From: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Between UCSI 1.2 and UCSI 2.0, the size of the MESSAGE_IN region was
increased from 16 to 256. In order to avoid overflowing reads for older
systems, add a mechanism to use the read UCSI version to truncate read
sizes on UCSI v1.2.
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
---
Tested on 6.6 kernel. Dmesg output from this change:
[ 105.058162] ucsi_um_test ucsi_um_test_device.0: Registered UCSI
interface with version 3.0.0
drivers/usb/typec/ucsi/ucsi.c | 26 ++++++++++++++++++++++++--
drivers/usb/typec/ucsi/ucsi.h | 11 +++++++++++
2 files changed, 35 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 5392ec698959..4edf785d203b 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -36,6 +36,19 @@
*/
#define UCSI_SWAP_TIMEOUT_MS 5000
+static int ucsi_read_message_in(struct ucsi *ucsi, void *buf,
+ size_t buf_size)
+{
+ /*
+ * Below UCSI 2.0, MESSAGE_IN was limited to 16 bytes. Truncate the
+ * reads here.
+ */
+ if (ucsi->version <= UCSI_VERSION_1_2)
+ buf_size = min_t(size_t, 16, buf_size);
+
+ return ucsi->ops->read(ucsi, UCSI_MESSAGE_IN, buf, buf_size);
+}
+
static int ucsi_acknowledge_command(struct ucsi *ucsi)
{
u64 ctrl;
@@ -72,7 +85,7 @@ static int ucsi_read_error(struct ucsi *ucsi)
if (ret < 0)
return ret;
- ret = ucsi->ops->read(ucsi, UCSI_MESSAGE_IN, &error, sizeof(error));
+ ret = ucsi_read_message_in(ucsi, &error, sizeof(error));
if (ret)
return ret;
@@ -170,7 +183,7 @@ int ucsi_send_command(struct ucsi *ucsi, u64 command,
length = ret;
if (data) {
- ret = ucsi->ops->read(ucsi, UCSI_MESSAGE_IN, data, size);
+ ret = ucsi_read_message_in(ucsi, data, size);
if (ret)
goto out;
}
@@ -1556,6 +1569,15 @@ int ucsi_register(struct ucsi *ucsi)
if (!ucsi->version)
return -ENODEV;
+ /*
+ * Version format is JJ.M.N (JJ = Major version, M = Minor version,
+ * N = sub-minor version).
+ */
+ dev_info(ucsi->dev, "Registered UCSI interface with version %x.%x.%x",
+ UCSI_BCD_GET_MAJOR(ucsi->version),
+ UCSI_BCD_GET_MINOR(ucsi->version),
+ UCSI_BCD_GET_SUBMINOR(ucsi->version));
+
queue_delayed_work(system_long_wq, &ucsi->work, 0);
ucsi_debugfs_register(ucsi);
diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
index 6478016d5cb8..bec920fa6b8a 100644
--- a/drivers/usb/typec/ucsi/ucsi.h
+++ b/drivers/usb/typec/ucsi/ucsi.h
@@ -23,6 +23,17 @@ struct dentry;
#define UCSI_CONTROL 8
#define UCSI_MESSAGE_IN 16
#define UCSI_MESSAGE_OUT 32
+#define UCSIv2_MESSAGE_OUT 272
+
+/* UCSI versions */
+#define UCSI_VERSION_1_2 0x0120
+#define UCSI_VERSION_2_0 0x0200
+#define UCSI_VERSION_2_1 0x0210
+#define UCSI_VERSION_3_0 0x0300
+
+#define UCSI_BCD_GET_MAJOR(_v_) (((_v_) >> 8) & 0xFF)
+#define UCSI_BCD_GET_MINOR(_v_) (((_v_) >> 4) & 0x0F)
+#define UCSI_BCD_GET_SUBMINOR(_v_) ((_v_) & 0x0F)
/* Command Status and Connector Change Indication (CCI) bits */
#define UCSI_CCI_CONNECTOR(_c_) (((_c_) & GENMASK(7, 1)) >> 1)
--
2.43.0.429.g432eaa2c6b-googHi Abhishek, On Tue, Jan 23, 2024 at 2:30 PM Abhishek Pandit-Subedi <abhishekpandit@google.com> wrote: > > From: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> > > Between UCSI 1.2 and UCSI 2.0, the size of the MESSAGE_IN region was > increased from 16 to 256. In order to avoid overflowing reads for older > systems, add a mechanism to use the read UCSI version to truncate read > sizes on UCSI v1.2. > > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> I have one nit (mentioned in side-band but reproducing here for consistency), but will defer to the maintainer on that. The above notwithstanding, FWIW: Reviewed-by: Prashant Malani<pmalani@chromium.org> > @@ -1556,6 +1569,15 @@ int ucsi_register(struct ucsi *ucsi) > if (!ucsi->version) > return -ENODEV; > > + /* > + * Version format is JJ.M.N (JJ = Major version, M = Minor version, > + * N = sub-minor version). > + */ > + dev_info(ucsi->dev, "Registered UCSI interface with version %x.%x.%x", > + UCSI_BCD_GET_MAJOR(ucsi->version), > + UCSI_BCD_GET_MINOR(ucsi->version), > + UCSI_BCD_GET_SUBMINOR(ucsi->version)); nit: I think this doesn't need to be dev_info() and can be just dev_dbg(), but will defer to the maintainer. Thanks, -Prashant
On Wed, Jan 24, 2024 at 12:12:26AM -0800, Prashant Malani wrote: > Hi Abhishek, > > On Tue, Jan 23, 2024 at 2:30 PM Abhishek Pandit-Subedi > <abhishekpandit@google.com> wrote: > > > > From: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> > > > > Between UCSI 1.2 and UCSI 2.0, the size of the MESSAGE_IN region was > > increased from 16 to 256. In order to avoid overflowing reads for older > > systems, add a mechanism to use the read UCSI version to truncate read > > sizes on UCSI v1.2. > > > > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> > I have one nit (mentioned in side-band but reproducing here for consistency), > but will defer to the maintainer on that. > > The above notwithstanding, FWIW: > Reviewed-by: Prashant Malani<pmalani@chromium.org> > > > @@ -1556,6 +1569,15 @@ int ucsi_register(struct ucsi *ucsi) > > if (!ucsi->version) > > return -ENODEV; > > > > + /* > > + * Version format is JJ.M.N (JJ = Major version, M = Minor version, > > + * N = sub-minor version). > > + */ > > + dev_info(ucsi->dev, "Registered UCSI interface with version %x.%x.%x", > > + UCSI_BCD_GET_MAJOR(ucsi->version), > > + UCSI_BCD_GET_MINOR(ucsi->version), > > + UCSI_BCD_GET_SUBMINOR(ucsi->version)); > > nit: I think this doesn't need to be dev_info() and can be just > dev_dbg(), but will > defer to the maintainer. I think that's okay. Reviewewd-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> -- heikki
On Wed, Jan 24, 2024 at 03:51:58PM +0200, Heikki Krogerus wrote: > On Wed, Jan 24, 2024 at 12:12:26AM -0800, Prashant Malani wrote: > > Hi Abhishek, > > > > On Tue, Jan 23, 2024 at 2:30 PM Abhishek Pandit-Subedi > > <abhishekpandit@google.com> wrote: > > > > > > From: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> > > > > > > Between UCSI 1.2 and UCSI 2.0, the size of the MESSAGE_IN region was > > > increased from 16 to 256. In order to avoid overflowing reads for older > > > systems, add a mechanism to use the read UCSI version to truncate read > > > sizes on UCSI v1.2. > > > > > > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> > > I have one nit (mentioned in side-band but reproducing here for consistency), > > but will defer to the maintainer on that. > > > > The above notwithstanding, FWIW: > > Reviewed-by: Prashant Malani<pmalani@chromium.org> > > > > > @@ -1556,6 +1569,15 @@ int ucsi_register(struct ucsi *ucsi) > > > if (!ucsi->version) > > > return -ENODEV; > > > > > > + /* > > > + * Version format is JJ.M.N (JJ = Major version, M = Minor version, > > > + * N = sub-minor version). > > > + */ > > > + dev_info(ucsi->dev, "Registered UCSI interface with version %x.%x.%x", > > > + UCSI_BCD_GET_MAJOR(ucsi->version), > > > + UCSI_BCD_GET_MINOR(ucsi->version), > > > + UCSI_BCD_GET_SUBMINOR(ucsi->version)); > > > > nit: I think this doesn't need to be dev_info() and can be just > > dev_dbg(), but will > > defer to the maintainer. > > I think that's okay. > > Reviewewd-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> No, when drivers are working properly they are quiet, this needs to be dev_dbg(). thanks, greg k-h
Ack. Will make dev_dbg on the next iteration. This seems like a good addition to the style guide too: https://www.kernel.org/doc/html/v6.7/process/coding-style.html#printing-kernel-messages. "When drivers are working properly, they are quiet. Prefer to use DEBUG messages unless something is wrong." What do you think Greg? On Wed, Jan 24, 2024 at 6:17 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > On Wed, Jan 24, 2024 at 03:51:58PM +0200, Heikki Krogerus wrote: > > On Wed, Jan 24, 2024 at 12:12:26AM -0800, Prashant Malani wrote: > > > Hi Abhishek, > > > > > > On Tue, Jan 23, 2024 at 2:30 PM Abhishek Pandit-Subedi > > > <abhishekpandit@google.com> wrote: > > > > > > > > From: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> > > > > > > > > Between UCSI 1.2 and UCSI 2.0, the size of the MESSAGE_IN region was > > > > increased from 16 to 256. In order to avoid overflowing reads for older > > > > systems, add a mechanism to use the read UCSI version to truncate read > > > > sizes on UCSI v1.2. > > > > > > > > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org> > > > I have one nit (mentioned in side-band but reproducing here for consistency), > > > but will defer to the maintainer on that. > > > > > > The above notwithstanding, FWIW: > > > Reviewed-by: Prashant Malani<pmalani@chromium.org> > > > > > > > @@ -1556,6 +1569,15 @@ int ucsi_register(struct ucsi *ucsi) > > > > if (!ucsi->version) > > > > return -ENODEV; > > > > > > > > + /* > > > > + * Version format is JJ.M.N (JJ = Major version, M = Minor version, > > > > + * N = sub-minor version). > > > > + */ > > > > + dev_info(ucsi->dev, "Registered UCSI interface with version %x.%x.%x", > > > > + UCSI_BCD_GET_MAJOR(ucsi->version), > > > > + UCSI_BCD_GET_MINOR(ucsi->version), > > > > + UCSI_BCD_GET_SUBMINOR(ucsi->version)); > > > > > > nit: I think this doesn't need to be dev_info() and can be just > > > dev_dbg(), but will > > > defer to the maintainer. > > > > I think that's okay. > > > > Reviewewd-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> > > No, when drivers are working properly they are quiet, this needs to be > dev_dbg(). > > thanks, > > greg k-h >
On Wed, Jan 24, 2024 at 10:59:28AM -0800, Abhishek Pandit-Subedi wrote: > Ack. Will make dev_dbg on the next iteration. > > This seems like a good addition to the style guide too: > https://www.kernel.org/doc/html/v6.7/process/coding-style.html#printing-kernel-messages. > "When drivers are working properly, they are quiet. Prefer to use > DEBUG messages unless something is wrong." > > What do you think Greg? I think you need to stop top-posting :) But yes, that would be nice, hopefully people actually notice it there. Would you have read this and seen it? thanks, greg k-h
On Thu, Jan 25, 2024 at 3:16 PM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > On Wed, Jan 24, 2024 at 10:59:28AM -0800, Abhishek Pandit-Subedi wrote: > > Ack. Will make dev_dbg on the next iteration. > > > > This seems like a good addition to the style guide too: > > https://www.kernel.org/doc/html/v6.7/process/coding-style.html#printing-kernel-messages. > > "When drivers are working properly, they are quiet. Prefer to use > > DEBUG messages unless something is wrong." > > > > What do you think Greg? > > I think you need to stop top-posting :) > > But yes, that would be nice, hopefully people actually notice it there. > Would you have read this and seen it? > > thanks, > > greg k-h I blame gmail web-interface for the top-posting :) Prashant also mentioned the dev_info when we were reviewing this so I did a quick search for "kernel coding style" (to see if there was guidance) before sending this up so I would definitely have noticed it there. In Bluetooth (where I've previously contributed), dev_info is used for printing version info (example: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/bluetooth/btintel.c?h=v6.8-rc1#n337) and it's very useful for debugging so I assumed it was acceptable. The added benefit of this guidance being in the coding style guide is it's a quick change to checkpatch.pl to add a warning for this (and point to the coding style as the source). I'm fairly sure Chromium actually has a lint that warns whenever you use LOG_INFO(...) for similar reasons (too many INFO messages that should be DEBUG). I will send up a patch with the change soon (both to coding style and checkpatch.pl). Thanks, Abhishek
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