platform/x86: think-lmi: Add bulk save feature

On Lenovo platforms there is a limitation in the number of times an
attribute can be saved. This is an architectural limitation and it limits
the number of attributes that can be modified to 48.
A solution for this is instead of the attribute being saved after every
modification allow a user to bulk set the attributes and then trigger a
final save. This allows unlimited attributes.

This patch introduces a save_settings attribute that can be configured to
either single or bulk mode by the user.
Single mode is the default but customers who want to avoid the 48
attribute limit can enable bulk mode.

Displaying the save_settings attribute will display the enabled mode.

When in bulk mode writing 'save' to the save_settings attribute will
trigger a save. Once this has been done a reboot is required before more
attributes can be modified.

Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://lore.kernel.org/r/20230919141530.4805-1-mpearson-lenovo@squebb.ca
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/platform/x86/think-lmi.h b/drivers/platform/x86/think-lmi.h
index 4daba6151cd6..e1975ffebeb4 100644
--- a/drivers/platform/x86/think-lmi.h
+++ b/drivers/platform/x86/think-lmi.h
@@ -27,6 +27,19 @@ enum level_option {
 	TLMI_LEVEL_MASTER,
 };
 
+/*
+ * There are a limit on the number of WMI operations you can do if you use
+ * the default implementation of saving on every set. This is due to a
+ * limitation in EFI variable space used.
+ * Have a 'bulk save' mode where you can manually trigger the save, and can
+ * therefore set unlimited variables - for users that need it.
+ */
+enum save_mode {
+	TLMI_SAVE_SINGLE,
+	TLMI_SAVE_BULK,
+	TLMI_SAVE_SAVE,
+};
+
 /* password configuration details */
 struct tlmi_pwdcfg_core {
 	uint32_t password_mode;
@@ -86,6 +99,9 @@ struct think_lmi {
 	bool can_debug_cmd;
 	bool opcode_support;
 	bool certificate_support;
+	enum save_mode save_mode;
+	bool save_required;
+	bool reboot_required;
 
 	struct tlmi_attr_setting *setting[TLMI_SETTINGS_COUNT];
 	struct device *class_dev;