diff options
| -rw-r--r-- | drivers/tty/hvc/hvc_dcc.c | 30 |
1 files changed, 8 insertions, 22 deletions
diff --git a/drivers/tty/hvc/hvc_dcc.c b/drivers/tty/hvc/hvc_dcc.c index dfc5c9c38f07..0223b26b5b28 100644 --- a/drivers/tty/hvc/hvc_dcc.c +++ b/drivers/tty/hvc/hvc_dcc.c @@ -29,6 +29,9 @@ static DEFINE_SPINLOCK(dcc_lock); static DEFINE_KFIFO(inbuf, u8, DCC_INBUF_SIZE); static DEFINE_KFIFO(outbuf, u8, DCC_OUTBUF_SIZE); +/* Cached result of hvc_dcc_check() on core 0 */ +static bool dcc_core0_available; + static void dcc_uart_console_putchar(struct uart_port *port, u8 ch) { while (__dcc_getstatus() & DCC_STATUS_TX) @@ -90,36 +93,18 @@ static ssize_t hvc_dcc_get_chars(uint32_t vt, u8 *buf, size_t count) } /* - * Check if the DCC is enabled. If CONFIG_HVC_DCC_SERIALIZE_SMP is enabled, - * then we assume then this function will be called first on core0. That way, - * dcc_core0_available will be true only if it's available on core0. + * Check if the DCC is enabled. This function will be called once on core 0. */ static bool hvc_dcc_check(void) { unsigned long time = jiffies + (HZ / 10); - static bool dcc_core0_available; - - /* - * If we're not on core 0, but we previously confirmed that DCC is - * active, then just return true. - */ - int cpu = get_cpu(); - - if (IS_ENABLED(CONFIG_HVC_DCC_SERIALIZE_SMP) && cpu && dcc_core0_available) { - put_cpu(); - return true; - } - - put_cpu(); /* Write a test character to check if it is handled */ __dcc_putchar('\n'); while (time_is_after_jiffies(time)) { - if (!(__dcc_getstatus() & DCC_STATUS_TX)) { - dcc_core0_available = true; + if (!(__dcc_getstatus() & DCC_STATUS_TX)) return true; - } } return false; @@ -265,7 +250,8 @@ static int __init hvc_dcc_console_init(void) { int ret; - if (!hvc_dcc_check()) + dcc_core0_available = hvc_dcc_check(); + if (!dcc_core0_available) return -ENODEV; /* Returns -1 if error */ @@ -279,7 +265,7 @@ static int __init hvc_dcc_init(void) { struct hvc_struct *p; - if (!hvc_dcc_check()) + if (!dcc_core0_available) return -ENODEV; if (IS_ENABLED(CONFIG_HVC_DCC_SERIALIZE_SMP)) { |