[PATCHv2 2/2] remoteproc: add support to handle internal memories

[Suman Anna]

A remote processor may need to load certain firmware sections into
internal memories (eg: RAM at L1 or L2 levels) for performance or
other reasons. Introduce a new resource type (RSC_INTMEM) and add
an associated handler function to handle such memories. The handler
creates a kernel mapping for the resource's 'pa' (physical address).

Note that no iommu mapping is performed for this resource, as the
resource is primarily used to represent physical internal memories.
If the internal memory region can only be accessed through an iommu,
a devmem resource entry should be used instead.

Signed-off-by: Robert Tivy <rtivy@xxxxxx>
Signed-off-by: Suman Anna <s-anna@xxxxxx>
---
v2:
- fixed a minor checkpatch warning

 drivers/remoteproc/remoteproc_core.c | 83 +++++++++++++++++++++++++++++++++++-
 include/linux/remoteproc.h           | 43 ++++++++++++++++++-
 2 files changed, 124 insertions(+), 2 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 11cdb11..1d668e5 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -664,6 +664,82 @@ free_carv:
 	return ret;
 }
 
+/**
+ * rproc_handle_intmem() - handle internal memory resource entry
+ * @rproc: rproc handle
+ * @rsc: the intmem resource entry
+ * @offset: offset of the resource data in resource table
+ * @avail: size of available data (for image validation)
+ *
+ * This function will handle firmware requests for mapping a memory region
+ * internal to a remote processor into kernel. It neither allocates any
+ * physical pages, nor performs any iommu mapping, as this resource entry
+ * is primarily used for representing physical internal memories. If the
+ * internal memory region can only be accessed through an iommu, please
+ * use a devmem resource entry.
+ *
+ * These resource entries should be grouped near the carveout entries in
+ * the firmware's resource table, as other firmware entries might request
+ * placing other data objects inside these memory regions (e.g. data/code
+ * segments, trace resource entries, ...).
+ */
+static int rproc_handle_intmem(struct rproc *rproc, struct fw_rsc_intmem *rsc,
+			       int offset, int avail)
+{
+	struct rproc_mem_entry *intmem;
+	struct device *dev = &rproc->dev;
+	void *va;
+	int ret;
+
+	if (sizeof(*rsc) > avail) {
+		dev_err(dev, "intmem rsc is truncated\n");
+		return -EINVAL;
+	}
+
+	if (rsc->version != 1) {
+		dev_err(dev, "intmem rsc version %d is not supported\n",
+			rsc->version);
+		return -EINVAL;
+	}
+
+	if (rsc->reserved) {
+		dev_err(dev, "intmem rsc has non zero reserved bytes\n");
+		return -EINVAL;
+	}
+
+	dev_dbg(dev, "intmem rsc: da 0x%x, pa 0x%x, len 0x%x\n",
+		rsc->da, rsc->pa, rsc->len);
+
+	intmem = kzalloc(sizeof(*intmem), GFP_KERNEL);
+	if (!intmem)
+		return -ENOMEM;
+
+	va = (__force void *)ioremap_nocache(rsc->pa, rsc->len);
+	if (!va) {
+		dev_err(dev, "ioremap_nocache err: %d\n", rsc->len);
+		ret = -ENOMEM;
+		goto free_intmem;
+	}
+
+	dev_dbg(dev, "intmem mapped pa 0x%x of len 0x%x into kernel va %p\n",
+		rsc->pa, rsc->len, va);
+
+	intmem->va = va;
+	intmem->len = rsc->len;
+	intmem->dma = rsc->pa;
+	intmem->da = rsc->da;
+	intmem->priv = (void *)1;    /* prevents freeing */
+
+	/* reuse the rproc->carveouts list, so that loading is automatic */
+	list_add_tail(&intmem->node, &rproc->carveouts);
+
+	return 0;
+
+free_intmem:
+	kfree(intmem);
+	return ret;
+}
+
 static int rproc_count_vrings(struct rproc *rproc, struct fw_rsc_vdev *rsc,
 			      int offset, int avail)
 {
@@ -681,6 +757,7 @@ static rproc_handle_resource_t rproc_loading_handlers[RSC_LAST] = {
 	[RSC_CARVEOUT] = (rproc_handle_resource_t)rproc_handle_carveout,
 	[RSC_DEVMEM] = (rproc_handle_resource_t)rproc_handle_devmem,
 	[RSC_TRACE] = (rproc_handle_resource_t)rproc_handle_trace,
+	[RSC_INTMEM] = (rproc_handle_resource_t)rproc_handle_intmem,
 	[RSC_VDEV] = NULL, /* VDEVs were handled upon registrarion */
 };
 
@@ -768,7 +845,11 @@ static void rproc_resource_cleanup(struct rproc *rproc)
 
 	/* clean up carveout allocations */
 	list_for_each_entry_safe(entry, tmp, &rproc->carveouts, node) {
-		dma_free_coherent(dev->parent, entry->len, entry->va, entry->dma);
+		if (!entry->priv)
+			dma_free_coherent(dev->parent, entry->len, entry->va,
+					  entry->dma);
+		else
+			iounmap((__force void __iomem *)entry->va);
 		list_del(&entry->node);
 		kfree(entry);
 	}
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index 78b8a9b..2a25ee8 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -100,6 +100,7 @@ struct fw_rsc_hdr {
  *		    the remote processor will be writing logs.
  * @RSC_VDEV:       declare support for a virtio device, and serve as its
  *		    virtio header.
+ * @RSC_INTMEM:     request to map into kernel an internal memory region.
  * @RSC_LAST:       just keep this one at the end
  *
  * For more details regarding a specific resource type, please see its
@@ -115,7 +116,8 @@ enum fw_resource_type {
 	RSC_DEVMEM	= 1,
 	RSC_TRACE	= 2,
 	RSC_VDEV	= 3,
-	RSC_LAST	= 4,
+	RSC_INTMEM	= 4,
+	RSC_LAST	= 5,
 };
 
 #define FW_RSC_ADDR_ANY (0xFFFFFFFFFFFFFFFF)
@@ -306,6 +308,45 @@ struct fw_rsc_vdev {
 } __packed;
 
 /**
+ * struct fw_rsc_intmem - internal memory publishing request
+ * @version: version for this resource type (must be one)
+ * @da: device address
+ * @pa: physical address
+ * @len: length (in bytes)
+ * @reserved: reserved (must be zero)
+ * @name: human-readable name of the region being published
+ *
+ * This resource entry allows a remote processor to publish an internal
+ * memory region to the host. This resource type allows a remote processor
+ * to publish the whole or just a portion of certain internal memories,
+ * while it owns and manages any unpublished portion (eg: a shared L1
+ * memory that can be split configured as RAM and/or cache). This is
+ * primarily provided to allow a host to load code/data into internal
+ * memories, the memory for which is neither allocated nor required to
+ * be mapped into an iommu.
+ *
+ * @da should specify the required address as accessible by the device
+ * without going through an iommu, @pa should specify the physical address
+ * for the region as seen on the bus, @len should specify the size of the
+ * memory region. As always, @name may (optionally) contain a human readable
+ * name of this mapping (mainly for debugging purposes). The @version field
+ * is added for future scalability, and should be 1 for now.
+ *
+ * Note: at this point we just "trust" these intmem entries to contain valid
+ * physical bus addresses. these are not currently intended to be managed
+ * as host-controlled heaps, as it is much better to do that from the remote
+ * processor side.
+ */
+struct fw_rsc_intmem {
+	u32 version;
+	u32 da;
+	u32 pa;
+	u32 len;
+	u32 reserved;
+	u8 name[32];
+} __packed;
+
+/**
  * struct rproc_mem_entry - memory entry descriptor
  * @va:	virtual address
  * @dma: dma address
-- 
2.0.4

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