ddr: fsl: Fix fsl_ddr_sdram_size() for 4GB modules with 32-bit phys_size_t

Function fsl_ddr_compute() always return size in unsigned long long type,
but function fsl_ddr_sdram_size() returns size in phys_size_t type.

When 36-bit addressing mode is not enabled then phys_size_t type is only
32-bit and thus it cannot store value 4GB (0x100000000). Function
fsl_ddr_sdram_size() in this case returns truncated value 0x0.

Fix this issue by returning the highest representable value, which is
0xffffffff (4GB - 1 byte).

This change fixes crashing of proper U-Boot because it detected 4 GB module
as RAM with zero size.

Signed-off-by: Pali Rohár <pali@kernel.org>

diff --git a/drivers/ddr/fsl/main.c b/drivers/ddr/fsl/main.c
index 020adb0abb658f3cbb481a21faf8172fb73b5033..d44f16cdba169dd4ab66405dd3943513d98eb404 100644 (file)
--- a/drivers/ddr/fsl/main.c
+++ b/drivers/ddr/fsl/main.c
@@ -950,5 +950,9 @@ fsl_ddr_sdram_size(void)
        /* Compute it once normally. */
        total_memory = fsl_ddr_compute(&info, STEP_GET_SPD, 1);
 
+       /* Ensure that total_memory does not overflow on return */
+       if (total_memory > (phys_size_t)~0ULL)
+               total_memory = (phys_size_t)~0ULL;
+
        return total_memory;
 }