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authorPaul Walmsley <paul@pwsan.com>2012-01-21 00:27:40 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2012-01-24 14:11:07 -0800
commit0a697b22252c9d7208b5fb3e9fbd124dd229f1d2 (patch)
treee1558fc3fe171d9e30394afe90982aa69733e449 /drivers/tty
parentb5148856a2f732e7e99edad22bb8e2037af28ad3 (diff)
downloadlinux-0a697b22252c9d7208b5fb3e9fbd124dd229f1d2.tar.bz2
tty: serial: OMAP: ensure FIFO levels are set correctly in non-DMA mode
Ensure FIFO levels are set correctly in non-DMA mode (the default). This patch will cause a receive FIFO threshold interrupt to be raised when there is at least one byte in the RX FIFO. It will also cause a transmit FIFO threshold interrupt when there is only one byte remaining in the TX FIFO. These changes fix the receive interrupt problem and part of the transmit interrupt problem. A separate set of issues must be worked around for the transmit path to have a basic level of functionality; a subsequent patch will address these. DMA operation is unaffected by this patch. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: Govindraj Raja <govindraj.r@ti.com> Cc: Kevin Hilman <khilman@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/omap-serial.c35
1 files changed, 31 insertions, 4 deletions
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 1c2426931484..ca54f038ab45 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -46,6 +46,18 @@
#define DEFAULT_CLK_SPEED 48000000 /* 48Mhz*/
+/* SCR register bitmasks */
+#define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK (1 << 7)
+#define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK (1 << 6)
+
+/* FCR register bitmasks */
+#define OMAP_UART_FCR_RX_FIFO_TRIG_SHIFT 6
+#define OMAP_UART_FCR_RX_FIFO_TRIG_MASK (0x3 << 6)
+#define OMAP_UART_FCR_TX_FIFO_TRIG_SHIFT 4
+
+/* TLR register bitmasks */
+#define OMAP_UART_TLR_TX_FIFO_TRIG_DMA_SHIFT 0
+
static struct uart_omap_port *ui[OMAP_MAX_HSUART_PORTS];
/* Forward declaration of functions */
@@ -694,6 +706,7 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
unsigned char efr = 0;
unsigned long flags = 0;
unsigned int baud, quot;
+ u32 tlr;
switch (termios->c_cflag & CSIZE) {
case CS5:
@@ -811,14 +824,28 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
up->mcr = serial_in(up, UART_MCR);
serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);
/* FIFO ENABLE, DMA MODE */
- serial_out(up, UART_FCR, up->fcr);
- serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+
+ up->scr |= OMAP_UART_SCR_TX_TRIG_GRANU1_MASK;
+ up->scr |= OMAP_UART_SCR_RX_TRIG_GRANU1_MASK;
if (up->use_dma) {
- serial_out(up, UART_TI752_TLR, 0);
- up->scr |= (UART_FCR_TRIGGER_4 | UART_FCR_TRIGGER_8);
+ tlr = 0;
+ } else {
+ up->scr &= ~OMAP_UART_SCR_TX_EMPTY;
+
+ /* Set receive FIFO threshold to 1 */
+ up->fcr &= ~OMAP_UART_FCR_RX_FIFO_TRIG_MASK;
+ up->fcr |= (0x1 << OMAP_UART_FCR_RX_FIFO_TRIG_SHIFT);
+
+ /* Set TX FIFO threshold to "63" (actually 1) */
+ up->fcr |= (0x3 << OMAP_UART_FCR_TX_FIFO_TRIG_SHIFT);
+ tlr = (0xf << OMAP_UART_TLR_TX_FIFO_TRIG_DMA_SHIFT);
}
+ serial_out(up, UART_TI752_TLR, tlr);
+ serial_out(up, UART_FCR, up->fcr);
+ serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+
serial_out(up, UART_OMAP_SCR, up->scr);
serial_out(up, UART_EFR, up->efr);