183 lines
5.4 KiB
C
183 lines
5.4 KiB
C
/*
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* Copyright(c) 2015, 2016 Intel Corporation.
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*
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* This file is provided under a dual BSD/GPLv2 license. When using or
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* redistributing this file, you may do so under either license.
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*
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* GPL LICENSE SUMMARY
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* BSD LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* - Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <linux/ctype.h>
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#include "efivar.h"
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/* GUID for HFI1 variables in EFI */
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#define HFI1_EFIVAR_GUID EFI_GUID(0xc50a953e, 0xa8b2, 0x42a6, \
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0xbf, 0x89, 0xd3, 0x33, 0xa6, 0xe9, 0xe6, 0xd4)
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/* largest EFI data size we expect */
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#define EFI_DATA_SIZE 4096
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/*
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* Read the named EFI variable. Return the size of the actual data in *size
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* and a kmalloc'ed buffer in *return_data. The caller must free the
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* data. It is guaranteed that *return_data will be NULL and *size = 0
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* if this routine fails.
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*
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* Return 0 on success, -errno on failure.
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*/
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static int read_efi_var(const char *name, unsigned long *size,
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void **return_data)
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{
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efi_status_t status;
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efi_char16_t *uni_name;
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efi_guid_t guid;
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unsigned long temp_size;
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void *temp_buffer;
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void *data;
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int i;
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int ret;
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/* set failure return values */
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*size = 0;
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*return_data = NULL;
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if (!efi_enabled(EFI_RUNTIME_SERVICES))
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return -EOPNOTSUPP;
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uni_name = kcalloc(strlen(name) + 1, sizeof(efi_char16_t), GFP_KERNEL);
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temp_buffer = kzalloc(EFI_DATA_SIZE, GFP_KERNEL);
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if (!uni_name || !temp_buffer) {
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ret = -ENOMEM;
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goto fail;
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}
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/* input: the size of the buffer */
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temp_size = EFI_DATA_SIZE;
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/* convert ASCII to unicode - it is a 1:1 mapping */
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for (i = 0; name[i]; i++)
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uni_name[i] = name[i];
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/* need a variable for our GUID */
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guid = HFI1_EFIVAR_GUID;
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/* call into EFI runtime services */
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status = efi.get_variable(
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uni_name,
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&guid,
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NULL,
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&temp_size,
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temp_buffer);
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/*
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* It would be nice to call efi_status_to_err() here, but that
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* is in the EFIVAR_FS code and may not be compiled in.
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* However, even that is insufficient since it does not cover
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* EFI_BUFFER_TOO_SMALL which could be an important return.
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* For now, just split out succces or not found.
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*/
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ret = status == EFI_SUCCESS ? 0 :
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status == EFI_NOT_FOUND ? -ENOENT :
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-EINVAL;
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if (ret)
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goto fail;
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/*
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* We have successfully read the EFI variable into our
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* temporary buffer. Now allocate a correctly sized
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* buffer.
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*/
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data = kmemdup(temp_buffer, temp_size, GFP_KERNEL);
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if (!data) {
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ret = -ENOMEM;
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goto fail;
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}
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*size = temp_size;
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*return_data = data;
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fail:
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kfree(uni_name);
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kfree(temp_buffer);
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return ret;
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}
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/*
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* Read an HFI1 EFI variable of the form:
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* <PCIe address>-<kind>
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* Return an kalloc'ed array and size of the data.
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*
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* Returns 0 on success, -errno on failure.
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*/
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int read_hfi1_efi_var(struct hfi1_devdata *dd, const char *kind,
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unsigned long *size, void **return_data)
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{
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char prefix_name[64];
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char name[64];
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int result;
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int i;
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/* create a common prefix */
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snprintf(prefix_name, sizeof(prefix_name), "%04x:%02x:%02x.%x",
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pci_domain_nr(dd->pcidev->bus),
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dd->pcidev->bus->number,
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PCI_SLOT(dd->pcidev->devfn),
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PCI_FUNC(dd->pcidev->devfn));
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snprintf(name, sizeof(name), "%s-%s", prefix_name, kind);
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result = read_efi_var(name, size, return_data);
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/*
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* If reading the lowercase EFI variable fail, read the uppercase
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* variable.
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*/
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if (result) {
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/* Converting to uppercase */
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for (i = 0; prefix_name[i]; i++)
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if (isalpha(prefix_name[i]))
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prefix_name[i] = toupper(prefix_name[i]);
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snprintf(name, sizeof(name), "%s-%s", prefix_name, kind);
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result = read_efi_var(name, size, return_data);
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}
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return result;
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}
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