lwn.git/drivers/tty/serial/pch_uart.c, branch docs-6.1

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

serial: pch: remove xmit circ_buf size double check

2022-05-05T20:42:46+00:00

One is in handle_tx() (as "min(xmit->head - xmit->tail, fifo_size))", another one in pop_tx() (as uart_circ_empty(xmit)). So keep only the latter. This makes the code simpler and size variable is not needed now. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20220503080808.28332-4-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

serial: pch: remove debug print from pop_tx

2022-05-05T20:42:46+00:00

It makes the code overly complicated for no good reason. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20220503080808.28332-3-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

serial: pch: decomission pch_uart_hal_write()

2022-05-05T20:42:46+00:00

It's horrid and if we inline it into callers, we can get rid of a lot of sugar around. So: * x_char handling becomes a single iowrite8. * xmit->buf handling is a single loop simply writing characters one by one directly from the buf instead of complex cnt_to_end computations. Until the buf is empty or fifo size is reached. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20220503080808.28332-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

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

2022-05-05T20:42:45+00:00

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: pch: move size check from pop_tx one level up

2022-05-05T20:42:45+00:00

'count' is zero in the pop_tx()'s comparison against 'size'. So the 'if' tries to find out if 'size' is negative or zero and returns in that case. But it cannot be negative, due to previous (size < 0) check in the caller: handle_tx(). So simply move this check from pop_tx() to handle_tx(). Now it's clear that pop_tx() is called only if fifo_size is non-zero. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20220503080613.27601-2-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