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* serial: sifive: Add suspend and resume operationsNick Hu2023-08-221-0/+18
| | | | | | | | | | | If the Sifive Uart is not used as the wake up source, suspend the uart before the system enter the suspend state to prevent it woken up by unexpected uart interrupt. Resume the uart once the system woken up. Signed-off-by: Nick Hu <nick.hu@sifive.com> Reviewed-by: Ben Dooks <ben.dooks@codethink.co.uk> Link: https://lore.kernel.org/r/20230815090216.2575971-1-nick.hu@sifive.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: sifive: Remove redundant of_match_ptr()Ruan Jinjie2023-08-091-1/+1
| | | | | | | | | The driver depends on CONFIG_OF, it is not necessary to use of_match_ptr() here. Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com> Link: https://lore.kernel.org/r/20230809085541.2969654-1-ruanjinjie@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge 6.5-rc4 into tty-nextGreg Kroah-Hartman2023-07-311-1/+1
|\ | | | | | | | | | | | | We need the serial/tty fixes in here as well for testing and future development. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: sifive: Fix sifive_serial_console_setup() sectionSamuel Holland2023-07-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | This function is called indirectly from the platform driver probe function. Even if the driver is built in, it may be probed after free_initmem() due to deferral or unbinding/binding via sysfs. Thus the function cannot be marked as __init. Fixes: 45c054d0815b ("tty: serial: add driver for the SiFive UART") Cc: stable <stable@kernel.org> Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Link: https://lore.kernel.org/r/20230624060159.3401369-1-samuel.holland@sifive.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: sifive: Use devm_platform_get_and_ioremap_resource()Yangtao Li2023-07-251-5/+2
| | | | | | | | | | | | | | | | | | | | Convert platform_get_resource(), devm_ioremap_resource() to a single call to devm_platform_get_and_ioremap_resource(), as this is exactly what this function does. Signed-off-by: Yangtao Li <frank.li@vivo.com> Link: https://lore.kernel.org/r/20230712062853.11007-13-frank.li@vivo.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: drivers: switch ch and flag to u8Jiri Slaby2023-07-251-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that the serial layer explicitly expects 'u8' for flags and characters, propagate this type to drivers' (RX) routines. Note that amba-pl011's, clps711x's and st-asc's 'ch' are left unchanged because 'ch' contains not only a character, but whole status. Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Russell King <linux@armlinux.org.uk> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Richard Genoud <richard.genoud@gmail.com> Cc: Nicolas Ferre <nicolas.ferre@microchip.com> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Claudiu Beznea <claudiu.beznea@microchip.com> Cc: Alexander Shiyan <shc_work@mail.ru> Cc: Baruch Siach <baruch@tkos.co.il> Cc: "Maciej W. Rozycki" <macro@orcam.me.uk> Cc: Taichi Sugaya <sugaya.taichi@socionext.com> Cc: Takao Orito <orito.takao@socionext.com> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Pengutronix Kernel Team <kernel@pengutronix.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: NXP Linux Team <linux-imx@nxp.com> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Cc: Alim Akhtar <alim.akhtar@samsung.com> Cc: Laxman Dewangan <ldewangan@nvidia.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Jonathan Hunter <jonathanh@nvidia.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Orson Zhai <orsonzhai@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Chunyan Zhang <zhang.lyra@gmail.com> Cc: Patrice Chotard <patrice.chotard@foss.st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: Hammer Hsieh <hammerh0314@gmail.com> Acked-by: Richard GENOUD <richard.genoud@gmail.com> Acked-by: Tobias Klauser <tklauser@distanz.ch> Acked-by: Thierry Reding <treding@nvidia.com> Acked-by: Maciej W. Rozycki <macro@orcam.me.uk> Link: https://lore.kernel.org/r/20230712081811.29004-11-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: use uart_port_tx_limited()Jiri Slaby (SUSE)2022-11-031-26/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | uart_port_tx_limited() is a new helper to send characters to the device. Use it in these drivers. mux.c also needs to define tx_done(). But I'm not sure if the driver really wants to wait for all the characters to dismiss from the HW fifo at this code point. Hence I marked this as FIXME. Cc: Russell King <linux@armlinux.org.uk> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: bcm-kernel-feedback-list@broadcom.com Cc: "Pali Rohár" <pali@kernel.org> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Orson Zhai <orsonzhai@gmail.com> Cc: Baolin Wang <baolin.wang7@gmail.com> Cc: Chunyan Zhang <zhang.lyra@gmail.com> Cc: Patrice Chotard <patrice.chotard@foss.st.com> Cc: linux-riscv@lists.infradead.org Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20221004104927.14361-4-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge 7e2cd21e02b3 ("Merge tag 'tty-6.0-rc7' of ↵Greg Kroah-Hartman2022-09-251-1/+1
|\ | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty") into tty-next We need the tty fixes and api additions in this branch. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: sifive: enable clocks for UART when probedOlof Johansson2022-09-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the PWM driver was changed to disable clocks if no PWMs are enabled, it ended up also disabling the shared parent with the UART, since the UART doesn't do any clock enablement on its own. To avoid these surprises, switch to clk_get_enabled(). Fixes: ace41d7564e655 ("pwm: sifive: Ensure the clk is enabled exactly once per running PWM") Cc: stable <stable@kernel.org> Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Cc: Emil Renner Berthing <emil.renner.berthing@canonical.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Olof Johansson <olof@lixom.net> Link: https://lore.kernel.org/r/20220920160017.7315-1-olof@lixom.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: Make ->set_termios() old ktermios constIlpo Järvinen2022-08-301-1/+1
|/ | | | | | | | | | There should be no reason to adjust old ktermios which is going to get discarded anyway. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220816115739.10928-7-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: sifive: Remove useless license text when SPDX-License-Identifier is ↵Christophe JAILLET2022-06-271-10/+0
| | | | | | | | | | | already used An SPDX-License-Identifier is already in place. There is no need to duplicate part of the corresponding license. Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Link: https://lore.kernel.org/r/dbc54eff6f4e077d9126054f395d5bc5b3405917.1654936915.git.christophe.jaillet@wanadoo.fr Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: sifive: Sanitize CSIZE and c_iflagIlpo Järvinen2022-05-191-1/+5
| | | | | | | | | | | | | | | | | | | Only CS8 is supported but CSIZE was not sanitized to CS8. Set CSIZE correctly so that userspace knows the effective value. Incorrect CSIZE also results in miscalculation of the frame bits in tty_get_char_size() or in its predecessor where the roughly the same code is directly within uart_update_timeout(). Similarly, INPCK, PARMRK, and BRKINT are reported textually unsupported but were not cleared in termios c_iflag which is the machine-readable format. Fixes: 45c054d0815b (tty: serial: add driver for the SiFive UART) Cc: Paul Walmsley <paul.walmsley@sifive.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220519081808.3776-7-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: sifive: Remove duplicate `clkin_rate' settingMaciej W. Rozycki2022-05-051-8/+6
| | | | | | | | | | The `clkin_rate' member of `struct sifive_serial_port' now duplicates `uartclk' from nested `struct uart_port', so use `uartclk' throughout and remove `clkin_rate'. Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204291656150.9383@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: sifive: Report actual baud base rather than fixed 115200Maciej W. Rozycki2022-05-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The base baud value reported is supposed to be the highest baud rate that can be set for a serial port. The SiFive FU740-C000 SOC's on-chip UART supports baud rates of up to 1/16 of the input clock rate, which is the bus clock `tlclk'[1], often at 130MHz in the case of the HiFive Unmatched board. However the sifive UART driver reports a fixed value of 115200 instead: 10010000.serial: ttySIF0 at MMIO 0x10010000 (irq = 1, base_baud = 115200) is a SiFive UART v0 10011000.serial: ttySIF1 at MMIO 0x10011000 (irq = 2, base_baud = 115200) is a SiFive UART v0 even though we already support setting higher baud rates, e.g.: $ tty /dev/ttySIF1 $ stty speed 230400 The baud base value is computed by the serial core by dividing the UART clock recorded in `struct uart_port' by 16, which is also the minimum value of the clock divider supported, so correct the baud base value reported by setting the UART clock recorded to the input clock rate rather than 115200: 10010000.serial: ttySIF0 at MMIO 0x10010000 (irq = 1, base_baud = 8125000) is a SiFive UART v0 10011000.serial: ttySIF1 at MMIO 0x10011000 (irq = 2, base_baud = 8125000) is a SiFive UART v0 References: [1] "SiFive FU740-C000 Manual", v1p3, SiFive, Inc., August 13, 2021, Section 16.9 "Baud Rate Divisor Register (div)", pp.143-144 Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Fixes: 1f1496a923b6 ("riscv: Fix sifive serial driver") Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204291656280.9383@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: make uart_console_write->putchar()'s character an unsigned charJiri Slaby2022-03-031-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <paul@crapouillou.net> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Russell King <linux@armlinux.org.uk> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Nicolas Ferre <nicolas.ferre@microchip.com> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Ludovic Desroches <ludovic.desroches@microchip.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: bcm-kernel-feedback-list@broadcom.com Cc: Alexander Shiyan <shc_work@mail.ru> Cc: Baruch Siach <baruch@tkos.co.il> Cc: "Maciej W. Rozycki" <macro@orcam.me.uk> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Pengutronix Kernel Team <kernel@pengutronix.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: NXP Linux Team <linux-imx@nxp.com> Cc: Karol Gugala <kgugala@antmicro.com> Cc: Mateusz Holenko <mholenko@antmicro.com> Cc: Vladimir Zapolskiy <vz@mleia.com> Cc: Neil Armstrong <narmstrong@baylibre.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: Jerome Brunet <jbrunet@baylibre.com> Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Cc: Taichi Sugaya <sugaya.taichi@socionext.com> Cc: Takao Orito <orito.takao@socionext.com> Cc: Liviu Dudau <liviu.dudau@arm.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: "Andreas Färber" <afaerber@suse.de> Cc: Manivannan Sadhasivam <mani@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Andy Gross <agross@kernel.org> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> Cc: Orson Zhai <orsonzhai@gmail.com> Cc: Baolin Wang <baolin.wang7@gmail.com> Cc: Chunyan Zhang <zhang.lyra@gmail.com> Cc: Patrice Chotard <patrice.chotard@foss.st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Korsgaard <peter@korsgaard.com> Cc: Michal Simek <michal.simek@xilinx.com> Acked-by: Richard Genoud <richard.genoud@gmail.com> [atmel_serial] Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Paul Cercueil <paul@crapouillou.net> Acked-by: Neil Armstrong <narmstrong@baylibre.com> # meson_serial Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220303080831.21783-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: sifive: set pointer to NULL rather than 0.Colin Ian King2021-10-051-1/+1
| | | | | | | | | | Clean up the assignment of sifive_serial_console_ports[ssp->port.line], this is a pointer to a struct sifive_serial_port so the assignment should be a NULL rather than a integer 0. Signed-off-by: Colin Ian King <colin.king@canonical.com> Link: https://lore.kernel.org/r/20210925224726.183360-1-colin.king@canonical.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: sifive: drop low-latency workaroundJohan Hovold2021-04-221-2/+0
| | | | | | | | | | | | | | | | | The sifive driver has always carried an unnecessary workaround for the infamous low_latency behaviour of tty_flip_buffer_push() which had been removed years before the driver was added by commit 45c054d0815b ("tty: serial: add driver for the SiFive UART"). Specifically, since commit a9c3f68f3cd8 ("tty: Fix low_latency BUG"), tty_flip_buffer_push() always schedules a work item to push data to the line discipline and there's no need to keep any low_latency hacks around. Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210421095509.3024-23-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* riscv: Fix sifive serial driverDamien Le Moal2021-01-081-0/+1
| | | | | | | | | | | | | | | | | | | Setup the port uartclk in sifive_serial_probe() so that the base baud rate is correctly printed during device probe instead of always showing "0". I.e. the probe message is changed from 38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1, base_baud = 0) is a SiFive UART v0 to the correct: 38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1, base_baud = 115200) is a SiFive UART v0 Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
* tty: serial: sifive: Struct headers should start with 'struct <name>'Lee Jones2020-11-061-1/+2
| | | | | | | | | | | | | | | | | | | Also supply a missing member description. Fixes the following W=1 kernel build warning(s): drivers/tty/serial/sifive.c:157: warning: cannot understand function prototype: 'struct sifive_serial_port ' Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: linux-serial@vger.kernel.org Cc: linux-riscv@lists.infradead.org Signed-off-by: Lee Jones <lee.jones@linaro.org> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> Link: https://lore.kernel.org/r/20201104193549.4026187-26-lee.jones@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "tty: serial: add missing spin_lock_init for SiFive serial console"Andy Shevchenko2020-07-211-1/+0
| | | | | | | | | | | | | | | This reverts commit 17b4efdf4e4867079012a48ca10d965fe9d68822. There has been a quick fix against uninitialised lock revealed by the commit f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()"). Since we have now better fix in serial core, this may be safely reverted. Fixes: 17b4efdf4e48 ("tty: serial: add missing spin_lock_init for SiFive serial console") Depends-on: f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()") Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200711135346.71171-3-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: add missing spin_lock_init for SiFive serial consoleSagar Shrikant Kadam2020-05-151-0/+1
| | | | | | | | | | | | | | | | | | | | An uninitialised spin lock for sifive serial console raises a bad magic spin_lock error as reported and discussed here [1]. Initialising the spin lock resolves the issue. The fix is tested on HiFive Unleashed A00 board with Linux 5.7-rc4 and OpenSBI v0.7 [1] https://lore.kernel.org/linux-riscv/b9fe49483a903f404e7acc15a6efbef756db28ae.camel@wdc.com Fixes: 45c054d0815b ("tty: serial: add driver for the SiFive UART") Reported-by: Atish Patra <Atish.Patra@wdc.com> Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/1589019852-21505-2-git-send-email-sagar.kadam@sifive.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: Add CONSOLE_POLL support to SiFive UARTVincent Chen2020-03-181-0/+27
| | | | | | | | | | | | Add CONSOLE_POLL support for future KGDB porting. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Changes since v1: 1. Fix the compile error reported by kbuild test robot Link: https://lore.kernel.org/r/1584492027-23236-1-git-send-email-vincent.chen@sifive.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: sifive: Finish transmission before changing the clockPalmer Dabbelt2020-03-121-4/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SiFive's UART has a software controller clock divider that produces the final baud rate clock. Whenever the clock that drives the UART is changed this divider must be updated accordingly, and given that these two events are controlled by software they cannot be done atomically. During the period between updating the UART's driving clock and internal divider the UART will transmit a different baud rate than what the user has configured, which will probably result in a corrupted transmission stream. The SiFive UART has a FIFO, but due to an issue with the programming interface there is no way to directly determine when the UART has finished transmitting. We're essentially restricted to dead reckoning in order to figure that out: we can use the FIFO's TX busy register to figure out when the last frame has begun transmission and just delay for a long enough that the last frame is guaranteed to get out. As far as the actual implementation goes: I've modified the existing existing clock notifier function to drain both the FIFO and the shift register in on PRE_RATE_CHANGE. As far as I know there is no hardware flow control in this UART, so there's no good way to ask the other end to stop transmission while we can't receive (inserting software flow control messages seems like a bad idea here). Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> Tested-by: Yash Shah <yash.shah@sifive.com> Link: https://lore.kernel.org/r/20200307042637.83728-1-palmer@dabbelt.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Remove dev_err() usage after platform_get_irq()Stephen Boyd2019-09-041-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't need dev_err() messages when platform_get_irq() fails now that platform_get_irq() prints an error message itself when something goes wrong. Let's remove these prints with a simple semantic patch. // <smpl> @@ expression ret; struct platform_device *E; @@ ret = ( platform_get_irq(E, ...) | platform_get_irq_byname(E, ...) ); if ( \( ret < 0 \| ret <= 0 \) ) { ( -if (ret != -EPROBE_DEFER) -{ ... -dev_err(...); -... } | ... -dev_err(...); ) ... } // </smpl> While we're here, remove braces on if statements that only have one statement (manually). Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Stephen Boyd <swboyd@chromium.org> Link: https://lore.kernel.org/r/20190730181557.90391-45-swboyd@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: add driver for the SiFive UARTPaul Walmsley2019-04-291-0/+1056
Add a serial driver for the SiFive UART, found on SiFive FU540 devices (among others). The underlying serial IP block is relatively basic, and currently does not support serial break detection. Further information on the IP block can be found in the documentation and Chisel sources: https://static.dev.sifive.com/FU540-C000-v1.0.pdf https://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/uart This driver was written in collaboration with Wesley Terpstra <wesley@sifive.com>. Tested on a SiFive HiFive Unleashed A00 board, using BBL and the open- source FSBL (using a DT file based on what's targeted for mainline). This revision incorporates changes based on comments by Julia Lawall <julia.lawall@lip6.fr>, Emil Renner Berthing <kernel@esmil.dk>, and Andreas Schwab <schwab@suse.de>. Thanks also to Andreas for testing the driver with his userspace and reporting a bug with the set_termios implementation. Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com> Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Wesley Terpstra <wesley@sifive.com> Cc: linux-serial@vger.kernel.org Cc: linux-riscv@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: Julia Lawall <julia.lawall@lip6.fr> Cc: Emil Renner Berthing <kernel@esmil.dk> Cc: Andreas Schwab <schwab@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>