This patch adds support for polling work mode, i.e. system is perform
periodical check chip status when IRQ-line is not connected to CPU.
Signed-off-by: Alexander Shiyan <shc_work@xxxxxxx>
---
drivers/tty/serial/sccnxp.c | 148 +++++++++++++++++++++++----------
include/linux/platform_data/sccnxp.h | 2 +
2 files changed, 105 insertions(+), 45 deletions(-)
diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c
index 418b495..ae68e8c 100644
--- a/drivers/tty/serial/sccnxp.c
+++ b/drivers/tty/serial/sccnxp.c
@@ -23,6 +23,7 @@
#include <linux/io.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
+#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/platform_data/sccnxp.h>
@@ -106,6 +107,7 @@ enum {
struct sccnxp_port {
struct uart_driver uart;
struct uart_port port[SCCNXP_MAX_UARTS];
+ bool opened[SCCNXP_MAX_UARTS];
const char *name;
int irq;
@@ -122,7 +124,10 @@ struct sccnxp_port {
struct console console;
#endif
- struct mutex sccnxp_mutex;
+ spinlock_t lock;
+
+ bool poll;
+ struct timer_list timer;
struct sccnxp_pdata pdata;
};
@@ -377,31 +382,48 @@ static void sccnxp_handle_tx(struct uart_port *port)
uart_write_wakeup(port);
}
-static irqreturn_t sccnxp_ist(int irq, void *dev_id)
+static void sccnxp_handle_events(struct sccnxp_port *s)
{
int i;
u8 isr;
- struct sccnxp_port *s = (struct sccnxp_port *)dev_id;
-
- mutex_lock(&s->sccnxp_mutex);
- for (;;) {
+ do {
isr = sccnxp_read(&s->port[0], SCCNXP_ISR_REG);
isr &= s->imr;
if (!isr)
break;
- dev_dbg(s->port[0].dev, "IRQ status: 0x%02x\n", isr);
-
for (i = 0; i < s->uart.nr; i++) {
- if (isr & ISR_RXRDY(i))
+ if (s->opened[i] && (isr & ISR_RXRDY(i)))
sccnxp_handle_rx(&s->port[i]);
- if (isr & ISR_TXRDY(i))
+ if (s->opened[i] && (isr & ISR_TXRDY(i)))
sccnxp_handle_tx(&s->port[i]);
}
- }
+ } while (1);
+}
+
+static void sccnxp_timer(unsigned long data)
+{
+ struct sccnxp_port *s = (struct sccnxp_port *)data;
+ unsigned long flags;
- mutex_unlock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
+ sccnxp_handle_events(s);
+ spin_unlock_irqrestore(&s->lock, flags);
+
+ if (!timer_pending(&s->timer))
+ mod_timer(&s->timer, jiffies +
+ usecs_to_jiffies(s->pdata.poll_time_us));
+}
+
+static irqreturn_t sccnxp_ist(int irq, void *dev_id)
+{
+ struct sccnxp_port *s = (struct sccnxp_port *)dev_id;
+ unsigned long flags;
+
+ spin_lock_irqsave(&s->lock, flags);
+ sccnxp_handle_events(s);
+ spin_unlock_irqrestore(&s->lock, flags);
return IRQ_HANDLED;
}
@@ -409,8 +431,9 @@ static irqreturn_t sccnxp_ist(int irq, void *dev_id)
static void sccnxp_start_tx(struct uart_port *port)
{
struct sccnxp_port *s = dev_get_drvdata(port->dev);
+ unsigned long flags;
- mutex_lock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
/* Set direction to output */
if (s->flags & SCCNXP_HAVE_IO)
@@ -418,7 +441,7 @@ static void sccnxp_start_tx(struct uart_port *port)
sccnxp_enable_irq(port, IMR_TXRDY);
- mutex_unlock(&s->sccnxp_mutex);
+ spin_unlock_irqrestore(&s->lock, flags);
}
static void sccnxp_stop_tx(struct uart_port *port)
@@ -429,20 +452,22 @@ static void sccnxp_stop_tx(struct uart_port *port)
static void sccnxp_stop_rx(struct uart_port *port)
{
struct sccnxp_port *s = dev_get_drvdata(port->dev);
+ unsigned long flags;
- mutex_lock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
sccnxp_port_write(port, SCCNXP_CR_REG, CR_RX_DISABLE);
- mutex_unlock(&s->sccnxp_mutex);
+ spin_unlock_irqrestore(&s->lock, flags);
}
static unsigned int sccnxp_tx_empty(struct uart_port *port)
{
u8 val;
+ unsigned long flags;
struct sccnxp_port *s = dev_get_drvdata(port->dev);
- mutex_lock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
val = sccnxp_port_read(port, SCCNXP_SR_REG);
- mutex_unlock(&s->sccnxp_mutex);
+ spin_unlock_irqrestore(&s->lock, flags);
return (val & SR_TXEMT) ? TIOCSER_TEMT : 0;
}
@@ -455,28 +480,30 @@ static void sccnxp_enable_ms(struct uart_port *port)
static void sccnxp_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct sccnxp_port *s = dev_get_drvdata(port->dev);
+ unsigned long flags;
if (!(s->flags & SCCNXP_HAVE_IO))
return;
- mutex_lock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
sccnxp_set_bit(port, DTR_OP, mctrl & TIOCM_DTR);
sccnxp_set_bit(port, RTS_OP, mctrl & TIOCM_RTS);
- mutex_unlock(&s->sccnxp_mutex);
+ spin_unlock_irqrestore(&s->lock, flags);
}
static unsigned int sccnxp_get_mctrl(struct uart_port *port)
{
u8 bitmask, ipr;
+ unsigned long flags;
struct sccnxp_port *s = dev_get_drvdata(port->dev);
unsigned int mctrl = TIOCM_DSR | TIOCM_CTS | TIOCM_CAR;
if (!(s->flags & SCCNXP_HAVE_IO))
return mctrl;
- mutex_lock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
ipr = ~sccnxp_read(port, SCCNXP_IPCR_REG);
@@ -505,7 +532,7 @@ static unsigned int sccnxp_get_mctrl(struct uart_port *port)
mctrl |= (ipr & bitmask) ? TIOCM_RNG : 0;
}
- mutex_unlock(&s->sccnxp_mutex);
+ spin_unlock_irqrestore(&s->lock, flags);
return mctrl;
}
@@ -513,21 +540,23 @@ static unsigned int sccnxp_get_mctrl(struct uart_port *port)
static void sccnxp_break_ctl(struct uart_port *port, int break_state)
{
struct sccnxp_port *s = dev_get_drvdata(port->dev);
+ unsigned long flags;
- mutex_lock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
sccnxp_port_write(port, SCCNXP_CR_REG, break_state ?
CR_CMD_START_BREAK : CR_CMD_STOP_BREAK);
- mutex_unlock(&s->sccnxp_mutex);
+ spin_unlock_irqrestore(&s->lock, flags);
}
static void sccnxp_set_termios(struct uart_port *port,
struct ktermios *termios, struct ktermios *old)
{
struct sccnxp_port *s = dev_get_drvdata(port->dev);
+ unsigned long flags;
u8 mr1, mr2;
int baud;
- mutex_lock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
/* Mask termios capabilities we don't support */
termios->c_cflag &= ~CMSPAR;
@@ -594,20 +623,22 @@ static void sccnxp_set_termios(struct uart_port *port,
/* Update timeout according to new baud rate */
uart_update_timeout(port, termios->c_cflag, baud);
+ /* Report actual baudrate back to core */
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);
/* Enable RX & TX */
sccnxp_port_write(port, SCCNXP_CR_REG, CR_RX_ENABLE | CR_TX_ENABLE);
- mutex_unlock(&s->sccnxp_mutex);
+ spin_unlock_irqrestore(&s->lock, flags);
}
static int sccnxp_startup(struct uart_port *port)
{
struct sccnxp_port *s = dev_get_drvdata(port->dev);
+ unsigned long flags;
- mutex_lock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
if (s->flags & SCCNXP_HAVE_IO) {
/* Outputs are controlled manually */
@@ -626,7 +657,9 @@ static int sccnxp_startup(struct uart_port *port)
/* Enable RX interrupt */
sccnxp_enable_irq(port, IMR_RXRDY);
- mutex_unlock(&s->sccnxp_mutex);
+ s->opened[port->line] = 1;
+
+ spin_unlock_irqrestore(&s->lock, flags);
return 0;
}
@@ -634,8 +667,11 @@ static int sccnxp_startup(struct uart_port *port)
static void sccnxp_shutdown(struct uart_port *port)
{
struct sccnxp_port *s = dev_get_drvdata(port->dev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&s->lock, flags);
- mutex_lock(&s->sccnxp_mutex);
+ s->opened[port->line] = 0;
/* Disable interrupts */
sccnxp_disable_irq(port, IMR_TXRDY | IMR_RXRDY);
@@ -647,7 +683,7 @@ static void sccnxp_shutdown(struct uart_port *port)
if (s->flags & SCCNXP_HAVE_IO)
sccnxp_set_bit(port, DIR_OP, 0);
- mutex_unlock(&s->sccnxp_mutex);
+ spin_unlock_irqrestore(&s->lock, flags);
}
static const char *sccnxp_type(struct uart_port *port)
@@ -721,10 +757,11 @@ static void sccnxp_console_write(struct console *co, const char *c, unsigned n)
{
struct sccnxp_port *s = (struct sccnxp_port *)co->data;
struct uart_port *port = &s->port[co->index];
+ unsigned long flags;
- mutex_lock(&s->sccnxp_mutex);
+ spin_lock_irqsave(&s->lock, flags);
uart_console_write(port, c, n, sccnxp_console_putchar);
- mutex_unlock(&s->sccnxp_mutex);
+ spin_unlock_irqrestore(&s->lock, flags);
}
static int sccnxp_console_setup(struct console *co, char *options)
@@ -763,7 +800,7 @@ static int sccnxp_probe(struct platform_device *pdev)
}
platform_set_drvdata(pdev, s);
- mutex_init(&s->sccnxp_mutex);
+ spin_lock_init(&s->lock);
/* Individual chip settings */
switch (chiptype) {
@@ -860,11 +897,19 @@ static int sccnxp_probe(struct platform_device *pdev)
} else
memcpy(&s->pdata, pdata, sizeof(struct sccnxp_pdata));
- s->irq = platform_get_irq(pdev, 0);
- if (s->irq <= 0) {
- dev_err(&pdev->dev, "Missing irq resource data\n");
- ret = -ENXIO;
- goto err_out;
+ if (pdata->poll_time_us) {
+ dev_info(&pdev->dev, "Using poll mode, resolution %u usecs\n",
+ pdata->poll_time_us);
+ s->poll = 1;
+ }
+
+ if (!s->poll) {
+ s->irq = platform_get_irq(pdev, 0);
+ if (s->irq < 0) {
+ dev_err(&pdev->dev, "Missing irq resource data\n");
+ ret = -ENXIO;
+ goto err_out;
+ }
}
/* Check input frequency */
@@ -929,13 +974,23 @@ static int sccnxp_probe(struct platform_device *pdev)
if (s->pdata.init)
s->pdata.init();
- ret = devm_request_threaded_irq(&pdev->dev, s->irq, NULL, sccnxp_ist,
- IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
- dev_name(&pdev->dev), s);
- if (!ret)
+ if (!s->poll) {
+ ret = devm_request_threaded_irq(&pdev->dev, s->irq, NULL,
+ sccnxp_ist,
+ IRQF_TRIGGER_FALLING |
+ IRQF_ONESHOT,
+ dev_name(&pdev->dev), s);
+ if (!ret)
+ return 0;
+
+ dev_err(&pdev->dev, "Unable to reguest IRQ %i\n", s->irq);
+ } else {
+ init_timer(&s->timer);
+ setup_timer(&s->timer, sccnxp_timer, (unsigned long)s);
+ mod_timer(&s->timer, jiffies +
+ usecs_to_jiffies(s->pdata.poll_time_us));
return 0;
-
- dev_err(&pdev->dev, "Unable to reguest IRQ %i\n", s->irq);
+ }
err_out:
platform_set_drvdata(pdev, NULL);
@@ -948,7 +1003,10 @@ static int sccnxp_remove(struct platform_device *pdev)
int i;
struct sccnxp_port *s = platform_get_drvdata(pdev);
- devm_free_irq(&pdev->dev, s->irq, s);
+ if (!s->poll)
+ devm_free_irq(&pdev->dev, s->irq, s);
+ else
+ del_timer_sync(&s->timer);
for (i = 0; i < s->uart.nr; i++)
uart_remove_one_port(&s->uart, &s->port[i]);
diff --git a/include/linux/platform_data/sccnxp.h b/include/linux/platform_data/sccnxp.h
index 7311ccd..096de90 100644
--- a/include/linux/platform_data/sccnxp.h
+++ b/include/linux/platform_data/sccnxp.h
@@ -84,6 +84,8 @@ struct sccnxp_pdata {
const u8 reg_shift;
/* Modem control lines configuration */
const u32 mctrl_cfg[SCCNXP_MAX_UARTS];
+ /* Timer value for polling mode (usecs) */
+ const unsigned int poll_time_us;
/* Called during startup */
void (*init)(void);
/* Called before finish */
--
1.7.8.6
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