kernel.git/drivers/tty/serial/imx.c, branch linux-5.14.y

serial: imx: fix detach/attach of serial console

2021-11-17T10:04:27Z

[ Upstream commit 6d0d1b5a1b4870911beb89544ec1a9751c42fec7 ] If the device used as a serial console gets detached/attached at runtime, register_console() will try to call imx_uart_setup_console(), but this is not possible since it is marked as __init. For instance # cat /sys/devices/virtual/tty/console/active tty1 ttymxc0 # echo -n N > /sys/devices/virtual/tty/console/subsystem/ttymxc0/console # echo -n Y > /sys/devices/virtual/tty/console/subsystem/ttymxc0/console [ 73.166649] 8<--- cut here --- [ 73.167005] Unable to handle kernel paging request at virtual address c154d928 [ 73.167601] pgd = 55433e84 [ 73.167875] [c154d928] *pgd=8141941e(bad) [ 73.168304] Internal error: Oops: 8000000d [#1] SMP ARM [ 73.168429] Modules linked in: [ 73.168522] CPU: 0 PID: 536 Comm: sh Not tainted 5.15.0-rc6-00056-g3968ddcf05fb #3 [ 73.168675] Hardware name: Freescale i.MX6 Ultralite (Device Tree) [ 73.168791] PC is at imx_uart_console_setup+0x0/0x238 [ 73.168927] LR is at try_enable_new_console+0x98/0x124 [ 73.169056] pc : [] lr : [] psr: a0000013 [ 73.169178] sp : c2ef5e70 ip : 00000000 fp : 00000000 [ 73.169281] r10: 00000000 r9 : c02cf970 r8 : 00000000 [ 73.169389] r7 : 00000001 r6 : 00000001 r5 : c1760164 r4 : c1e0fb08 [ 73.169512] r3 : c154d928 r2 : 00000000 r1 : efffcbd1 r0 : c1760164 [ 73.169641] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 73.169782] Control: 10c5387d Table: 8345406a DAC: 00000051 [ 73.169895] Register r0 information: non-slab/vmalloc memory [ 73.170032] Register r1 information: non-slab/vmalloc memory [ 73.170158] Register r2 information: NULL pointer [ 73.170273] Register r3 information: non-slab/vmalloc memory [ 73.170397] Register r4 information: non-slab/vmalloc memory [ 73.170521] Register r5 information: non-slab/vmalloc memory [ 73.170647] Register r6 information: non-paged memory [ 73.170771] Register r7 information: non-paged memory [ 73.170892] Register r8 information: NULL pointer [ 73.171009] Register r9 information: non-slab/vmalloc memory [ 73.171142] Register r10 information: NULL pointer [ 73.171259] Register r11 information: NULL pointer [ 73.171375] Register r12 information: NULL pointer [ 73.171494] Process sh (pid: 536, stack limit = 0xcd1ba82f) [ 73.171621] Stack: (0xc2ef5e70 to 0xc2ef6000) [ 73.171731] 5e60: ???????? ???????? ???????? ???????? [ 73.171899] 5e80: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172059] 5ea0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172217] 5ec0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172377] 5ee0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172537] 5f00: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172698] 5f20: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172856] 5f40: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173016] 5f60: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173177] 5f80: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173336] 5fa0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173496] 5fc0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173654] 5fe0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173826] [] (try_enable_new_console) from [] (register_console+0x10c/0x2ec) [ 73.174053] [] (register_console) from [] (console_store+0x14c/0x168) [ 73.174262] [] (console_store) from [] (kernfs_fop_write_iter+0x110/0x1cc) [ 73.174470] [] (kernfs_fop_write_iter) from [] (vfs_write+0x31c/0x548) [ 73.174679] [] (vfs_write) from [] (ksys_write+0x60/0xec) [ 73.174863] [] (ksys_write) from [] (ret_fast_syscall+0x0/0x1c) [ 73.175052] Exception stack(0xc2ef5fa8 to 0xc2ef5ff0) [ 73.175167] 5fa0: ???????? ???????? ???????? ???????? ???????? ???????? [ 73.175327] 5fc0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.175486] 5fe0: ???????? ???????? ???????? ???????? [ 73.175608] Code: 00000000 00000000 00000000 00000000 (00000000) [ 73.175744] ---[ end trace 9b75121265109bf1 ]--- A similar issue could be triggered by unbinding/binding the serial console device [*]. Drop __init so that imx_uart_setup_console() can be safely called at runtime. [*] https://lore.kernel.org/all/20181114174940.7865-3-stefan@agner.ch/ Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Reviewed-by: Andy Shevchenko Acked-by: Uwe Kleine-König Signed-off-by: Stefan Agner Signed-off-by: Francesco Dolcini Link: https://lore.kernel.org/r/20211020192643.476895-2-francesco.dolcini@toradex.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: imx: Add DMA buffer configuration via DT

2021-06-04T13:11:16Z

In order to optimize serial communication (performance/throughput VS latency), we may need to tweak DMA period number and size. This adds DT properties to configure those values before initialising DMA. The defaults will stay the same as before. [update documentation and commit message, rebase to current master, switch back to DT instead of sysfs] Signed-off-by: Fabien Lahoudere Signed-off-by: Sebastian Reichel Link: https://lore.kernel.org/r/20210430175038.103226-2-sebastian.reichel@collabora.com Signed-off-by: Greg Kroah-Hartman

serial: drop irq-flags initialisations

2021-05-20T14:24:05Z

There's no need to initialise irq-flags variables before saving the interrupt state. Drop the redundant initialisations from drivers that got this wrong. Acked-by: Uwe Kleine-König Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210519092541.10137-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

serial: imx: drop workaround for forced irq threading

2021-03-23T09:32:44Z

Force-threaded interrupt handlers used to run with interrupts enabled, something which could lead to deadlocks in case a threaded handler shared a lock with code running in hard interrupt context (e.g. timer callbacks) and did not explicitly disable interrupts. This was specifically the case for serial drivers that take the port lock in their console write path as printk can be called from hard interrupt context also with forced threading ("threadirqs"). Since commit 81e2073c175b ("genirq: Disable interrupts for force threaded handlers") interrupt handlers always run with interrupts disabled on non-RT so that drivers no longer need to do handle this. Drop the now obsolete workaround added by commit 33f16855dcb9 ("tty: serial: imx: fix potential deadlock"). Cc: Sam Nobs Cc: Uwe Kleine-König Cc: Thomas Gleixner Cc: Sebastian Andrzej Siewior Cc: Peter Zijlstra Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210322111036.31966-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: imx, use ms_to_ktime

2021-03-10T08:34:06Z

This really eliminates multiplications from the assembly. I would have thought they are optimized by inlining ktime_set, but not on x86_64 with gcc 10. Cc: Shawn Guo Cc: Sascha Hauer Cc: Pengutronix Kernel Team Cc: Fabio Estevam Cc: NXP Linux Team Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210302062214.29627-10-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty/serial/imx: convert comma to semicolon

2020-12-28T15:10:45Z

Replace a comma between expression statements by a semicolon. Acked-by: Uwe Kleine-König Signed-off-by: Zheng Yongjun Link: https://lore.kernel.org/r/20201214133719.3893-1-zhengyongjun3@huawei.com Signed-off-by: Greg Kroah-Hartman

serial: imx: Move imx_uart_probe_dt() content into probe()

2020-12-10T15:24:52Z

Now that the driver only probes via devicetree, we can move the content of imx_uart_probe_dt() directly into imx_uart_probe() to make the code simpler. Suggested-by: Uwe Kleine-König Reviewed-by: Uwe Kleine-König Signed-off-by: Fabio Estevam Link: https://lore.kernel.org/r/20201209214712.15247-1-festevam@gmail.com Signed-off-by: Greg Kroah-Hartman

serial: imx: Remove unneeded of_device_get_match_data() NULL check

2020-12-09T18:48:10Z

Since 5.10-rc1 i.MX is a devicetree-only platform and the NULL check on of_device_get_match_data() is no longer needed. This check was only needed when this driver supported both DT and non-DT platforms. Remove the unneeded of_device_get_match_data() NULL check. Signed-off-by: Fabio Estevam Link: https://lore.kernel.org/r/20201126124643.3371-1-festevam@gmail.com Signed-off-by: Greg Kroah-Hartman

tty/serial/imx: Enable TXEN bit in imx_poll_init().

2020-12-04T15:54:20Z

As described in Documentation, poll_init() is called by kgdb to initialize hardware which supports both poll_put_char() and poll_get_char(). It's necessary to enable TXEN bit, otherwise, it will cause hardware fault and kernel panic when calling imx_poll_put_char(). Generally, if use /dev/ttymxc0 as kgdb console as well as system console, ttymxc0 is initialized early by system console which does enable TXEN bit.But when use /dev/ttymxc1 as kgbd console, ttymxc1 is only initialized by imx_poll_init() cannot enable the TXEN bit, which will cause kernel panic. Signed-off-by: Mingrui Ren Link: https://lore.kernel.org/r/20201202072543.151-1-972931182@qq.com Signed-off-by: Greg Kroah-Hartman

Merge 5.10-rc5 into tty-next

2020-11-23T07:25:08Z

We need the tty/serial fixes in here as well. Signed-off-by: Greg Kroah-Hartman