kernel.git/drivers/tty/serial/imx.c, branch linux-5.9.y

tty: serial: imx: keep console clocks always on

2020-11-24T12:39:08Z

commit e67c139c488e84e7eae6c333231e791f0e89b3fb upstream. For below code, there has chance to cause deadlock in SMP system: Thread 1: clk_enable_lock(); pr_info("debug message"); clk_enable_unlock(); Thread 2: imx_uart_console_write() clk_enable() clk_enable_lock(); Thread 1: Acuired clk enable_lock -> printk -> console_trylock_spinning Thread 2: console_unlock() -> imx_uart_console_write -> clk_disable -> Acquite clk enable_lock So the patch is to keep console port clocks always on like other console drivers. Fixes: 1cf93e0d5488 ("serial: imx: remove the uart_console() check") Acked-by: Uwe Kleine-König Signed-off-by: Fugang Duan Link: https://lore.kernel.org/r/20201111025136.29818-1-fugang.duan@nxp.com Cc: stable [fix up build warning - gregkh] Signed-off-by: Greg Kroah-Hartman

tty: serial: imx: fix potential deadlock

2020-11-24T12:39:08Z

commit 33f16855dcb973f745c51882d0e286601ff3be2b upstream. Enabling the lock dependency validator has revealed that the way spinlocks are used in the IMX serial port could result in a deadlock. Specifically, imx_uart_int() acquires a spinlock without disabling the interrupts, meaning that another interrupt could come along and try to acquire the same spinlock, potentially causing the two to wait for each other indefinitely. Use spin_lock_irqsave() instead to disable interrupts upon acquisition of the spinlock. Fixes: c974991d2620 ("tty:serial:imx: use spin_lock instead of spin_lock_irqsave in isr") Reviewed-by: Uwe Kleine-König Signed-off-by: Sam Nobs Link: https://lore.kernel.org/r/1604955006-9363-1-git-send-email-samuel.nobs@taitradio.com Cc: stable Signed-off-by: Greg Kroah-Hartman

tty: serial: imx: enable imx serial console port as module

2020-07-29T15:10:59Z

Add support for building i.MX serial driver as module. The changes of the patch: - imx console driver can be built as module. - move out earlycon code to separated driver like imx_earlycon.c, and imx earlycon driver only support build-in. Signed-off-by: Fugang Duan Link: https://lore.kernel.org/r/20200724070815.11445-2-fugang.duan@nxp.com Signed-off-by: Greg Kroah-Hartman

serial: imx: use hrtimers for rs485 delays

2020-07-21T19:08:11Z

This patch imitates 6e0a5de213 ("serial: 8250: Use hrtimers for rs485 delays") in replacing the previously used classic timers with hrtimers. The old way provided a too coarse resolution on systems with configs of less than 1000 HZ. Use of hrtimers addresses this and can be easily extended to support microsecond resolution in future when support for this arrives upstream. Signed-off-by: Ahmad Fatoum Link: https://lore.kernel.org/r/20200714093012.21621-3-uwe@kleine-koenig.org Signed-off-by: Greg Kroah-Hartman

serial: imx: implement rts delaying for rs485

2020-07-21T19:08:10Z

This adds support for delays between assertion of RTS (which is supposed to enable the rs485 transmitter) and sending as well as between the last send char and deassertionof RTS. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20200714093012.21621-2-uwe@kleine-koenig.org Signed-off-by: Greg Kroah-Hartman

Revert "serial: imx: Initialize lock for non-registered console"

2020-07-21T16:21:49Z

This reverts commit 8f065acec7573672dd15916e31d1e9b2e785566c. There has been a quick fix against uninitialised lock revealed by the commit f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()"). Since we have now better fix in serial core, this may be safely reverted. Fixes: 8f065acec757 ("serial: imx: Initialize lock for non-registered console") Depends-on: f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()") Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200711135346.71171-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

tty: serial: imx: clear Ageing Timer Interrupt in handler

2020-05-29T11:00:54Z

The AGTIM flag must be cleared explicitly, otherwise the IRQ handler will be called in an endless loop. Fortunately, this issue currently doesn't affect mainline kernels in practice, as the the RX FIFO trigger level is set to 1 in UFCR. When setting the trigger level to a higher number, the issue is trivially reproducible by any RX without DMA that doesn't fill the FIFO up to the configured level. Signed-off-by: Matthias Schiffer Link: https://lore.kernel.org/r/20200528154747.14201-1-matthias.schiffer@ew.tq-group.com Signed-off-by: Greg Kroah-Hartman

serial: imx: Initialize lock for non-registered console

2020-05-27T08:55:35Z

The commit a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") changed a bit logic behind lock initialization since for most of the console driver it's supposed to have lock already initialized even if console is not enabled. However, it's not the case for Freescale IMX console. Initialize lock explicitly in the ->probe(). Note, there is still an open question should or shouldn't not this driver register console properly. Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Reported-by: Guenter Roeck Cc: stable Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200525105952.13744-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: Allow uart_get_rs485_mode() to return errno

2020-05-15T12:47:05Z

We're about to amend uart_get_rs485_mode() to support a GPIO pin for rs485 bus termination. Retrieving the GPIO descriptor may fail, so allow uart_get_rs485_mode() to return an errno and change all callers to check for failure. The GPIO descriptor is going to be stored in struct uart_port. Pass that struct to uart_get_rs485_mode() in lieu of a struct device and struct serial_rs485, both of which are directly accessible from struct uart_port. A few drivers call uart_get_rs485_mode() before setting the struct device pointer in struct uart_port. Shuffle those calls around where necessary. [Heiko Stuebner did the ar933x_uart.c portion, hence his Signed-off-by.] Signed-off-by: Heiko Stuebner Signed-off-by: Lukas Wunner Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman

tty: serial: imx: Add return value check for platform_get_irq()

2020-05-15T10:25:15Z

RX irq is required, so add return value check for platform_get_irq(). Signed-off-by: Anson Huang Link: https://lore.kernel.org/r/1589180996-618-1-git-send-email-Anson.Huang@nxp.com Signed-off-by: Greg Kroah-Hartman