diff options
| author | Paul Walmsley <paul@pwsan.com> | 2012-01-21 00:27:40 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2012-01-24 14:11:07 -0800 |
| commit | 0a697b22252c9d7208b5fb3e9fbd124dd229f1d2 (patch) | |
| tree | e1558fc3fe171d9e30394afe90982aa69733e449 /drivers/tty | |
| parent | b5148856a2f732e7e99edad22bb8e2037af28ad3 (diff) | |
| download | linux-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.c | 35 |
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); |