linux-kernel - [PATCH 1/2] thunderbolt: Add support for separating the flush to SPI and authenticate

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Message-Id: <20200622143035.25327-2-mario.limonciello@dell.com>
Date:   Mon, 22 Jun 2020 09:30:34 -0500
From:   Mario Limonciello <mario.limonciello@...l.com>
To:     Andreas Noever <andreas.noever@...il.com>,
        Michael Jamet <michael.jamet@...el.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Yehezkel Bernat <YehezkelShB@...il.com>
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Mario Limonciello <mario.limonciello@...l.com>
Subject: [PATCH 1/2] 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@...l.com>
---
 .../ABI/testing/sysfs-bus-thunderbolt         | 11 ++++-
 drivers/thunderbolt/switch.c                  | 43 ++++++++++++-------
 drivers/thunderbolt/tb.h                      |  1 +
 3 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-thunderbolt b/Documentation/ABI/testing/sysfs-bus-thunderbolt
index 82e80de78dd0..26b15cbc9881 100644
--- a/Documentation/ABI/testing/sysfs-bus-thunderbolt
+++ b/Documentation/ABI/testing/sysfs-bus-thunderbolt
@@ -178,11 +178,18 @@ KernelVersion:	4.13
 Contact:	thunderbolt-software@...ts.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 only flush the image 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
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index d7d60cd9226f..4c476a58db38 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -27,6 +27,11 @@
 #define NVM_MIN_SIZE		SZ_32K
 #define NVM_MAX_SIZE		SZ_512K
 
+enum nvm_write_ops {
+	WRITE_AND_AUTHENTICATE = 1,
+	WRITE_ONLY = 2,
+};
+
 static DEFINE_IDA(nvm_ida);
 
 struct nvm_auth_status {
@@ -164,8 +169,12 @@ 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)
@@ -371,6 +380,7 @@ static int tb_switch_nvm_write(void *priv, unsigned int offset, void *val,
 		}
 	}
 
+	sw->nvm->flushed = false;
 	sw->nvm->buf_data_size = offset + bytes;
 	memcpy(sw->nvm->buf + offset, val, bytes);
 
@@ -1536,7 +1546,7 @@ 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);
@@ -1552,25 +1562,28 @@ 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 (!sw->nvm->buf) {
-			ret = -EINVAL;
-			goto exit_unlock;
-		}
-
-		ret = nvm_validate_and_write(sw);
-		if (ret)
-			goto exit_unlock;
+	if (val > 0) {
+		if (!sw->nvm->flushed) {
+			if (!sw->nvm->buf) {
+				ret = -EINVAL;
+				goto exit_unlock;
+			}
 
-		sw->nvm->authenticating = true;
-		ret = nvm_authenticate(sw);
+			ret = nvm_validate_and_write(sw);
+			if (ret || val == WRITE_ONLY)
+				goto exit_unlock;
+		}
+		if (val == WRITE_AND_AUTHENTICATE) {
+			sw->nvm->authenticating = true;
+			ret = nvm_authenticate(sw);
+		}
 	}
 
 exit_unlock:
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 2eb2bcd3cca3..222ec19737fa 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -40,6 +40,7 @@ struct tb_switch_nvm {
 	void *buf;
 	size_t buf_data_size;
 	bool authenticating;
+	bool flushed;
 };
 
 #define TB_SWITCH_KEY_SIZE		32
-- 
2.25.1