serial: sh-sci: make RX FIFO parameters tunable via sysfs

Allows tuning of the RX FIFO fill threshold and timeout. (The latter is
only applicable to SCIFA and SCIFB).

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 4a165ed..f95a56c 100644 (file)
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1055,6 +1055,66 @@ static void rx_fifo_timer_fn(unsigned long arg)
        scif_set_rtrg(port, 1);
 }
 
+static ssize_t rx_trigger_show(struct device *dev,
+                              struct device_attribute *attr,
+                              char *buf)
+{
+       struct uart_port *port = dev_get_drvdata(dev);
+       struct sci_port *sci = to_sci_port(port);
+
+       return sprintf(buf, "%d\n", sci->rx_trigger);
+}
+
+static ssize_t rx_trigger_store(struct device *dev,
+                               struct device_attribute *attr,
+                               const char *buf,
+                               size_t count)
+{
+       struct uart_port *port = dev_get_drvdata(dev);
+       struct sci_port *sci = to_sci_port(port);
+       long r;
+
+       if (kstrtol(buf, 0, &r) == -EINVAL)
+               return -EINVAL;
+       sci->rx_trigger = scif_set_rtrg(port, r);
+       scif_set_rtrg(port, 1);
+       return count;
+}
+
+static DEVICE_ATTR(rx_fifo_trigger, 0644, rx_trigger_show, rx_trigger_store);
+
+static ssize_t rx_fifo_timeout_show(struct device *dev,
+                              struct device_attribute *attr,
+                              char *buf)
+{
+       struct uart_port *port = dev_get_drvdata(dev);
+       struct sci_port *sci = to_sci_port(port);
+
+       return sprintf(buf, "%d\n", sci->rx_fifo_timeout);
+}
+
+static ssize_t rx_fifo_timeout_store(struct device *dev,
+                               struct device_attribute *attr,
+                               const char *buf,
+                               size_t count)
+{
+       struct uart_port *port = dev_get_drvdata(dev);
+       struct sci_port *sci = to_sci_port(port);
+       long r;
+
+       if (kstrtol(buf, 0, &r) == -EINVAL)
+               return -EINVAL;
+       sci->rx_fifo_timeout = r;
+       scif_set_rtrg(port, 1);
+       if (r > 0)
+               setup_timer(&sci->rx_fifo_timer, rx_fifo_timer_fn,
+                           (unsigned long)sci);
+       return count;
+}
+
+static DEVICE_ATTR(rx_fifo_timeout, 0644, rx_fifo_timeout_show, rx_fifo_timeout_store);
+
+
 #ifdef CONFIG_SERIAL_SH_SCI_DMA
 static void sci_dma_tx_complete(void *arg)
 {
@@ -2886,6 +2946,15 @@ static int sci_remove(struct platform_device *dev)
 
        sci_cleanup_single(port);
 
+       if (port->port.fifosize > 1) {
+               sysfs_remove_file(&dev->dev.kobj,
+                                 &dev_attr_rx_fifo_trigger.attr);
+       }
+       if (port->port.type == PORT_SCIFA || port->port.type == PORT_SCIFB) {
+               sysfs_remove_file(&dev->dev.kobj,
+                                 &dev_attr_rx_fifo_timeout.attr);
+       }
+
        return 0;
 }
 
@@ -3051,6 +3120,24 @@ static int sci_probe(struct platform_device *dev)
        if (ret)
                return ret;
 
+       if (sp->port.fifosize > 1) {
+               ret = sysfs_create_file(&dev->dev.kobj,
+                               &dev_attr_rx_fifo_trigger.attr);
+               if (ret)
+                       return ret;
+       }
+       if (sp->port.type == PORT_SCIFA || sp->port.type ==  PORT_SCIFB) {
+               ret = sysfs_create_file(&dev->dev.kobj,
+                               &dev_attr_rx_fifo_timeout.attr);
+               if (ret) {
+                       if (sp->port.fifosize > 1) {
+                               sysfs_remove_file(&dev->dev.kobj,
+                                       &dev_attr_rx_fifo_trigger.attr);
+                       }
+                       return ret;
+               }
+       }
+
 #ifdef CONFIG_SH_STANDARD_BIOS
        sh_bios_gdb_detach();
 #endif