thunderbolt: Add support for separating the flush to SPI and authenticate

This allows userspace to have a shorter period of time that the device
is unusable and to call it at a more convenient time.

For example flushing the image may happen while the user is using the
machine and authenticating/rebooting may happen while logging out.
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Documentation/ABI/testing/sysfs-bus-thunderbolt

@@ -178,11 +178,18 @@ KernelVersion:	4.13
 Contact:	thunderbolt-software@lists.01.org
 Description:	When new NVM image is written to the non-active NVM
 		area (through non_activeX NVMem device), the
-		authentication procedure is started by writing 1 to
-		this file. If everything goes well, the device is
+		authentication procedure is started by writing to
+		this file.
+		If everything goes well, the device is
 		restarted with the new NVM firmware. If the image
 		verification fails an error code is returned instead.
 
+		This file will accept writing values "1" or "2"
+		- Writing "1" will flush the image to the storage
+		area and authenticate the image in one action.
+		- Writing "2" will run some basic validation on the image
+		and flush it to the storage area.
+
 		When read holds status of the last authentication
 		operation if an error occurred during the process. This
 		is directly the status value from the DMA configuration

drivers/thunderbolt/nvm.c

@@ -100,6 +100,7 @@ int tb_nvm_write_buf(struct tb_nvm *nvm, unsigned int offset, void *val,
 			return -ENOMEM;
 	}
 
+	nvm->flushed = false;
 	nvm->buf_data_size = offset + bytes;
 	memcpy(nvm->buf + offset, val, bytes);
 	return 0;

drivers/thunderbolt/switch.c

@@ -26,6 +26,11 @@ struct nvm_auth_status {
 	u32 status;
 };
 
+enum nvm_write_ops {
+	WRITE_AND_AUTHENTICATE = 1,
+	WRITE_ONLY = 2,
+};
+
 /*
  * Hold NVM authentication failure status per switch This information
  * needs to stay around even when the switch gets power cycled so we
@@ -155,8 +160,12 @@ static int nvm_validate_and_write(struct tb_switch *sw)
 	}
 
 	if (tb_switch_is_usb4(sw))
-		return usb4_switch_nvm_write(sw, 0, buf, image_size);
-	return dma_port_flash_write(sw->dma_port, 0, buf, image_size);
+		ret = usb4_switch_nvm_write(sw, 0, buf, image_size);
+	else
+		ret = dma_port_flash_write(sw->dma_port, 0, buf, image_size);
+	if (!ret)
+		sw->nvm->flushed = true;
+	return ret;
 }
 
 static int nvm_authenticate_host_dma_port(struct tb_switch *sw)
@@ -1488,7 +1497,7 @@ static ssize_t nvm_authenticate_store(struct device *dev,
 	struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct tb_switch *sw = tb_to_switch(dev);
-	bool val;
+	int val;
 	int ret;
 
 	pm_runtime_get_sync(&sw->dev);
@@ -1504,26 +1513,29 @@ static ssize_t nvm_authenticate_store(struct device *dev,
 		goto exit_unlock;
 	}
 
-	ret = kstrtobool(buf, &val);
+	ret = kstrtoint(buf, 10, &val);
 	if (ret)
 		goto exit_unlock;
 
 	/* Always clear the authentication status */
 	nvm_clear_auth_status(sw);
 
-	if (val) {
+	if (val > 0) {
+		if (!sw->nvm->flushed) {
 			if (!sw->nvm->buf) {
 				ret = -EINVAL;
 				goto exit_unlock;
 			}
 
 			ret = nvm_validate_and_write(sw);
-		if (ret)
+			if (ret || val == WRITE_ONLY)
 				goto exit_unlock;
-
+		}
+		if (val == WRITE_AND_AUTHENTICATE) {
 			sw->nvm->authenticating = true;
 			ret = nvm_authenticate(sw);
 		}
+	}
 
 exit_unlock:
 	mutex_unlock(&sw->tb->lock);

drivers/thunderbolt/tb.h

@@ -39,6 +39,7 @@
  * @buf_data_size: Number of bytes actually consumed by the new NVM
  *		   image
  * @authenticating: The device is authenticating the new NVM
+ * @flushed: The image has been flushed to the storage area
  *
  * The user of this structure needs to handle serialization of possible
  * concurrent access.
@@ -53,6 +54,7 @@ struct tb_nvm {
 	void *buf;
 	size_t buf_data_size;
 	bool authenticating;
+	bool flushed;
 };
 
 #define TB_SWITCH_KEY_SIZE		32