tty: serial: 8250: omap: add custom irq handling

We have (or will have) custom DMA callbacks in the omap driver due to
the different behaviour in the RX and TX case. To make this work
we need a few changes in the IRQ handler to invoke the rx_handler again
after the "manual" mode or retry the tx_handler again before falling
back to the manual mode.

Heikki didn't want to see the extra hacks in the generic / default irq
handler and Peter wasn't too happy about an OMAP-only IRQ handler. The
way I planned it is to use this extra IRQ routine only in DMA case. If
Peter dislike this approach then I hope Heikki doesn't block changes in
the default IRQ handler :)

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 0dc1cb6b2706744c6a8c6a45c34e872e86c31872..458ad28338fee4e4e898c61aac870d8b01a0fbbd 100644 (file)
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -119,6 +119,8 @@ static inline void serial_dl_write(struct uart_8250_port *up, int value)
 }
 
 struct uart_8250_port *serial8250_get_port(int line);
+void serial8250_rpm_get(struct uart_8250_port *p);
+void serial8250_rpm_put(struct uart_8250_port *p);
 
 #if defined(__alpha__) && !defined(CONFIG_PCI)
 /*

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 39450ba03a2f922782bb0088688907080e9c078c..7e78f3077b5dd7a1ff9a63f64397d21c096ab9a9 100644 (file)
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -541,20 +541,22 @@ void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p)
 }
 EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos);
 
-static void serial8250_rpm_get(struct uart_8250_port *p)
+void serial8250_rpm_get(struct uart_8250_port *p)
 {
        if (!(p->capabilities & UART_CAP_RPM))
                return;
        pm_runtime_get_sync(p->port.dev);
 }
+EXPORT_SYMBOL_GPL(serial8250_rpm_get);
 
-static void serial8250_rpm_put(struct uart_8250_port *p)
+void serial8250_rpm_put(struct uart_8250_port *p)
 {
        if (!(p->capabilities & UART_CAP_RPM))
                return;
        pm_runtime_mark_last_busy(p->port.dev);
        pm_runtime_put_autosuspend(p->port.dev);
 }
+EXPORT_SYMBOL_GPL(serial8250_rpm_put);
 
 /*
  * These two wrappers ensure that enable_runtime_pm_tx() can be called more than

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 1659858e595a0b8b93b3a6ba4350761aaa3cb108..6500547f8fda9f2cf11e33321349e2edc5d236d7 100644 (file)
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -13,6 +13,7 @@
 #include <linux/serial_8250.h>
 #include <linux/serial_core.h>
 #include <linux/serial_reg.h>
+#include <linux/tty_flip.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/of.h>
@@ -854,6 +855,60 @@ err:
        return ret;
 }
 
+/*
+ * This is mostly serial8250_handle_irq(). We have a slightly different DMA
+ * hoook for RX/TX and need different logic for them in the ISR. Therefore we
+ * use the default routine in the non-DMA case and this one for with DMA.
+ */
+static int omap_8250_dma_handle_irq(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned char status;
+       unsigned long flags;
+       u8 iir;
+       int dma_err = 0;
+
+       serial8250_rpm_get(up);
+
+       iir = serial_port_in(port, UART_IIR);
+       if (iir & UART_IIR_NO_INT) {
+               serial8250_rpm_put(up);
+               return 0;
+       }
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       status = serial_port_in(port, UART_LSR);
+
+       if (status & (UART_LSR_DR | UART_LSR_BI)) {
+
+               dma_err = omap_8250_rx_dma(up, iir);
+               if (dma_err) {
+                       status = serial8250_rx_chars(up, status);
+                       omap_8250_rx_dma(up, 0);
+               }
+       }
+       serial8250_modem_status(up);
+       if (status & UART_LSR_THRE && up->dma->tx_err) {
+               if (uart_tx_stopped(&up->port) ||
+                   uart_circ_empty(&up->port.state->xmit)) {
+                       up->dma->tx_err = 0;
+                       serial8250_tx_chars(up);
+               } else  {
+                       /*
+                        * try again due to an earlier failer which
+                        * might have been resolved by now.
+                        */
+                       dma_err = omap_8250_tx_dma(up);
+                       if (dma_err)
+                               serial8250_tx_chars(up);
+               }
+       }
+
+       spin_unlock_irqrestore(&port->lock, flags);
+       serial8250_rpm_put(up);
+       return 1;
+}
 #endif
 
 static int omap8250_probe(struct platform_device *pdev)