[PATCH v2 2/2] tty: serial: qcom_geni_serial: Keep console RX functional after deep idle

[Viken Dadhaniya]

At baud rates up to 115200, the serial console uses only a 1 kBps keepalive
vote for the GENI_TO_CORE ("qup-core") ICC path. This vote keeps the path
active but does not request a QUP Core 2X clock rate.

When the CPU enters a deeper idle state, the missing Core clock vote can
leave the console RX path unresponsive.

Use the 19.2 MHz Core 2X vote at low baud rates, while retaining the 50 MHz
vote at higher baud rates, so that console RX remains functional after deep
idle transitions.

Fixes: 7cf563b2c846 ("tty: serial: qcom_geni_serial: Add interconnect support")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
Signed-off-by: Viken Dadhaniya <viken.dadhaniya@xxxxxxxxxxxxxxxx>
---
 drivers/tty/serial/qcom_geni_serial.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 3633723acef8..f7e81b652255 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -1482,9 +1482,8 @@ static int geni_serial_set_rate(struct geni_se *se, unsigned long baud)
 	 * Bump up BW vote on CPU and CORE path as driver supports FIFO mode
 	 * only.
 	 */
-	avg_bw_core = (baud > 115200) ? Bps_to_icc(CORE_2X_50_MHZ)
-						: GENI_DEFAULT_BW;
-	port->se.icc_paths[GENI_TO_CORE].avg_bw = avg_bw_core;
+	avg_bw_core = baud > 115200 ? CORE_2X_50_MHZ : CORE_2X_19_2_MHZ;
+	port->se.icc_paths[GENI_TO_CORE].avg_bw = Bps_to_icc(avg_bw_core);
 	port->se.icc_paths[CPU_TO_GENI].avg_bw = Bps_to_icc(baud);
 	geni_icc_set_bw(&port->se);
 

-- 
2.34.1