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| * | | | serial: pch: don't overwrite xmit->buf[0] by x_charJiri Slaby2022-05-051-20/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: <stable@vger.kernel.org> Fixes: 3c6a483275f4 (Serial: EG20T: add PCH_UART driver) Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503080808.28332-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pch: move size check from pop_tx one level upJiri Slaby2022-05-051-6/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | '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 <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503080613.27601-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: restore disabled irqs in pic32_uart_startup()Jiri Slaby2022-05-051-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pic32_uart_startup() disables interrupts by local_irq_save(). But the function never enables them. The serial core only holds a mutex, so irqs are not restored. So how could this driver work? This irq handling was already present in the driver's initial commit 157b9394709ed (serial: pic32_uart: Add PIC32 UART driver). So is it a candidate for removal? Anyone has a contact to the author: Andrei Pistirica (I believe the one below -- @microchip.com -- will bounce)? Or to someone else @microchip.com? Cc: Andrei Pistirica <andrei.pistirica@microchip.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-12-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: free up irq names correctlyJiri Slaby2022-05-051-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | struct pic32_sport contains built-up names for irqs. These are freed only in error path of pic32_uart_startup(). And even there, the freeing happens before free_irq(). So fix this by: * moving frees after free_irq(), and * add frees to pic32_uart_shutdown() -- the opposite of pic32_uart_startup(). Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-11-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: don't zero members of kzalloc-ated structureJiri Slaby2022-05-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | struct pic32_sport (sport) has just been kzallocated. So there is no need to zero its member (sport->port) now. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-10-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: don't assign pic32_sport::cts_gpio twiceJiri Slaby2022-05-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sport->cts_gpio is first assigned -EINVAL and few lines below using of_get_named_gpio(). Remove the first (useless) assignment. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-9-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: convert to_pic32_sport() to an inlineJiri Slaby2022-05-051-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'c' is not in wrapped in parentheses in the to_pic32_sport() macro, so it might be problematic wrt macro expansion. Using an inline is always safer in these cases. Both type-wise and macro-expansion-wise. So switch the macro to an inline. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-8-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: remove pic32_get_port() macroJiri Slaby2022-05-051-12/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's just &sport->port. First, sport was not in parenthesis, so macro expansion could be an issue. Second, it's so simple, that we can expand the macro and make the code really straightforward. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-7-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: simplify pic32_sport::enable_tx_irq handlingJiri Slaby2022-05-051-7/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make it a bool, so use true+false. And remove the wrap-around macro -- i.e. access the member directly. It makes the code more obvious. BTW the macro did not have 'sport' in parentheses, so it was potentially problematic wrt expansion. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-6-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: simplify clk handlingJiri Slaby2022-05-051-23/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | struct pic32_sport::ref_clk is only set, but not read. That means we can remove it. And when we do so, pic32_enable_clock() and pic32_disable_clock() are simple wrappers around clk_prepare_enable() and clk_disable_unprepare() respectively. So we can remove the former two from the code and replace it by the latter two. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-5-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: remove constants from struct pic32_sportJiri Slaby2022-05-051-12/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All the irqflags_* in struct pic32_sport are set to IRQF_NO_THREAD and never updated. So remove pic32_sport::irqflags_* and use the flag directly. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-4-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: move header content to .cJiri Slaby2022-05-052-117/+103
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no point keeping the header content separated. So move the content to the appropriate source file. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-3-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: pic32: remove unused items from the headerJiri Slaby2022-05-051-9/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | struct pic32_console_opt and its support are unused in pic32. So remove all that. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220503063122.20957-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: stm32: Use TC interrupt to deassert GPIO RTS in RS485 modeMarek Vasut2022-05-052-2/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In case the RS485 mode is emulated using GPIO RTS, use the TC interrupt to deassert the GPIO RTS, otherwise the GPIO RTS stays asserted after a transmission ended and the RS485 cannot work. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: Erwan Le Ray <erwan.leray@foss.st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jean Philippe Romain <jean-philippe.romain@foss.st.com> Cc: Valentin Caron <valentin.caron@foss.st.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-stm32@st-md-mailman.stormreply.com To: linux-serial@vger.kernel.org Link: https://lore.kernel.org/r/20220430162845.244655-2-marex@denx.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: stm32: Factor out GPIO RTS toggling into separate functionMarek Vasut2022-05-051-21/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull out the GPIO RTS enable and disable handling into separate function. Limit the scope of GPIO RTS toggling only to GPIO emulated RS485 too. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: Erwan Le Ray <erwan.leray@foss.st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jean Philippe Romain <jean-philippe.romain@foss.st.com> Cc: Valentin Caron <valentin.caron@foss.st.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-stm32@st-md-mailman.stormreply.com To: linux-serial@vger.kernel.org Link: https://lore.kernel.org/r/20220430162845.244655-1-marex@denx.de 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: 8250: Add proper clock handling for OxSemi PCIe devicesMaciej W. Rozycki2022-05-051-68/+271
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Oxford Semiconductor PCIe (Tornado) 950 serial port devices are driven by a fixed 62.5MHz clock input derived from the 100MHz PCI Express clock. We currently drive the device using its default oversampling rate of 16 and the clock prescaler disabled, consequently yielding the baud base of 3906250. This base is inadequate for some of the high-speed baud rates such as 460800bps, for which the closest rate possible can be obtained by dividing the baud base by 8, yielding the baud rate of 488281.25bps, which is off by 5.9638%. This is enough for data communication to break with the remote end talking actual 460800bps, where missed stop bits have been observed. We can do better however, by taking advantage of a reduced oversampling rate, which can be set to any integer value from 4 to 16 inclusive by programming the TCR register, and by using the clock prescaler, which can be set to any value from 1 to 63.875 in increments of 0.125 in the CPR/CPR2 register pair. The prescaler has to be explicitly enabled though by setting bit 7 in the MCR or otherwise it is bypassed (in the enhanced mode that we enable) as if the value of 1 was used. Make use of these features then as follows: - Set the baud base to 15625000, reflecting the minimum oversampling rate of 4 with the clock prescaler and divisor both set to 1. - Override the `set_mctrl' and set the MCR shadow there so as to have MCR[7] always set and have the 8250 core propagate these settings. - Override the `get_divisor' handler and determine a good combination of parameters by using a lookup table with predetermined value pairs of the oversampling rate and the clock prescaler and finding a pair that divides the input clock such that the quotient, when rounded to the nearest integer, deviates the least from the exact result. Calculate the clock divisor accordingly. Scale the resulting oversampling rate (only by powers of two) if possible so as to maximise it, reducing the divisor accordingly, and avoid a divisor overflow for very low baud rates by scaling the oversampling rate and/or the prescaler even if that causes some accuracy loss. Also handle the historic spd_cust feature so as to allow one to set all the three parameters manually to arbitrary values, by keeping the low 16 bits for the divisor and then putting TCR in bits 19:16 and CPR/CPR2 in bits 28:20, sanitising the bit pattern supplied such as to clamp CPR/CPR2 values between 0.000 and 0.875 inclusive to 33.875. This preserves compatibility with any existing setups, that is where requesting a custom divisor that only has any bits set among the low 16 the oversampling rate of 16 and the clock prescaler of 33.875 will be used as with the original 8250. Finally abuse the `frac' argument to store the determined bit patterns for the TCR, CPR and CPR2 registers. - Override the `set_divisor' handler so as to set the TCR, CPR and CPR2 registers from the `frac' value supplied. Set the divisor as usual. With the baud base set to 15625000 and the unsigned 16-bit UART_DIV_MAX limitation imposed by `serial8250_get_baud_rate' standard baud rates below 300bps become unavailable in the regular way, e.g. the rate of 200bps requires the baud base to be divided by 78125 and that is beyond the unsigned 16-bit range. The historic spd_cust feature can still be used to obtain such rates if so required. See Documentation/tty/device_drivers/oxsemi-tornado.rst for more details. Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181519450.9383@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: 8250: Export ICR access helpers for internal useMaciej W. Rozycki2022-05-052-21/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make ICR access helpers available outside 8250_port.c, however retain them as ordinary static functions so as not to regress code generation. This is because `serial_icr_write' is currently automatically inlined by GCC, however `serial_icr_read' is not. Making them both static inline would grow code produced, e.g.: $ i386-linux-gnu-size --format=gnu 8250_port-{old,new}.o text data bss total filename 15065 3378 0 18443 8250_port-old.o 15289 3378 0 18667 8250_port-new.o and: $ riscv64-linux-gnu-size --format=gnu 8250_port-{old,new}.o text data bss total filename 16980 5306 0 22286 8250_port-old.o 17124 5306 0 22430 8250_port-new.o while making them external would needlessly add a new module interface and lose the benefit from `serial_icr_write' getting inlined outside 8250_port.o. Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181517500.9383@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: 8250: Fold EndRun device support into OxSemi Tornado codeMaciej W. Rozycki2022-05-051-51/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The EndRun PTP/1588 dual serial port device is based on the Oxford Semiconductor OXPCIe952 UART device with the PCI vendor:device ID set for EndRun Technologies and uses the same sequence to determine the number of ports available. Despite that we have duplicate code specific to the EndRun device. Remove redundant code then and factor out OxSemi Tornado device detection. Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181516220.9383@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: men_z135_uart: Drop duplicated iotype assignmentIlpo Järvinen2022-05-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The driver assigns same iotype twice. Drop one of them. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/14b71e1-2396-3d83-3a97-9582765d453@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: 8250: pxa: Remove unneeded <linux/pm_runtime.h>Geert Uytterhoeven2022-05-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 8250 PXA driver never used Runtime PM, so there was never a need to include <linux/pm_runtime.h>. Fixes: ab28f51c77cd4618 ("serial: rewrite pxa2xx-uart to use 8250_core") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/9fd96fba9bbbbdeb16af0dc07ae9dee21c8e297c.1651494971.git.geert+renesas@glider.be Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: 8250: core: Remove unneeded <linux/pm_runtime.h>Geert Uytterhoeven2022-05-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The last calls into Runtime PM were moved to 8250_port.c a long time ago. Fixes: b6830f6df8914faa ("serial: 8250: Split base port operations from universal driver") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/2545eaa7fc552013a5d04c4df027255204e64834.1651494971.git.geert+renesas@glider.be Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | serial: 8250: dw: Fix NULL pointer dereferenceHeikki Krogerus2022-05-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | dw8250_platform_data is only used on DT platforms for now. Fixes: 4a218b277fdb ("serial: 8250: dw: Create a generic platform data structure") Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20220502115621.77985-1-heikki.krogerus@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | Merge 5.18-rc5 into tty-nextGreg Kroah-Hartman2022-05-026-215/+293
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We need the tty/serial fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250_dwlib: Implement SW half duplex supportIlpo Järvinen2022-04-261-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch enables support for SW half-duplex mode using em485. Cc: Eric Tremblay <etremblay@distech-controls.com> Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Tested-by: Vicente Bergas <vicencb@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220426122448.38997-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250_dwlib: RS485 HW half & full duplex supportIlpo Järvinen2022-04-262-0/+85
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Synopsys DesignWare UART can be configured to have HW support for the RS485 protocol from IP version 4.0 onward. Add support for hardware-controlled half duplex and full duplex modes. HW will take care of managing DE and RE, the driver just gives it permission to use either by setting both to 1. To ask for full duplex mode, userspace sets SER_RS485_RX_DURING_TX flag and HW will take care of the rest. Set delay_rts_before_send and delay_rts_after_send to zero for now. The granularity of that ABI is too coarse to be useful. Co-developed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Co-developed-by: Raymond Tan <raymond.tan@intel.com> Signed-off-by: Raymond Tan <raymond.tan@intel.com> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220426122448.38997-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: Handle UART without interrupt on TEMTIlpo Järvinen2022-04-261-9/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add UART_CAP_NOTEMT for UARTs that lack interrupt on TEMT but want to use em485. Em485 framework needs to ensure not only FIFO is empty but also that tx shift register is empty. This approach uses Uwe Kleine-König's suggestion on simply using/incrementing stop_tx timer rather than adding another timer. When UART_CAP_NOTEMT is set and THRE is present w/o TEMT, stop tx timer is reused to wait for the emptying of the shift register. This change does not add the UART_CAP_NOTEMT define as it already exist but is currently no-op. See 7a107b2c6b81 (Revert "serial: 8250: Handle UART without interrupt on TEMT using em485") for further details. Vicente Bergas reported that RTS is deasserted roughly one bit too early losing stop bit tx. To address this problem, stop_delay now accounts for one extra bit using rough formula /7 (assumes worst-case of 2+5 bits). I suspect this glitch had to do with when THRE is getting asserted. If FIFO is emptied already during the tx of the stop bit, perhaps it leads to HW asserting THRE early for the normal frame time formula to work accurately. Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Cc: Eric Tremblay <etremblay@distech-controls.com> Tested-by: Vicente Bergas <vicencb@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220425143410.12703-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: use THRE & __stop_tx also with DMAIlpo Järvinen2022-04-262-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 8250 DMA tx complete path lacks calls to normal 8250 stop handling. It does not use THRE to detect true completion of the tx and also doesn't call __stop_tx. This leads to problems with em485 that needs to handle RTS timing. Instead of handling tx stop internally within 8250 dma code, enable THRE when tx'able data runs out and tweak serial8250_handle_irq to call only __stop_tx when uart is using DMA. It also seems bit early to call serial8250_rpm_put_tx from there while tx is still underway(?). Tested-by: Vicente Bergas <vicencb@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220425143410.12703-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: Store character timing information to uart_portIlpo Järvinen2022-04-261-6/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Struct uart_port currently stores FIFO timeout. Having character timing information readily available is useful. Even serial core itself determines char_time from port->timeout using inverse calculation. Store frame_time directly into uart_port. Character time is stored in nanoseconds to have reasonable precision with high rates. To avoid overflow, 64-bit math is necessary. It might be possible to determine timeout from frame_time by multiplying it with fifosize as needed but only part of the users seem to be protected by a lock. Thus, this patch does not pursue storing only frame_time in uart_port. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220425143410.12703-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: dw: Improve RZN1 supportPhil Edworthy2022-04-261-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Renesas RZ/N1 SoC features a slightly modified DW UART. On this SoC, the CPR register value is known but not synthetized in hardware. We hence need to provide a CPR value in the platform data. This version of the controller also relies on acting as flow controller when using DMA, so we need to provide the "is dma flow controller" quirk. Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20220422180615.9098-10-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: dw: Add support for DMA flow controlling devicesPhil Edworthy2022-04-261-0/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | DW based controllers like the one on Renesas RZ/N1 must be programmed as flow controllers when using DMA. * Table 11.45 of the system manual, "Flow Control Combinations", states that using UART with DMA requires setting the DMA in the peripheral flow controller mode regardless of the direction. * Chapter 11.6.1.3 of the system manual, "Basic Interface Definitions", explains that the burst size in the above case must be configured in the peripheral's register DEST/SRC_BURST_SIZE. Experiments shown that upon Rx timeout, the DMA transaction needed to be manually cleared as well. Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20220422180615.9098-9-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: dw: Move the IO accessors to 8250_dwlib.hMiquel Raynal2022-04-262-16/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These accessors should be used instead of the regular readl/writel() helpers. In order to use them also from 8250_dw.c in this directory, move the helpers to 8250_dwlib.h There is no functional change. There is no need for declaring `struct uart_port` or even UPIO_MEM32BE which both are already included in the 8250_dwlib.h header by 8250.h. Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20220422180615.9098-8-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: dw: Introduce an rx_timeout variable in the IRQ pathMiquel Raynal2022-04-261-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a next change we are going to need the same Rx timeout condition as we already have in the IRQ handling code. Let's just create a boolean to clarify what this operation does before reusing it. There is no functional change. Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20220422180615.9098-7-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: dma: Allow driver operations before starting DMA transfersMiquel Raynal2022-04-262-0/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One situation where this could be used is when configuring the UART controller to be the DMA flow controller. This is a typical case where the driver might need to program a few more registers before starting a DMA transfer. Provide the necessary infrastructure to support this case. Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20220422180615.9098-6-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: dw: Allow to use a fallback CPR value if not synthesizedMiquel Raynal2022-04-262-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | DW UART controllers can be synthesized without the CPR register. In this case, allow to the platform information to provide a CPR value. Co-developed-by: Phil Edworthy <phil.edworthy@renesas.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20220422180615.9098-5-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: dw: Move the USR register to pdataMiquel Raynal2022-04-262-4/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This offset is a good candidate to pdata's because it changes depending on the vendor implementation. Let's move the usr_reg entry from regular to pdata. This way we can drop initializing it at run time. Let's also use a define for it instead of defining only the default value. Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20220422180615.9098-4-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: dw: Create a generic platform data structureEmil Renner Berthing2022-04-262-8/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use device tree match data rather than multiple calls to of_device_is_compatible() by introducing a platform data structure and adding a quirks mask. Provide a stub to the compatibles without quirks to simplify the handling of the upcoming changes. Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Emil Renner Berthing <kernel@esmil.dk> [<miquel.raynal@bootlin.com: Minor changes + creation of a real pdata structure] Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20220422180615.9098-3-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: 8250: dw: Move definitions to the shared headerPhil Edworthy2022-04-262-21/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the per-device structure and a helper out of the main .c file, into a shared header as they will both be reused from another .c file. There is no functional change. Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com> [miquel.raynal@bootlin.com: Extracted from a bigger change] Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20220422180615.9098-2-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | sysrq: do not omit current cpu when showing backtrace of all active CPUsChangbin Du2022-04-261-4/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The backtrace of current CPU also should be printed as it is active. This change add stack trace for current CPU and print a hint for idle CPU for the generic workqueue based printing. (x86 already does this) Now it looks like below: [ 279.401567] sysrq: Show backtrace of all active CPUs [ 279.407234] sysrq: CPU5: [ 279.407505] Call Trace: [ 279.408789] [<ffffffff8000606c>] dump_backtrace+0x2c/0x3a [ 279.411698] [<ffffffff800060ac>] show_stack+0x32/0x3e [ 279.411809] [<ffffffff80542258>] sysrq_handle_showallcpus+0x4c/0xc6 [ 279.411929] [<ffffffff80542f16>] __handle_sysrq+0x106/0x26c [ 279.412034] [<ffffffff805436a8>] write_sysrq_trigger+0x64/0x74 [ 279.412139] [<ffffffff8029cd48>] proc_reg_write+0x8e/0xe2 [ 279.412252] [<ffffffff8021a8f8>] vfs_write+0x90/0x2be [ 279.412362] [<ffffffff8021acd2>] ksys_write+0xa6/0xce [ 279.412467] [<ffffffff8021ad24>] sys_write+0x2a/0x38 [ 279.412689] [<ffffffff80003ff8>] ret_from_syscall+0x0/0x2 [ 279.417173] sysrq: CPU6: backtrace skipped as idling [ 279.417185] sysrq: CPU4: backtrace skipped as idling [ 279.417187] sysrq: CPU0: backtrace skipped as idling [ 279.417181] sysrq: CPU7: backtrace skipped as idling [ 279.417190] sysrq: CPU1: backtrace skipped as idling [ 279.417193] sysrq: CPU3: backtrace skipped as idling [ 279.417219] sysrq: CPU2: [ 279.419179] Call Trace: [ 279.419440] [<ffffffff8000606c>] dump_backtrace+0x2c/0x3a [ 279.419782] [<ffffffff800060ac>] show_stack+0x32/0x3e [ 279.420015] [<ffffffff80542b30>] showacpu+0x5c/0x96 [ 279.420317] [<ffffffff800ba71c>] flush_smp_call_function_queue+0xd6/0x218 [ 279.420569] [<ffffffff800bb438>] generic_smp_call_function_single_interrupt+0x14/0x1c [ 279.420798] [<ffffffff800079ae>] handle_IPI+0xaa/0x13a [ 279.421024] [<ffffffff804dcb92>] riscv_intc_irq+0x56/0x70 [ 279.421274] [<ffffffff80a05b70>] generic_handle_arch_irq+0x6a/0xfa [ 279.421518] [<ffffffff80004006>] ret_from_exception+0x0/0x10 [ 279.421750] [<ffffffff80096492>] rcu_idle_enter+0x16/0x1e Signed-off-by: Changbin Du <changbin.du@gmail.com> Link: https://lore.kernel.org/r/20220117154300.2808-1-changbin.du@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | tty: hvcs: simplify if-if to if-elseWan Jiabing2022-04-261-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use if and else instead of if(A) and if (!A) and fix a coding style. Signed-off-by: Wan Jiabing <wanjiabing@vivo.com> Link: https://lore.kernel.org/r/20220424091310.98780-1-wanjiabing@vivo.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | tty/hvc_opal: simplify if-if to if-elseWan Jiabing2022-04-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use if and else instead of if(A) and if (!A). Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Wan Jiabing <wanjiabing@vivo.com> Link: https://lore.kernel.org/r/20220426071041.168282-1-wanjiabing@vivo.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: stm32: add earlycon supportValentin Caron2022-04-222-0/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add early console support in stm32 uart driver. Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com> Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Link: https://lore.kernel.org/r/20220419085330.1178925-4-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: stm32: add KGDB supportValentin Caron2022-04-221-2/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for KGDB in stm32 serial driver by implementing characters polling callbacks (poll_init, poll_get_char and poll_put_char). Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Signed-off-by: Jean Philippe Romain <jean-philippe.romain@foss.st.com> Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Link: https://lore.kernel.org/r/20220419085330.1178925-3-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: stm32: remove infinite loop possibility in putchar functionValentin Caron2022-04-222-3/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rework stm32_usart_console_putchar() function in order to anticipate the case where the character can never be sent. Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Link: https://lore.kernel.org/r/20220419085330.1178925-2-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | tty: Add function for handling flow control charsIlpo Järvinen2022-04-221-11/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move receive path flow control character handling to own function. No functional changes. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220411094859.10894-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial: core: fix tcdrain() with CTS enabledTomasz Moń2022-04-221-12/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Do not set timeout to twice the approximate amount of time to send the entire FIFO if CTS is enabled. If the caller requested no timeout, e.g. when userspace program called tcdrain(), then wait without any timeout. Premature return from tcdrain() was observed on imx based system which has 32 character long transmitter FIFO with hardware CTS handling. Simple userspace application that reproduces problem has to: * Open tty device, enable hardware flow control (CRTSCTS) * Write data, e.g. 26 bytes * Call tcdrain() to wait for the transmitter * Close tty device The other side of serial connection has to: * Receive some data, e.g. 10 bytes * Set RTS output (CTS input from sender perspective) inactive for at least twice the port timeout * Try to receive remaining data Without this patch, userspace application will finish without any error while the other side of connection will never receive remaining data. Signed-off-by: Tomasz Moń <tomasz.mon@camlingroup.com> Link: https://lore.kernel.org/r/20220228054911.1420221-1-tomasz.mon@camlingroup.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | serial/8250: Use fifo in 8250 console driverWander Lairson Costa2022-04-221-6/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Note: I am using a small test app + driver located at [0] for the problem description. serco is a driver whose write function dispatches to the serial controller. sertest is a user-mode app that writes n bytes to the serial console using the serco driver. While investigating a bug in the RHEL kernel, I noticed that the serial console throughput is way below the configured speed of 115200 bps in a HP Proliant DL380 Gen9. I was expecting something above 10KB/s, but I got 2.5KB/s. $ time ./sertest -n 2500 /tmp/serco real 0m0.997s user 0m0.000s sys 0m0.997s With the help of the function tracer, I then noticed the serial controller was taking around 410us seconds to dispatch one single byte: $ trace-cmd record -p function_graph -g serial8250_console_write \ ./sertest -n 1 /tmp/serco $ trace-cmd report | serial8250_console_write() { 0.384 us | _raw_spin_lock_irqsave(); 1.836 us | io_serial_in(); 1.667 us | io_serial_out(); | uart_console_write() { | serial8250_console_putchar() { | wait_for_xmitr() { 1.870 us | io_serial_in(); 2.238 us | } 1.737 us | io_serial_out(); 4.318 us | } 4.675 us | } | wait_for_xmitr() { 1.635 us | io_serial_in(); | __const_udelay() { 1.125 us | delay_tsc(); 1.429 us | } ... ... ... 1.683 us | io_serial_in(); | __const_udelay() { 1.248 us | delay_tsc(); 1.486 us | } 1.671 us | io_serial_in(); 411.342 us | } In another machine, I measured a throughput of 11.5KB/s, with the serial controller taking between 80-90us to send each byte. That matches the expected throughput for a configuration of 115200 bps. This patch changes the serial8250_console_write to use the 16550 fifo if available. In my benchmarks I got around 25% improvement in the slow machine, and no performance penalty in the fast machine. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20220411174841.34936-2-wander@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | drivers: tty: serial: Fix deadlock in sa1100_set_termios()Duoming Zhou2022-04-221-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a deadlock in sa1100_set_termios(), which is shown below: (Thread 1) | (Thread 2) | sa1100_enable_ms() sa1100_set_termios() | mod_timer() spin_lock_irqsave() //(1) | (wait a time) ... | sa1100_timeout() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold sport->port.lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need sport->port.lock in position (2) of thread 2. As a result, sa1100_set_termios() will block forever. This patch moves del_timer_sync() before spin_lock_irqsave() in order to prevent the deadlock. Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> Link: https://lore.kernel.org/r/20220417111626.7802-1-duoming@zju.edu.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | | | tty/sysrq: change the definition of sysrq_key_table's element to make it ↵Junwen Wu2022-04-221-8/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | more readable The definition of sysrq_key_table's elements, like sysrq_thaw_op and sysrq_showallcpus_op are not consistent with sysrq_ftrace_dump_op, Consistency makes code more readable. Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Junwen Wu <wudaemon@gmail.com> Link: https://lore.kernel.org/r/20220418153703.97705-1-wudaemon@163.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-19 13:14:02 +0000