remoteproc: qcom: q6v5-pil: Add PDC reset for modem on SDM845 SoCs

In the presence of a PDC block working with subsystem RSC, assert/deassert
PDC reset in modem start/stop path.
Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/qcom_q6v5_mss.c

@@ -149,6 +149,7 @@ struct q6v5 {
 	u32 halt_nc;
 
 	struct reset_control *mss_restart;
+	struct reset_control *pdc_reset;
 
 	struct qcom_q6v5 q6v5;
 
@@ -347,10 +348,17 @@ static int q6v5_load(struct rproc *rproc, const struct firmware *fw)
 
 static int q6v5_reset_assert(struct q6v5 *qproc)
 {
-	if (qproc->has_alt_reset)
-		return reset_control_reset(qproc->mss_restart);
-	else
-		return reset_control_assert(qproc->mss_restart);
+	int ret;
+
+	if (qproc->has_alt_reset) {
+		reset_control_assert(qproc->pdc_reset);
+		ret = reset_control_reset(qproc->mss_restart);
+		reset_control_deassert(qproc->pdc_reset);
+	} else {
+		ret = reset_control_assert(qproc->mss_restart);
+	}
+
+	return ret;
 }
 
 static int q6v5_reset_deassert(struct q6v5 *qproc)
@@ -358,9 +366,11 @@ static int q6v5_reset_deassert(struct q6v5 *qproc)
 	int ret;
 
 	if (qproc->has_alt_reset) {
+		reset_control_assert(qproc->pdc_reset);
 		writel(1, qproc->rmb_base + RMB_MBA_ALT_RESET);
 		ret = reset_control_reset(qproc->mss_restart);
 		writel(0, qproc->rmb_base + RMB_MBA_ALT_RESET);
+		reset_control_deassert(qproc->pdc_reset);
 	} else {
 		ret = reset_control_deassert(qproc->mss_restart);
 	}
@@ -1072,6 +1082,15 @@ static int q6v5_init_reset(struct q6v5 *qproc)
 		return PTR_ERR(qproc->mss_restart);
 	}
 
+	if (qproc->has_alt_reset) {
+		qproc->pdc_reset = devm_reset_control_get_exclusive(qproc->dev,
+								    "pdc_reset");
+		if (IS_ERR(qproc->pdc_reset)) {
+			dev_err(qproc->dev, "failed to acquire pdc reset\n");
+			return PTR_ERR(qproc->pdc_reset);
+		}
+	}
+
 	return 0;
 }
 
@@ -1192,12 +1211,12 @@ static int q6v5_probe(struct platform_device *pdev)
 	}
 	qproc->active_reg_count = ret;
 
+	qproc->has_alt_reset = desc->has_alt_reset;
 	ret = q6v5_init_reset(qproc);
 	if (ret)
 		goto free_rproc;
 
 	qproc->version = desc->version;
-	qproc->has_alt_reset = desc->has_alt_reset;
 	qproc->need_mem_protection = desc->need_mem_protection;
 
 	ret = qcom_q6v5_init(&qproc->q6v5, pdev, rproc, MPSS_CRASH_REASON_SMEM,