linux-kernel - [PATCH V8 4/8] tty: serial: qcom_geni

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Message-Id: <1592908737-7068-5-git-send-email-akashast@codeaurora.org>
Date:   Tue, 23 Jun 2020 16:08:53 +0530
From:   Akash Asthana <akashast@...eaurora.org>
To:     gregkh@...uxfoundation.org, agross@...nel.org,
        bjorn.andersson@...aro.org, wsa@...-dreams.de, broonie@...nel.org
Cc:     linux-i2c@...r.kernel.org, linux-spi@...r.kernel.org,
        devicetree@...r.kernel.org, swboyd@...omium.org,
        mgautam@...eaurora.org, linux-arm-msm@...r.kernel.org,
        linux-serial@...r.kernel.org, mka@...omium.org,
        dianders@...omium.org, evgreen@...eaurora.org,
        linux-kernel@...r.kernel.org,
        Akash Asthana <akashast@...eaurora.org>
Subject: [PATCH V8 4/8] tty: serial: qcom_geni_serial: Add interconnect support

Get the interconnect paths for Uart based Serial Engine device
and vote according to the baud rate requirement of the driver.

Signed-off-by: Akash Asthana <akashast@...eaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
Acked-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
Changes in V2:
 - As per Bjorn's comment, removed se == NULL check from geni_serial_icc_get
 - As per Bjorn's comment, removed code to set se->icc_path* to NULL in failure
 - As per Bjorn's comment, introduced and using devm_of_icc_get API for getting
   path handle
 - As per Matthias comment, added error handling for icc_set_bw call

Changes in V3:
 - As per Matthias comment, use common library APIs defined in geni-se
   driver for ICC functionality.

Changes in V4:
 - As per Mark's comment move peak_bw guess as twice of avg_bw if
   nothing mentioned explicitly to ICC core.
 - As per Matthias's comment select core clock BW based on baud rate.
   If it's less than 115200 go for GENI_DEFAULT_BW else CORE_2X_50_MHZ

Changes in V5:
 - Add icc_enable/disable to power on/off call.
 - Save some non-zero avg/peak value to ICC core by calling geni_icc_set_bw
   from probe so that when resume/icc_enable is called NOC are running at
   some non-zero value. No need to call icc_disable after BW vote because
   console devices are expected to be in active state from the probe itself
   and qcom_geni_serial_pm(STATE_OFF) will be called for non-console ones.

Changes in V6:
 - No change

Changes in V7:
 - As per Matthias's comment removed usage of peak_bw variable because we don't
   have explicit peak requirement, we were voting peak = avg and this can be
   tracked using single variable for avg bw.

Changes in V8:
 - No change.

 drivers/tty/serial/qcom_geni_serial.c | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index a4468db..f701c7e 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -945,6 +945,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
 	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
 	unsigned long clk_rate;
 	u32 ver, sampling_rate;
+	unsigned int avg_bw_core;
 
 	qcom_geni_serial_stop_rx(uport);
 	/* baud rate */
@@ -966,6 +967,16 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
 	ser_clk_cfg = SER_CLK_EN;
 	ser_clk_cfg |= clk_div << CLK_DIV_SHFT;
 
+	/*
+	 * 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;
+	port->se.icc_paths[CPU_TO_GENI].avg_bw = Bps_to_icc(baud);
+	geni_icc_set_bw(&port->se);
+
 	/* parity */
 	tx_trans_cfg = readl(uport->membase + SE_UART_TX_TRANS_CFG);
 	tx_parity_cfg = readl(uport->membase + SE_UART_TX_PARITY_CFG);
@@ -1235,11 +1246,14 @@ static void qcom_geni_serial_pm(struct uart_port *uport,
 	if (old_state == UART_PM_STATE_UNDEFINED)
 		old_state = UART_PM_STATE_OFF;
 
-	if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF)
+	if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF) {
+		geni_icc_enable(&port->se);
 		geni_se_resources_on(&port->se);
-	else if (new_state == UART_PM_STATE_OFF &&
-			old_state == UART_PM_STATE_ON)
+	} else if (new_state == UART_PM_STATE_OFF &&
+			old_state == UART_PM_STATE_ON) {
 		geni_se_resources_off(&port->se);
+		geni_icc_disable(&port->se);
+	}
 }
 
 static const struct uart_ops qcom_geni_console_pops = {
@@ -1337,6 +1351,17 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 			return -ENOMEM;
 	}
 
+	ret = geni_icc_get(&port->se, NULL);
+	if (ret)
+		return ret;
+	port->se.icc_paths[GENI_TO_CORE].avg_bw = GENI_DEFAULT_BW;
+	port->se.icc_paths[CPU_TO_GENI].avg_bw = GENI_DEFAULT_BW;
+
+	/* Set BW for register access */
+	ret = geni_icc_set_bw(&port->se);
+	if (ret)
+		return ret;
+
 	port->name = devm_kasprintf(uport->dev, GFP_KERNEL,
 			"qcom_geni_serial_%s%d",
 			uart_console(uport) ? "console" : "uart", uport->line);
-- 
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