[RFC PATCH] OMAP: Serial: Keep uart in no idle mode when DMA ongoing

[Vikram Pandita]

Keep UART in NoIdle mode when DMA is going on.

Only once UART transfers are complete, switch to smart idle and
allow OsIdle to kick in

Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
---
 arch/arm/mach-omap2/serial.c |   12 ++++++++++++
 drivers/serial/omap-serial.c |    2 +-
 2 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index ff9beb7..a6ee6ab 100755
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -359,9 +359,21 @@ static void omap_uart_allow_sleep(struct omap_uart_state *uart)
 	del_timer(&uart->timer);
 }
 
+extern int are_driveromap_uarts_active(int *);
+
 static void omap_uart_idle_timer(unsigned long data)
 {
 	struct omap_uart_state *uart = (struct omap_uart_state *)data;
+	int dummy;
+
+	if (are_driveromap_uarts_active(&dummy)){
+		/* Keep UART on NoIdle when DMA channel is enabled in omap
+		 * serial: do not allow UART to goto Smart-idle till its done
+		 * dma'ing
+		 */
+		omap_uart_block_sleep(uart);
+		return;
+	}
 
 	omap_uart_allow_sleep(uart);
 }
diff --git a/drivers/serial/omap-serial.c b/drivers/serial/omap-serial.c
index 938f29f..f105e24 100644
--- a/drivers/serial/omap-serial.c
+++ b/drivers/serial/omap-serial.c
@@ -1641,6 +1641,7 @@ int omap24xx_uart_cts_wakeup(int uart_no, int state)
 	return 0;
 }
 EXPORT_SYMBOL(omap24xx_uart_cts_wakeup);
+#endif
 /**
  * are_driver8250_uarts_active() - Check if any ports managed by this
  * driver are currently busy.  This should be called with interrupts
@@ -1709,7 +1710,6 @@ int are_driveromap_uarts_active(int *driver8250_managed)
 }
 EXPORT_SYMBOL(are_driveromap_uarts_active);
 
-#endif
 
 static void serial_omap_display_reg(struct uart_port *port)
 {
-- 
1.6.3.3.334.g916e1


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