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From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: bjorn.andersson@linaro.org, ohad@wizery.com
Cc: linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 07/13] remoteproc: Introduce function rproc_detach()
Date: Wed, 26 Aug 2020 10:45:23 -0600
Message-ID: <20200826164529.224476-8-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <20200826164529.224476-1-mathieu.poirier@linaro.org>

Introduce function rproc_detach() to enable the remoteproc
core to release the resources associated with a remote processor
without stopping its operation.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/remoteproc/remoteproc_core.c | 65 +++++++++++++++++++++++++++-
 include/linux/remoteproc.h           |  1 +
 2 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 7a1fc7e0620f..f3943a1e2754 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -1644,7 +1644,7 @@ static int rproc_stop(struct rproc *rproc, bool crashed)
 /*
  * __rproc_detach(): Does the opposite of rproc_attach()
  */
-static int __maybe_unused __rproc_detach(struct rproc *rproc)
+static int __rproc_detach(struct rproc *rproc)
 {
 	struct device *dev = &rproc->dev;
 	int ret;
@@ -1887,6 +1887,69 @@ void rproc_shutdown(struct rproc *rproc)
 }
 EXPORT_SYMBOL(rproc_shutdown);
 
+/**
+ * rproc_detach() - Detach the remote processor from the
+ * remoteproc core
+ *
+ * @rproc: the remote processor
+ *
+ * Detach a remote processor (previously attached to with rproc_actuate()).
+ *
+ * In case @rproc is still being used by an additional user(s), then
+ * this function will just decrement the power refcount and exit,
+ * without disconnecting the device.
+ *
+ * Function rproc_detach() calls __rproc_detach() in order to let a remote
+ * processor know that services provided by the application processor are
+ * no longer available.  From there it should be possible to remove the
+ * platform driver and even power cycle the application processor (if the HW
+ * supports it) without needing to switch off the remote processor.
+ */
+int rproc_detach(struct rproc *rproc)
+{
+	struct device *dev = &rproc->dev;
+	int ret;
+
+	ret = mutex_lock_interruptible(&rproc->lock);
+	if (ret) {
+		dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, ret);
+		return ret;
+	}
+
+	if (rproc->state != RPROC_RUNNING && rproc->state != RPROC_ATTACHED) {
+		ret = -EPERM;
+		goto out;
+	}
+
+	/* if the remote proc is still needed, bail out */
+	if (!atomic_dec_and_test(&rproc->power)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ret = __rproc_detach(rproc);
+	if (ret) {
+		atomic_inc(&rproc->power);
+		goto out;
+	}
+
+	/* clean up all acquired resources */
+	rproc_resource_cleanup(rproc);
+
+	rproc_disable_iommu(rproc);
+
+	/*
+	 * Set the remote processor's table pointer to NULL.  Since mapping
+	 * of the resource table to a virtual address is done in the platform
+	 * driver, unmapping should also be done there.
+	 */
+	rproc->table_ptr = NULL;
+out:
+	mutex_unlock(&rproc->lock);
+	return ret;
+}
+EXPORT_SYMBOL(rproc_detach);
+
 /**
  * rproc_get_by_phandle() - find a remote processor by phandle
  * @phandle: phandle to the rproc
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index 1a57e165da2c..6250491ee851 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -656,6 +656,7 @@ rproc_of_resm_mem_entry_init(struct device *dev, u32 of_resm_idx, size_t len,
 
 int rproc_boot(struct rproc *rproc);
 void rproc_shutdown(struct rproc *rproc);
+int rproc_detach(struct rproc *rproc);
 void rproc_report_crash(struct rproc *rproc, enum rproc_crash_type type);
 int rproc_coredump_add_segment(struct rproc *rproc, dma_addr_t da, size_t size);
 int rproc_coredump_add_custom_segment(struct rproc *rproc,
-- 
2.25.1


  parent reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-26 16:45 [PATCH 00/13] remoteproc: Add support for detaching from rproc Mathieu Poirier
2020-08-26 16:45 ` [PATCH 01/13] remoteproc: Re-check state in rproc_shutdown() Mathieu Poirier
2020-10-15  1:28   ` Peng Fan
2020-08-26 16:45 ` [PATCH 02/13] remoteproc: Remove useless check in rproc_del() Mathieu Poirier
2020-10-15  1:29   ` Peng Fan
2020-08-26 16:45 ` [PATCH 03/13] remoteproc: Add new RPROC_ATTACHED state Mathieu Poirier
2020-10-15  1:31   ` Peng Fan
2020-08-26 16:45 ` [PATCH 04/13] remoteproc: Properly represent the attached state Mathieu Poirier
2020-10-15  1:33   ` Peng Fan
2020-08-26 16:45 ` [PATCH 05/13] remoteproc: Add new detach() remoteproc operation Mathieu Poirier
2020-10-15  1:37   ` Peng Fan
2020-10-22 21:51     ` Mathieu Poirier
2020-08-26 16:45 ` [PATCH 06/13] remoteproc: Introduce function __rproc_detach() Mathieu Poirier
2020-10-15  1:39   ` Peng Fan
2020-08-26 16:45 ` Mathieu Poirier [this message]
2020-10-15  1:52   ` [PATCH 07/13] remoteproc: Introduce function rproc_detach() Peng Fan
2020-10-22 21:55     ` Mathieu Poirier
2020-08-26 16:45 ` [PATCH 08/13] remoteproc: Rename function rproc_actuate() Mathieu Poirier
2020-10-15  2:15   ` Peng Fan
2020-08-26 16:45 ` [PATCH 09/13] remoteproc: Add return value to function rproc_shutdown() Mathieu Poirier
2020-10-15  2:21   ` Peng Fan
2020-08-26 16:45 ` [PATCH 10/13] remoteproc: Properly deal with a stop request when attached Mathieu Poirier
2020-10-15  2:29   ` Peng Fan
2020-08-26 16:45 ` [PATCH 11/13] remoteproc: Properly deal with detach request Mathieu Poirier
2020-10-15  2:30   ` Peng Fan
2020-08-26 16:45 ` [PATCH 12/13] remoteproc: Refactor rproc delete and cdev release path Mathieu Poirier
2020-10-15  2:31   ` Peng Fan
2020-08-26 16:45 ` [PATCH 13/13] remoteproc: Properly deal with a kernel panic when attached Mathieu Poirier
2020-10-15  2:28   ` Peng Fan
2020-09-01 16:55 ` [PATCH 00/13] remoteproc: Add support for detaching from rproc Arnaud POULIQUEN
2020-09-01 18:02   ` Mathieu Poirier

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