[PATCH v7 2/6] serial: 8250: create lsr_save_mask

Ilpo Järvinen
2022-06-15T12:49:08Z

Allow drivers to alter LSR save mask.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/8250/8250.h | 2 +-
drivers/tty/serial/8250/8250_core.c | 4 ++++
drivers/tty/serial/8250/8250_dw.c | 2 +-
include/linux/serial_8250.h | 1 +
4 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 0ff5688ba90c..5cc967fe3b59 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -138,7 +138,7 @@ static inline u16 serial_lsr_in(struct uart_8250_port *up)
u16 lsr = up->lsr_saved_flags;

lsr |= serial_in(up, UART_LSR);
- up->lsr_saved_flags = lsr & LSR_SAVE_FLAGS;
+ up->lsr_saved_flags = lsr & up->lsr_save_mask;

return lsr;
}
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 90ddc8924811..57e86133af4f 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1007,6 +1007,7 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
uart->port.rs485 = up->port.rs485;
uart->rs485_start_tx = up->rs485_start_tx;
uart->rs485_stop_tx = up->rs485_stop_tx;
+ uart->lsr_save_mask = up->lsr_save_mask;
uart->dma = up->dma;

/* Take tx_loadsz from fifosize if it wasn't set separately */
@@ -1094,6 +1095,9 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
ret = 0;
}

+ if (!uart->lsr_save_mask)
+ uart->lsr_save_mask = LSR_SAVE_FLAGS; /* Use default LSR mask */
+
/* Initialise interrupt backoff work if required */
if (up->overrun_backoff_time_ms > 0) {
uart->overrun_backoff_time_ms =
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 4cc69bb612ab..167a691c7b19 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -129,7 +129,7 @@ static void dw8250_tx_wait_empty(struct uart_port *p)

while (tries--) {
lsr = readb (p->membase + (UART_LSR << p->regshift));
- up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+ up->lsr_saved_flags |= lsr & up->lsr_save_mask;

if (lsr & UART_LSR_TEMT)
break;
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 4565f25ba9a2..8c7b793aa4d7 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -120,6 +120,7 @@ struct uart_8250_port {
*/
#define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS
u16 lsr_saved_flags;
+ u16 lsr_save_mask;
#define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
unsigned char msr_saved_flags;

--
2.30.2