[PATCH v4 18/22] dm: core: Correctly read <ranges> of simple-bus

[Bin Meng]

At present we decode simple bus <ranges> using the following assumption:

- parent #address-cells 1
- child #address-cells 1
- child #size-cells 1

However this might not always be the case.

Update to use fdt_addr_t and fdt_size_t in 'struct simple_bus_plat', and
use fdt_read_ranges() to correctly decode it according to the actual
parent and child #address-cells / #size-cells under a Kconfig option
CONFIG_SIMPLE_BUS_CORRECT_RANGE which can be turned on for any board
that needs it.

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
Reviewed-by: Simon Glass <sjg at chromium.org>

---

(no changes since v2)

Changes in v2:
- include <asm/global_data.h>
- use a Kconfig option CONFIG_SIMPLE_BUS_CORRECT_RANGE to control the
  new behavior for boards that want this

 drivers/core/Kconfig      | 13 +++++++++++++
 drivers/core/simple-bus.c | 32 +++++++++++++++++++++++++-------
 include/dm/simple_bus.h   |  6 +++---
 3 files changed, 41 insertions(+), 10 deletions(-)

diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index 1eccac28c6..c7504edaf8 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -235,6 +235,19 @@ config SPL_SIMPLE_BUS
 	  Supports the 'simple-bus' driver, which is used on some systems
 	  in SPL.
 
+config SIMPLE_BUS_CORRECT_RANGE
+	bool "Decode the 'simple-bus' <range> by honoring the #address-cells and #size-cells"
+	depends on SIMPLE_BUS
+	help
+	  Decoding the 'simple-bus' <range> by honoring the #address-cells
+	  and #size-cells of parent/child bus. If unset, #address-cells of
+	  parent bus is assumed to be 1, #address-cells and #size-cells of
+	  child bus is also assumed to be 1, to save some spaces of using
+	  an advanced API to decode the <range>, which benefits SPL image
+	  builds that have size limits.
+
+	  If you are unsure about this, Say N here.
+
 config SIMPLE_PM_BUS
 	bool "Support simple-pm-bus driver"
 	depends on DM && OF_CONTROL && CLK && POWER_DOMAIN
diff --git a/drivers/core/simple-bus.c b/drivers/core/simple-bus.c
index b0c2c20958..18f52d26df 100644
--- a/drivers/core/simple-bus.c
+++ b/drivers/core/simple-bus.c
@@ -4,8 +4,12 @@
  */
 
 #include <common.h>
+#include <asm/global_data.h>
 #include <dm.h>
 #include <dm/simple_bus.h>
+#include <fdt_support.h>
+
+DECLARE_GLOBAL_DATA_PTR;
 
 fdt_addr_t simple_bus_translate(struct udevice *dev, fdt_addr_t addr)
 {
@@ -22,16 +26,30 @@ static int simple_bus_post_bind(struct udevice *dev)
 #if CONFIG_IS_ENABLED(OF_PLATDATA)
 	return 0;
 #else
-	u32 cell[3];
+	struct simple_bus_plat *plat = dev_get_uclass_plat(dev);
 	int ret;
 
-	ret = dev_read_u32_array(dev, "ranges", cell, ARRAY_SIZE(cell));
-	if (!ret) {
-		struct simple_bus_plat *plat = dev_get_uclass_plat(dev);
+	if (CONFIG_IS_ENABLED(SIMPLE_BUS_CORRECT_RANGE)) {
+		uint64_t caddr, paddr, len;
+
+		/* only read range index 0 */
+		ret = fdt_read_range((void *)gd->fdt_blob, dev_of_offset(dev),
+				     0, &caddr, &paddr, &len);
+		if (!ret) {
+			plat->base = caddr;
+			plat->target = paddr;
+			plat->size = len;
+		}
+	} else {
+		u32 cell[3];
 
-		plat->base = cell[0];
-		plat->target = cell[1];
-		plat->size = cell[2];
+		ret = dev_read_u32_array(dev, "ranges", cell,
+					 ARRAY_SIZE(cell));
+		if (!ret) {
+			plat->base = cell[0];
+			plat->target = cell[1];
+			plat->size = cell[2];
+		}
 	}
 
 	return dm_scan_fdt_dev(dev);
diff --git a/include/dm/simple_bus.h b/include/dm/simple_bus.h
index 4ad4cc4051..b7104013c0 100644
--- a/include/dm/simple_bus.h
+++ b/include/dm/simple_bus.h
@@ -7,9 +7,9 @@
 #define __DM_SIMPLE_BUS_H
 
 struct simple_bus_plat {
-	u32 base;
-	u32 size;
-	u32 target;
+	fdt_addr_t base;
+	fdt_size_t size;
+	fdt_addr_t target;
 };
 
 #endif
-- 
2.25.1