Commit c9ca43d4 authored Sep 30, 2020 by Paras Sharma Committed by Greg Kroah-Hartman Sep 30, 2020

serial: qcom_geni_serial: To correct QUP Version detection logic



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

Commit ce734600 ("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: ce734600 ("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>

parent 58e49346

drivers/tty/serial/qcom_geni_serial.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1000,7 +1000,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
		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);

include/linux/qcom-geni-se.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -248,6 +248,9 @@ 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

		/*
		* Define bandwidth thresholds that cause the underlying Core 2X interconnect
		* clock to run at the named frequency. These baseline values are recommended

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