region: Add writeat and eraseat support

Implement writeat and eraseat support into the region_device_ops struct.

Change-Id: Iac2cf32e523d2f19ee9e5feefe1fba8c68982f3d
Signed-off-by: Antonello Dettori <dev@dettori.io>
Reviewed-on: https://review.coreboot.org/15318
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

2 files changed, 220 insertions, 22 deletions

diff --git a/src/commonlib/include/commonlib/region.h b/src/commonlib/include/commonlib/region.h
index 634132a695..ffc507beae 100644
--- a/src/commonlib/include/commonlib/region.h
+++ b/src/commonlib/include/commonlib/region.h
@@ -48,6 +48,20 @@ int rdev_munmap(const struct region_device *rd, void *mapping);
 ssize_t rdev_readat(const struct region_device *rd, void *b, size_t offset,
 			size_t size);
 
+/*
+ * Returns < 0 on error otherwise returns size of data wrote at provided
+ * offset from the buffer passed.
+ */
+ssize_t rdev_writeat(const struct region_device *rd, void *b, size_t offset,
+			size_t size);
+
+/*
+ * Returns < 0 on error otherwise returns size of data erased.
+ * If eraseat ops is not defined it returns size which indicates
+ * that operation was successful.
+ */
+ssize_t rdev_eraseat(const struct region_device *rd, size_t offset,
+			size_t size);
 
 /****************************************
  *  Implementation of a region device   *
@@ -67,6 +81,9 @@ struct region_device_ops {
 	void *(*mmap)(const struct region_device *, size_t, size_t);
 	int (*munmap)(const struct region_device *, void *);
 	ssize_t (*readat)(const struct region_device *, void *, size_t, size_t);
+	ssize_t (*writeat)(const struct region_device *, void *, size_t,
+		size_t);
+	ssize_t (*eraseat)(const struct region_device *, size_t, size_t);
 };
 
 struct region {
@@ -139,26 +156,38 @@ struct mem_region_device {
 	struct region_device rdev;
 };
 
-/* Iniitalize at runtime a mem_region_device. This would be used when
- * the base and size are dynamic or can't be known during linking. */
-void mem_region_device_init(struct mem_region_device *mdev, void *base,
+/* Inititalize at runtime a mem_region_device. This would be used when
+ * the base and size are dynamic or can't be known during linking.
+ * There are two variants: read-only and read-write. */
+void mem_region_device_ro_init(struct mem_region_device *mdev, void *base,
 				size_t size);
 
-extern const struct region_device_ops mem_rdev_ops;
+void mem_region_device_rw_init(struct mem_region_device *mdev, void *base,
+				size_t size);
+
+extern const struct region_device_ops mem_rdev_ro_ops;
+
+extern const struct region_device_ops mem_rdev_rw_ops;
 
 /* Statically initialize mem_region_device. */
-#define MEM_REGION_DEV_INIT(base_, size_)				\
+#define MEM_REGION_DEV_INIT(base_, size_, ops_)				\
 	{								\
 		.base = (void *)(base_),				\
-		.rdev = REGION_DEV_INIT(&mem_rdev_ops, 0, (size_)),	\
+		.rdev = REGION_DEV_INIT((ops_), 0, (size_)),		\
 	}
 
+#define MEM_REGION_DEV_RO_INIT(base_, size_)				\
+		MEM_REGION_DEV_INIT(base_, size_, &mem_rdev_ro_ops)	\
+
+#define MEM_REGION_DEV_RW_INIT(base_, size_)				\
+		MEM_REGION_DEV_INIT(base_, size_, &mem_rdev_rw_ops)	\
+
 struct mmap_helper_region_device {
 	struct mem_pool pool;
 	struct region_device rdev;
 };
 
-#define MMAP_HELPER_REGION_INIT(ops_, offset_, size_) \
+#define MMAP_HELPER_REGION_INIT(ops_, offset_, size_)			\
 	{								\
 		.rdev = REGION_DEV_INIT((ops_), (offset_), (size_)),	\
 	}
@@ -170,7 +199,7 @@ void *mmap_helper_rdev_mmap(const struct region_device *, size_t, size_t);
 int mmap_helper_rdev_munmap(const struct region_device *, void *);
 
 /* A translated region device provides the ability to publish a region device
- * in one address space and use an access mechansim within another address
+ * in one address space and use an access mechanism within another address
  * space. The sub region is the window within the 1st address space and
  * the request is modified prior to accessing the second address space
  * provided by access_dev. */
@@ -180,20 +209,38 @@ struct xlate_region_device {
 	struct region_device rdev;
 };
 
-extern const struct region_device_ops xlate_rdev_ops;
+extern const struct region_device_ops xlate_rdev_ro_ops;
+
+extern const struct region_device_ops xlate_rdev_rw_ops;
 
-#define XLATE_REGION_DEV_INIT(access_dev_, sub_offset_, sub_size_, parent_sz_) \
+#define XLATE_REGION_DEV_INIT(access_dev_, sub_offset_, sub_size_,	\
+		parent_sz_, ops_)					\
 	{								\
 		.access_dev = access_dev_,				\
 		.sub_region = {						\
 			.offset = (sub_offset_),			\
 			.size = (sub_size_),				\
 		},							\
-		.rdev = REGION_DEV_INIT(&xlate_rdev_ops, 0,  (parent_sz_)),\
+		.rdev = REGION_DEV_INIT((ops_), 0,  (parent_sz_)),	\
 	}
 
+#define XLATE_REGION_DEV_RO_INIT(access_dev_, sub_offset_, sub_size_,	\
+		parent_sz_)						\
+		XLATE_REGION_DEV_INIT(access_dev_, sub_offset_,		\
+			sub_size_, parent_sz_, &xlate_rdev_ro_ops),	\
+
+#define XLATE_REGION_DEV_RW_INIT(access_dev_, sub_offset_, sub_size_,	\
+		parent_sz_)						\
+		XLATE_REGION_DEV_INIT(access_dev_, sub_offset_,		\
+			sub_size_, parent_sz_, &xlate_rdev_rw_ops),	\
+
 /* Helper to dynamically initialize xlate region device. */
-void xlate_region_device_init(struct xlate_region_device *xdev,
+void xlate_region_device_ro_init(struct xlate_region_device *xdev,
+			      const struct region_device *access_dev,
+			      size_t sub_offset, size_t sub_size,
+			      size_t parent_size);
+
+void xlate_region_device_rw_init(struct xlate_region_device *xdev,
 			      const struct region_device *access_dev,
 			      size_t sub_offset, size_t sub_size,
 			      size_t parent_size);
diff --git a/src/commonlib/region.c b/src/commonlib/region.c
index 6f710746ca..d7bea03ae9 100644
--- a/src/commonlib/region.c
+++ b/src/commonlib/region.c
@@ -103,6 +103,48 @@ ssize_t rdev_readat(const struct region_device *rd, void *b, size_t offset,
 	return rdev->ops->readat(rdev, b, req.offset, req.size);
 }
 
+ssize_t rdev_writeat(const struct region_device *rd, void *b, size_t offset,
+			size_t size)
+{
+	const struct region_device *rdev;
+	struct region req = {
+		.offset = offset,
+		.size = size,
+	};
+
+	if (!normalize_and_ok(&rd->region, &req))
+		return -1;
+
+	rdev = rdev_root(rd);
+
+	if (rdev->ops->writeat == NULL)
+		return -1;
+
+	return rdev->ops->writeat(rdev, b, req.offset, req.size);
+}
+
+ssize_t rdev_eraseat(const struct region_device *rd, size_t offset,
+			size_t size)
+{
+	const struct region_device *rdev;
+	struct region req = {
+		.offset = offset,
+		.size = size,
+	};
+
+	if (!normalize_and_ok(&rd->region, &req))
+		return -1;
+
+	rdev = rdev_root(rd);
+
+	/* If the eraseat ptr is NULL we assume that the erase
+	 * function was completed successfully. */
+	if (rdev->ops->eraseat == NULL)
+		return size;
+
+	return rdev->ops->eraseat(rdev, req.offset, req.size);
+}
+
 int rdev_chain(struct region_device *child, const struct region_device *parent,
 		size_t offset, size_t size)
 {
@@ -124,15 +166,27 @@ int rdev_chain(struct region_device *child, const struct region_device *parent,
 	return 0;
 }
 
-void mem_region_device_init(struct mem_region_device *mdev, void *base,
-				size_t size)
+static void mem_region_device_init(struct mem_region_device *mdev,
+		const struct region_device_ops *ops, void *base, size_t size)
 {
 	memset(mdev, 0, sizeof(*mdev));
 	mdev->base = base;
-	mdev->rdev.ops = &mem_rdev_ops;
+	mdev->rdev.ops = ops;
 	mdev->rdev.region.size = size;
 }
 
+void mem_region_device_ro_init(struct mem_region_device *mdev, void *base,
+				size_t size)
+{
+	return mem_region_device_init(mdev, &mem_rdev_ro_ops, base, size);
+}
+
+void mem_region_device_rw_init(struct mem_region_device *mdev, void *base,
+		size_t size)
+{
+	return mem_region_device_init(mdev, &mem_rdev_rw_ops, base, size);
+}
+
 void region_device_init(struct region_device *rdev,
 			const struct region_device_ops *ops, size_t offset,
 			size_t size)
@@ -144,16 +198,35 @@ void region_device_init(struct region_device *rdev,
 	rdev->region.size = size;
 }
 
-void xlate_region_device_init(struct xlate_region_device *xdev,
-			      const struct region_device *access_dev,
-			      size_t sub_offset, size_t sub_size,
-			      size_t parent_size)
+static void xlate_region_device_init(struct xlate_region_device *xdev,
+			const struct region_device_ops *ops,
+			const struct region_device *access_dev,
+			size_t sub_offset, size_t sub_size,
+			size_t parent_size)
 {
 	memset(xdev, 0, sizeof(*xdev));
 	xdev->access_dev = access_dev;
 	xdev->sub_region.offset = sub_offset;
 	xdev->sub_region.size = sub_size;
-	region_device_init(&xdev->rdev, &xlate_rdev_ops, 0, parent_size);
+	region_device_init(&xdev->rdev, ops, 0, parent_size);
+}
+
+void xlate_region_device_ro_init(struct xlate_region_device *xdev,
+			      const struct region_device *access_dev,
+			      size_t sub_offset, size_t sub_size,
+			      size_t parent_size)
+{
+	xlate_region_device_init(xdev, &xlate_rdev_ro_ops, access_dev,
+			sub_offset, sub_size, parent_size);
+}
+
+void xlate_region_device_rw_init(struct xlate_region_device *xdev,
+			      const struct region_device *access_dev,
+			      size_t sub_offset, size_t sub_size,
+			      size_t parent_size)
+{
+	xlate_region_device_init(xdev, &xlate_rdev_rw_ops, access_dev,
+			sub_offset, sub_size, parent_size);
 }
 
 static void *mdev_mmap(const struct region_device *rd, size_t offset,
@@ -184,10 +257,42 @@ static ssize_t mdev_readat(const struct region_device *rd, void *b,
 	return size;
 }
 
-const struct region_device_ops mem_rdev_ops = {
+static ssize_t mdev_writeat(const struct region_device *rd, void *b,
+				size_t offset, size_t size)
+{
+	const struct mem_region_device *mdev;
+
+	mdev = container_of(rd, __typeof__(*mdev), rdev);
+
+	memcpy(&mdev->base[offset], b, size);
+
+	return size;
+}
+
+static ssize_t mdev_eraseat(const struct region_device *rd, size_t offset,
+				size_t size)
+{
+	const struct mem_region_device *mdev;
+
+	mdev = container_of(rd, __typeof__(*mdev), rdev);
+
+	memset(&mdev->base[offset], 0, size);
+
+	return size;
+}
+
+const struct region_device_ops mem_rdev_ro_ops = {
+	.mmap = mdev_mmap,
+	.munmap = mdev_munmap,
+	.readat = mdev_readat,
+};
+
+const struct region_device_ops mem_rdev_rw_ops = {
 	.mmap = mdev_mmap,
 	.munmap = mdev_munmap,
 	.readat = mdev_readat,
+	.writeat = mdev_writeat,
+	.eraseat = mdev_eraseat,
 };
 
 void mmap_helper_device_init(struct mmap_helper_region_device *mdev,
@@ -275,8 +380,54 @@ static ssize_t xlate_readat(const struct region_device *rd, void *b,
 	return rdev_readat(xldev->access_dev, b, offset, size);
 }
 
-const struct region_device_ops xlate_rdev_ops = {
+static ssize_t xlate_writeat(const struct region_device *rd, void *b,
+				size_t offset, size_t size)
+{
+	struct region req = {
+		.offset = offset,
+		.size = size,
+	};
+	const struct xlate_region_device *xldev;
+
+	xldev = container_of(rd, __typeof__(*xldev), rdev);
+
+	if (!is_subregion(&xldev->sub_region, &req))
+		return -1;
+
+	offset -= region_offset(&xldev->sub_region);
+
+	return rdev_writeat(xldev->access_dev, b, offset, size);
+}
+
+static ssize_t xlate_eraseat(const struct region_device *rd,
+				size_t offset, size_t size)
+{
+	struct region req = {
+		.offset = offset,
+		.size = size,
+	};
+	const struct xlate_region_device *xldev;
+
+	xldev = container_of(rd, __typeof__(*xldev), rdev);
+
+	if (!is_subregion(&xldev->sub_region, &req))
+		return -1;
+
+	offset -= region_offset(&xldev->sub_region);
+
+	return rdev_eraseat(xldev->access_dev, offset, size);
+}
+
+const struct region_device_ops xlate_rdev_ro_ops = {
+	.mmap = xlate_mmap,
+	.munmap = xlate_munmap,
+	.readat = xlate_readat,
+};
+
+const struct region_device_ops xlate_rdev_rw_ops = {
 	.mmap = xlate_mmap,
 	.munmap = xlate_munmap,
 	.readat = xlate_readat,
+	.writeat = xlate_writeat,
+	.eraseat = xlate_eraseat,
 };