fdt: add new fdt address parsing functions

fdtdec_get_addr_size() hard-codes the number of cells used to represent
an address or size in DT. This is incorrect in many cases depending on
the DT binding for a particular node or property (e.g. it is incorrect
for the "reg" property). In most cases, DT parsing code must use the
properties #address-cells and #size-cells to parse addres properties.

This change splits up the implementation of fdtdec_get_addr_size() so
that the core logic can be used for both hard-coded and non-hard-coded
cases. Various wrapper functions are implemented that support cases
where hard-coded cell counts should or should not be used, and where
the client does and doesn't know the parent node ID that contains the
properties #address-cells and #size-cells.

dev_get_addr() is updated to use the new functions.

Core functionality in fdtdec_get_addr_size_fixed() is widely tested via
fdtdec_get_addr_size(). I tested fdtdec_get_addr_size_auto_noparent() and
dev_get_addr() by manually modifying the Tegra I2C driver to invoke them.

Much of the core implementation of fdtdec_get_addr_size_fixed(),
fdtdec_get_addr_size_auto_parent(), and
fdtdec_get_addr_size_auto_noparent() comes from Thierry Reding's
previous commit "fdt: Fix fdtdec_get_addr_size() for 64-bit".

Based-on-work-by: Thierry Reding <treding@nvidia.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Michal Suchanek <hramrach@gmail.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
Dropped #define DEBUG at the top of fdtdec.c:
Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/core/device.c

@@ -581,7 +581,10 @@ fdt_addr_t dev_get_addr(struct udevice *dev)
 #if CONFIG_IS_ENABLED(OF_CONTROL)
 	fdt_addr_t addr;
 
-	addr = fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
+	addr = fdtdec_get_addr_size_auto_parent(gd->fdt_blob,
+						dev->parent->of_offset,
+						dev->of_offset, "reg",
+						0, NULL);
 	if (CONFIG_IS_ENABLED(SIMPLE_BUS) && addr != FDT_ADDR_T_NONE) {
 		if (device_get_uclass_id(dev->parent) == UCLASS_SIMPLE_BUS)
 			addr = simple_bus_translate(dev->parent, addr);

include/fdtdec.h

@@ -295,10 +295,90 @@ int fdtdec_next_compatible(const void *blob, int node,
 int fdtdec_next_compatible_subnode(const void *blob, int node,
 		enum fdt_compat_id id, int *depthp);
 
-/**
- * Look up an address property in a node and return it as an address.
- * The property must hold either one address with no trailing data or
- * one address with a length. This is only tested on 32-bit machines.
+/*
+ * Look up an address property in a node and return the parsed address, and
+ * optionally the parsed size.
+ *
+ * This variant assumes a known and fixed number of cells are used to
+ * represent the address and size.
+ *
+ * You probably don't want to use this function directly except to parse
+ * non-standard properties, and never to parse the "reg" property. Instead,
+ * use one of the "auto" variants below, which automatically honor the
+ * #address-cells and #size-cells properties in the parent node.
+ *
+ * @param blob	FDT blob
+ * @param node	node to examine
+ * @param prop_name	name of property to find
+ * @param index	which address to retrieve from a list of addresses. Often 0.
+ * @param na	the number of cells used to represent an address
+ * @param ns	the number of cells used to represent a size
+ * @param sizep	a pointer to store the size into. Use NULL if not required
+ * @return address, if found, or FDT_ADDR_T_NONE if not
+ */
+fdt_addr_t fdtdec_get_addr_size_fixed(const void *blob, int node,
+		const char *prop_name, int index, int na, int ns,
+		fdt_size_t *sizep);
+
+/*
+ * Look up an address property in a node and return the parsed address, and
+ * optionally the parsed size.
+ *
+ * This variant automatically determines the number of cells used to represent
+ * the address and size by parsing the provided parent node's #address-cells
+ * and #size-cells properties.
+ *
+ * @param blob	FDT blob
+ * @param parent	parent node of @node
+ * @param node	node to examine
+ * @param prop_name	name of property to find
+ * @param index	which address to retrieve from a list of addresses. Often 0.
+ * @param sizep	a pointer to store the size into. Use NULL if not required
+ * @return address, if found, or FDT_ADDR_T_NONE if not
+ */
+fdt_addr_t fdtdec_get_addr_size_auto_parent(const void *blob, int parent,
+		int node, const char *prop_name, int index, fdt_size_t *sizep);
+
+/*
+ * Look up an address property in a node and return the parsed address, and
+ * optionally the parsed size.
+ *
+ * This variant automatically determines the number of cells used to represent
+ * the address and size by parsing the parent node's #address-cells
+ * and #size-cells properties. The parent node is automatically found.
+ *
+ * The automatic parent lookup implemented by this function is slow.
+ * Consequently, fdtdec_get_addr_size_auto_parent() should be used where
+ * possible.
+ *
+ * @param blob	FDT blob
+ * @param parent	parent node of @node
+ * @param node	node to examine
+ * @param prop_name	name of property to find
+ * @param index	which address to retrieve from a list of addresses. Often 0.
+ * @param sizep	a pointer to store the size into. Use NULL if not required
+ * @return address, if found, or FDT_ADDR_T_NONE if not
+ */
+fdt_addr_t fdtdec_get_addr_size_auto_noparent(const void *blob, int node,
+		const char *prop_name, int index, fdt_size_t *sizep);
+
+/*
+ * Look up an address property in a node and return the parsed address.
+ *
+ * This variant hard-codes the number of cells used to represent the address
+ * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
+ * always returns the first address value in the property (index 0).
+ *
+ * Use of this function is not recommended due to the hard-coding of cell
+ * counts. There is no programmatic validation that these hard-coded values
+ * actually match the device tree content in any way at all. This assumption
+ * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
+ * set in the U-Boot build and exercising strict control over DT content to
+ * ensure use of matching #address-cells/#size-cells properties. However, this
+ * approach is error-prone; those familiar with DT will not expect the
+ * assumption to exist, and could easily invalidate it. If the assumption is
+ * invalidated, this function will not report the issue, and debugging will
+ * be required. Instead, use fdtdec_get_addr_size_auto_parent().
  *
  * @param blob	FDT blob
  * @param node	node to examine
@@ -308,14 +388,29 @@ int fdtdec_next_compatible_subnode(const void *blob, int node,
 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
 		const char *prop_name);
 
-/**
- * Look up an address property in a node and return it as an address.
- * The property must hold one address with a length. This is only tested
- * on 32-bit machines.
+/*
+ * Look up an address property in a node and return the parsed address, and
+ * optionally the parsed size.
+ *
+ * This variant hard-codes the number of cells used to represent the address
+ * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
+ * always returns the first address value in the property (index 0).
+ *
+ * Use of this function is not recommended due to the hard-coding of cell
+ * counts. There is no programmatic validation that these hard-coded values
+ * actually match the device tree content in any way at all. This assumption
+ * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
+ * set in the U-Boot build and exercising strict control over DT content to
+ * ensure use of matching #address-cells/#size-cells properties. However, this
+ * approach is error-prone; those familiar with DT will not expect the
+ * assumption to exist, and could easily invalidate it. If the assumption is
+ * invalidated, this function will not report the issue, and debugging will
+ * be required. Instead, use fdtdec_get_addr_size_auto_parent().
  *
  * @param blob	FDT blob
  * @param node	node to examine
  * @param prop_name	name of property to find
+ * @param sizep	a pointer to store the size into. Use NULL if not required
  * @return address, if found, or FDT_ADDR_T_NONE if not
  */
 fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,

lib/fdtdec.c

@@ -86,32 +86,104 @@ const char *fdtdec_get_compatible(enum fdt_compat_id id)
 	return compat_names[id];
 }
 
-fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
-		const char *prop_name, fdt_size_t *sizep)
+fdt_addr_t fdtdec_get_addr_size_fixed(const void *blob, int node,
+		const char *prop_name, int index, int na, int ns,
+		fdt_size_t *sizep)
 {
-	const fdt_addr_t *cell;
+	const fdt32_t *prop, *prop_end;
+	const fdt32_t *prop_addr, *prop_size, *prop_after_size;
 	int len;
+	fdt_addr_t addr;
 
 	debug("%s: %s: ", __func__, prop_name);
-	cell = fdt_getprop(blob, node, prop_name, &len);
-	if (cell && ((!sizep && len == sizeof(fdt_addr_t)) ||
-		     len == sizeof(fdt_addr_t) * 2)) {
-		fdt_addr_t addr = fdt_addr_to_cpu(*cell);
-		if (sizep) {
-			const fdt_size_t *size;
-
-			size = (fdt_size_t *)((char *)cell +
-					sizeof(fdt_addr_t));
-			*sizep = fdt_size_to_cpu(*size);
-			debug("addr=%08lx, size=%llx\n",
-			      (ulong)addr, (u64)*sizep);
-		} else {
-			debug("%08lx\n", (ulong)addr);
-		}
-		return addr;
+
+	if (na > (sizeof(fdt_addr_t) / sizeof(fdt32_t))) {
+		debug("(na too large for fdt_addr_t type)\n");
+		return FDT_ADDR_T_NONE;
 	}
-	debug("(not found)\n");
-	return FDT_ADDR_T_NONE;
+
+	if (ns > (sizeof(fdt_size_t) / sizeof(fdt32_t))) {
+		debug("(ns too large for fdt_size_t type)\n");
+		return FDT_ADDR_T_NONE;
+	}
+
+	prop = fdt_getprop(blob, node, prop_name, &len);
+	if (!prop) {
+		debug("(not found)\n");
+		return FDT_ADDR_T_NONE;
+	}
+	prop_end = prop + (len / sizeof(*prop));
+
+	prop_addr = prop + (index * (na + ns));
+	prop_size = prop_addr + na;
+	prop_after_size = prop_size + ns;
+	if (prop_after_size > prop_end) {
+		debug("(not enough data: expected >= %d cells, got %d cells)\n",
+		      (u32)(prop_after_size - prop), ((u32)(prop_end - prop)));
+		return FDT_ADDR_T_NONE;
+	}
+
+	addr = fdtdec_get_number(prop_addr, na);
+
+	if (sizep) {
+		*sizep = fdtdec_get_number(prop_size, ns);
+		debug("addr=%08llx, size=%llx\n", (u64)addr, (u64)*sizep);
+	} else {
+		debug("addr=%08llx\n", (u64)addr);
+	}
+
+	return addr;
+}
+
+fdt_addr_t fdtdec_get_addr_size_auto_parent(const void *blob, int parent,
+		int node, const char *prop_name, int index, fdt_size_t *sizep)
+{
+	int na, ns;
+
+	debug("%s: ", __func__);
+
+	na = fdt_address_cells(blob, parent);
+	if (na < 1) {
+		debug("(bad #address-cells)\n");
+		return FDT_ADDR_T_NONE;
+	}
+
+	ns = fdt_size_cells(blob, parent);
+	if (ns < 1) {
+		debug("(bad #size-cells)\n");
+		return FDT_ADDR_T_NONE;
+	}
+
+	debug("na=%d, ns=%d, ", na, ns);
+
+	return fdtdec_get_addr_size_fixed(blob, node, prop_name, index, na,
+					  ns, sizep);
+}
+
+fdt_addr_t fdtdec_get_addr_size_auto_noparent(const void *blob, int node,
+		const char *prop_name, int index, fdt_size_t *sizep)
+{
+	int parent;
+
+	debug("%s: ", __func__);
+
+	parent = fdt_parent_offset(blob, node);
+	if (parent < 0) {
+		debug("(no parent found)\n");
+		return FDT_ADDR_T_NONE;
+	}
+
+	return fdtdec_get_addr_size_auto_parent(blob, parent, node, prop_name,
+						index, sizep);
+}
+
+fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
+		const char *prop_name, fdt_size_t *sizep)
+{
+	return fdtdec_get_addr_size_fixed(blob, node, prop_name, 0,
+					  sizeof(fdt_addr_t) / sizeof(fdt32_t),
+					  sizeof(fdt_size_t) / sizeof(fdt32_t),
+					  sizep);
 }
 
 fdt_addr_t fdtdec_get_addr(const void *blob, int node,