linux-kernel - [PATCH v4 3/4] soc: qcom: geni-se: Do not keep GPIOs to sleep state for shared SE usecase

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Message-Id: <20241113161413.3821858-4-quic_msavaliy@quicinc.com>
Date: Wed, 13 Nov 2024 21:44:12 +0530
From: Mukesh Kumar Savaliya <quic_msavaliy@...cinc.com>
To: konrad.dybcio@...aro.org, andersson@...nel.org, andi.shyti@...nel.org,
        linux-arm-msm@...r.kernel.org, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-i2c@...r.kernel.org,
        conor+dt@...nel.org, agross@...nel.org, devicetree@...r.kernel.org,
        vkoul@...nel.org, linux@...blig.org, dan.carpenter@...aro.org,
        Frank.Li@....com, konradybcio@...nel.org, bryan.odonoghue@...aro.org,
        krzk+dt@...nel.org, robh@...nel.org
Cc: quic_vdadhani@...cinc.com,
        Mukesh Kumar Savaliya <quic_msavaliy@...cinc.com>
Subject: [PATCH v4 3/4] soc: qcom: geni-se: Do not keep GPIOs to sleep state for shared SE usecase

Currently the driver provides a function called geni_serial_resources_off()
to turn off resources like clocks and  pinctrl.

For shared SE between two SS, we don't need to keep pinctrl to sleep state
as other SS may be actively transferring data over SE. Hence,bypass
keeping pinctrl to sleep state conditionally using shared_geni_se flag.
This will allow other SS to continue to transfer the data without any
disturbance over the IO lines.

Signed-off-by: Mukesh Kumar Savaliya <quic_msavaliy@...cinc.com>
---
 drivers/soc/qcom/qcom-geni-se.c  | 13 +++++++++----
 include/linux/soc/qcom/geni-se.h |  3 +++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index 4cb959106efa..2116593c4d3b 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
+// Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
 
 /* Disable MMIO tracing to prevent excessive logging of unwanted MMIO traces */
 #define __DISABLE_TRACE_MMIO__
@@ -503,10 +504,14 @@ int geni_se_resources_off(struct geni_se *se)
 
 	if (has_acpi_companion(se->dev))
 		return 0;
-
-	ret = pinctrl_pm_select_sleep_state(se->dev);
-	if (ret)
-		return ret;
+	/* Don't alter pin states on shared SEs to avoid potentially
+	 * interrupting transfers started by other subsystems.
+	 */
+	if (!se->shared_geni_se) {
+		ret = pinctrl_pm_select_sleep_state(se->dev);
+		if (ret)
+			return ret;
+	}
 
 	geni_se_clks_off(se);
 	return 0;
diff --git a/include/linux/soc/qcom/geni-se.h b/include/linux/soc/qcom/geni-se.h
index 2996a3c28ef3..f330588873c1 100644
--- a/include/linux/soc/qcom/geni-se.h
+++ b/include/linux/soc/qcom/geni-se.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #ifndef _LINUX_QCOM_GENI_SE
@@ -61,6 +62,7 @@ struct geni_icc_path {
  * @num_clk_levels:	Number of valid clock levels in clk_perf_tbl
  * @clk_perf_tbl:	Table of clock frequency input to serial engine clock
  * @icc_paths:		Array of ICC paths for SE
+ * @shared_geni_se:	True if SE is shared between multiprocessors.
  */
 struct geni_se {
 	void __iomem *base;
@@ -70,6 +72,7 @@ struct geni_se {
 	unsigned int num_clk_levels;
 	unsigned long *clk_perf_tbl;
 	struct geni_icc_path icc_paths[3];
+	bool shared_geni_se;
 };
 
 /* Common SE registers */
-- 
2.25.1