Designware UART has an optional feature to enable Fractional Baud Rate
Divisor (DLF) through the FRACTIONAL_BAUD_DIVISOR_EN configuration
parameter, and it is not dependent on ADDITIONAL_FEATURES.
dw8250_setup_port() checks DLF to determine dlf_size only when UART
Component Version (UCV) is non-zero. As mentioned above DLF and UCV are
independent features. Move the logic corresponding to DLF size
calculation ahead of the UCV check to prevent early return. Otherwise,
dlf_size will be zero and driver will not be able to use the
controller's fractional baud rate divisor (DLF) feature.
Signed-off-by: Vamshi Gajjela <vamshigajjela@xxxxxxxxxx>
---
drivers/tty/serial/8250/8250_dwlib.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c
index 84843e204a5e..136ad093c5b6 100644
--- a/drivers/tty/serial/8250/8250_dwlib.c
+++ b/drivers/tty/serial/8250/8250_dwlib.c
@@ -259,17 +259,6 @@ void dw8250_setup_port(struct uart_port *p)
}
up->capabilities |= UART_CAP_NOTEMT;
- /*
- * If the Component Version Register returns zero, we know that
- * ADDITIONAL_FEATURES are not enabled. No need to go any further.
- */
- reg = dw8250_readl_ext(p, DW_UART_UCV);
- if (!reg)
- return;
-
- dev_dbg(p->dev, "Designware UART version %c.%c%c\n",
- (reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);
-
/* Preserve value written by firmware or bootloader */
old_dlf = dw8250_readl_ext(p, DW_UART_DLF);
dw8250_writel_ext(p, DW_UART_DLF, ~0U);
@@ -282,6 +271,17 @@ void dw8250_setup_port(struct uart_port *p)
p->set_divisor = dw8250_set_divisor;
}
+ /*
+ * If the Component Version Register returns zero, we know that
+ * ADDITIONAL_FEATURES are not enabled. No need to go any further.
+ */
+ reg = dw8250_readl_ext(p, DW_UART_UCV);
+ if (!reg)
+ return;
+
+ dev_dbg(p->dev, "Designware UART version %c.%c%c\n",
+ (reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);
+
reg = dw8250_readl_ext(p, DW_UART_CPR);
if (!reg) {
reg = data->pdata->cpr_val;
--
2.43.0.rc1.413.gea7ed67945-goog
