linux-stable.git/drivers/tty/serial/pch_uart.c, branch linux-6.8.y

serial: pch: Use port lock wrappers

2023-09-18T09:18:13+00:00

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 
Signed-off-by: John Ogness 
Link: https://lore.kernel.org/r/20230914183831.587273-46-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman

tty: pcn_uart: fix memory leak with using debugfs_lookup()

2023-02-08T12:09:55+00:00

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Cc: Jiri Slaby 
Link: https://lore.kernel.org/r/20230202141221.2293012-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

serial: pch_uart: Pass correct sg to dma_unmap_sg()

2023-01-19T13:54:56+00:00

A local variable sg is used to store scatterlist pointer in
pch_dma_tx_complete(). The for loop doing Tx byte accounting before
dma_unmap_sg() alters sg in its increment statement. Therefore, the
pointer passed into dma_unmap_sg() won't match to the one given to
dma_map_sg().

To fix the problem, use priv->sg_tx_p directly in dma_unmap_sg()
instead of the local variable.

Fixes: da3564ee027e ("pch_uart: add multi-scatter processing")
Cc: stable@vger.kernel.org
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20230103093435.4396-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: pch: Fix PCI device refcount leak in pch_request_dma()

2022-11-22T16:58:51+00:00

As comment of pci_get_slot() says, it returns a pci_device with its
refcount increased. The caller must decrement the reference count by
calling pci_dev_put().

Since 'dma_dev' is only used to filter the channel in filter(), we can
call pci_dev_put() before exiting from pch_request_dma(). Add the
missing pci_dev_put() for the normal and error path.

Fixes: 3c6a483275f4 ("Serial: EG20T: add PCH_UART driver")
Signed-off-by: Xiongfeng Wang 
Link: https://lore.kernel.org/r/20221122114559.27692-1-wangxiongfeng2@huawei.com
Signed-off-by: Greg Kroah-Hartman

serial: pch_uart: Use uart_xmit_advance()

2022-11-03T02:35:41+00:00

Take advantage of the new uart_xmit_advance() helper.

Reviewed-by: Andy Shevchenko 
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20221019091151.6692-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: pch_uart: CIRC_CNT_TO_END() is enough

2022-08-30T12:23:05+00:00

Testing also CIRC_CNT() with CIRC_CNT_TO_END() is unnecessary because
to latter alone covers all necessary cases.

Reviewed-by: Jiri Slaby 
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20220823141839.165244-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: Make ->set_termios() old ktermios const

2022-08-30T12:22:35+00:00

There should be no reason to adjust old ktermios which is going to get
discarded anyway.

Reviewed-by: Andy Shevchenko 
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20220816115739.10928-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: Consolidate BOTH_EMPTY use

2022-06-27T12:41:31+00:00

Per file BOTH_EMPTY defines are littering our source code here and
there. Define once in serial.h and create helper for the check
too.

Reviewed-by: Jiri Slaby 
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20220624205424.12686-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: pch: inline pop_tx() into handle_tx()

2022-05-05T20:42:47+00:00

Given pop_tx() is a simple loop, inline it directly into handle_tx().

The code in handle_tx() looks much saner and straightforward now.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20220503080808.28332-6-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

serial: pch: simplify pop_tx() even more

2022-05-05T20:42:47+00:00

1) take uart_tx_stopped into account every loop (the same as other uart
   drivers)
2) no need for 'count' variable, operate on 'size' directly

This allows inlining this into handle_tx() nicely in the next patch.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20220503080808.28332-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman