thunderbolt: Add WRITE_ONLY and AUTHENTICATE_ONLY NVM operations for retimers

The same way we support these two operations for USB4 routers we can
extend the retimer NVM operations to support retimers also.

Signed-off-by: Rajmohan Mani <[e-mail]>
Co-developed-by: Mika Westerberg <[e-mail]>
Signed-off-by: Mika Westerberg <[e-mail]>
Reviewed-by: Greg Kroah-Hartman <[e-mail]>

Documentation/ABI/testing/sysfs-bus-thunderbolt

···
 		  and flush it to the storage area.
 		- Writing "3" will authenticate the image that is
 		  currently written in the storage area. This is only
-		  supported with USB4 devices.
+		  supported with USB4 devices and retimers.
 
 		When read holds status of the last authentication
 		operation if an error occurred during the process. This

drivers/thunderbolt/retimer.c

···
 	unsigned int image_size, hdr_size;
 	const u8 *buf = rt->nvm->buf;
 	u16 ds_size, device;
+	int ret;
 
 	image_size = rt->nvm->buf_data_size;
 	if (image_size < NVM_MIN_SIZE || image_size > NVM_MAX_SIZE)
···
 	buf += hdr_size;
 	image_size -= hdr_size;
 
-	return usb4_port_retimer_nvm_write(rt->port, rt->index, 0, buf,
-					   image_size);
+	ret = usb4_port_retimer_nvm_write(rt->port, rt->index, 0, buf,
+					 image_size);
+	if (!ret)
+		rt->nvm->flushed = true;
+
+	return ret;
+}
+
+static int tb_retimer_nvm_authenticate(struct tb_retimer *rt, bool auth_only)
+{
+	int ret;
+
+	if (auth_only) {
+		ret = usb4_port_retimer_nvm_set_offset(rt->port, rt->index, 0);
+		if (ret)
+			return ret;
+	}
+
+	return usb4_port_retimer_nvm_authenticate(rt->port, rt->index);
 }
 
 static ssize_t device_show(struct device *dev, struct device_attribute *attr,
···
 	struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct tb_retimer *rt = tb_to_retimer(dev);
-	bool val;
-	int ret;
+	int val, ret;
 
 	pm_runtime_get_sync(&rt->dev);
 
···
 		goto exit_unlock;
 	}
 
-	ret = kstrtobool(buf, &val);
+	ret = kstrtoint(buf, 10, &val);
 	if (ret)
 		goto exit_unlock;
 
···
 	rt->auth_status = 0;
 
 	if (val) {
-		if (!rt->nvm->buf) {
-			ret = -EINVAL;
-			goto exit_unlock;
+		if (val == AUTHENTICATE_ONLY) {
+			ret = tb_retimer_nvm_authenticate(rt, true);
+		} else {
+			if (!rt->nvm->flushed) {
+				if (!rt->nvm->buf) {
+					ret = -EINVAL;
+					goto exit_unlock;
+				}
+
+				ret = tb_retimer_nvm_validate_and_write(rt);
+				if (ret || val == WRITE_ONLY)
+					goto exit_unlock;
+			}
+			if (val == WRITE_AND_AUTHENTICATE)
+				ret = tb_retimer_nvm_authenticate(rt, false);
 		}
-
-		ret = tb_retimer_nvm_validate_and_write(rt);
-		if (ret)
-			goto exit_unlock;
-
-		ret = usb4_port_retimer_nvm_authenticate(rt->port, rt->index);
 	}
 
 exit_unlock:

drivers/thunderbolt/tb.h

···
 			    const void *buf, u8 size);
 int usb4_port_retimer_is_last(struct tb_port *port, u8 index);
 int usb4_port_retimer_nvm_sector_size(struct tb_port *port, u8 index);
+int usb4_port_retimer_nvm_set_offset(struct tb_port *port, u8 index,
+				     unsigned int address);
 int usb4_port_retimer_nvm_write(struct tb_port *port, u8 index,
 				unsigned int address, const void *buf,
 				size_t size);

drivers/thunderbolt/usb4.c

···
 	return ret ? ret : metadata & USB4_NVM_SECTOR_SIZE_MASK;
 }
 
-static int usb4_port_retimer_nvm_set_offset(struct tb_port *port, u8 index,
-					    unsigned int address)
+/**
+ * usb4_port_retimer_nvm_set_offset() - Set NVM write offset
+ * @port: USB4 port
+ * @index: Retimer index
+ * @address: Start offset
+ *
+ * Exlicitly sets NVM write offset. Normally when writing to NVM this is
+ * done automatically by usb4_port_retimer_nvm_write().
+ *
+ * Returns %0 in success and negative errno if there was a failure.
+ */
+int usb4_port_retimer_nvm_set_offset(struct tb_port *port, u8 index,
+				     unsigned int address)
 {
 	u32 metadata, dwaddress;
 	int ret;