[U-Boot] [PATCH] fdt: __of_translate_address(): check parent's 'ranges' before translate

[Przemyslaw Marczak <p.marczak@samsung.com>]

The present implementation of __of_translate_address() taken
from the Linux, is designed for translate bus/child address
mappings by using 'ranges' property - and it doesn't allow
for checking an address for a device's node with zero size-cells.

The 'size-cells > 0' is required for bus/child address mapping,
but is not required for non-memory mapped address, e.g.: I2C chip.
Then when we need only raw 'reg' property's value.

Since the I2C device address goes to a single-cell reg property,
support for that case is welcome, but currently calling dev_get_addr()
for I2C device will return 'FDT_ADDR_T_NONE', and print the warning:

warning:
__of_translate_address: Bad cell count for 'some-dev'

The fix:
The proper result by this commit, is achieved by skipping
the condition check: 'size-cells > 0', when the parent doesn't
provide the 'ranges' property and allows to return 1:1 address
translation, if caller want's just the reg property's value.

No additional argument is needed, the 'ranges' property existence
decides, what type of translation is done when calling dev_get_addr().
And this should be, what the compatible driver expects.

Now, by this commit the function __of_translate_address() can be used
for the both reg property use-cases:

Case 1: (ranges)
----------------
some-bus {
	address-cells = <1>;
	size-cells = <1>;
	ranges = <0x0 0x10000000 0x1000>;
	reg = <0x10000000 0x1000>;

	child1 {
		reg = <0xa00 0x100>;
	};

	child2 {
		reg = <0xb00 0x100>;
	};
};

Return values (CONFIG_OF_TRANSLATE=y):
 - dev_get_addr(some-bus) - retrurns: 0x10000000 - correct
 - dev_get_addr(child1)   - retrurns: 0x10000a00 - correct
 - dev_get_addr(child2)   - retrurns: 0x10000b00 - correct
This works as previous - this commit have no impact on this case.

Case 2: (no ranges - e.g. I2C bus childs) - fixed
-------------------------------------------------
I2C-bus {
	address-cells = <1>;
	size-cells = <0>;
	reg = <0x10000000>;

	chip1 {
		reg = <0xa00>;
	};

	chip2 {
		reg = <0xb00>;
	};
};

Return values (CONFIG_OF_TRANSLATE=y):
 - dev_get_addr(I2C-bus) - retrurns: 0x10000000 - correct
 - dev_get_addr(chip1)   - retrurns: 0xa00      - correct
 - dev_get_addr(chip2)   - retrurns: 0xb00      - correct

This is fixed, since the previously returned value for chip1 and chip2
was: 0xffffffff, which means: 'FDT_ADDR_T_NONE'.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Stefan Roese <sr@denx.de>
Cc: Tom Rini <trini@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
---
 common/fdt_support.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/common/fdt_support.c b/common/fdt_support.c
index 66464db..1f472ca 100644
--- a/common/fdt_support.c
+++ b/common/fdt_support.c
@@ -952,8 +952,9 @@ void fdt_del_node_and_alias(void *blob, const char *alias)
 /* Max address size we deal with */
 #define OF_MAX_ADDR_CELLS	4
 #define OF_BAD_ADDR	FDT_ADDR_T_NONE
-#define OF_CHECK_COUNTS(na, ns)	((na) > 0 && (na) <= OF_MAX_ADDR_CELLS && \
-			(ns) > 0)
+#define OF_CHECK_COUNTS(na, ns, skip_ns) \
+			((na) > 0 && (na) <= OF_MAX_ADDR_CELLS && \
+			(skip_ns || (ns) > 0))
 
 /* Debug utility */
 #ifdef DEBUG
@@ -1104,11 +1105,12 @@ static int of_translate_one(void * blob, int parent, struct of_bus *bus,
 static u64 __of_translate_address(void *blob, int node_offset, const fdt32_t *in_addr,
 				  const char *rprop)
 {
-	int parent;
-	struct of_bus *bus, *pbus;
+	const fdt32_t *pranges;
 	fdt32_t addr[OF_MAX_ADDR_CELLS];
-	int na, ns, pna, pns;
+	int na, ns, pna, pns, parent;
+	struct of_bus *bus, *pbus;
 	u64 result = OF_BAD_ADDR;
+	bool skip_ns_check;
 
 	debug("OF: ** translation for device %s **\n",
 		fdt_get_name(blob, node_offset, NULL));
@@ -1119,9 +1121,16 @@ static u64 __of_translate_address(void *blob, int node_offset, const fdt32_t *in
 		goto bail;
 	bus = &of_busses[0];
 
-	/* Cound address cells & copy address locally */
+	/* Chek 'ns' only if parent provides 'ranges' property */
+	pranges = fdt_getprop(blob, parent, rprop, NULL);
+	if (pranges)
+		skip_ns_check = false;
+	else
+		skip_ns_check = true;
+
+	/* Count address cells & copy address locally */
 	bus->count_cells(blob, parent, &na, &ns);
-	if (!OF_CHECK_COUNTS(na, ns)) {
+	if (!OF_CHECK_COUNTS(na, ns, skip_ns_check)) {
 		printf("%s: Bad cell count for %s\n", __FUNCTION__,
 		       fdt_get_name(blob, node_offset, NULL));
 		goto bail;
@@ -1148,7 +1157,7 @@ static u64 __of_translate_address(void *blob, int node_offset, const fdt32_t *in
 		/* Get new parent bus and counts */
 		pbus = &of_busses[0];
 		pbus->count_cells(blob, parent, &pna, &pns);
-		if (!OF_CHECK_COUNTS(pna, pns)) {
+		if (!OF_CHECK_COUNTS(pna, pns, skip_ns_check)) {
 			printf("%s: Bad cell count for %s\n", __FUNCTION__,
 				fdt_get_name(blob, node_offset, NULL));
 			break;
-- 
1.9.1