2018-12-13 06:25:41

by Ryder Lee

Subject: [PATCH] tty: serial: don't do termios for BTIF

The MediaTek BTIF controller doesn't need to set termios so add
a new capability 'UART_CAP_NMOD' for the unsupported case.


Signed-off-by: Sean Wang <[email protected]>
Signed-off-by: Ryder Lee <[email protected]>
---
drivers/tty/serial/8250/8250.h | 1 +
drivers/tty/serial/8250/8250_port.c | 7 ++++++-
2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index ebfb0bd..2b9ba39 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -80,6 +80,7 @@ struct serial8250_config {
#define UART_CAP_MINI (1 << 17) /* Mini UART on BCM283X family lacks:
* STOP PARITY EPAR SPAR WLEN5 WLEN6
*/
+#define UART_CAP_NMOD (1 << 18) /* UART doesn't do termios */

#define UART_BUG_QUOT (1 << 0) /* UART has buggy quot LSB */
#define UART_BUG_TXEN (1 << 1) /* UART has buggy TX IIR status */
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index c39482b..e4a69a0 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -297,7 +297,7 @@
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO |
UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
- .flags = UART_CAP_FIFO,
+ .flags = UART_CAP_FIFO | UART_CAP_NMOD,
},
[PORT_NPCM] = {
.name = "Nuvoton 16550",
@@ -2663,6 +2663,11 @@ static unsigned int serial8250_get_baud_rate(struct uart_port *port,
unsigned long flags;
unsigned int baud, quot, frac = 0;

+ if (up->capabilities & UART_CAP_NMOD) {
+ termios->c_cflag = 0;
+ return;
+ }
+
if (up->capabilities & UART_CAP_MINI) {
termios->c_cflag &= ~(CSTOPB | PARENB | PARODD | CMSPAR);
if ((termios->c_cflag & CSIZE) == CS5 ||
--
1.9.1

2018-12-13 11:03:09

by Russell King (Oracle)

Subject: Re: [PATCH] tty: serial: don't do termios for BTIF

On Thu, Dec 13, 2018 at 02:24:03PM +0800, Ryder Lee wrote:
> The MediaTek BTIF controller doesn't need to set termios so add
> a new capability 'UART_CAP_NMOD' for the unsupported case.
>
>
> Signed-off-by: Sean Wang <[email protected]>
> Signed-off-by: Ryder Lee <[email protected]>
> ---
> drivers/tty/serial/8250/8250.h | 1 +
> drivers/tty/serial/8250/8250_port.c | 7 ++++++-
> 2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
> index ebfb0bd..2b9ba39 100644
> --- a/drivers/tty/serial/8250/8250.h
> +++ b/drivers/tty/serial/8250/8250.h
> @@ -80,6 +80,7 @@ struct serial8250_config {
> #define UART_CAP_MINI (1 << 17) /* Mini UART on BCM283X family lacks:
> * STOP PARITY EPAR SPAR WLEN5 WLEN6
> */
> +#define UART_CAP_NMOD (1 << 18) /* UART doesn't do termios */
>
> #define UART_BUG_QUOT (1 << 0) /* UART has buggy quot LSB */
> #define UART_BUG_TXEN (1 << 1) /* UART has buggy TX IIR status */
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index c39482b..e4a69a0 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -297,7 +297,7 @@
> .tx_loadsz = 16,
> .fcr = UART_FCR_ENABLE_FIFO |
> UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
> - .flags = UART_CAP_FIFO,
> + .flags = UART_CAP_FIFO | UART_CAP_NMOD,
> },
> [PORT_NPCM] = {
> .name = "Nuvoton 16550",
> @@ -2663,6 +2663,11 @@ static unsigned int serial8250_get_baud_rate(struct uart_port *port,
> unsigned long flags;
> unsigned int baud, quot, frac = 0;
>
> + if (up->capabilities & UART_CAP_NMOD) {
> + termios->c_cflag = 0;

So your port is limited to 5-bits and is unable to receive characters?
That's what a zero cflag means, and that's what you'll be telling
userspace here.

--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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