kernel/linux.git/drivers/tty/serial/meson_uart.c, branch v6.3.2

serial: meson: Use uart_xmit_advance()

2022-11-03T02:35:42+00:00

Take advantage of the new uart_xmit_advance() helper. Acked-by: Martin Blumenstingl Acked-by: Neil Armstrong Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20221019091151.6692-23-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

tty: serial: meson: Use devm_clk_get_enabled() helper

2022-08-30T12:15:33+00:00

The devm_clk_get_enabled() helper: - calls devm_clk_get() - calls clk_prepare_enable() and registers what is needed in order to call clk_disable_unprepare() when needed, as a managed resource. This simplifies the code, the error handling paths and avoid the need of a dedicated function used with devm_add_action_or_reset(). That said, meson_uart_probe_clock() is now more or less the same as devm_clk_get_enabled(), so use this function directly instead. This also fixes an (unlikely) unchecked devm_add_action_or_reset() error. Based on my test with allyesconfig, this reduces the .o size from: text data bss dec hex filename 16350 5016 128 21494 53f6 drivers/tty/serial/meson_uart.o down to: 15415 4784 128 20327 4f67 drivers/tty/serial/meson_uart.o Reviewed-by: Neil Armstrong Signed-off-by: Christophe JAILLET Link: https://lore.kernel.org/r/3f18638cb3cf08ed8817addca1402ed5e3bd3602.1661328361.git.christophe.jaillet@wanadoo.fr Signed-off-by: Greg Kroah-Hartman

serial: Convert SERIAL_XMIT_SIZE to UART_XMIT_SIZE

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

Both UART_XMIT_SIZE and SERIAL_XMIT_SIZE are defined. Make them all UART_XMIT_SIZE. Reviewed-by: Jiri Slaby Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220624205424.12686-6-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: meson: acquire port->lock in startup()

2022-05-19T16:29:25+00:00

The uart_ops startup() callback is called without interrupts disabled and without port->lock locked, relatively late during the boot process (from the call path of console_on_rootfs()). If the device is a console, it was already previously registered and could be actively printing messages. Since the startup() callback is reading/writing registers used by the console write() callback (AML_UART_CONTROL), its access must be synchronized using the port->lock. Currently it is not. The startup() callback is the only function that explicitly enables interrupts. Without the synchronization, it is possible that interrupts become accidentally permanently disabled. CPU0 CPU1 meson_serial_console_write meson_uart_startup -------------------------- ------------------ spin_lock(port->lock) val = readl(AML_UART_CONTROL) uart_console_write() writel(INT_EN, AML_UART_CONTROL) writel(val, AML_UART_CONTROL) spin_unlock(port->lock) Add port->lock synchronization to meson_uart_startup() to avoid racing with meson_serial_console_write(). Also add detailed comments to meson_uart_reset() explaining why it is *not* using port->lock synchronization. Link: https://lore.kernel.org/lkml/2a82eae7-a256-f70c-fd82-4e510750906e@samsung.com Fixes: ff7693d079e5 ("ARM: meson: serial: add MesonX SoC on-chip uart driver") Reported-by: Marek Szyprowski Tested-by: Marek Szyprowski Reviewed-by: Petr Mladek Reviewed-by: Jiri Slaby Acked-by: Neil Armstrong Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20220508103547.626355-1-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman

tty: serial: meson: Added S4 SOC compatibility

2022-04-22T14:20:48+00:00

Make UART driver compatible with S4 SOC UART. Meanwhile, the S4 SOC UART uses 12MHz as the clock source for baud rate calculations. Reviewed-by: Neil Armstrong Signed-off-by: Yu Tu Link: https://lore.kernel.org/r/20220422111320.19234-3-yu.tu@amlogic.com Signed-off-by: Greg Kroah-Hartman

tty: serial: meson: Add a 12MHz internal clock rate to calculate baud rate in order to meet the baud rate requirements of special BT modules

2022-04-22T14:20:48+00:00

A /2 divider over XTAL was introduced since G12A, and is preferred to be used over the still present /3 divider since it provides much closer frequencies vs the request baudrate. Especially the BT module uses 3Mhz baud rate. 8Mhz calculations can lead to baud rate bias, causing some problems. Reviewed-by: Neil Armstrong Signed-off-by: Yu Tu Link: https://lore.kernel.org/r/20220422111320.19234-2-yu.tu@amlogic.com Signed-off-by: Greg Kroah-Hartman

tty: serial: meson: Use DIV_ROUND_CLOSEST to calculate baud rates

2022-04-15T09:28:10+00:00

Due to chip process differences, chip designers recommend using baud rates as close to and larger as possible in order to reduce clock errors. Signed-off-by: Yu Tu Reviewed-by: Neil Armstrong Link: https://lore.kernel.org/r/20220407081355.13602-2-yu.tu@amlogic.com 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

Revert "tty: serial: meson: *"

2022-03-01T21:13:38+00:00

This reverts the following commits: 31979060cc07 tty: serial: meson: Fix the compile link error reported by kernel test robot 5427c352a993 tty: serial: meson: Added S4 SOC compatibility 19b2ba0baffc tty: serial: meson: The system stuck when you run the stty command on the console to change the baud rate e5fc2b99840d tty: serial: meson: Make some bit of the REG5 register writable 44023b8e1f14 tty: serial: meson: Describes the calculation of the UART baud rate clock using a clock frame 6436dd8f9b25 tty: serial: meson: Use devm_ioremap_resource to get register mapped memory 841f913e770f tty: serial: meson: Move request the register region to probe They seem to cause lots of problems with existing hardware platforms, and caused build issues, so revert the whole series all at once. Link: https://lore.kernel.org/r/849a95fd-ae81-9a3b-0c06-dd7826af9eb2@baylibre.com Link: https://lore.kernel.org/all/20220225073922.3947-1-yu.tu@amlogic.com/ Reported-by: Marek Szyprowski Reported-by: Jerome Brunet Cc: Neil Armstrong Cc: Yu Tu Signed-off-by: Greg Kroah-Hartman