Working with RT patches reveals this driver have some spin_lock issues.
spin_lock moved from sc16is7xx_reg_proc to protect to call to
uart_handle_cts_change as it's the only call that isn't already
protected in serial-core.
Attached kernel dump:
-----------[ cut here ]------------
Kernel BUG at 80484398 [verbose debug info unavailable]
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
Modules linked in: sc16is7xx regmap_spi
CPU: 0 PID: 463 Comm: sc16is7xx Tainted: G O 4.1.15-rt17-00096-gbd1cd22 #1
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
task: aa991cc0 ti: aa640000 task.ti: aa640000
PC is at rt_spin_lock_slowlock+0x254/0x2c0
LR is at rt_spin_lock_slowlock+0x54/0x2c0
pc : [<80484398>] lr : [<80484198>] psr: 60070193
sp : aa641db0 ip : aa991cc1 fp : aa68dcdc
r10: 00000000 r9 : aa991cc0 r8 : 00000000
r7 : 00000000 r6 : aa641db0 r5 : 00000001 r4 : aa68dcc4
r3 : aa991cc0 r2 : 00000000 r1 : aa991cc0 r0 : 00000000
Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c5387d Table: 3a60004a DAC: 00000015
Process sc16is7xx (pid: 463, stack limit = 0xaa640210)
Stack: (0xaa641db0 to 0xaa642000)
1da0: aa641db0 aa8c4f40 00000000 aa641dbc
1dc0: aa641e24 aa641e60 00000000 00000000 802c9301 00000000 aa68dcc4 aa68dcf0
1de0: 0000006a ab0ce300 806e02cd 804858c8 00000000 8004018c 7f051258 aa5c8b80
1e00: 00000000 7f051268 7f051258 80062624 00000000 00000000 00000000 ab0ce300
1e20: aa5c8b80 00000005 ab11ba10 00000001 80731908 806b0cc4 aa68dcdc 80062774
1e40: 00020002 ab0ce300 00000020 80065bd8 0000006a 80061cb8 00000020 8023217c
1e60: aa641dc0 aa641e24 00000000 a8948800 aa8c4f40 ab11ba10 806b8948 ab0cdd80
1e80: 00000000 00000001 aa641ee8 ab008000 aa68dcdc 802322c8 00000063 00000000
1ea0: 00000063 80061cb8 806a3030 80061f80 f400010c 00000056 806b0fe0 aa641ee8
1ec0: f4000100 aa68dcdc 80723f68 80009468 804858c8 60070013 ffffffff aa641f1c
1ee0: 00000001 80013240 aa68dcc4 aa991cc0 aa640000 aa68dcd0 80723f68 aa68dcc4
1f00: aa640000 00000000 00000001 aa68dcdc 80723f68 aa68dcdc 00000000 aa641f34
1f20: 8003ffbc 804858c8 60070013 ffffffff aa68dcf0 80723f68 aa640000 aa641f38
1f40: aa68dcc4 aab04480 00000000 aa68dcc4 8003feb8 00000000 00000000 00000000
1f60: 00000000 80040104 00000000 00000000 00000000 aa68dcc4 00000000 00000000
1f80: aa641f80 aa641f80 00000000 00000000 aa641f90 aa641f90 aa641fac aab04480
1fa0: 80040034 00000000 00000000 8000f528 00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 3bf5a811 3bf5ac11
[<80484398>] (rt_spin_lock_slowlock) from [<8004018c>] (queue_kthread_work+0x18/0x74)
[<8004018c>] (queue_kthread_work) from [<7f051268>] (sc16is7xx_irq+0x10/0x18 [sc16is7xx])
[<7f051268>] (sc16is7xx_irq [sc16is7xx]) from [<80062624>] (handle_irq_event_percpu+0x70/0x158)
[<80062624>] (handle_irq_event_percpu) from [<80062774>] (handle_irq_event+0x68/0xa8)
[<80062774>] (handle_irq_event) from [<80065bd8>] (handle_level_irq+0x10c/0x184)
[<80065bd8>] (handle_level_irq) from [<80061cb8>] (generic_handle_irq+0x2c/0x3c)
[<80061cb8>] (generic_handle_irq) from [<8023217c>] (mxc_gpio_irq_handler+0x3c/0x108)
[<8023217c>] (mxc_gpio_irq_handler) from [<802322c8>] (mx3_gpio_irq_handler+0x80/0xcc)
[<802322c8>] (mx3_gpio_irq_handler) from [<80061cb8>] (generic_handle_irq+0x2c/0x3c)
[<80061cb8>] (generic_handle_irq) from [<80061f80>] (__handle_domain_irq+0x7c/0xe8)
[<80061f80>] (__handle_domain_irq) from [<80009468>] (gic_handle_irq+0x24/0x5c)
[<80009468>] (gic_handle_irq) from [<80013240>] (__irq_svc+0x40/0x88)
Exception stack(0xaa641ee8 to 0xaa641f30)
1ee0: aa68dcc4 aa991cc0 aa640000 aa68dcd0 80723f68 aa68dcc4
1f00: aa640000 00000000 00000001 aa68dcdc 80723f68 aa68dcdc 00000000 aa641f34
1f20: 8003ffbc 804858c8 60070013 ffffffff
[<80013240>] (__irq_svc) from [<804858c8>] (rt_spin_unlock+0x1c/0x68)
[<804858c8>] (rt_spin_unlock) from [<8003ffbc>] (kthread_worker_fn+0x104/0x17c)
[<8003ffbc>] (kthread_worker_fn) from [<80040104>] (kthread+0xd0/0xe8)
[<80040104>] (kthread) from [<8000f528>] (ret_from_fork+0x14/0x2c)
Code: 0a000002 e59d3000 e1530006 0a000000 (e7f001f2)
---[ end trace 0000000000000002 ]---
Kernel panic - not syncing: Fatal exception in interrupt
CPU1: stopping
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G D O 4.1.15-rt17-00096-gbd1cd22 #1
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[<80016718>] (unwind_backtrace) from [<80012700>] (show_stack+0x10/0x14)
[<80012700>] (show_stack) from [<80481808>] (dump_stack+0x7c/0x90)
[<80481808>] (dump_stack) from [<800155c8>] (handle_IPI+0x180/0x1dc)
[<800155c8>] (handle_IPI) from [<8000949c>] (gic_handle_irq+0x58/0x5c)
[<8000949c>] (gic_handle_irq) from [<80013240>] (__irq_svc+0x40/0x88)
Exception stack(0xab0a3f58 to 0xab0a3fa0)
3f40: 00000000 ab0a3f68
3f60: 00000001 ab0a2000 00000001 806b7f70 533b4c3a 00002c5b ab729128 00000001
3f80: 678b9ec8 00002c5b 00000000 ab0a3fa0 80080730 80338560 20070013 ffffffff
[<80013240>] (__irq_svc) from [<80338560>] (cpuidle_enter_state+0xb8/0x1ec)
[<80338560>] (cpuidle_enter_state) from [<80059c0c>] (cpu_startup_entry+0x234/0x37c)
[<80059c0c>] (cpu_startup_entry) from [<1000952c>] (0x1000952c)
Signed-off-by: Sean Nyekjaer <sean.nyekjaer@xxxxxxxxx>
---
drivers/tty/serial/sc16is7xx.c | 73 ++++++++----------------------------------
1 file changed, 14 insertions(+), 59 deletions(-)
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index e78fa99..f8b9ef1 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -316,8 +316,6 @@ struct sc16is7xx_one_config {
struct sc16is7xx_one {
struct uart_port port;
u8 line;
- struct kthread_work tx_work;
- struct kthread_work reg_work;
struct sc16is7xx_one_config config;
};
@@ -329,9 +327,6 @@ struct sc16is7xx_port {
struct gpio_chip gpio;
#endif
unsigned char buf[SC16IS7XX_FIFO_SIZE];
- struct kthread_worker kworker;
- struct task_struct *kworker_task;
- struct kthread_work irq_work;
struct sc16is7xx_one p[0];
};
@@ -661,9 +656,10 @@ static void sc16is7xx_handle_tx(struct uart_port *port)
uart_write_wakeup(port);
}
-static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
+static void sc16is7xx_port_ist(struct sc16is7xx_port *s, int portno)
{
struct uart_port *port = &s->p[portno].port;
+ unsigned long irqflags;
do {
unsigned int iir, msr, rxlen;
@@ -686,8 +682,10 @@ static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
case SC16IS7XX_IIR_CTSRTS_SRC:
msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
+ spin_lock_irqsave(&port->lock, irqflags);
uart_handle_cts_change(port,
!!(msr & SC16IS7XX_MSR_DCTS_BIT));
+ spin_unlock_irqrestore(&port->lock, irqflags);
break;
case SC16IS7XX_IIR_THRI_SRC:
sc16is7xx_handle_tx(port);
@@ -701,28 +699,19 @@ static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
} while (1);
}
-static void sc16is7xx_ist(struct kthread_work *ws)
+static irqreturn_t sc16is7xx_ist(int irq, void *dev_id)
{
- struct sc16is7xx_port *s = to_sc16is7xx_port(ws, irq_work);
+ struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
int i;
for (i = 0; i < s->devtype->nr_uart; ++i)
- sc16is7xx_port_irq(s, i);
-}
-
-static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
-{
- struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
-
- queue_kthread_work(&s->kworker, &s->irq_work);
+ sc16is7xx_port_ist(s, i);
return IRQ_HANDLED;
}
-static void sc16is7xx_tx_proc(struct kthread_work *ws)
+static void sc16is7xx_tx_proc(struct uart_port *port)
{
- struct uart_port *port = &(to_sc16is7xx_one(ws, tx_work)->port);
-
if ((port->rs485.flags & SER_RS485_ENABLED) &&
(port->rs485.delay_rts_before_send > 0))
msleep(port->rs485.delay_rts_before_send);
@@ -750,16 +739,12 @@ static void sc16is7xx_reconf_rs485(struct uart_port *port)
sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr);
}
-static void sc16is7xx_reg_proc(struct kthread_work *ws)
+static void sc16is7xx_reg_proc(struct sc16is7xx_one *one)
{
- struct sc16is7xx_one *one = to_sc16is7xx_one(ws, reg_work);
struct sc16is7xx_one_config config;
- unsigned long irqflags;
- spin_lock_irqsave(&one->port.lock, irqflags);
config = one->config;
memset(&one->config, 0, sizeof(one->config));
- spin_unlock_irqrestore(&one->port.lock, irqflags);
if (config.flags & SC16IS7XX_RECONF_MD) {
sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
@@ -785,12 +770,11 @@ static void sc16is7xx_reg_proc(struct kthread_work *ws)
static void sc16is7xx_ier_clear(struct uart_port *port, u8 bit)
{
- struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
one->config.flags |= SC16IS7XX_RECONF_IER;
one->config.ier_clear |= bit;
- queue_kthread_work(&s->kworker, &one->reg_work);
+ sc16is7xx_reg_proc(one);
}
static void sc16is7xx_stop_tx(struct uart_port *port)
@@ -805,10 +789,7 @@ static void sc16is7xx_stop_rx(struct uart_port *port)
static void sc16is7xx_start_tx(struct uart_port *port)
{
- struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
- struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
-
- queue_kthread_work(&s->kworker, &one->tx_work);
+ sc16is7xx_tx_proc(port);
}
static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
@@ -836,11 +817,10 @@ static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
- struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
one->config.flags |= SC16IS7XX_RECONF_MD;
- queue_kthread_work(&s->kworker, &one->reg_work);
+ sc16is7xx_reg_proc(one);
}
static void sc16is7xx_break_ctl(struct uart_port *port, int break_state)
@@ -944,7 +924,6 @@ static void sc16is7xx_set_termios(struct uart_port *port,
static int sc16is7xx_config_rs485(struct uart_port *port,
struct serial_rs485 *rs485)
{
- struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
if (rs485->flags & SER_RS485_ENABLED) {
@@ -969,7 +948,7 @@ static int sc16is7xx_config_rs485(struct uart_port *port,
port->rs485 = *rs485;
one->config.flags |= SC16IS7XX_RECONF_RS485;
- queue_kthread_work(&s->kworker, &one->reg_work);
+ sc16is7xx_reg_proc(one);
return 0;
}
@@ -1030,8 +1009,6 @@ static int sc16is7xx_startup(struct uart_port *port)
static void sc16is7xx_shutdown(struct uart_port *port)
{
- struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
-
/* Disable all interrupts */
sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
/* Disable TX/RX */
@@ -1042,8 +1019,6 @@ static void sc16is7xx_shutdown(struct uart_port *port)
SC16IS7XX_EFCR_TXDISABLE_BIT);
sc16is7xx_power(port, 0);
-
- flush_kthread_worker(&s->kworker);
}
static const char *sc16is7xx_type(struct uart_port *port)
@@ -1161,7 +1136,6 @@ static int sc16is7xx_probe(struct device *dev,
const struct sc16is7xx_devtype *devtype,
struct regmap *regmap, int irq, unsigned long flags)
{
- struct sched_param sched_param = { .sched_priority = MAX_RT_PRIO / 2 };
unsigned long freq, *pfreq = dev_get_platdata(dev);
int i, ret;
struct sc16is7xx_port *s;
@@ -1193,16 +1167,6 @@ static int sc16is7xx_probe(struct device *dev,
s->devtype = devtype;
dev_set_drvdata(dev, s);
- init_kthread_worker(&s->kworker);
- init_kthread_work(&s->irq_work, sc16is7xx_ist);
- s->kworker_task = kthread_run(kthread_worker_fn, &s->kworker,
- "sc16is7xx");
- if (IS_ERR(s->kworker_task)) {
- ret = PTR_ERR(s->kworker_task);
- goto out_clk;
- }
- sched_setscheduler(s->kworker_task, SCHED_FIFO, &sched_param);
-
#ifdef CONFIG_GPIOLIB
if (devtype->nr_gpio) {
/* Setup GPIO cotroller */
@@ -1246,9 +1210,6 @@ static int sc16is7xx_probe(struct device *dev,
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_RXDISABLE_BIT |
SC16IS7XX_EFCR_TXDISABLE_BIT);
- /* Initialize kthread work structs */
- init_kthread_work(&s->p[i].tx_work, sc16is7xx_tx_proc);
- init_kthread_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
/* Register port */
uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
/* Go to suspend mode */
@@ -1256,7 +1217,7 @@ static int sc16is7xx_probe(struct device *dev,
}
/* Setup interrupt */
- ret = devm_request_irq(dev, irq, sc16is7xx_irq,
+ ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_ist,
IRQF_ONESHOT | flags, dev_name(dev), s);
if (!ret)
return 0;
@@ -1273,9 +1234,6 @@ out_ports:
out_thread:
#endif
- kthread_stop(s->kworker_task);
-
-out_clk:
if (!IS_ERR(s->clk))
clk_disable_unprepare(s->clk);
@@ -1298,9 +1256,6 @@ static int sc16is7xx_remove(struct device *dev)
sc16is7xx_power(&s->p[i].port, 0);
}
- flush_kthread_worker(&s->kworker);
- kthread_stop(s->kworker_task);
-
if (!IS_ERR(s->clk))
clk_disable_unprepare(s->clk);
--
2.7.1
--
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