linux/drivers/tty
Shawn Guo 4561d8008a serial: imx: Add missing .thaw_noirq hook
The following warning is seen with non-console UART instance when
system hibernates.

[   37.371969] ------------[ cut here ]------------
[   37.376599] uart3_root_clk already disabled
[   37.380810] WARNING: CPU: 0 PID: 296 at drivers/clk/clk.c:952 clk_core_disable+0xa4/0xb0
...
[   37.506986] Call trace:
[   37.509432]  clk_core_disable+0xa4/0xb0
[   37.513270]  clk_disable+0x34/0x50
[   37.516672]  imx_uart_thaw+0x38/0x5c
[   37.520250]  platform_pm_thaw+0x30/0x6c
[   37.524089]  dpm_run_callback.constprop.0+0x3c/0xd4
[   37.528972]  device_resume+0x7c/0x160
[   37.532633]  dpm_resume+0xe8/0x230
[   37.536036]  hibernation_snapshot+0x288/0x430
[   37.540397]  hibernate+0x10c/0x2e0
[   37.543798]  state_store+0xc4/0xd0
[   37.547203]  kobj_attr_store+0x1c/0x30
[   37.550953]  sysfs_kf_write+0x48/0x60
[   37.554619]  kernfs_fop_write_iter+0x118/0x1ac
[   37.559063]  new_sync_write+0xe8/0x184
[   37.562812]  vfs_write+0x230/0x290
[   37.566214]  ksys_write+0x68/0xf4
[   37.569529]  __arm64_sys_write+0x20/0x2c
[   37.573452]  invoke_syscall.constprop.0+0x50/0xf0
[   37.578156]  do_el0_svc+0x11c/0x150
[   37.581648]  el0_svc+0x30/0x140
[   37.584792]  el0t_64_sync_handler+0xe8/0xf0
[   37.588976]  el0t_64_sync+0x1a0/0x1a4
[   37.592639] ---[ end trace 56e22eec54676d75 ]---

On hibernating, pm core calls into related hooks in sequence like:

    .freeze
    .freeze_noirq
    .thaw_noirq
    .thaw

With .thaw_noirq hook being absent, the clock will be disabled in a
unbalanced call which results the warning above.

    imx_uart_freeze()
        clk_prepare_enable()
    imx_uart_suspend_noirq()
        clk_disable()
    imx_uart_thaw
        clk_disable_unprepare()

Adding the missing .thaw_noirq hook as imx_uart_resume_noirq() will have
the call sequence corrected as below and thus fix the warning.

    imx_uart_freeze()
        clk_prepare_enable()
    imx_uart_suspend_noirq()
        clk_disable()
    imx_uart_resume_noirq()
        clk_enable()
    imx_uart_thaw
        clk_disable_unprepare()

Fixes: 09df0b3464 ("serial: imx: fix endless loop during suspend")
Reviewed-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Link: https://lore.kernel.org/r/20221012121353.2346280-1-shawn.guo@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-03 04:12:09 +01:00
..
hvc tty: hvc: remove HVC_IUCV_MAGIC 2022-09-22 16:12:34 +02:00
ipwireless tty: drop put_tty_driver 2021-07-27 12:17:21 +02:00
serdev tty: Replace acpi_bus_get_device() 2022-01-31 14:30:06 +01:00
serial serial: imx: Add missing .thaw_noirq hook 2022-11-03 04:12:09 +01:00
vt Merge 6.0-rc4 into tty-next 2022-09-05 07:59:28 +02:00
amiserial.c tty: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
ehv_bytechan.c tty: drop put_tty_driver 2021-07-27 12:17:21 +02:00
goldfish.c tty: goldfish: Fix free_irq() on remove 2022-06-10 13:31:31 +02:00
Kconfig tty: add rpmsg driver 2021-10-21 12:35:35 +02:00
Makefile tty: add rpmsg driver 2021-10-21 12:35:35 +02:00
mips_ejtag_fdc.c serial: Convert SERIAL_XMIT_SIZE to UART_XMIT_SIZE 2022-06-27 14:41:31 +02:00
moxa.c tty: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
mxser.c tty: mxser: remove redundant assignment to hwid 2022-09-01 17:59:36 +02:00
n_gsm.c tty: n_gsm: add debug bit for user payload 2022-09-22 16:05:00 +02:00
n_hdlc.c tty: n_hdlc: remove HDLC_MAGIC 2022-09-22 16:12:34 +02:00
n_null.c
n_tty.c tty: Make ldisc ->set_termios() old ktermios const 2022-08-30 14:22:34 +02:00
nozomi.c tty: drop put_tty_driver 2021-07-27 12:17:21 +02:00
pty.c tty: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
rpmsg_tty.c tty: rpmsg: Fix race condition releasing tty port 2022-01-26 14:50:26 +01:00
synclink_gt.c tty: synclink_gt: remove MGSL_MAGIC 2022-09-22 16:12:34 +02:00
sysrq.c Merge branch 'rework/kthreads' into for-linus 2022-06-23 19:11:28 +02:00
tty_audit.c
tty_baudrate.c tty: Fix comment style in tty_termios_input_baud_rate() 2022-08-30 14:22:34 +02:00
tty_buffer.c tty: Fix lookahead_buf crash with serdev 2022-08-30 14:31:53 +02:00
tty_io.c tty: remove TTY_DRIVER_MAGIC 2022-09-22 16:12:34 +02:00
tty_ioctl.c termios: start unifying non-UAPI parts of asm/termios.h 2022-09-09 10:44:34 +02:00
tty_jobctrl.c signal: Replace __group_send_sig_info with send_signal_locked 2022-05-11 14:33:17 -05:00
tty_ldisc.c tty: reformat kernel-doc in tty_ldisc.c 2021-11-26 16:27:43 +01:00
tty_ldsem.c tty/ldsem: Fix syntax errors in comments 2021-12-21 09:15:49 +01:00
tty_mutex.c tty: remove TTY_MAGIC 2022-09-22 16:12:34 +02:00
tty_port.c tty: Implement lookahead to process XON/XOFF timely 2022-06-10 13:51:31 +02:00
tty.h tty: Remove baudrate dead code & make ktermios params const 2022-08-30 14:22:34 +02:00
ttynull.c tty: drop put_tty_driver 2021-07-27 12:17:21 +02:00
vcc.c termios: start unifying non-UAPI parts of asm/termios.h 2022-09-09 10:44:34 +02:00