serial: sc16is7xx: change EFR lock to operate on each channels

commit 4409df5866b7ff7686ba27e449ca97a92ee063c9 upstream.

Now that the driver has been converted to use one regmap per port, change
efr locking to operate on a channel basis instead of on the whole IC.

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc:  <stable@vger.kernel.org> # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-5-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 388f9e7..f57ed74 100644 (file)
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -324,6 +324,7 @@ struct sc16is7xx_one_config {
 struct sc16is7xx_one {
        struct uart_port                port;
        struct regmap                   *regmap;
+       struct mutex                    efr_lock; /* EFR registers access */
        struct kthread_work             tx_work;
        struct kthread_work             reg_work;
        struct kthread_delayed_work     ms_work;
@@ -343,7 +344,6 @@ struct sc16is7xx_port {
        unsigned char                   buf[SC16IS7XX_FIFO_SIZE];
        struct kthread_worker           kworker;
        struct task_struct              *kworker_task;
-       struct mutex                    efr_lock;
        struct sc16is7xx_one            p[];
 };
 
@@ -496,7 +496,6 @@ static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg)
 
 static int sc16is7xx_set_baud(struct uart_port *port, int baud)
 {
-       struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
        struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
        u8 lcr;
        u8 prescaler = 0;
@@ -520,7 +519,7 @@ static int sc16is7xx_set_baud(struct uart_port *port, int baud)
         * because the bulk of the interrupt processing is run as a workqueue
         * job in thread context.
         */
-       mutex_lock(&s->efr_lock);
+       mutex_lock(&one->efr_lock);
 
        lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG);
 
@@ -539,7 +538,7 @@ static int sc16is7xx_set_baud(struct uart_port *port, int baud)
        /* Put LCR back to the normal mode */
        sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
 
-       mutex_unlock(&s->efr_lock);
+       mutex_unlock(&one->efr_lock);
 
        sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
                              SC16IS7XX_MCR_CLKSEL_BIT,
@@ -707,11 +706,10 @@ static unsigned int sc16is7xx_get_hwmctrl(struct uart_port *port)
 static void sc16is7xx_update_mlines(struct sc16is7xx_one *one)
 {
        struct uart_port *port = &one->port;
-       struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
        unsigned long flags;
        unsigned int status, changed;
 
-       lockdep_assert_held_once(&s->efr_lock);
+       lockdep_assert_held_once(&one->efr_lock);
 
        status = sc16is7xx_get_hwmctrl(port);
        changed = status ^ one->old_mctrl;
@@ -737,15 +735,20 @@ static void sc16is7xx_update_mlines(struct sc16is7xx_one *one)
 
 static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
 {
+       bool rc = true;
        struct uart_port *port = &s->p[portno].port;
+       struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
+
+       mutex_lock(&one->efr_lock);
 
        do {
                unsigned int iir, rxlen;
-               struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 
                iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
-               if (iir & SC16IS7XX_IIR_NO_INT_BIT)
-                       return false;
+               if (iir & SC16IS7XX_IIR_NO_INT_BIT) {
+                       rc = false;
+                       goto out_port_irq;
+               }
 
                iir &= SC16IS7XX_IIR_ID_MASK;
 
@@ -785,15 +788,17 @@ static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
                        break;
                }
        } while (0);
-       return true;
+
+out_port_irq:
+       mutex_unlock(&one->efr_lock);
+
+       return rc;
 }
 
 static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
 {
        struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
 
-       mutex_lock(&s->efr_lock);
-
        while (1) {
                bool keep_polling = false;
                int i;
@@ -804,24 +809,22 @@ static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
                        break;
        }
 
-       mutex_unlock(&s->efr_lock);
-
        return IRQ_HANDLED;
 }
 
 static void sc16is7xx_tx_proc(struct kthread_work *ws)
 {
        struct uart_port *port = &(to_sc16is7xx_one(ws, tx_work)->port);
-       struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
+       struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
        unsigned long flags;
 
        if ((port->rs485.flags & SER_RS485_ENABLED) &&
            (port->rs485.delay_rts_before_send > 0))
                msleep(port->rs485.delay_rts_before_send);
 
-       mutex_lock(&s->efr_lock);
+       mutex_lock(&one->efr_lock);
        sc16is7xx_handle_tx(port);
-       mutex_unlock(&s->efr_lock);
+       mutex_unlock(&one->efr_lock);
 
        spin_lock_irqsave(&port->lock, flags);
        sc16is7xx_ier_set(port, SC16IS7XX_IER_THRI_BIT);
@@ -928,9 +931,9 @@ static void sc16is7xx_ms_proc(struct kthread_work *ws)
        struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
 
        if (one->port.state) {
-               mutex_lock(&s->efr_lock);
+               mutex_lock(&one->efr_lock);
                sc16is7xx_update_mlines(one);
-               mutex_unlock(&s->efr_lock);
+               mutex_unlock(&one->efr_lock);
 
                kthread_queue_delayed_work(&s->kworker, &one->ms_work, HZ);
        }
@@ -1014,7 +1017,6 @@ static void sc16is7xx_set_termios(struct uart_port *port,
                                  struct ktermios *termios,
                                  const struct ktermios *old)
 {
-       struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
        struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
        unsigned int lcr, flow = 0;
        int baud;
@@ -1073,7 +1075,7 @@ static void sc16is7xx_set_termios(struct uart_port *port,
                port->ignore_status_mask |= SC16IS7XX_LSR_BRK_ERROR_MASK;
 
        /* As above, claim the mutex while accessing the EFR. */
-       mutex_lock(&s->efr_lock);
+       mutex_lock(&one->efr_lock);
 
        sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
                             SC16IS7XX_LCR_CONF_MODE_B);
@@ -1103,7 +1105,7 @@ static void sc16is7xx_set_termios(struct uart_port *port,
        /* Update LCR register */
        sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
 
-       mutex_unlock(&s->efr_lock);
+       mutex_unlock(&one->efr_lock);
 
        /* Get baud rate generator configuration */
        baud = uart_get_baud_rate(port, termios, old,
@@ -1514,7 +1516,6 @@ static int sc16is7xx_probe(struct device *dev,
 
        s->devtype = devtype;
        dev_set_drvdata(dev, s);
-       mutex_init(&s->efr_lock);
 
        kthread_init_worker(&s->kworker);
        s->kworker_task = kthread_run(kthread_worker_fn, &s->kworker,
@@ -1557,6 +1558,8 @@ static int sc16is7xx_probe(struct device *dev,
                        goto out_ports;
                }
 
+               mutex_init(&s->p[i].efr_lock);
+
                ret = uart_get_rs485_mode(&s->p[i].port);
                if (ret)
                        goto out_ports;