Even on 32bit systems a full 4GB of DRAM may be installed and reported
by the DRAM controller. Whether these 4GB are larger available
depends on the size/configuration of address decoding windows and
architectural features (e.g. consider a hypothetical architecture that
uses dedicated instructions to access the 'memory-mapped' peripheral
IO ranges). In U-Boot, the available DRAM, as reported by the
device-model is independent of the accessible DRAM (i.e. adjusted top
and effective size).
This was first reported against the RK3288, which may have 4GB DRAM
attached, but will have a small (e.g. 128MB) window not accessible due
to address decoding limitations.
The solution is to increase the types used for storing the ram_size to
have at least 33 bits even on 32bit systems... i.e. we need to use a
u64 for these always (this was previously only the case for
PHYS_64BIT, which will have unwanted side-effects for 32bit systems
and would require more intrusive changes).
This commit changes the size-field in 'struct ram' and the ram_size in
'gd' to be a u64.
Reported-by: Marty E. Plummer <hanet...@startmail.com>
Signed-off-by: Philipp Tomsich <philipp.toms...@theobroma-systems.com>
---
include/asm-generic/global_data.h | 2 +-
include/ram.h | 9 ++++++++-
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/global_data.h
b/include/asm-generic/global_data.h
index 0fd4900..f3d687c 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -55,7 +55,7 @@ typedef struct global_data {
unsigned long ram_base; /* Base address of RAM used by U-Boot */
unsigned long ram_top; /* Top address of RAM used by U-Boot */
unsigned long relocaddr; /* Start address of U-Boot in RAM */
- phys_size_t ram_size; /* RAM size */
+ u64 ram_size; /* RAM size */
unsigned long mon_len; /* monitor len */
unsigned long irq_sp; /* irq stack pointer */
unsigned long start_addr_sp; /* start_addr_stackpointer */
diff --git a/include/ram.h b/include/ram.h
index 67e22d7..1fe024f 100644
--- a/include/ram.h
+++ b/include/ram.h
@@ -9,7 +9,14 @@
struct ram_info {
phys_addr_t base;
- size_t size;
+ /*
+ * We use a 64bit type for the size to correctly handle 32bit
+ * systems with 4GB of DRAM (which would overflow a 32bit type
+ * and read back as 0). For 64bit systems, we assume (for now)
+ * that they will always have less than 2^65 byte of DRAM
+ * installed. -- prt
+ */
+ u64 size;
};
struct ram_ops {
--
2.1.4
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