linux-stable.git/drivers/tty/serial/pch_uart.c, branch linux-5.18.y

serial: pch: don't overwrite xmit->buf[0] by x_char

2022-06-09T08:30:53+00:00

commit d9f3af4fbb1d955bbaf872d9e76502f6e3e803cb upstream.

When x_char is to be sent, the TX path overwrites whatever is in the
circular buffer at offset 0 with x_char and sends it using
pch_uart_hal_write(). I don't understand how this was supposed to work
if xmit->buf[0] already contained some character. It must have been
lost.

Remove this whole pop_tx_x() concept and do the work directly in the
callers. (Without printing anything using dev_dbg().)

Cc: 
Fixes: 3c6a483275f4 (Serial: EG20T: add PCH_UART driver)
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20220503080808.28332-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

serial: make uart_console_write->putchar()'s character an unsigned char

2022-03-03T14:06:31+00:00

Currently, uart_console_write->putchar's second parameter (the
character) is of type int. It makes little sense, provided uart_console_write()
accepts the input string as "const char *s" and passes its content -- the
characters -- to putchar(). So switch the character's type to unsigned
char.

We don't use char as that is signed on some platforms. That would cause
troubles for drivers which (implicitly) cast the char to u16 when
writing to the device. Sign extension would happen in that case and the
value written would be completely different to the provided char. DZ is
an example of such a driver -- on MIPS, it uses u16 for dz_out in
dz_console_putchar().

Note we do the char -> uchar conversion implicitly in
uart_console_write(). Provided we do not change size of the data type,
sign extension does not happen there, so the problem is void.

This makes the types consistent and unified with the rest of the uart
layer, which uses unsigned char in most places already. One exception is
xmit_buf, but that is going to be converted later.

Cc: Paul Cercueil 
Cc: Tobias Klauser 
Cc: Russell King 
Cc: Vineet Gupta 
Cc: Nicolas Ferre 
Cc: Alexandre Belloni 
Cc: Ludovic Desroches 
Cc: Florian Fainelli 
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: Alexander Shiyan 
Cc: Baruch Siach 
Cc: "Maciej W. Rozycki" 
Cc: Paul Walmsley 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Pengutronix Kernel Team 
Cc: Fabio Estevam 
Cc: NXP Linux Team 
Cc: Karol Gugala 
Cc: Mateusz Holenko 
Cc: Vladimir Zapolskiy 
Cc: Neil Armstrong 
Cc: Kevin Hilman 
Cc: Jerome Brunet 
Cc: Martin Blumenstingl 
Cc: Taichi Sugaya 
Cc: Takao Orito 
Cc: Liviu Dudau 
Cc: Sudeep Holla 
Cc: Lorenzo Pieralisi 
Cc: "Andreas Färber" 
Cc: Manivannan Sadhasivam 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Andy Gross 
Cc: Bjorn Andersson 
Cc: Krzysztof Kozlowski 
Cc: Orson Zhai 
Cc: Baolin Wang 
Cc: Chunyan Zhang 
Cc: Patrice Chotard 
Cc: Maxime Coquelin 
Cc: Alexandre Torgue 
Cc: "David S. Miller" 
Cc: Peter Korsgaard 
Cc: Michal Simek 
Acked-by: Richard Genoud  [atmel_serial]
Acked-by: Uwe Kleine-König 
Acked-by: Paul Cercueil 
Acked-by: Neil Armstrong  # meson_serial
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20220303080831.21783-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

serial: pch_uart: fix build error with !CONFIG_DEBUG_FS

2021-03-23T09:31:09+00:00

Fix the build error with CONFIG_DEBUG_FS is not set:

drivers/tty/serial/pch_uart.c: In function 'pch_uart_init_port':
drivers/tty/serial/pch_uart.c:1815:9: error: 'port_regs_ops' undeclared (first use in this function)
 1815 |        &port_regs_ops);
      |         ^~~~~~~~~~~~~

This commit get rid of the CONFIG_PM_SLEEP ifdefery to
fix the build error.

Fixes: 1f8a51ee3242 ("tty: serial: pch_uart.c: remove debugfs dentry pointer")
Reported-by: Hulk Robot 
Signed-off-by: Wei Yongjun 
Link: https://lore.kernel.org/r/20210322122601.2980258-1-weiyongjun1@huawei.com
Signed-off-by: Greg Kroah-Hartman

tty: serial: pch_uart.c: remove debugfs dentry pointer

2021-03-10T08:34:05+00:00

No need to keep around the dentry pointer for the debugfs file if all it
is used for is to remove it when we are wanting to clean up, as the
pointer can be looked up directly from debugfs instead.

This also removes pointless #ifdef CONFIG_DEBUG_FS brackets as the
compiler is smart enough to handle this properly if debugfs is disabled
without us having to worry about it.

Cc: Jiri Slaby 
Cc: linux-serial@vger.kernel.org
Link: https://lore.kernel.org/r/20210216145900.3835160-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

pch_uart: drop double zeroing

2020-09-27T12:17:43+00:00

sg_init_table zeroes its first argument, so the allocation of that argument
doesn't have to.

the semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// 
@@
expression x,n,flags;
@@

x =
- kcalloc
+ kmalloc_array
  (n,sizeof(struct scatterlist),flags)
...
sg_init_table(x,n)
// 

Signed-off-by: Julia Lawall 

Link: https://lore.kernel.org/r/1600601186-7420-2-git-send-email-Julia.Lawall@inria.fr
Signed-off-by: Greg Kroah-Hartman

serial: pch_uart: use generic power management

2020-07-21T18:04:54+00:00

Drivers using legacy PM have to manage PCI states and device's PM states
themselves. They also need to take care of configuration registers.

With improved and powerful support of generic PM, PCI Core takes care of
above mentioned, device-independent, jobs.

This driver makes use of PCI helper functions like
pci_save/restore_state(), pci_enable_device() and pci_set_power_state()
to do required operations. In generic mode, they are no longer needed.

Change function parameter in both .suspend() and .resume() to
"struct device*" type. Use dev_get_drvdata() to get drv data.

Compile-tested only.

Signed-off-by: Vaibhav Gupta 
Link: https://lore.kernel.org/r/20200720120414.399961-1-vaibhavgupta40@gmail.com
Signed-off-by: Greg Kroah-Hartman

tty: serial: pch_uart: Use scnprintf() for avoiding potential buffer overflow

2020-03-18T11:59:29+00:00

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Signed-off-by: Takashi Iwai 
Link: https://lore.kernel.org/r/20200311092930.24433-1-tiwai@suse.de
Signed-off-by: Greg Kroah-Hartman

tty/serial: pmac_zilog: Don't check port->sysrq

2019-12-18T14:04:56+00:00

uart_handle_sysrq_char() already handles it.

Signed-off-by: Dmitry Safonov 
Link: https://lore.kernel.org/r/20191213000657.931618-31-dima@arista.com
Signed-off-by: Greg Kroah-Hartman

tty/serial: Migrate pch_uart to use has_sysrq

2019-12-18T14:04:55+00:00

The SUPPORT_SYSRQ ifdeffery is not nice as:
- May create misunderstanding about sizeof(struct uart_port) between
  different objects
- Prevents moving functions from serial_core.h
- Reduces readability (well, it's ifdeffery - it's hard to follow)

In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added.
Initialise it in driver's probe and remove ifdeffery.

Signed-off-by: Dmitry Safonov 
Link: https://lore.kernel.org/r/20191213000657.931618-30-dima@arista.com
Signed-off-by: Greg Kroah-Hartman

tty: serial: pch_uart: correct usage of dma_unmap_sg

2019-11-13T13:54:15+00:00

Per Documentation/DMA-API-HOWTO.txt,
To unmap a scatterlist, just call:
	dma_unmap_sg(dev, sglist, nents, direction);

.. note::

	The 'nents' argument to the dma_unmap_sg call must be
	the _same_ one you passed into the dma_map_sg call,
	it should _NOT_ be the 'count' value _returned_ from the
	dma_map_sg call.

However in the driver, priv->nent is directly assigned with value
returned from dma_map_sg, and dma_unmap_sg use priv->nent for unmap,
this breaks the API usage.

So introduce a new entry orig_nent to remember 'nents'.

Fixes: da3564ee027e ("pch_uart: add multi-scatter processing")
Signed-off-by: Peng Fan 
Link: https://lore.kernel.org/r/1573623259-6339-1-git-send-email-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman