remoteproc: qcom: q6v5: Add interconnect path proxy vote

Many remoteproc instances requires that Linux casts a proxy vote for an
interconnect path during boot, until they can do it themselves. Add
support for voting for a single path.

As this is a shared problem between both PAS and MSS drivers, the path
is acquired and votes casted from the common helper code.

Signed-off-by: Bjorn Andersson <[e-mail]>
Reviewed-by: Georgi Djakov <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/remoteproc/qcom_q6v5.c

···
  */
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
+#include <linux/interconnect.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/soc/qcom/qcom_aoss.h>
···
 {
 	int ret;
 
-	ret = q6v5_load_state_toggle(q6v5, true);
-	if (ret)
+	ret = icc_set_bw(q6v5->path, 0, UINT_MAX);
+	if (ret < 0) {
+		dev_err(q6v5->dev, "failed to set bandwidth request\n");
 		return ret;
+	}
+
+	ret = q6v5_load_state_toggle(q6v5, true);
+	if (ret) {
+		icc_set_bw(q6v5->path, 0, 0);
+		return ret;
+	}
 
 	reinit_completion(&q6v5->start_done);
 	reinit_completion(&q6v5->stop_done);
···
 {
 	disable_irq(q6v5->handover_irq);
 	q6v5_load_state_toggle(q6v5, false);
+
+	/* Disable interconnect vote, in case handover never happened */
+	icc_set_bw(q6v5->path, 0, 0);
 
 	return !q6v5->handover_issued;
 }
···
 
 	if (q6v5->handover)
 		q6v5->handover(q6v5);
+
+	icc_set_bw(q6v5->path, 0, 0);
 
 	q6v5->handover_issued = true;
 
···
 		qmp_put(q6v5->qmp);
 		return load_state ? -ENOMEM : -EINVAL;
 	}
+
+	q6v5->path = devm_of_icc_get(&pdev->dev, NULL);
+	if (IS_ERR(q6v5->path))
+		return dev_err_probe(&pdev->dev, PTR_ERR(q6v5->path),
+				     "failed to acquire interconnect path\n");
 
 	return 0;
 }

drivers/remoteproc/qcom_q6v5.h

···
 #include <linux/completion.h>
 #include <linux/soc/qcom/qcom_aoss.h>
 
+struct icc_path;
 struct rproc;
 struct qcom_smem_state;
 struct qcom_sysmon;
···
 
 	struct qcom_smem_state *state;
 	struct qmp *qmp;
+
+	struct icc_path *path;
 
 	unsigned stop_bit;