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ACPI / TPM: detect PPI features by checking availability of _DSM functions

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Detecting physical presence interface features by checking availbility
of corresponding ACPI _DSM functions, it should be more accurate than
checking TPM version number.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Jiang Liu 2013-12-19 20:38:18 +08:00 committed by Rafael J. Wysocki
parent 84b1667dea
commit 1569a4c4ce
1 changed files with 19 additions and 26 deletions
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45
drivers/char/tpm/tpm_ppi.c
View file

@ -23,39 +23,31 @@ static const u8 tpm_ppi_uuid[] = {
0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53
};
static char *tpm_device_name = "TPM";
static char tpm_ppi_version[PPI_VERSION_LEN + 1];
static acpi_handle tpm_ppi_handle;
static acpi_status ppi_callback(acpi_handle handle, u32 level, void *context,
void **return_value)
{
acpi_status status = AE_OK;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj;
status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
if (ACPI_FAILURE(status))
if (!acpi_check_dsm(handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
1 << TPM_PPI_FN_VERSION))
return AE_OK;
if (strstr(buffer.pointer, context) != NULL) {
union acpi_object *obj;
/* Cache version string */
obj = acpi_evaluate_dsm_typed(handle, tpm_ppi_uuid,
TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
NULL, ACPI_TYPE_STRING);
if (obj) {
strlcpy(tpm_ppi_version, obj->string.pointer,
PPI_VERSION_LEN + 1);
ACPI_FREE(obj);
}
*return_value = handle;
status = AE_CTRL_TERMINATE;
/* Cache version string */
obj = acpi_evaluate_dsm_typed(handle, tpm_ppi_uuid,
TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
NULL, ACPI_TYPE_STRING);
if (obj) {
strlcpy(tpm_ppi_version, obj->string.pointer,
PPI_VERSION_LEN + 1);
ACPI_FREE(obj);
}
kfree(buffer.pointer);
return status;
*return_value = handle;
return AE_CTRL_TERMINATE;
}
static inline union acpi_object *
@ -118,7 +110,8 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
* is updated with function index from SUBREQ to SUBREQ2 since PPI
* version 1.1
*/
if (strcmp(tpm_ppi_version, "1.1") >= 0)
if (acpi_check_dsm(tpm_ppi_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
1 << TPM_PPI_FN_SUBREQ2))
func = TPM_PPI_FN_SUBREQ2;
/*
@ -272,7 +265,8 @@ static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
"User not required",
};
if (strcmp(tpm_ppi_version, "1.2") < 0)
if (!acpi_check_dsm(tpm_ppi_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
1 << TPM_PPI_FN_GETOPR))
return -EPERM;
tmp.integer.type = ACPI_TYPE_INTEGER;
@ -334,8 +328,7 @@ int tpm_add_ppi(struct kobject *parent)
{
/* Cache TPM ACPI handle and version string */
acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
ppi_callback, NULL,
tpm_device_name, &tpm_ppi_handle);
ppi_callback, NULL, NULL, &tpm_ppi_handle);
if (tpm_ppi_handle == NULL)
return -ENODEV;