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* serial: core: Fix serial core port id, including multiport devicesTony Lindgren2023-08-112-1/+28
| | | | | | | | | | | | | | | | | | | | | We want to fix the serial core port DEVNAME to use a port id of the hardware specific controller port instance instead of the port->line. For example, the 8250 driver sets up a number of serial8250 ports initially that can be inherited by the hardware specific driver. At that the port->line no longer decribes the port's relation to the serial core controller instance. Let's fix the issue by assigning port->port_id for each serial core controller port instance. Fixes: 7d695d83767c ("serial: core: Fix serial_base_match() after fixing controller port name") Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Dhruva Gole <d-gole@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230811103648.2826-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: drop lockdep annotation from serial8250_clear_IER()Jiri Slaby (SUSE)2023-08-111-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The port lock is not always held when calling serial8250_clear_IER(). When an oops is in progress, the lock is tried to be taken and when it is not, a warning is issued: WARNING: CPU: 0 PID: 1 at drivers/tty/serial/8250/8250_port.c:707 +0x57/0x60 Modules linked in: CPU: 0 PID: 1 Comm: init Not tainted 6.5.0-rc5-1.g225bfb7-default+ #774 00f1be860db663ed29479b8255d3b01ab1135bd3 Hardware name: QEMU Standard PC ... RIP: 0010:serial8250_clear_IER+0x57/0x60 ... Call Trace: <TASK> serial8250_console_write+0x9e/0x4b0 console_flush_all+0x217/0x5f0 ... Therefore, remove the annotation as it doesn't hold for all invocations. The other option would be to make the lockdep test conditional on 'oops_in_progress' or pass 'locked' from serial8250_console_write(). I don't think, that is worth it. Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org> Reported-by: Vlastimil Babka <vbabka@suse.cz> Cc: John Ogness <john.ogness@linutronix.de> Fixes: d0b309a5d3f4 (serial: 8250: synchronize and annotate UART_IER access) Link: https://lore.kernel.org/r/20230811064340.13400-1-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: core: Revert port_id useTony Lindgren2023-08-091-1/+1
| | | | | | | | | | | | | | | | Guenter reports boot issues with duplicate sysfs entries for multiport drivers. Let's go back to using port->line for now to fix the regression. With this change, the serial core port device names are not correct for the hardware specific 8250 single port drivers, but that's a cosmetic issue for now. Fixes: d962de6ae51f ("serial: core: Fix serial core port id to not use port->line") Reported-by: Guenter Roeck <groeck7@gmail.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20230806062052.47737-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Fix oops for port->pm on uart_change_pm()Tony Lindgren2023-08-041-0/+1
| | | | | | | | | | | | | | | | | | Unloading a hardware specific 8250 driver can produce error "Unable to handle kernel paging request at virtual address" about ten seconds after unloading the driver. This happens on uart_hangup() calling uart_change_pm(). Turns out commit 04e82793f068 ("serial: 8250: Reinit port->pm on port specific driver unbind") was only a partial fix. If the hardware specific driver has initialized port->pm function, we need to clear port->pm too. Just reinitializing port->ops does not do this. Otherwise serial8250_pm() will call port->pm() instead of serial8250_do_pm(). Fixes: 04e82793f068 ("serial: 8250: Reinit port->pm on port specific driver unbind") Signed-off-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230804131553.52927-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: 8250: Reinit port_id when adding back serial8250_isa_devsTony Lindgren2023-08-041-0/+1
| | | | | | | | | | | | | | | | | | | | After fixing the serial core port device to use port->port_id instead of port->line, unloading a hardware specific 8250 port driver started producing an error for "sysfs: cannot create duplicate filename". This is happening as we are wrongly initializing port->port_id to zero when adding back serial8250_isa_devs instances, and the serial8250:0.0 sysfs entry may already exist. For serial8250 devices, we typically have multiple devices mapped to a single driver instance. For the serial8250_isa_devs instances, the port->port_id is the same as port->line. Let's fix the issue by re-initializing port_id when adding back the serial8250_isa_devs instances in serial8250_unregister_port(). Fixes: d962de6ae51f ("serial: core: Fix serial core port id to not use port->line") Signed-off-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230804123546.25293-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: core: Fix kmemleak issue for serial core device removeTony Lindgren2023-08-041-0/+2
| | | | | | | | | | | | | | | | | | | | Kmemleak reports issues for serial8250 ports after the hardware specific driver takes over on boot as noted by Tomi. The kerneldoc for device_initialize() says we must call device_put() after calling device_initialize(). We are calling device_put() on the error path, but are missing it from the device remove path. This causes release() to never get called for the devices on remove. Let's add the missing put_device() calls for both serial ctrl and port devices. Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Reported-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Link: https://lore.kernel.org/r/20230804090909.51529-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: core: Fix serial_base_match() after fixing controller port nameTony Lindgren2023-08-031-2/+8
| | | | | | | | | | | | | | | | | | | While fixing DEVNAME to be more usable, I broke serial_base_match() as the ctrl and port prefix for device names seemed unnecessary. The prefixes are still needed by serial_base_match() to probe the serial base controller port, and serial tx is now broken. Let's fix the issue by checking against dev->type and drv->name instead of the prefixes that are no longer in the DEVNAME. Fixes: 1ef2c2df1199 ("serial: core: Fix serial core controller port name to show controller id") Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202308021529.35b3ad6c-oliver.sang@intel.com Signed-off-by: Tony Lindgren <tony@atomide.com> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20230803071034.25571-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: core: Fix serial core controller port name to show controller idTony Lindgren2023-08-011-12/+20
| | | | | | | | | | | | | | | | | | | | | | | | | We are missing the serial core controller id for the serial core port name. Let's fix the issue for sane sysfs output, and to avoid issues addressing serial ports later on. And as we're now showing the controller id, the "ctrl" and "port" prefix for the DEVNAME become useless, we can just drop them. Let's standardize on DEVNAME:0 for controller name, where 0 is the controller id. And DEVNAME:0.0 for port name, where 0.0 are the controller id and port id. This makes the sysfs output nicer, on qemu for example: $ ls /sys/bus/serial-base/devices 00:04:0 serial8250:0 serial8250:0.2 00:04:0.0 serial8250:0.1 serial8250:0.3 Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230725054216.45696-4-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* serial: core: Fix serial core port id to not use port->lineTony Lindgren2023-08-012-1/+3
| | | | | | | | | | | | | | | | | | | | | The serial core port id should be serial core controller specific port instance, which is not always the port->line index. For example, 8250 driver maps a number of legacy ports, and when a hardware specific device driver takes over, we typically have one driver instance for each port. Let's instead add port->port_id to keep track serial ports mapped to each serial core controller instance. Currently this is only a cosmetic issue for the serial core port device names. The issue can be noticed looking at /sys/bus/serial-base/devices for example though. Let's fix the issue to avoid port addressing issues later on. Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230725054216.45696-3-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: serial: fsl_lpuart: Clear the error flags by writing 1 for lpuart32 ↵Sherry Sun2023-08-011-2/+2
| | | | | | | | | | | | | | | | platforms Do not read the data register to clear the error flags for lpuart32 platforms, the additional read may cause the receive FIFO underflow since the DMA has already read the data register. Actually all lpuart32 platforms support write 1 to clear those error bits, let's use this method to better clear the error flags. Fixes: 42b68768e51b ("serial: fsl_lpuart: DMA support for 32-bit variant") Cc: stable <stable@kernel.org> Signed-off-by: Sherry Sun <sherry.sun@nxp.com> Link: https://lore.kernel.org/r/20230801022304.24251-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'tty-6.5-rc4' of ↵Linus Torvalds2023-07-304-5/+7
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial fixes from Greg KH: "Here are some small TTY and serial driver fixes for 6.5-rc4 for some reported problems. Included in here is: - TIOCSTI fix for braille readers - documentation fix for minor numbers - MAINTAINERS update for new serial files in -rc1 - minor serial driver fixes for reported problems All of these have been in linux-next with no reported problems" * tag 'tty-6.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: serial: 8250_dw: Preserve original value of DLF register tty: serial: sh-sci: Fix sleeping in atomic context serial: sifive: Fix sifive_serial_console_setup() section Documentation: devices.txt: reconcile serial/ucc_uart minor numers MAINTAINERS: Update TTY layer for lists and recently added files tty: n_gsm: fix UAF in gsm_cleanup_mux TIOCSTI: always enable for CAP_SYS_ADMIN
| * serial: 8250_dw: Preserve original value of DLF registerRuihong Luo2023-07-251-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Preserve the original value of the Divisor Latch Fraction (DLF) register. When the DLF register is modified without preservation, it can disrupt the baudrate settings established by firmware or bootloader, leading to data corruption and the generation of unreadable or distorted characters. Fixes: 701c5e73b296 ("serial: 8250_dw: add fractional divisor support") Cc: stable <stable@kernel.org> Signed-off-by: Ruihong Luo <colorsu1922@gmail.com> Link: https://lore.kernel.org/stable/20230713004235.35904-1-colorsu1922%40gmail.com Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230713004235.35904-1-colorsu1922@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * tty: serial: sh-sci: Fix sleeping in atomic contextBiju Das2023-07-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix sleeping in atomic context warning as reported by the Smatch static checker tool by replacing disable_irq->disable_irq_nosync. Reported by: Dan Carpenter <dan.carpenter@linaro.org> Fixes: 8749061be196 ("tty: serial: sh-sci: Add RZ/G2L SCIFA DMA tx support") Cc: stable@kernel.org Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Link: https://lore.kernel.org/r/20230704154818.406913-1-biju.das.jz@bp.renesas.com 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>
| * Documentation: devices.txt: reconcile serial/ucc_uart minor numersRandy Dunlap2023-07-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reconcile devices.txt with serial/ucc_uart.c regarding device number assignments. ucc_uart.c supports 4 ports and uses minor devnums 46-49, so update devices.txt with that info. Then update ucc_uart.c's reference to the location of the devices.txt list in the kernel source tree. Fixes: d7584ed2b994 ("[POWERPC] qe-uart: add support for Freescale QUICCEngine UART") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Timur Tabi <timur@kernel.org> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: linuxppc-dev@lists.ozlabs.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: linux-serial@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-doc@vger.kernel.org Link: https://lore.kernel.org/r/20230724063341.28198-1-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | serial: qcom-geni: drop bogus runtime pm state updateJohan Hovold2023-07-241-7/+0
|/ | | | | | | | | | | | | | | The runtime PM state should not be changed by drivers that do not implement runtime PM even if it happens to work around a bug in PM core. With the wake irq arming now fixed, drop the bogus runtime PM state update which left the device in active state (and could potentially prevent a parent device from suspending). Fixes: f3974413cf02 ("tty: serial: qcom_geni_serial: Wakeup IRQ cleanup") Cc: 5.6+ <stable@vger.kernel.org> # 5.6+ Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Reviewed-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Merge tag 'tty-6.5-rc1' of ↵Linus Torvalds2023-07-0340-368/+2055
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial driver updates from Greg KH: "Here is the big set of tty/serial driver updates for 6.5-rc1. Included in here are: - tty_audit code cleanups from Jiri - more 8250 cleanups from Ilpo - samsung_tty driver bugfixes - 8250 lock port updates - usual fsl_lpuart driver updates and fixes - other small serial driver fixes and updates, full details in the shortlog All of these have been in linux-next for a while with no reported issues" * tag 'tty-6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (58 commits) tty_audit: make data of tty_audit_log() const tty_audit: make tty pointers in exposed functions const tty_audit: make icanon a bool tty_audit: invert the condition in tty_audit_log() tty_audit: use kzalloc() in tty_audit_buf_alloc() tty_audit: use TASK_COMM_LEN for task comm Revert "8250: add support for ASIX devices with a FIFO bug" serial: atmel: don't enable IRQs prematurely tty: serial: Add Nuvoton ma35d1 serial driver support tty: serial: fsl_lpuart: add earlycon for imx8ulp platform tty: serial: imx: fix rs485 rx after tx selftests: tty: add selftest for tty timestamp updates tty: tty_io: update timestamps on all device nodes tty: fix hang on tty device with no_room set serial: core: fix -EPROBE_DEFER handling in init serial: 8250_omap: Use force_suspend and resume for system suspend tty: serial: samsung_tty: Use abs() to simplify some code tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() when iterating clk tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() in case of error serial: 8250: Apply FSL workarounds also without SERIAL_8250_CONSOLE ...
| * Revert "8250: add support for ASIX devices with a FIFO bug"Jiaqing Zhao2023-06-213-28/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit eb26dfe8aa7eeb5a5aa0b7574550125f8aa4c3b3. Commit eb26dfe8aa7e ("8250: add support for ASIX devices with a FIFO bug") merged on Jul 13, 2012 adds a quirk for PCI_VENDOR_ID_ASIX (0x9710). But that ID is the same as PCI_VENDOR_ID_NETMOS defined in 1f8b061050c7 ("[PATCH] Netmos parallel/serial/combo support") merged on Mar 28, 2005. In pci_serial_quirks array, the NetMos entry always takes precedence over the ASIX entry even since it was initially merged, code in that commit is always unreachable. In my tests, adding the FIFO workaround to pci_netmos_init() makes no difference, and the vendor driver also does not have such workaround. Given that the code was never used for over a decade, it's safe to revert it. Also, the real PCI_VENDOR_ID_ASIX should be 0x125b, which is used on their newer AX99100 PCIe serial controllers released on 2016. The FIFO workaround should not be intended for these newer controllers, and it was never implemented in vendor driver. Fixes: eb26dfe8aa7e ("8250: add support for ASIX devices with a FIFO bug") Cc: stable <stable@kernel.org> Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230619155743.827859-1-jiaqing.zhao@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: atmel: don't enable IRQs prematurelyDan Carpenter2023-06-211-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The atmel_complete_tx_dma() function disables IRQs at the start of the function by calling spin_lock_irqsave(&port->lock, flags); There is no need to disable them a second time using the spin_lock_irq() function and, in fact, doing so is a bug because it will enable IRQs prematurely when we call spin_unlock_irq(). Just use spin_lock/unlock() instead without disabling or enabling IRQs. Fixes: 08f738be88bb ("serial: at91: add tx dma support") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Acked-by: Richard Genoud <richard.genoud@gmail.com> Link: https://lore.kernel.org/r/cb7c39a9-c004-4673-92e1-be4e34b85368@moroto.mountain Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * tty: serial: Add Nuvoton ma35d1 serial driver supportJacky Huang2023-06-193-0/+845
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds UART and console driver for Nuvoton ma35d1 Soc. It supports full-duplex communication, FIFO control, and hardware flow control. Command line set "console=ttyNVT0,115200", NVT means Nuvoton MA35 UART port. The UART driver probe will create path named "/dev/ttyNVTx". Signed-off-by: Jacky Huang <ychuang3@nuvoton.com> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20230619032330.233796-2-ychuang570808@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * tty: serial: fsl_lpuart: add earlycon for imx8ulp platformSherry Sun2023-06-191-0/+1
| | | | | | | | | | | | | | | | | | Add earlycon support for imx8ulp platform. Signed-off-by: Sherry Sun <sherry.sun@nxp.com> Cc: stable <stable@kernel.org> Link: https://lore.kernel.org/r/20230619080613.16522-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * tty: serial: imx: fix rs485 rx after txMartin Fuzzey2023-06-191-5/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 79d0224f6bf2 ("tty: serial: imx: Handle RS485 DE signal active high") RS485 reception no longer works after a transmission. The following scenario shows the problem: 1) Open a port in RS485 mode 2) Receive data from remote (OK) 3) Transmit data to remote (OK) 4) Receive data from remote (Nothing received) In RS485 mode, imx_uart_start_tx() calls imx_uart_stop_rx() and, when the transmission is complete, imx_uart_stop_tx() calls imx_uart_start_rx(). Since the above commit imx_uart_stop_rx() now sets the loopback bit but imx_uart_start_rx() does not clear it causing the hardware to remain in loopback mode and not receive external data. Fix this by moving the existing loopback disable code to a helper function and calling it from imx_uart_start_rx() too. Fixes: 79d0224f6bf2 ("tty: serial: imx: Handle RS485 DE signal active high") Cc: stable@vger.kernel.org Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20230616104838.2729694-1-martin.fuzzey@flowbird.group Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: core: fix -EPROBE_DEFER handling in initDan Carpenter2023-06-151-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The -EPROBE_DEFER error path in serial_base_device_init() is a bit awkward. Before the call to device_initialize(dev) then we need to manually release all the device resources. And after the call then we need to call put_device() to release the resources. Doing either one wrong will result in a leak or a use after free. So let's wait to return -EPROBE_DEFER until after the call to device_initialize(dev) so that way callers do not have to handle -EPROBE_DEFER as a special case. Now callers can just use put_device() for clean up. The second issue with the -EPROBE_DEFER path is that deferring is not supposed to be a fatal error, but instead it's normal part of the init process and the kernel recovers from it automatically. That means we should not print an error message but just a debug message on this path. Fixes: 539914240a01 ("serial: core: Fix probing serial_base_bus devices") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Tony Lindgren <tony@atomide.com> Message-ID: <18318adb-ab2c-4dcc-9f96-498a13d16b80@moroto.mountain> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: 8250_omap: Use force_suspend and resume for system suspendTony Lindgren2023-06-151-5/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We should not rely on autosuspend timeout for system suspend. Instead, let's use force_suspend and force_resume functions. Otherwise the serial port controller device may not be idled on suspend. As we are doing a register write on suspend to configure the serial port, we still need to runtime PM resume the port on suspend. While at it, let's switch to pm_runtime_resume_and_get() and check for errors returned. And let's add the missing line break before return to the suspend function while at it. Fixes: 09d8b2bdbc5c ("serial: 8250: omap: Provide ability to enable/disable UART as wakeup source") Signed-off-by: Tony Lindgren <tony@atomide.com> Tested-by: Dhruva Gole <d-gole@ti.com> Message-ID: <20230614045922.4798-1-tony@atomide.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * tty: serial: samsung_tty: Use abs() to simplify some codeChristophe JAILLET2023-06-131-3/+2
| | | | | | | | | | | | | | | | | | | | | | Use abs() instead of hand-writing it. Suggested-by: Walter Harms <wharms@bfs.de> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reviewed-by: Andi Shyti <andi.shyti@kernel.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Message-ID: <7bd165e82ed3675d4ddee343ab373031e995a126.1686412569.git.christophe.jaillet@wanadoo.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() when ↵Christophe JAILLET2023-06-131-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | iterating clk When the best clk is searched, we iterate over all possible clk. If we find a better match, the previous one, if any, needs to be freed. If a better match has already been found, we still need to free the new one, otherwise it leaks. Cc: <stable@vger.kernel.org> # v3.3+ Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Reviewed-by: Andi Shyti <andi.shyti@kernel.org> Fixes: 5f5a7a5578c5 ("serial: samsung: switch to clkdev based clock lookup") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Message-ID: <cf3e0053d2fc7391b2d906a86cd01a5ef15fb9dc.1686412569.git.christophe.jaillet@wanadoo.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() in ↵Christophe JAILLET2023-06-131-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | case of error If clk_get_rate() fails, the clk that has just been allocated needs to be freed. Cc: <stable@vger.kernel.org> # v3.3+ Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Reviewed-by: Andi Shyti <andi.shyti@kernel.org> Fixes: 5f5a7a5578c5 ("serial: samsung: switch to clkdev based clock lookup") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Message-ID: <e4baf6039368f52e5a5453982ddcb9a330fc689e.1686412569.git.christophe.jaillet@wanadoo.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: 8250: Apply FSL workarounds also without SERIAL_8250_CONSOLEUwe Kleine-König2023-06-133-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The need to handle the FSL variant of 8250 in a special way is also present without console support. So soften the dependency for SERIAL_8250_FSL from SERIAL_8250_CONSOLE to SERIAL_8250. To handle SERIAL_8250=m, the FSL code can be modular, too, thus SERIAL_8250_FSL becomes tristate. Compiling 8250_fsl as a module requires adding a module license so this is added, too. While add it also add a appropriate module description. As then SERIAL_OF_PLATFORM=y + SERIAL_8250_FSL=m is a valid combination (if COMPILE_TEST is enabled on a platform that is neither PPC, ARM nor ARM64), the check in 8250_of.c must be weakened a bit. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Message-ID: <20230609133932.786117-3-u.kleine-koenig@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: core: don't kfree device managed dataDan Carpenter2023-06-061-6/+2
| | | | | | | | | | | | | | | | | | | | | | The put_device() function will call serial_base_ctrl_release() or serial_base_port_release() so these kfrees() are a double free bug. Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Tony Lindgren <tony@atomide.com> Message-ID: <ZH7tsTmWY5b/4m+6@moroto> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: 8250_mtk: Simplify clock sequencing and runtime PMChen-Yu Tsai2023-06-061-40/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 8250_mtk driver's runtime PM support has some issues: - The bus clock is enabled (through runtime PM callback) later than a register write - runtime PM resume callback directly called in probe, but no pm_runtime_set_active() call is present - UART PM function calls the callbacks directly, _and_ calls runtime PM API - runtime PM callbacks try to do reference counting, adding yet another count between runtime PM and clocks This fragile setup worked in a way, but broke recently with runtime PM support added to the serial core. The system would hang when the UART console was probed and brought up. Tony provided some potential fixes [1][2], though they were still a bit complicated. The 8250_dw driver, which the 8250_mtk driver might have been based on, has a similar structure but simpler runtime PM usage. Simplify clock sequencing and runtime PM support in the 8250_mtk driver. Specifically, the clock is acquired enabled and assumed to be active, unless toggled through runtime PM suspend/resume. Reference counting is removed and left to the runtime PM core. The serial pm function now only calls the runtime PM API. [1] https://lore.kernel.org/linux-serial/20230602092701.GP14287@atomide.com/ [2] https://lore.kernel.org/linux-serial/20230605061511.GW14287@atomide.com/ Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Suggested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Reviewed-by: Tony Lindgren <tony@atomide.com> Message-ID: <20230606091747.2031168-1-wenst@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * serial: st-asc: fix typo in property nameRaphael Gallais-Pou2023-06-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | Changes the property name read in the driver according to the YAML. According to device-tree documentation, property names should not include underscores. Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com> Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com> Message-ID: <20230604083558.16661-1-rgallaispou@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * Merge 6.4-rc5 into tty-nextGreg Kroah-Hartman2023-06-054-25/+27
| |\ | | | | | | | | | | | | | | | We need the tty fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: core: Fix error handling for serial_core_ctrl_device_add()Tony Lindgren2023-06-021-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Checking for NULL is incorrect as serial_base_ctrl_add() uses ERR_PTR(). Let's also pass any returned error along, there's no reason to translate all errors to -ENODEV. Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Signed-off-by: Tony Lindgren <tony@atomide.com> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20230602070007.59268-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: core: Fix probing serial_base_bus devicesTony Lindgren2023-06-011-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a physical serial port device driver uses arch_initcall() we fail to probe the serial_base_bus devices and the serial port tx fails. This is because as serial_base_bus uses module_initcall(). Let's fix the issue by changing serial_base_bus to use arch_initcall(). Let's also return an error if a driver attempts to call uart_add_one_port() too early. Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Closes: https://lore.kernel.org/linux-serial/20230601132012.GB14287@atomide.com/T/#m6a40440fc04d551d27b147da8602e065c982a115 Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Signed-off-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230601141445.11321-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: core: Don't drop port_mutex in serial_core_remove_one_portSteven Price2023-06-011-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") required the caller to hold port_mutex rather than taking it locally. However the mutex_unlock() call wasn't removed causing the mutex to be dropped unexpectly. Remove the call to mutex_unlock() (and fix up the early return) to restore correct behaviour. Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Signed-off-by: Steven Price <steven.price@arm.com> Reviewed-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230601105548.29965-1-steven.price@arm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: core: Start managing serial controllers to enable runtime PMTony Lindgren2023-05-318-22/+594
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We want to enable runtime PM for serial port device drivers in a generic way. To do this, we want to have the serial core layer manage the registered physical serial controller devices. To manage serial controllers, let's set up a struct bus and struct device for the serial core controller as suggested by Greg and Jiri. The serial core controller devices are children of the physical serial port device. The serial core controller device is needed to support multiple different kind of ports connected to single physical serial port device. Let's also set up a struct device for the serial core port. The serial core port instances are children of the serial core controller device. With the serial core port device we can now flush pending TX on the runtime PM resume as suggested by Johan. Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Suggested-by: Jiri Slaby <jirislaby@kernel.org> Suggested-by: Johan Hovold <johan@kernel.org> Signed-off-by: Tony Lindgren <tony@atomide.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230525113034.46880-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: omap: convert to modern PM opsArnd Bergmann2023-05-311-12/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The new uart_write() function is only called from suspend/resume code, causing a build warning when those are left out: drivers/tty/serial/8250/8250_omap.c:169:13: error: 'uart_write' defined but not used [-Werror=unused-function] Remove the #ifdefs and use the modern pm_ops/pm_sleep_ops and their wrappers to let the compiler see where it's used but still drop the dead code. Fixes: 398cecc24846 ("serial: 8250: omap: Fix imprecise external abort for omap_8250_pm()") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230517202012.634386-1-arnd@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: omap: Move uart_write() inside PM sectionGeert Uytterhoeven2023-05-311-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If CONFIG_PM is not set (e.g. m68k/allmodconfig): drivers/tty/serial/8250/8250_omap.c:169:13: error: ‘uart_write’ defined but not used [-Werror=unused-function] 169 | static void uart_write(struct omap8250_priv *priv, u32 reg, u32 val) | ^~~~~~~~~~ Fix tis by moving uart_write() inside the existing section protected by #ifdef CONFIG_PM. Reported-by: noreply@ellerman.id.au Link: http://kisskb.ellerman.id.au/kisskb/buildresult/14925095/ Fixes: 398cecc24846e867 ("serial: 8250: omap: Fix imprecise external abort for omap_8250_pm()") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230515065706.1723477-1-geert@linux-m68k.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250-fsl: Expand description of the MPC83xx UART's misbehaviourUwe Kleine-König2023-05-311-1/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After working quite a bit on erratic behaviour of the MPC83xx UART I (think I) understood the problem. Expand the description accoringly to conserve the knowledge for the future. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20230524122754.481816-2-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: Indicate fintek option may also be required for RS232 supportJames Hilliard2023-05-301-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current config comment for SERIAL_8250_FINTEK implies that this option is only needed when one wants to support RS485. As it turns out we also need to enable this option for RS232 support to function correctly on some variants. For example for variants such as the F71869AD attempting to use multiple RS232 ports simultaneously without this option enabled can result in data corruption. Signed-off-by: James Hilliard <james.hilliard1@gmail.com> Link: https://lore.kernel.org/r/20230521075046.3539376-1-james.hilliard1@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty: serial: fsl_lpuart: Check the return value of dmaengine_tx_statusSherry Sun2023-05-301-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Coverity reports the Unchecked return value (CHECKED_RETURN) warning: Calling dmaengine_tx_status without checking return value. So here add the return value check for dmaengine_tx_status() function to make coverity happy. Fixes: cf9aa72d2f91 ("tty: serial: fsl_lpuart: optimize the timer based EOP logic") Signed-off-by: Sherry Sun <sherry.sun@nxp.com> Link: https://lore.kernel.org/r/20230522025111.3747-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: Switch i2c drivers back to use .probe()Uwe Kleine-König2023-05-302-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new() call-back type"), all drivers being converted to .probe_new() and then 03c835f498b5 ("i2c: Switch .probe() to not take an id parameter") convert back to (the new) .probe() to be able to eventually drop .probe_new() from struct i2c_driver. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20230525210147.734737-1-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: synchronize and annotate UART_IER accessJohn Ogness2023-05-305-0/+85
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The UART_IER register is modified twice by each console write (serial8250_console_write()) under the port lock. Any driver code that accesses UART_IER must do so with the port locked in order to ensure consistent values, even when for read accesses. Add locking, lockdep notation, and/or comments everywhere UART_IER is accessed. The added locking is not fixing a real problem because it occurs where the console is not active. However, adding the locking to these non-critical paths greatly simplifies UART_IER access tracking by establishing a general policy that all UART_IER access is performed with the port locked. Signed-off-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/r/20230525093159.223817-9-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: lock port for UART_IER access in omap8250_irq()John Ogness2023-05-301-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | omap8250_irq() accesses UART_IER. This register is modified twice by each console write (serial8250_console_write()) under the port lock. omap8250_irq() must also take the port lock to guanentee synchronized access to UART_IER. Since the port lock is already being taken for the stop_rx() callback and since it is safe to call cancel_delayed_work() while holding the port lock, simply extend the port lock region to include UART_IER access. Fixes: 1fe0e1fa3209 ("serial: 8250_omap: Handle optional overrun-throttle-ms property") Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230525093159.223817-8-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: lock port for omap8250_restore_regs()John Ogness2023-05-301-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | omap8250_restore_regs() accesses UART_IER. This register is modified twice by each console write (serial8250_console_write()) under the port lock. However, not all calls to omap8250_restore_regs() are under the port lock. Add the missing port locking around omap8250_restore_regs() calls. Add lockdep notation to the omap8250_restore_regs(). Note that this is not fixing a real problem because the serial devices are resumed before console printing is enabled. However, adding this locking allows for clean locking semantics for omap8250_restore_regs() so that lockdep can be used to identify possible problems in the future. It also simplifies synchronization of UART_IER in general by not needing to rely on such implementation details. Signed-off-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/r/20230525093159.223817-7-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: lock port for rx_dma() callbackJohn Ogness2023-05-301-2/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rx_dma() callback (omap_8250_rx_dma) accesses UART_IER. This register is modified twice by each console write (serial8250_console_write()) under the port lock. However, not all calls to the rx_dma() callback are under the port lock. Add the missing port locking around rx_dma() callback calls. Add lockdep notation to the omap_8250_rx_dma(). Note that this is not fixing a real problem because: 1. Currently DMA is forced off for 8250_omap consoles. 2. The serial devices are resumed before console printing is enabled. However, adding this locking allows for clean locking semantics for the rx_dma() callback so that lockdep can be used to identify possible problems in the future. It also simplifies synchronization of UART_IER in general by not needing to rely on implementation details such as 1 and 2. Signed-off-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/r/20230525093159.223817-6-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: core: lock port for start_rx() in uart_resume_port()John Ogness2023-05-301-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only user of the start_rx() callback (qcom_geni) directly calls its own stop_rx() callback. Since stop_rx() requires that the port->lock is taken and interrupts are disabled, the start_rx() callback has the same requirement. Fixes: cfab87c2c271 ("serial: core: Introduce callback for start_rx and do stop_rx in suspend only if this callback implementation is present.") Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20230525093159.223817-5-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: lock port for stop_rx() in omap8250_irq()John Ogness2023-05-301-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The uarts_ops stop_rx() callback expects that the port->lock is taken and interrupts are disabled. Fixes: 1fe0e1fa3209 ("serial: 8250_omap: Handle optional overrun-throttle-ms property") Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230525093159.223817-4-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: core: lock port for stop_rx() in uart_suspend_port()John Ogness2023-05-301-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The uarts_ops stop_rx() callback expects that the port->lock is taken and interrupts are disabled. Fixes: c9d2325cdb92 ("serial: core: Do stop_rx in suspend path for console if console_suspend is disabled") Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20230525093159.223817-3-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: lock port in startup() callbacksJohn Ogness2023-05-304-2/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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. The console printing function serial8250_console_write() modifies the interrupt register (UART_IER) under the port->lock with the pattern: read, clear, restore. Since some startup() callbacks are modifying UART_IER without the port->lock locked, it is possible that the value intended to be written by the startup() callback will get overwritten and be lost. CPU0 CPU1 serial8250_console_write omap_8250_startup -------------------------- ----------------- spin_lock(port->lock) oldval = read(UART_IER) uart_console_write() write(newval, UART_IER) write(oldval, UART_IER) spin_unlock(port->lock) Add port->lock synchronization to the 8250 startup() callbacks where they need to access UART_IER. This avoids racing with serial8250_console_write(). Signed-off-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/r/20230525093159.223817-2-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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