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Revert "serial: imx: remove unbalanced clk_prepare" 

This reverts commit 9e7b399d65.

Commit ("9e7b399d6528ea") causes the following warning and sometimes
also hangs the system:

------------[ cut here ]------------
 WARNING: CPU: 0 PID: 0 at kernel/locking/mutex.c:868 mutex_trylock+0x20c/0x22c()
 DEBUG_LOCKS_WARN_ON(in_interrupt())
 Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.2.0-rc7-next-20150818-00001-g14418a6 #4
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Backtrace:
[<80012f08>] (dump_backtrace) from [<800130a4>] (show_stack+0x18/0x1c)
r6:00000364 r5:00000000 r4:00000000 r3:00000000
[<8001308c>] (show_stack) from [<807902b8>] (dump_stack+0x88/0xa4)
[<80790230>] (dump_stack) from [<8002a604>] (warn_slowpath_common+0x80/0xbc)
r5:807945c4 r4:80ab3b50
[<8002a584>] (warn_slowpath_common) from [<8002a6e4>] (warn_slowpath_fmt+0x38/0x40)
r8:00000000 r7:8131100c r6:8054c3cc r5:8131300c r4:80b0a570
[<8002a6b0>] (warn_slowpath_fmt) from [<807945c4>] (mutex_trylock+0x20c/0x22c)
r3:8095d0d8 r2:8095ab28
[<807943b8>] (mutex_trylock) from [<8054c3cc>] (clk_prepare_lock+0x14/0xf4)
r7:8131100c r6:be3f0c80 r5:00000037 r4:be3f0c80
[<8054c3b8>] (clk_prepare_lock) from [<8054dbfc>] (clk_prepare+0x18/0x30)
r5:00000037 r4:be3f0c80
[<8054dbe4>] (clk_prepare) from [<8036a600>] (imx_console_write+0x30/0x244)
r4:812d0bc8 r3:8132b9a4

To reproduce the problem we only need to let the board idle for something
like 30 seconds.

Tested on a imx6q-sabresd.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Reviewed-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Fabio Estevam 2015-08-18 12:43:12 -03:00 committed by Greg Kroah-Hartman
parent 9ffecb1028
commit 0c727a4204
1 changed files with 14 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/tty/serial/imx.c
View File

@ -1631,12 +1631,12 @@ imx_console_write(struct console *co, const char *s, unsigned int count)
int locked = 1;
int retval;
retval = clk_prepare_enable(sport->clk_per);
retval = clk_enable(sport->clk_per);
if (retval)
return;
retval = clk_prepare_enable(sport->clk_ipg);
retval = clk_enable(sport->clk_ipg);
if (retval) {
clk_disable_unprepare(sport->clk_per);
clk_disable(sport->clk_per);
return;
}
@ -1675,8 +1675,8 @@ imx_console_write(struct console *co, const char *s, unsigned int count)
if (locked)
spin_unlock_irqrestore(&sport->port.lock, flags);
clk_disable_unprepare(sport->clk_ipg);
clk_disable_unprepare(sport->clk_per);
clk_disable(sport->clk_ipg);
clk_disable(sport->clk_per);
}
/*
@ -1777,7 +1777,15 @@ imx_console_setup(struct console *co, char *options)
retval = uart_set_options(&sport->port, co, baud, parity, bits, flow);
clk_disable_unprepare(sport->clk_ipg);
clk_disable(sport->clk_ipg);
if (retval) {
clk_unprepare(sport->clk_ipg);
goto error_console;
}
retval = clk_prepare(sport->clk_per);
if (retval)
clk_disable_unprepare(sport->clk_ipg);
error_console:
return retval;