[PATCH 5.4 41/49] serial: qcom_geni_serial: To correct QUP Version detection logic

Greg Kroah-Hartman
2020-10-31T11:38:11Z

From: Paras Sharma <parashar@codeaurora.org>

commit c9ca43d42ed8d5fd635d327a664ed1d8579eb2af upstream.

For QUP IP versions 2.5 and above the oversampling rate is
halved from 32 to 16.

Commit ce734600545f ("tty: serial: qcom_geni_serial: Update
the oversampling rate") is pushed to handle this scenario.
But the existing logic is failing to classify QUP Version 3.0
into the correct group ( 2.5 and above).

As result Serial Engine clocks are not configured properly for
baud rate and garbage data is sampled to FIFOs from the line.

So, fix the logic to detect QUP with versions 2.5 and above.

Fixes: ce734600545f ("tty: serial: qcom_geni_serial: Update the oversampling rate")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Paras Sharma <parashar@codeaurora.org>
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
Link: https://lore.kernel.org/r/1601445926-23673-1-git-send-email-parashar@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/tty/serial/qcom_geni_serial.c | 2 +-
include/linux/qcom-geni-se.h | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -970,7 +970,7 @@ static void qcom_geni_serial_set_termios
sampling_rate = UART_OVERSAMPLING;
/* Sampling rate is halved for IP versions >= 2.5 */
ver = geni_se_get_qup_hw_version(&port->se);
- if (GENI_SE_VERSION_MAJOR(ver) >= 2 && GENI_SE_VERSION_MINOR(ver) >= 5)
+ if (ver >= QUP_SE_VERSION_2_5)
sampling_rate /= 2;

clk_rate = get_clk_div_rate(baud, sampling_rate, &clk_div);
--- a/include/linux/qcom-geni-se.h
+++ b/include/linux/qcom-geni-se.h
@@ -229,6 +229,9 @@ struct geni_se {
#define GENI_SE_VERSION_MINOR(ver) ((ver & HW_VER_MINOR_MASK) >> HW_VER_MINOR_SHFT)
#define GENI_SE_VERSION_STEP(ver) (ver & HW_VER_STEP_MASK)

+/* QUP SE VERSION value for major number 2 and minor number 5 */
+#define QUP_SE_VERSION_2_5 0x20050000
+
#if IS_ENABLED(CONFIG_QCOM_GENI_SE)

u32 geni_se_get_qup_hw_version(struct geni_se *se);