<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/i2c, branch v5.4.277</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>i2c: smbus: fix NULL function pointer dereference</title>
<updated>2024-05-02T14:18:37+00:00</updated>
<author>
<name>Wolfram Sang</name>
<email>wsa+renesas@sang-engineering.com</email>
</author>
<published>2024-04-26T06:44:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ad3c3ac7a03be3697114f781193dd3e9d97e6e23'/>
<id>ad3c3ac7a03be3697114f781193dd3e9d97e6e23</id>
<content type='text'>
[ Upstream commit 91811a31b68d3765b3065f4bb6d7d6d84a7cfc9f ]

Baruch reported an OOPS when using the designware controller as target
only. Target-only modes break the assumption of one transfer function
always being available. Fix this by always checking the pointer in
__i2c_transfer.

Reported-by: Baruch Siach &lt;baruch@tkos.co.il&gt;
Closes: https://lore.kernel.org/r/4269631780e5ba789cf1ae391eec1b959def7d99.1712761976.git.baruch@tkos.co.il
Fixes: 4b1acc43331d ("i2c: core changes for slave support")
[wsa: dropped the simplification in core-smbus to avoid theoretical regressions]
Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Tested-by: Baruch Siach &lt;baruch@tkos.co.il&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 91811a31b68d3765b3065f4bb6d7d6d84a7cfc9f ]

Baruch reported an OOPS when using the designware controller as target
only. Target-only modes break the assumption of one transfer function
always being available. Fix this by always checking the pointer in
__i2c_transfer.

Reported-by: Baruch Siach &lt;baruch@tkos.co.il&gt;
Closes: https://lore.kernel.org/r/4269631780e5ba789cf1ae391eec1b959def7d99.1712761976.git.baruch@tkos.co.il
Fixes: 4b1acc43331d ("i2c: core changes for slave support")
[wsa: dropped the simplification in core-smbus to avoid theoretical regressions]
Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Tested-by: Baruch Siach &lt;baruch@tkos.co.il&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: i801: Fix block process call transactions</title>
<updated>2024-02-23T07:25:10+00:00</updated>
<author>
<name>Jean Delvare</name>
<email>jdelvare@suse.de</email>
</author>
<published>2024-02-14T14:59:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d074d5ff5ae77b18300e5079c6bda6342a4d44b7'/>
<id>d074d5ff5ae77b18300e5079c6bda6342a4d44b7</id>
<content type='text'>
[ Upstream commit c1c9d0f6f7f1dbf29db996bd8e166242843a5f21 ]

According to the Intel datasheets, software must reset the block
buffer index twice for block process call transactions: once before
writing the outgoing data to the buffer, and once again before
reading the incoming data from the buffer.

The driver is currently missing the second reset, causing the wrong
portion of the block buffer to be read.

Signed-off-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Reported-by: Piotr Zakowski &lt;piotr.zakowski@intel.com&gt;
Closes: https://lore.kernel.org/linux-i2c/20240213120553.7b0ab120@endymion.delvare/
Fixes: 315cd67c9453 ("i2c: i801: Add Block Write-Block Read Process Call support")
Reviewed-by: Alexander Sverdlin &lt;alexander.sverdlin@gmail.com&gt;
Signed-off-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit c1c9d0f6f7f1dbf29db996bd8e166242843a5f21 ]

According to the Intel datasheets, software must reset the block
buffer index twice for block process call transactions: once before
writing the outgoing data to the buffer, and once again before
reading the incoming data from the buffer.

The driver is currently missing the second reset, causing the wrong
portion of the block buffer to be read.

Signed-off-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Reported-by: Piotr Zakowski &lt;piotr.zakowski@intel.com&gt;
Closes: https://lore.kernel.org/linux-i2c/20240213120553.7b0ab120@endymion.delvare/
Fixes: 315cd67c9453 ("i2c: i801: Add Block Write-Block Read Process Call support")
Reviewed-by: Alexander Sverdlin &lt;alexander.sverdlin@gmail.com&gt;
Signed-off-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: i801: Remove i801_set_block_buffer_mode</title>
<updated>2024-02-23T07:25:10+00:00</updated>
<author>
<name>Heiner Kallweit</name>
<email>hkallweit1@gmail.com</email>
</author>
<published>2021-11-18T22:58:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4de1489d8092e4aa3b9bdaf7c4fc444a53f09ef8'/>
<id>4de1489d8092e4aa3b9bdaf7c4fc444a53f09ef8</id>
<content type='text'>
[ Upstream commit 1e1d6582f483a4dba4ea03445e6f2f05d9de5bcf ]

If FEATURE_BLOCK_BUFFER is set then bit SMBAUXCTL_E32B is supported
and there's no benefit in reading it back. Origin of this check
seems to be 14 yrs ago when people were not completely sure which
chip versions support the block buffer mode.

Signed-off-by: Heiner Kallweit &lt;hkallweit1@gmail.com&gt;
Reviewed-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Tested-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Stable-dep-of: c1c9d0f6f7f1 ("i2c: i801: Fix block process call transactions")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 1e1d6582f483a4dba4ea03445e6f2f05d9de5bcf ]

If FEATURE_BLOCK_BUFFER is set then bit SMBAUXCTL_E32B is supported
and there's no benefit in reading it back. Origin of this check
seems to be 14 yrs ago when people were not completely sure which
chip versions support the block buffer mode.

Signed-off-by: Heiner Kallweit &lt;hkallweit1@gmail.com&gt;
Reviewed-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Tested-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Stable-dep-of: c1c9d0f6f7f1 ("i2c: i801: Fix block process call transactions")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: s3c24xx: fix transferring more than one message in polling mode</title>
<updated>2024-01-25T22:34:32+00:00</updated>
<author>
<name>Marek Szyprowski</name>
<email>m.szyprowski@samsung.com</email>
</author>
<published>2023-11-08T16:43:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ea5587946a15ef8df0498aced6f68ddb28f054fc'/>
<id>ea5587946a15ef8df0498aced6f68ddb28f054fc</id>
<content type='text'>
[ Upstream commit 990489e1042c6c5d6bccf56deca68f8dbeed8180 ]

To properly handle ACK on the bus when transferring more than one
message in polling mode, move the polling handling loop from
s3c24xx_i2c_message_start() to s3c24xx_i2c_doxfer(). This way
i2c_s3c_irq_nextbyte() is always executed till the end, properly
acknowledging the IRQ bits and no recursive calls to
i2c_s3c_irq_nextbyte() are made.

While touching this, also fix finishing transfers in polling mode by
using common code path and always waiting for the bus to become idle
and disabled.

Fixes: 117053f77a5a ("i2c: s3c2410: Add polling mode support")
Signed-off-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Reviewed-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 990489e1042c6c5d6bccf56deca68f8dbeed8180 ]

To properly handle ACK on the bus when transferring more than one
message in polling mode, move the polling handling loop from
s3c24xx_i2c_message_start() to s3c24xx_i2c_doxfer(). This way
i2c_s3c_irq_nextbyte() is always executed till the end, properly
acknowledging the IRQ bits and no recursive calls to
i2c_s3c_irq_nextbyte() are made.

While touching this, also fix finishing transfers in polling mode by
using common code path and always waiting for the bus to become idle
and disabled.

Fixes: 117053f77a5a ("i2c: s3c2410: Add polling mode support")
Signed-off-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Reviewed-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: s3c24xx: fix read transfers in polling mode</title>
<updated>2024-01-25T22:34:32+00:00</updated>
<author>
<name>Marek Szyprowski</name>
<email>m.szyprowski@samsung.com</email>
</author>
<published>2023-11-08T16:43:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=90734f1cdee848769dc4135deedf9309c00f697e'/>
<id>90734f1cdee848769dc4135deedf9309c00f697e</id>
<content type='text'>
[ Upstream commit 0d9cf23ed55d7ba3ab26d617a3ae507863674c8f ]

To properly handle read transfers in polling mode, no waiting for the ACK
state is needed as it will never come. Just wait a bit to ensure start
state is on the bus and continue processing next bytes.

Fixes: 117053f77a5a ("i2c: s3c2410: Add polling mode support")
Signed-off-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Reviewed-by: Chanho Park &lt;chanho61.park@samsung.com&gt;
Reviewed-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 0d9cf23ed55d7ba3ab26d617a3ae507863674c8f ]

To properly handle read transfers in polling mode, no waiting for the ACK
state is needed as it will never come. Just wait a bit to ensure start
state is on the bus and continue processing next bytes.

Fixes: 117053f77a5a ("i2c: s3c2410: Add polling mode support")
Signed-off-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Reviewed-by: Chanho Park &lt;chanho61.park@samsung.com&gt;
Reviewed-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: core: Fix atomic xfer check for non-preempt config</title>
<updated>2024-01-15T17:25:27+00:00</updated>
<author>
<name>Benjamin Bara</name>
<email>benjamin.bara@skidata.com</email>
</author>
<published>2024-01-04T08:17:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5af5e946c4dd209c877bd2b5616aa82f20bed54e'/>
<id>5af5e946c4dd209c877bd2b5616aa82f20bed54e</id>
<content type='text'>
commit a3368e1186e3ce8e38f78cbca019622095b1f331 upstream.

Since commit aa49c90894d0 ("i2c: core: Run atomic i2c xfer when
!preemptible"), the whole reboot/power off sequence on non-preempt kernels
is using atomic i2c xfer, as !preemptible() always results to 1.

During device_shutdown(), the i2c might be used a lot and not all busses
have implemented an atomic xfer handler. This results in a lot of
avoidable noise, like:

[   12.687169] No atomic I2C transfer handler for 'i2c-0'
[   12.692313] WARNING: CPU: 6 PID: 275 at drivers/i2c/i2c-core.h:40 i2c_smbus_xfer+0x100/0x118
...

Fix this by allowing non-atomic xfer when the interrupts are enabled, as
it was before.

Link: https://lore.kernel.org/r/20231222230106.73f030a5@yea
Link: https://lore.kernel.org/r/20240102150350.3180741-1-mwalle@kernel.org
Link: https://lore.kernel.org/linux-i2c/13271b9b-4132-46ef-abf8-2c311967bb46@mailbox.org/
Fixes: aa49c90894d0 ("i2c: core: Run atomic i2c xfer when !preemptible")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Benjamin Bara &lt;benjamin.bara@skidata.com&gt;
Tested-by: Michael Walle &lt;mwalle@kernel.org&gt;
Tested-by: Tor Vic &lt;torvic9@mailbox.org&gt;
[wsa: removed a comment which needs more work, code is ok]
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a3368e1186e3ce8e38f78cbca019622095b1f331 upstream.

Since commit aa49c90894d0 ("i2c: core: Run atomic i2c xfer when
!preemptible"), the whole reboot/power off sequence on non-preempt kernels
is using atomic i2c xfer, as !preemptible() always results to 1.

During device_shutdown(), the i2c might be used a lot and not all busses
have implemented an atomic xfer handler. This results in a lot of
avoidable noise, like:

[   12.687169] No atomic I2C transfer handler for 'i2c-0'
[   12.692313] WARNING: CPU: 6 PID: 275 at drivers/i2c/i2c-core.h:40 i2c_smbus_xfer+0x100/0x118
...

Fix this by allowing non-atomic xfer when the interrupts are enabled, as
it was before.

Link: https://lore.kernel.org/r/20231222230106.73f030a5@yea
Link: https://lore.kernel.org/r/20240102150350.3180741-1-mwalle@kernel.org
Link: https://lore.kernel.org/linux-i2c/13271b9b-4132-46ef-abf8-2c311967bb46@mailbox.org/
Fixes: aa49c90894d0 ("i2c: core: Run atomic i2c xfer when !preemptible")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Benjamin Bara &lt;benjamin.bara@skidata.com&gt;
Tested-by: Michael Walle &lt;mwalle@kernel.org&gt;
Tested-by: Tor Vic &lt;torvic9@mailbox.org&gt;
[wsa: removed a comment which needs more work, code is ok]
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: aspeed: Handle the coalesced stop conditions with the start conditions.</title>
<updated>2024-01-08T10:29:45+00:00</updated>
<author>
<name>Quan Nguyen</name>
<email>quan@os.amperecomputing.com</email>
</author>
<published>2023-12-11T10:22:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=624659563e2693010879e5486dd632a58d1605ea'/>
<id>624659563e2693010879e5486dd632a58d1605ea</id>
<content type='text'>
[ Upstream commit b4cc1cbba5195a4dd497cf2f8f09e7807977d543 ]

Some masters may drive the transfers with low enough latency between
the nak/stop phase of the current command and the start/address phase
of the following command that the interrupts are coalesced by the
time we process them.
Handle the stop conditions before processing SLAVE_MATCH to fix the
complaints that sometimes occur below.

"aspeed-i2c-bus 1e78a040.i2c-bus: irq handled != irq. Expected
0x00000086, but was 0x00000084"

Fixes: f9eb91350bb2 ("i2c: aspeed: added slave support for Aspeed I2C driver")
Signed-off-by: Quan Nguyen &lt;quan@os.amperecomputing.com&gt;
Reviewed-by: Andrew Jeffery &lt;andrew@codeconstruct.com.au&gt;
Reviewed-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b4cc1cbba5195a4dd497cf2f8f09e7807977d543 ]

Some masters may drive the transfers with low enough latency between
the nak/stop phase of the current command and the start/address phase
of the following command that the interrupts are coalesced by the
time we process them.
Handle the stop conditions before processing SLAVE_MATCH to fix the
complaints that sometimes occur below.

"aspeed-i2c-bus 1e78a040.i2c-bus: irq handled != irq. Expected
0x00000086, but was 0x00000084"

Fixes: f9eb91350bb2 ("i2c: aspeed: added slave support for Aspeed I2C driver")
Signed-off-by: Quan Nguyen &lt;quan@os.amperecomputing.com&gt;
Reviewed-by: Andrew Jeffery &lt;andrew@codeconstruct.com.au&gt;
Reviewed-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: i801: fix potential race in i801_block_transaction_byte_by_byte</title>
<updated>2023-11-28T16:50:21+00:00</updated>
<author>
<name>Heiner Kallweit</name>
<email>hkallweit1@gmail.com</email>
</author>
<published>2023-09-09T20:25:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cac054d103249aa3d92061c989c9ae99fdf848ce'/>
<id>cac054d103249aa3d92061c989c9ae99fdf848ce</id>
<content type='text'>
commit f78ca48a8ba9cdec96e8839351e49eec3233b177 upstream.

Currently we set SMBHSTCNT_LAST_BYTE only after the host has started
receiving the last byte. If we get e.g. preempted before setting
SMBHSTCNT_LAST_BYTE, the host may be finished with receiving the byte
before SMBHSTCNT_LAST_BYTE is set.
Therefore change the code to set SMBHSTCNT_LAST_BYTE before writing
SMBHSTSTS_BYTE_DONE for the byte before the last byte. Now the code
is also consistent with what we do in i801_isr_byte_done().

Reported-by: Jean Delvare &lt;jdelvare@suse.com&gt;
Closes: https://lore.kernel.org/linux-i2c/20230828152747.09444625@endymion.delvare/
Cc: stable@vger.kernel.org
Acked-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Heiner Kallweit &lt;hkallweit1@gmail.com&gt;
Reviewed-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit f78ca48a8ba9cdec96e8839351e49eec3233b177 upstream.

Currently we set SMBHSTCNT_LAST_BYTE only after the host has started
receiving the last byte. If we get e.g. preempted before setting
SMBHSTCNT_LAST_BYTE, the host may be finished with receiving the byte
before SMBHSTCNT_LAST_BYTE is set.
Therefore change the code to set SMBHSTCNT_LAST_BYTE before writing
SMBHSTSTS_BYTE_DONE for the byte before the last byte. Now the code
is also consistent with what we do in i801_isr_byte_done().

Reported-by: Jean Delvare &lt;jdelvare@suse.com&gt;
Closes: https://lore.kernel.org/linux-i2c/20230828152747.09444625@endymion.delvare/
Cc: stable@vger.kernel.org
Acked-by: Andi Shyti &lt;andi.shyti@kernel.org&gt;
Signed-off-by: Heiner Kallweit &lt;hkallweit1@gmail.com&gt;
Reviewed-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: core: Run atomic i2c xfer when !preemptible</title>
<updated>2023-11-28T16:50:19+00:00</updated>
<author>
<name>Benjamin Bara</name>
<email>benjamin.bara@skidata.com</email>
</author>
<published>2023-07-15T07:53:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=25eb381a736e7ae39a4245ef5c96484eb1073809'/>
<id>25eb381a736e7ae39a4245ef5c96484eb1073809</id>
<content type='text'>
commit aa49c90894d06e18a1ee7c095edbd2f37c232d02 upstream.

Since bae1d3a05a8b, i2c transfers are non-atomic if preemption is
disabled. However, non-atomic i2c transfers require preemption (e.g. in
wait_for_completion() while waiting for the DMA).

panic() calls preempt_disable_notrace() before calling
emergency_restart(). Therefore, if an i2c device is used for the
restart, the xfer should be atomic. This avoids warnings like:

[   12.667612] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x33c/0x6b0
[   12.676926] Voluntary context switch within RCU read-side critical section!
...
[   12.742376]  schedule_timeout from wait_for_completion_timeout+0x90/0x114
[   12.749179]  wait_for_completion_timeout from tegra_i2c_wait_completion+0x40/0x70
...
[   12.994527]  atomic_notifier_call_chain from machine_restart+0x34/0x58
[   13.001050]  machine_restart from panic+0x2a8/0x32c

Use !preemptible() instead, which is basically the same check as
pre-v5.2.

Fixes: bae1d3a05a8b ("i2c: core: remove use of in_atomic()")
Cc: stable@vger.kernel.org # v5.2+
Suggested-by: Dmitry Osipenko &lt;dmitry.osipenko@collabora.com&gt;
Acked-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Reviewed-by: Dmitry Osipenko &lt;dmitry.osipenko@collabora.com&gt;
Tested-by: Nishanth Menon &lt;nm@ti.com&gt;
Signed-off-by: Benjamin Bara &lt;benjamin.bara@skidata.com&gt;
Link: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v7-2-18699d5dcd76@skidata.com
Signed-off-by: Lee Jones &lt;lee@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit aa49c90894d06e18a1ee7c095edbd2f37c232d02 upstream.

Since bae1d3a05a8b, i2c transfers are non-atomic if preemption is
disabled. However, non-atomic i2c transfers require preemption (e.g. in
wait_for_completion() while waiting for the DMA).

panic() calls preempt_disable_notrace() before calling
emergency_restart(). Therefore, if an i2c device is used for the
restart, the xfer should be atomic. This avoids warnings like:

[   12.667612] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x33c/0x6b0
[   12.676926] Voluntary context switch within RCU read-side critical section!
...
[   12.742376]  schedule_timeout from wait_for_completion_timeout+0x90/0x114
[   12.749179]  wait_for_completion_timeout from tegra_i2c_wait_completion+0x40/0x70
...
[   12.994527]  atomic_notifier_call_chain from machine_restart+0x34/0x58
[   13.001050]  machine_restart from panic+0x2a8/0x32c

Use !preemptible() instead, which is basically the same check as
pre-v5.2.

Fixes: bae1d3a05a8b ("i2c: core: remove use of in_atomic()")
Cc: stable@vger.kernel.org # v5.2+
Suggested-by: Dmitry Osipenko &lt;dmitry.osipenko@collabora.com&gt;
Acked-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Reviewed-by: Dmitry Osipenko &lt;dmitry.osipenko@collabora.com&gt;
Tested-by: Nishanth Menon &lt;nm@ti.com&gt;
Signed-off-by: Benjamin Bara &lt;benjamin.bara@skidata.com&gt;
Link: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v7-2-18699d5dcd76@skidata.com
Signed-off-by: Lee Jones &lt;lee@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: sun6i-p2wi: Prevent potential division by zero</title>
<updated>2023-11-28T16:50:15+00:00</updated>
<author>
<name>Axel Lin</name>
<email>axel.lin@ingics.com</email>
</author>
<published>2016-04-13T00:54:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a8f829886d47dba8d19834332fbdac67f2f7d26a'/>
<id>a8f829886d47dba8d19834332fbdac67f2f7d26a</id>
<content type='text'>
[ Upstream commit 5ac61d26b8baff5b2e5a9f3dc1ef63297e4b53e7 ]

Make sure we don't OOPS in case clock-frequency is set to 0 in a DT. The
variable set here is later used as a divisor.

Signed-off-by: Axel Lin &lt;axel.lin@ingics.com&gt;
Acked-by: Boris Brezillon &lt;boris.brezillon@free-electrons.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 5ac61d26b8baff5b2e5a9f3dc1ef63297e4b53e7 ]

Make sure we don't OOPS in case clock-frequency is set to 0 in a DT. The
variable set here is later used as a divisor.

Signed-off-by: Axel Lin &lt;axel.lin@ingics.com&gt;
Acked-by: Boris Brezillon &lt;boris.brezillon@free-electrons.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
