linux-stable.git/drivers/tty/serial, branch v6.1.78 Linux kernel stable tree serial: sc16is7xx: fix unconditional activation of THRI interrupt 2024-02-01T00:17:10+00:00 Hugo Villeneuve hvilleneuve@dimonoff.com 2023-12-11T17:13:53+00:00 b168029d67e95ada58023b7d6f2e0630c044ffd6 [ Upstream commit 9915753037eba7135b209fef4f2afeca841af816 ] Commit cc4c1d05eb10 ("sc16is7xx: Properly resume TX after stop") changed behavior to unconditionnaly set the THRI interrupt in sc16is7xx_tx_proc(). For example when sending a 65 bytes message, and assuming the Tx FIFO is initially empty, sc16is7xx_handle_tx() will write the first 64 bytes of the message to the FIFO and sc16is7xx_tx_proc() will then activate THRI. When the THRI IRQ is fired, the driver will write the remaining byte of the message to the FIFO, and disable THRI by calling sc16is7xx_stop_tx(). When sending a 2 bytes message, sc16is7xx_handle_tx() will write the 2 bytes of the message to the FIFO and call sc16is7xx_stop_tx(), disabling THRI. After sc16is7xx_handle_tx() exits, control returns to sc16is7xx_tx_proc() which will unconditionally set THRI. When the THRI IRQ is fired, the driver simply acknowledges the interrupt and does nothing more, since all the data has already been written to the FIFO. This results in 2 register writes and 4 register reads all for nothing and taking precious cycles from the I2C/SPI bus. Fix this by enabling the THRI interrupt only when we fill the Tx FIFO to its maximum capacity and there are remaining bytes to send in the message. Fixes: cc4c1d05eb10 ("sc16is7xx: Properly resume TX after stop") Cc: <stable@vger.kernel.org> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231211171353.2901416-7-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 9915753037eba7135b209fef4f2afeca841af816 ]

Commit cc4c1d05eb10 ("sc16is7xx: Properly resume TX after stop") changed
behavior to unconditionnaly set the THRI interrupt in sc16is7xx_tx_proc().

For example when sending a 65 bytes message, and assuming the Tx FIFO is
initially empty, sc16is7xx_handle_tx() will write the first 64 bytes of the
message to the FIFO and sc16is7xx_tx_proc() will then activate THRI. When
the THRI IRQ is fired, the driver will write the remaining byte of the
message to the FIFO, and disable THRI by calling sc16is7xx_stop_tx().

When sending a 2 bytes message, sc16is7xx_handle_tx() will write the 2
bytes of the message to the FIFO and call sc16is7xx_stop_tx(), disabling
THRI. After sc16is7xx_handle_tx() exits, control returns to
sc16is7xx_tx_proc() which will unconditionally set THRI. When the THRI IRQ
is fired, the driver simply acknowledges the interrupt and does nothing
more, since all the data has already been written to the FIFO. This results
in 2 register writes and 4 register reads all for nothing and taking
precious cycles from the I2C/SPI bus.

Fix this by enabling the THRI interrupt only when we fill the Tx FIFO to
its maximum capacity and there are remaining bytes to send in the message.

Fixes: cc4c1d05eb10 ("sc16is7xx: Properly resume TX after stop")
Cc:  <stable@vger.kernel.org>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-7-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: sc16is7xx: Use port lock wrappers 2024-02-01T00:17:10+00:00 Thomas Gleixner tglx@linutronix.de 2023-09-14T18:38:12+00:00 49d733c4bbeeba0bb523d8b947ae717fdc70347c [ Upstream commit b465848be8a652e2c5fefe102661fb660cff8497 ] When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/r/20230914183831.587273-56-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: 9915753037eb ("serial: sc16is7xx: fix unconditional activation of THRI interrupt") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b465848be8a652e2c5fefe102661fb660cff8497 ]

When a serial port is used for kernel console output, then all
modifications to the UART registers which are done from other contexts,
e.g. getty, termios, are interference points for the kernel console.

So far this has been ignored and the printk output is based on the
principle of hope. The rework of the console infrastructure which aims to
support threaded and atomic consoles, requires to mark sections which
modify the UART registers as unsafe. This allows the atomic write function
to make informed decisions and eventually to restore operational state. It
also allows to prevent the regular UART code from modifying UART registers
while printk output is in progress.

All modifications of UART registers are guarded by the UART port lock,
which provides an obvious synchronization point with the console
infrastructure.

To avoid adding this functionality to all UART drivers, wrap the
spin_[un]lock*() invocations for uart_port::lock into helper functions
which just contain the spin_[un]lock*() invocations for now. In a
subsequent step these helpers will gain the console synchronization
mechanisms.

Converted with coccinelle. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20230914183831.587273-56-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 9915753037eb ("serial: sc16is7xx: fix unconditional activation of THRI interrupt")
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: sc16is7xx: improve do/while loop in sc16is7xx_irq() 2024-02-01T00:17:02+00:00 Hugo Villeneuve hvilleneuve@dimonoff.com 2023-12-21T23:18:12+00:00 0e0653d53af88120893a58164dff4dbb92c0b0b7 commit d5078509c8b06c5c472a60232815e41af81c6446 upstream. Simplify and improve readability by replacing while(1) loop with do {} while, and by using the keep_polling variable as the exit condition, making it more explicit. Fixes: 834449872105 ("sc16is7xx: Fix for multi-channel stall") Cc: <stable@vger.kernel.org> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231221231823.2327894-6-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d5078509c8b06c5c472a60232815e41af81c6446 upstream.

Simplify and improve readability by replacing while(1) loop with
do {} while, and by using the keep_polling variable as the exit
condition, making it more explicit.

Fixes: 834449872105 ("sc16is7xx: Fix for multi-channel stall")
Cc:  <stable@vger.kernel.org>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231221231823.2327894-6-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sc16is7xx: remove obsolete loop in sc16is7xx_port_irq() 2024-02-01T00:17:02+00:00 Hugo Villeneuve hvilleneuve@dimonoff.com 2023-12-21T23:18:11+00:00 80beb4424d48701f0e4cf924fb5263ce98a796f8 commit ed647256e8f226241ecff7baaecdb8632ffc7ec1 upstream. Commit 834449872105 ("sc16is7xx: Fix for multi-channel stall") changed sc16is7xx_port_irq() from looping multiple times when there was still interrupts to serve. It simply changed the do {} while(1) loop to a do {} while(0) loop, which makes the loop itself now obsolete. Clean the code by removing this obsolete do {} while(0) loop. Fixes: 834449872105 ("sc16is7xx: Fix for multi-channel stall") Cc: <stable@vger.kernel.org> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231221231823.2327894-5-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ed647256e8f226241ecff7baaecdb8632ffc7ec1 upstream.

Commit 834449872105 ("sc16is7xx: Fix for multi-channel stall") changed
sc16is7xx_port_irq() from looping multiple times when there was still
interrupts to serve. It simply changed the do {} while(1) loop to a
do {} while(0) loop, which makes the loop itself now obsolete.

Clean the code by removing this obsolete do {} while(0) loop.

Fixes: 834449872105 ("sc16is7xx: Fix for multi-channel stall")
Cc:  <stable@vger.kernel.org>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231221231823.2327894-5-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sc16is7xx: fix invalid sc16is7xx_lines bitfield in case of probe error 2024-02-01T00:17:02+00:00 Hugo Villeneuve hvilleneuve@dimonoff.com 2023-12-21T23:18:08+00:00 de8e41f78f76c7fb4d20f69e687b38a5122dff2a commit 8a1060ce974919f2a79807527ad82ac39336eda2 upstream. If an error occurs during probing, the sc16is7xx_lines bitfield may be left in a state that doesn't represent the correct state of lines allocation. For example, in a system with two SC16 devices, if an error occurs only during probing of channel (port) B of the second device, sc16is7xx_lines final state will be 00001011b instead of the expected 00000011b. This is caused in part because of the "i--" in the for/loop located in the out_ports: error path. Fix this by checking the return value of uart_add_one_port() and set line allocation bit only if this was successful. This allows the refactor of the obfuscated for(i--...) loop in the error path, and properly call uart_remove_one_port() only when needed, and properly unset line allocation bits. Also use same mechanism in remove() when calling uart_remove_one_port(). Fixes: c64349722d14 ("sc16is7xx: support multiple devices") Cc: <stable@vger.kernel.org> Cc: Yury Norov <yury.norov@gmail.com> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231221231823.2327894-2-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8a1060ce974919f2a79807527ad82ac39336eda2 upstream.

If an error occurs during probing, the sc16is7xx_lines bitfield may be left
in a state that doesn't represent the correct state of lines allocation.

For example, in a system with two SC16 devices, if an error occurs only
during probing of channel (port) B of the second device, sc16is7xx_lines
final state will be 00001011b instead of the expected 00000011b.

This is caused in part because of the "i--" in the for/loop located in
the out_ports: error path.

Fix this by checking the return value of uart_add_one_port() and set line
allocation bit only if this was successful. This allows the refactor of
the obfuscated for(i--...) loop in the error path, and properly call
uart_remove_one_port() only when needed, and properly unset line allocation
bits.

Also use same mechanism in remove() when calling uart_remove_one_port().

Fixes: c64349722d14 ("sc16is7xx: support multiple devices")
Cc:  <stable@vger.kernel.org>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231221231823.2327894-2-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO 2024-02-01T00:17:02+00:00 Hugo Villeneuve hvilleneuve@dimonoff.com 2023-12-11T17:13:52+00:00 416b10d2817c94db86829fb92ad43ce7d002c573 commit dbf4ab821804df071c8b566d9813083125e6d97b upstream. The SC16IS7XX IC supports a burst mode to access the FIFOs where the initial register address is sent ($00), followed by all the FIFO data without having to resend the register address each time. In this mode, the IC doesn't increment the register address for each R/W byte. The regmap_raw_read() and regmap_raw_write() are functions which can perform IO over multiple registers. They are currently used to read/write from/to the FIFO, and although they operate correctly in this burst mode on the SPI bus, they would corrupt the regmap cache if it was not disabled manually. The reason is that when the R/W size is more than 1 byte, these functions assume that the register address is incremented and handle the cache accordingly. Convert FIFO R/W functions to use the regmap _noinc_ versions in order to remove the manual cache control which was a workaround when using the _raw_ versions. FIFO registers are properly declared as volatile so cache will not be used/updated for FIFO accesses. Fixes: dfeae619d781 ("serial: sc16is7xx") Cc: <stable@vger.kernel.org> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231211171353.2901416-6-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit dbf4ab821804df071c8b566d9813083125e6d97b upstream.

The SC16IS7XX IC supports a burst mode to access the FIFOs where the
initial register address is sent ($00), followed by all the FIFO data
without having to resend the register address each time. In this mode, the
IC doesn't increment the register address for each R/W byte.

The regmap_raw_read() and regmap_raw_write() are functions which can
perform IO over multiple registers. They are currently used to read/write
from/to the FIFO, and although they operate correctly in this burst mode on
the SPI bus, they would corrupt the regmap cache if it was not disabled
manually. The reason is that when the R/W size is more than 1 byte, these
functions assume that the register address is incremented and handle the
cache accordingly.

Convert FIFO R/W functions to use the regmap _noinc_ versions in order to
remove the manual cache control which was a workaround when using the
_raw_ versions. FIFO registers are properly declared as volatile so
cache will not be used/updated for FIFO accesses.

Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc:  <stable@vger.kernel.org>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-6-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sc16is7xx: change EFR lock to operate on each channels 2024-02-01T00:17:02+00:00 Hugo Villeneuve hvilleneuve@dimonoff.com 2023-12-11T17:13:51+00:00 4b068e55bf5ea7bab4d8a282c6a24b03e80c0b68 commit 4409df5866b7ff7686ba27e449ca97a92ee063c9 upstream. Now that the driver has been converted to use one regmap per port, change efr locking to operate on a channel basis instead of on the whole IC. Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port") Cc: <stable@vger.kernel.org> # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231211171353.2901416-5-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4409df5866b7ff7686ba27e449ca97a92ee063c9 upstream.

Now that the driver has been converted to use one regmap per port, change
efr locking to operate on a channel basis instead of on the whole IC.

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc:  <stable@vger.kernel.org> # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-5-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sc16is7xx: remove unused line structure member 2024-02-01T00:17:02+00:00 Hugo Villeneuve hvilleneuve@dimonoff.com 2023-12-11T17:13:50+00:00 f6c58552a8d9801b340211da41a94713fcb456f6 commit 41a308cbedb2a68a6831f0f2e992e296c4b8aff0 upstream. Now that the driver has been converted to use one regmap per port, the line structure member is no longer used, so remove it. Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port") Cc: <stable@vger.kernel.org> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231211171353.2901416-4-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 41a308cbedb2a68a6831f0f2e992e296c4b8aff0 upstream.

Now that the driver has been converted to use one regmap per port, the line
structure member is no longer used, so remove it.

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc:  <stable@vger.kernel.org>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-4-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sc16is7xx: remove global regmap from struct sc16is7xx_port 2024-02-01T00:17:02+00:00 Hugo Villeneuve hvilleneuve@dimonoff.com 2023-12-11T17:13:49+00:00 6dca71e6e14addf8955dd00c7e93f8116a1e67f6 commit f6959c5217bd799bcb770b95d3c09b3244e175c6 upstream. Remove global struct regmap so that it is more obvious that this regmap is to be used only in the probe function. Also add a comment to that effect in probe function. Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port") Cc: <stable@vger.kernel.org> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231211171353.2901416-3-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f6959c5217bd799bcb770b95d3c09b3244e175c6 upstream.

Remove global struct regmap so that it is more obvious that this
regmap is to be used only in the probe function.

Also add a comment to that effect in probe function.

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc:  <stable@vger.kernel.org>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-3-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sc16is7xx: remove wasteful static buffer in sc16is7xx_regmap_name() 2024-02-01T00:17:02+00:00 Hugo Villeneuve hvilleneuve@dimonoff.com 2023-12-11T17:13:48+00:00 9bcb019aee475179aa439b785497dcb0392b5ef4 commit 6bcab3c8acc88e265c570dea969fd04f137c8a4c upstream. Using a static buffer inside sc16is7xx_regmap_name() was a convenient and simple way to set the regmap name without having to allocate and free a buffer each time it is called. The drawback is that the static buffer wastes memory for nothing once regmap is fully initialized. Remove static buffer and use constant strings instead. This also avoids a truncation warning when using "%d" or "%u" in snprintf which was flagged by kernel test robot. Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port") Cc: <stable@vger.kernel.org> # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231211171353.2901416-2-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 6bcab3c8acc88e265c570dea969fd04f137c8a4c upstream.

Using a static buffer inside sc16is7xx_regmap_name() was a convenient and
simple way to set the regmap name without having to allocate and free a
buffer each time it is called. The drawback is that the static buffer
wastes memory for nothing once regmap is fully initialized.

Remove static buffer and use constant strings instead.

This also avoids a truncation warning when using "%d" or "%u" in snprintf
which was flagged by kernel test robot.

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc:  <stable@vger.kernel.org> # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-2-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>