d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Plumb the cn_grab and cn_ungrab routines down into the uart

Browse Source 
clients. Mask RX interrupts while grabbed on the atmel serial
driver. This UART interrupts every character. When interrupts are
enabled at the mountroot> prompt, this means the ISR eats the
characters. Rather than try to create a cooperative buffering system
for the low level kernel console, instead just mask out the ISR. For
NS8250 and decsendents this isn't needed, since interrupts only happen
after 14 or more characters (depending on the fifo settings). Plumb
such that these are optional so there's no change in behavior for all
the other UART clients. ddb worked on this platform because all
interrupts were disabled while it was running, so this problem wasn't
noticed. The mountroot> issue has been around for a very very long
time.

MFC after:	3 days
This commit is contained in:
imp 2013-12-21 16:23:31 +00:00
parent 33f08bf94d
commit 0c05071015
3 changed files with 43 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
sys/arm/at91/uart_dev_at91usart.c
View File

@ -219,6 +219,20 @@ at91_usart_param(struct uart_bas *bas, int baudrate, int databits,
return (0);
}
static void
at91_usart_grab(struct uart_bas *bas)
{
WR4(bas, USART_IDR, USART_CSR_RXRDY);
}
static void
at91_usart_ungrab(struct uart_bas *bas)
{
WR4(bas, USART_IER, USART_CSR_RXRDY);
}
static struct uart_ops at91_usart_ops = {
.probe = at91_usart_probe,
.init = at91_usart_init,
@ -226,6 +240,8 @@ static struct uart_ops at91_usart_ops = {
.putc = at91_usart_putc,
.rxready = at91_usart_rxready,
.getc = at91_usart_getc,
.grab = at91_usart_grab,
.ungrab = at91_usart_ungrab,
};
static int

23
sys/dev/uart/uart_cpu.h
View File

@ -43,6 +43,8 @@ struct uart_ops {
void (*putc)(struct uart_bas *, int);
int (*rxready)(struct uart_bas *);
int (*getc)(struct uart_bas *, struct mtx *);
void (*grab)(struct uart_bas *);
void (*ungrab)(struct uart_bas *);
};
extern bus_space_tag_t uart_bus_space_io;
@ -135,6 +137,27 @@ uart_putc(struct uart_devinfo *di, int c)
uart_unlock(di->hwmtx);
}
static __inline void
uart_grab(struct uart_devinfo *di)
{
uart_lock(di->hwmtx);
if (di->ops->grab)
di->ops->grab(&di->bas);
uart_unlock(di->hwmtx);
}
static __inline void
uart_ungrab(struct uart_devinfo *di)
{
uart_lock(di->hwmtx);
if (di->ops->ungrab)
di->ops->ungrab(&di->bas);
uart_unlock(di->hwmtx);
}
static __inline int
uart_rxready(struct uart_devinfo *di)
{

4
sys/dev/uart/uart_tty.c
View File

@ -112,11 +112,15 @@ uart_cnterm(struct consdev *cp)
static void
uart_cngrab(struct consdev *cp)
{
uart_grab(cp->cn_arg);
}
static void
uart_cnungrab(struct consdev *cp)
{
uart_ungrab(cp->cn_arg);
}
static void