linux-kernel - [PATCH 4/5] soundwire: qcom: add software workaround for bus clash interrupt assertion

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Message-Id: <20230209131336.18252-5-srinivas.kandagatla@linaro.org>
Date:   Thu,  9 Feb 2023 13:13:35 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     vkoul@...nel.org
Cc:     yung-chuan.liao@...ux.intel.com,
        pierre-louis.bossart@...ux.intel.com, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org, steev@...i.org,
        johan+linaro@...nel.org, quic_bjorande@...cinc.com,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: [PATCH 4/5] soundwire: qcom: add software workaround for bus clash interrupt assertion

Sometimes Hard reset does not clear some of the registers,
this sometimes results in firing a bus clash interrupt.
Add workaround for this during power up sequence, as
suggested by hardware manual.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
---
 drivers/soundwire/qcom.c | 55 ++++++++++++++++++++++++----------------
 1 file changed, 33 insertions(+), 22 deletions(-)

diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
index 465b2a2ef0d5..74e38c0d651b 100644
--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -697,6 +697,26 @@ static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id)
 	return ret;
 }
 
+static bool swrm_wait_for_frame_gen_enabled(struct qcom_swrm_ctrl *swrm)
+{
+	int retry = SWRM_LINK_STATUS_RETRY_CNT;
+	int comp_sts;
+
+	do {
+		swrm->reg_read(swrm, SWRM_COMP_STATUS, &comp_sts);
+
+		if (comp_sts & SWRM_FRM_GEN_ENABLED)
+			return true;
+
+		usleep_range(500, 510);
+	} while (retry--);
+
+	dev_err(swrm->dev, "%s: link status %s\n", __func__,
+		comp_sts & SWRM_FRM_GEN_ENABLED ? "connected" : "disconnected");
+
+	return false;
+}
+
 static int qcom_swrm_init(struct qcom_swrm_ctrl *ctrl)
 {
 	u32 val;
@@ -741,16 +761,27 @@ static int qcom_swrm_init(struct qcom_swrm_ctrl *ctrl)
 				SWRM_RD_WR_CMD_RETRIES);
 	}
 
+	/* COMP Enable */
+	ctrl->reg_write(ctrl, SWRM_COMP_CFG_ADDR, SWRM_COMP_CFG_ENABLE_MSK);
+
 	/* Set IRQ to PULSE */
 	ctrl->reg_write(ctrl, SWRM_COMP_CFG_ADDR,
-			SWRM_COMP_CFG_IRQ_LEVEL_OR_PULSE_MSK |
-			SWRM_COMP_CFG_ENABLE_MSK);
+			SWRM_COMP_CFG_IRQ_LEVEL_OR_PULSE_MSK);
+
+	ctrl->reg_write(ctrl, SWRM_INTERRUPT_CLEAR, 0xFFFFFFFF);
 
 	/* enable CPU IRQs */
 	if (ctrl->mmio) {
 		ctrl->reg_write(ctrl, SWRM_INTERRUPT_CPU_EN,
 				SWRM_INTERRUPT_STATUS_RMSK);
 	}
+
+	/* Set IRQ to PULSE */
+	ctrl->reg_write(ctrl, SWRM_COMP_CFG_ADDR,
+			SWRM_COMP_CFG_IRQ_LEVEL_OR_PULSE_MSK |
+			SWRM_COMP_CFG_ENABLE_MSK);
+
+	swrm_wait_for_frame_gen_enabled(ctrl);
 	ctrl->slave_status = 0;
 	ctrl->reg_read(ctrl, SWRM_COMP_PARAMS, &val);
 	ctrl->rd_fifo_depth = FIELD_GET(SWRM_COMP_PARAMS_RD_FIFO_DEPTH, val);
@@ -1504,26 +1535,6 @@ static int qcom_swrm_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static bool swrm_wait_for_frame_gen_enabled(struct qcom_swrm_ctrl *swrm)
-{
-	int retry = SWRM_LINK_STATUS_RETRY_CNT;
-	int comp_sts;
-
-	do {
-		swrm->reg_read(swrm, SWRM_COMP_STATUS, &comp_sts);
-
-		if (comp_sts & SWRM_FRM_GEN_ENABLED)
-			return true;
-
-		usleep_range(500, 510);
-	} while (retry--);
-
-	dev_err(swrm->dev, "%s: link status not %s\n", __func__,
-		comp_sts & SWRM_FRM_GEN_ENABLED ? "connected" : "disconnected");
-
-	return false;
-}
-
 static int __maybe_unused swrm_runtime_resume(struct device *dev)
 {
 	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev);
-- 
2.21.0