From: Tony Lindgren tony@atomide.com
[ Upstream commit 93810191f5d23652c0b8a1a9b3a4a89d6fd5063e ]
There are cases where omap8250_set_mctrl() may get called after the UART has already autoidled causing an asynchronous external abort.
This can happen on ttyport_open():
mem_serial_in from omap8250_set_mctrl+0x38/0xa0 omap8250_set_mctrl from uart_update_mctrl+0x4c/0x58 uart_update_mctrl from uart_dtr_rts+0x60/0xa8 uart_dtr_rts from tty_port_block_til_ready+0xd0/0x2a8 tty_port_block_til_ready from uart_open+0x14/0x1c uart_open from ttyport_open+0x64/0x148
And on ttyport_close():
omap8250_set_mctrl from uart_update_mctrl+0x3c/0x48 uart_update_mctrl from uart_dtr_rts+0x54/0x9c uart_dtr_rts from tty_port_shutdown+0x78/0x9c tty_port_shutdown from tty_port_close+0x3c/0x74 tty_port_close from ttyport_close+0x40/0x58
It can also happen on disassociate_ctty() calling uart_shutdown() that ends up calling omap8250_set_mctrl().
Let's fix the issue by adding missing PM runtime calls to omap8250_set_mctrl(). To do this, we need to add __omap8250_set_mctrl() that can be called from both omap8250_set_mctrl(), and from runtime PM resume path when restoring the registers.
Fixes: 61929cf0169d ("tty: serial: Add 8250-core based omap driver") Reported-by: Merlijn Wajer merlijn@wizzup.org Reported-by: Romain Naour romain.naour@smile.fr Reported-by: Ivaylo Dimitrov ivo.g.dimitrov.75@gmail.com Tested-by: Ivaylo Dimitrov ivo.g.dimitrov.75@gmail.com Signed-off-by: Tony Lindgren tony@atomide.com Depends-on: dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter") Link: https://lore.kernel.org/r/20221024063613.25943-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/8250/8250_omap.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index 38ee3e42251a..03a026bdba3c 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -157,7 +157,11 @@ static u32 uart_read(struct uart_8250_port *up, u32 reg) return readl(up->port.membase + (reg << up->port.regshift)); }
-static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) +/* + * Called on runtime PM resume path from omap8250_restore_regs(), and + * omap8250_set_mctrl(). + */ +static void __omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct uart_8250_port *up = up_to_u8250p(port); struct omap8250_priv *priv = up->port.private_data; @@ -181,6 +185,20 @@ static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) } }
+static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + int err; + + err = pm_runtime_resume_and_get(port->dev); + if (err) + return; + + __omap8250_set_mctrl(port, mctrl); + + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); +} + /* * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460) * The access to uart register after MDR1 Access @@ -341,7 +359,7 @@ static void omap8250_restore_regs(struct uart_8250_port *up)
omap8250_update_mdr1(up, priv);
- up->port.ops->set_mctrl(&up->port, up->port.mctrl); + __omap8250_set_mctrl(&up->port, up->port.mctrl);
if (up->port.rs485.flags & SER_RS485_ENABLED) serial8250_em485_stop_tx(up);