[PATCH v2 1/2] thunderbolt: Add support for separating the flush to SPI and authenticate

From: Mario Limonciello
Date: Mon Jun 22 2020 - 14:58:24 EST


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@xxxxxxxx>
---
.../ABI/testing/sysfs-bus-thunderbolt | 11 ++++-
drivers/thunderbolt/nvm.c | 1 +
drivers/thunderbolt/switch.c | 42 ++++++++++++-------
drivers/thunderbolt/tb.h | 2 +
4 files changed, 39 insertions(+), 17 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-thunderbolt b/Documentation/ABI/testing/sysfs-bus-thunderbolt
index bd504ed323e8..7d0500b4d58a 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@xxxxxxxxxxxx
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
diff --git a/drivers/thunderbolt/nvm.c b/drivers/thunderbolt/nvm.c
index 4c6aa06ab3d5..29de6d95c6e7 100644
--- a/drivers/thunderbolt/nvm.c
+++ b/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;
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 817c66c7adcf..bbfbfebeee7f 100644
--- a/drivers/thunderbolt/switch.c
+++ b/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);
@@ -1504,25 +1513,28 @@ 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 736d1589c31e..43a8ca2eb3d8 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -42,6 +42,7 @@
*
* The user of this structure needs to handle serialization of possible
* concurrent access.
+ * @flushed: The image has been flushed to the storage area
*/
struct tb_nvm {
struct device *dev;
@@ -53,6 +54,7 @@ struct tb_nvm {
void *buf;
size_t buf_data_size;
bool authenticating;
+ bool flushed;
};

#define TB_SWITCH_KEY_SIZE 32
--
2.25.1