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authorMathieu Poirier <mathieu.poirier@linaro.org>2021-03-12 09:24:46 -0700
committerBjorn Andersson <bjorn.andersson@linaro.org>2021-03-18 07:55:47 -0500
commitd3962a397885518a85d2dc6b0c51e6594f71c30f (patch)
tree4e3b259b7e77083b992c10133800c878e0c76826 /drivers/remoteproc/remoteproc_core.c
parent6070203fe43335a02b7fd103bae582095411adc5 (diff)
remoteproc: Introduce function rproc_detach()
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> Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@st.com> Link: https://lore.kernel.org/r/20210312162453.1234145-11-mathieu.poirier@linaro.org Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Diffstat (limited to 'drivers/remoteproc/remoteproc_core.c')
-rw-r--r--drivers/remoteproc/remoteproc_core.c58
1 files changed, 57 insertions, 1 deletions
diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 23e9040386c2..78a36a3723ec 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -1715,7 +1715,7 @@ 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;
@@ -1955,6 +1955,62 @@ out:
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_attach()).
+ *
+ * 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 the remote proc is still needed, bail out */
+ if (!atomic_dec_and_test(&rproc->power)) {
+ ret = 0;
+ goto out;
+ }
+
+ ret = __rproc_detach(rproc);
+ if (ret) {
+ atomic_inc(&rproc->power);
+ goto out;
+ }
+
+ /* clean up all acquired resources */
+ rproc_resource_cleanup(rproc);
+
+ /* release HW resources if needed */
+ rproc_unprepare_device(rproc);
+
+ rproc_disable_iommu(rproc);
+
+ 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
*