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Diffstat (limited to 'drivers/infiniband/hw/hfi1/efivar.c')
-rw-r--r--drivers/infiniband/hw/hfi1/efivar.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/drivers/infiniband/hw/hfi1/efivar.c b/drivers/infiniband/hw/hfi1/efivar.c
new file mode 100644
index 0000000000..2b5d264f41
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/efivar.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
+/*
+ * Copyright(c) 2015, 2016 Intel Corporation.
+ */
+
+#include <linux/string.h>
+#include <linux/string_helpers.h>
+
+#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_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
+ 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 success 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 prefix_name[64];
+ char name[128];
+ int result;
+
+ /* create a common prefix */
+ snprintf(prefix_name, sizeof(prefix_name), "%04x:%02x:%02x.%x",
+ pci_domain_nr(dd->pcidev->bus),
+ dd->pcidev->bus->number,
+ PCI_SLOT(dd->pcidev->devfn),
+ PCI_FUNC(dd->pcidev->devfn));
+ snprintf(name, sizeof(name), "%s-%s", prefix_name, kind);
+ result = read_efi_var(name, size, return_data);
+
+ /*
+ * If reading the lowercase EFI variable fail, read the uppercase
+ * variable.
+ */
+ if (result) {
+ string_upper(prefix_name, prefix_name);
+ snprintf(name, sizeof(name), "%s-%s", prefix_name, kind);
+ result = read_efi_var(name, size, return_data);
+ }
+
+ return result;
+}