Public License as
	11	* published by the Free Software Foundation.
	12	*
	13	* This program is distributed in the hope that it will be useful, but
	14	* WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* General Public License for more details.
	17	*
	18	* BSD LICENSE
	19	*
5d9157aa DL	20	* Redistribution and use in source and binary forms, with or without
	21	* modification, are permitted provided that the following conditions
	22	* are met:
	23	*
	24	* - Redistributions of source code must retain the above copyright
	25	* notice, this list of conditions and the following disclaimer.
	26	* - Redistributions in binary form must reproduce the above copyright
	27	* notice, this list of conditions and the following disclaimer in
	28	* the documentation and/or other materials provided with the
	29	* distribution.
	30	* - Neither the name of Intel Corporation nor the names of its
	31	* contributors may be used to endorse or promote products derived
	32	* from this software without specific prior written permission.
	33	*
	34	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	35	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	36	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	37	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	38	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	39	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	40	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	41	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	42	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	43	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	44	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	45	*
	46	*/
	47
	48	#include "efivar.h"
	49
	50	/* GUID for HFI1 variables in EFI */
	51	#define HFI1_EFIVAR_GUID EFI_GUID(0xc50a953e, 0xa8b2, 0x42a6, \
	52	0xbf, 0x89, 0xd3, 0x33, 0xa6, 0xe9, 0xe6, 0xd4)
	53	/* largest EFI data size we expect */
	54	#define EFI_DATA_SIZE 4096
	55
	56	/*
	57	* Read the named EFI variable. Return the size of the actual data in *size
	58	* and a kmalloc'ed buffer in *return_data. The caller must free the
	59	* data. It is guaranteed that return_data will be NULL and size = 0
	60	* if this routine fails.
	61	*
	62	* Return 0 on success, -errno on failure.
	63	*/
	64	static int read_efi_var(const char name, unsigned long size,
	65	void **return_data)
	66	{
	67	efi_status_t status;
	68	efi_char16_t *uni_name;
	69	efi_guid_t guid;
	70	unsigned long temp_size;
	71	void *temp_buffer;
	72	void *data;
	73	int i;
	74	int ret;
	75
	76	/* set failure return values */
	77	*size = 0;
	78	*return_data = NULL;
	79
	80	if (!efi_enabled(EFI_RUNTIME_SERVICES))
	81	return -EOPNOTSUPP;
	82
5a267953	83	uni_name = kcalloc(strlen(name) + 1, sizeof(efi_char16_t), GFP_KERNEL);
5d9157aa DL	84	temp_buffer = kzalloc(EFI_DATA_SIZE, GFP_KERNEL);
	85
	86	if (!uni_name \|\| !temp_buffer) {
	87	ret = -ENOMEM;
	88	goto fail;
	89	}
	90
	91	/* input: the size of the buffer */
	92	temp_size = EFI_DATA_SIZE;
	93
	94	/* convert ASCII to unicode - it is a 1:1 mapping */
	95	for (i = 0; name[i]; i++)
	96	uni_name[i] = name[i];
	97
	98	/* need a variable for our GUID */
	99	guid = HFI1_EFIVAR_GUID;
	100
	101	/* call into EFI runtime services */
	102	status = efi.get_variable(
	103	uni_name,
	104	&guid,
	105	NULL,
	106	&temp_size,
	107	temp_buffer);
	108
	109	/*
	110	* It would be nice to call efi_status_to_err() here, but that
	111	* is in the EFIVAR_FS code and may not be compiled in.
	112	* However, even that is insufficient since it does not cover
	113	* EFI_BUFFER_TOO_SMALL which could be an important return.
	114	* For now, just split out succces or not found.
	115	*/
	116	ret = status == EFI_SUCCESS ? 0 :
	117	status == EFI_NOT_FOUND ? -ENOENT :
	118	-EINVAL;
	119	if (ret)
	120	goto fail;
	121
	122	/*
	123	* We have successfully read the EFI variable into our
	124	* temporary buffer. Now allocate a correctly sized
	125	* buffer.
	126	*/
94b397cd	127	data = kmemdup(temp_buffer, temp_size, GFP_KERNEL);
5d9157aa DL	128	if (!data) {
	129	ret = -ENOMEM;
	130	goto fail;
	131	}
	132
5d9157aa DL	133	*size = temp_size;
	134	*return_data = data;
	135
	136	fail:
	137	kfree(uni_name);
	138	kfree(temp_buffer);
	139
	140	return ret;
	141	}
	142
	143	/*
	144	* Read an HFI1 EFI variable of the form:
	145	* <PCIe address>-<kind>
	146	* Return an kalloc'ed array and size of the data.
	147	*
	148	* Returns 0 on success, -errno on failure.
	149	*/
	150	int read_hfi1_efi_var(struct hfi1_devdata dd, const char kind,
	151	unsigned long size, void *return_data)
	152	{
	153	char name[64];
	154
	155	/* create a common prefix */
	156	snprintf(name, sizeof(name), "%04x:%02x:%02x.%x-%s",
	157	pci_domain_nr(dd->pcidev->bus),
	158	dd->pcidev->bus->number,
	159	PCI_SLOT(dd->pcidev->devfn),
	160	PCI_FUNC(dd->pcidev->devfn),
	161	kind);
	162
	163	return read_efi_var(name, size, return_data);
	164	}