remoteproc: Add prepare and unprepare ops

On some SoC architecture, it is needed to enable HW like
clock, bus, regulator, memory region... before loading
co-processor firmware.

This patch introduces prepare and unprepare ops to execute
platform specific function before firmware loading and after
stop execution.

Signed-off-by: Loic Pallardy <loic.pallardy@st.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200417002036.24359-2-s-anna@ti.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/remoteproc_core.c

@@ -1394,12 +1394,19 @@ static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
 		return ret;
 	}
 
+	/* Prepare rproc for firmware loading if needed */
+	ret = rproc_prepare_device(rproc);
+	if (ret) {
+		dev_err(dev, "can't prepare rproc %s: %d\n", rproc->name, ret);
+		goto disable_iommu;
+	}
+
 	rproc->bootaddr = rproc_get_boot_addr(rproc, fw);
 
 	/* Load resource table, core dump segment list etc from the firmware */
 	ret = rproc_parse_fw(rproc, fw);
 	if (ret)
-		goto disable_iommu;
+		goto unprepare_rproc;
 
 	/* reset max_notifyid */
 	rproc->max_notifyid = -1;
@@ -1433,6 +1440,9 @@ clean_up_resources:
 	kfree(rproc->cached_table);
 	rproc->cached_table = NULL;
 	rproc->table_ptr = NULL;
+unprepare_rproc:
+	/* release HW resources if needed */
+	rproc_unprepare_device(rproc);
 disable_iommu:
 	rproc_disable_iommu(rproc);
 	return ret;
@@ -1865,6 +1875,9 @@ void rproc_shutdown(struct rproc *rproc)
 	/* clean up all acquired resources */
 	rproc_resource_cleanup(rproc);
 
+	/* release HW resources if needed */
+	rproc_unprepare_device(rproc);
+
 	rproc_disable_iommu(rproc);
 
 	/* Free the copy of the resource table */

drivers/remoteproc/remoteproc_internal.h

@@ -63,6 +63,22 @@ struct resource_table *rproc_elf_find_loaded_rsc_table(struct rproc *rproc,
 struct rproc_mem_entry *
 rproc_find_carveout_by_name(struct rproc *rproc, const char *name, ...);
 
+static inline int rproc_prepare_device(struct rproc *rproc)
+{
+	if (rproc->ops->prepare)
+		return rproc->ops->prepare(rproc);
+
+	return 0;
+}
+
+static inline int rproc_unprepare_device(struct rproc *rproc)
+{
+	if (rproc->ops->unprepare)
+		return rproc->ops->unprepare(rproc);
+
+	return 0;
+}
+
 static inline
 int rproc_fw_sanity_check(struct rproc *rproc, const struct firmware *fw)
 {

include/linux/remoteproc.h

@@ -355,6 +355,8 @@ enum rsc_handling_status {
 
 /**
  * struct rproc_ops - platform-specific device handlers
+ * @prepare:	prepare device for code loading
+ * @unprepare:	unprepare device after stop
  * @start:	power on the device and boot it
  * @stop:	power off the device
  * @kick:	kick a virtqueue (virtqueue id given as a parameter)
@@ -373,6 +375,8 @@ enum rsc_handling_status {
  *		panic at least the returned number of milliseconds
  */
 struct rproc_ops {
+	int (*prepare)(struct rproc *rproc);
+	int (*unprepare)(struct rproc *rproc);
 	int (*start)(struct rproc *rproc);
 	int (*stop)(struct rproc *rproc);
 	void (*kick)(struct rproc *rproc, int vqid);