firmware: ti_sci: Allow for device shared and exclusive requests

Sysfw provides an option for requesting exclusive access for a
device using the flags MSG_FLAG_DEVICE_EXCLUSIVE. If this flag is
not used, the device is meant to be shared across hosts. Once a device
is requested from a host with this flag set, any request to this
device from a different host will be nacked by sysfw. Current tisci
driver enables this flag for every device requests. But this may not
be true for all the devices. So provide a separate commands in driver
for exclusive and shared device requests.

Reviewed-by: Nishanth Menon <[e-mail]>
Signed-off-by: Lokesh Vutla <[e-mail]>
Signed-off-by: Santosh Shilimkar <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>

drivers/firmware/ti_sci.c

···
 
 /**
  * ti_sci_cmd_get_device() - command to request for device managed by TISCI
+ *			     that can be shared with other hosts.
  * @handle:	Pointer to TISCI handle as retrieved by *ti_sci_get_handle
  * @id:		Device Identifier
  *
···
  * usage count by balancing get_device with put_device. No refcounting is
  * managed by driver for that purpose.
  *
- * NOTE: The request is for exclusive access for the processor.
- *
  * Return: 0 if all went fine, else return appropriate error.
  */
 static int ti_sci_cmd_get_device(const struct ti_sci_handle *handle, u32 id)
+{
+	return ti_sci_set_device_state(handle, id, 0,
+				       MSG_DEVICE_SW_STATE_ON);
+}
+
+/**
+ * ti_sci_cmd_get_device_exclusive() - command to request for device managed by
+ *				       TISCI that is exclusively owned by the
+ *				       requesting host.
+ * @handle:	Pointer to TISCI handle as retrieved by *ti_sci_get_handle
+ * @id:		Device Identifier
+ *
+ * Request for the device - NOTE: the client MUST maintain integrity of
+ * usage count by balancing get_device with put_device. No refcounting is
+ * managed by driver for that purpose.
+ *
+ * Return: 0 if all went fine, else return appropriate error.
+ */
+static int ti_sci_cmd_get_device_exclusive(const struct ti_sci_handle *handle,
+					   u32 id)
 {
 	return ti_sci_set_device_state(handle, id,
 				       MSG_FLAG_DEVICE_EXCLUSIVE,
···
  * Return: 0 if all went fine, else return appropriate error.
  */
 static int ti_sci_cmd_idle_device(const struct ti_sci_handle *handle, u32 id)
+{
+	return ti_sci_set_device_state(handle, id, 0,
+				       MSG_DEVICE_SW_STATE_RETENTION);
+}
+
+/**
+ * ti_sci_cmd_idle_device_exclusive() - Command to idle a device managed by
+ *					TISCI that is exclusively owned by
+ *					requesting host.
+ * @handle:	Pointer to TISCI handle as retrieved by *ti_sci_get_handle
+ * @id:		Device Identifier
+ *
+ * Request for the device - NOTE: the client MUST maintain integrity of
+ * usage count by balancing get_device with put_device. No refcounting is
+ * managed by driver for that purpose.
+ *
+ * Return: 0 if all went fine, else return appropriate error.
+ */
+static int ti_sci_cmd_idle_device_exclusive(const struct ti_sci_handle *handle,
+					    u32 id)
 {
 	return ti_sci_set_device_state(handle, id,
 				       MSG_FLAG_DEVICE_EXCLUSIVE,
···
 	core_ops->reboot_device = ti_sci_cmd_core_reboot;
 
 	dops->get_device = ti_sci_cmd_get_device;
+	dops->get_device_exclusive = ti_sci_cmd_get_device_exclusive;
 	dops->idle_device = ti_sci_cmd_idle_device;
+	dops->idle_device_exclusive = ti_sci_cmd_idle_device_exclusive;
 	dops->put_device = ti_sci_cmd_put_device;
 
 	dops->is_valid = ti_sci_cmd_dev_is_valid;

include/linux/soc/ti/ti_sci_protocol.h

···
  */
 struct ti_sci_dev_ops {
 	int (*get_device)(const struct ti_sci_handle *handle, u32 id);
+	int (*get_device_exclusive)(const struct ti_sci_handle *handle, u32 id);
 	int (*idle_device)(const struct ti_sci_handle *handle, u32 id);
+	int (*idle_device_exclusive)(const struct ti_sci_handle *handle,
+				     u32 id);
 	int (*put_device)(const struct ti_sci_handle *handle, u32 id);
 	int (*is_valid)(const struct ti_sci_handle *handle, u32 id);
 	int (*get_context_loss_count)(const struct ti_sci_handle *handle,