Hi Stephen,
On 7 August 2015 at 16:12, Stephen Warren swarren@wwwdotorg.org wrote:
From: Stephen Warren swarren@nvidia.com
The return value of query_sdram_size() is assigned directly to gd->ram_size in dram_init(). Adjust the return type to match the field it's assigned to. This has the beneficial effect that on 64-bit systems, the return value can correctly represent large RAM sizes over 4GB.
For similar reasons, change the type of variable size_bytes in the same way.
query_sdram_size() would previously clip the detected RAM size to at most just under 4GB in all cases, since on 32-bit systems, larger values could not be represented. Disable this feature on 64-bit systems since the representation restriction does not exist.
On 64-bit systems, never call get_ram_size() to validate the detected/ calculated RAM size. On any system with a secure OS/... carve-out, RAM may not have a single contiguous usable area, and this can confuse get_ram_size(). Ideally, we'd make this call conditional upon some other flag that indicates specifically that a carve-out is actually in use. At present, building for a 64-bit system is the best indication we have of this fact. In fact, the call to get_ram_size() is not useful by the time U-Boot runs on any system, since U-Boot (and potentially much other early boot software) always runs from RAM on Tegra, so any mistakes in memory controller register programming will already have manifested themselves and prevented U-Boot from running to this point. In the future, we may simply delete the call to get_ram_size() in all cases.
Signed-off-by: Stephen Warren swarren@nvidia.com
arch/arm/mach-tegra/board.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-tegra/board.c b/arch/arm/mach-tegra/board.c index 40de72dc575f..b00e4b5c1e25 100644 --- a/arch/arm/mach-tegra/board.c +++ b/arch/arm/mach-tegra/board.c @@ -66,10 +66,11 @@ bool tegra_cpu_is_non_secure(void) #endif
/* Read the RAM size directly from the memory controller */ -unsigned int query_sdram_size(void) +static phys_size_t query_sdram_size(void) { struct mc_ctlr *const mc = (struct mc_ctlr *)NV_PA_MC_BASE;
u32 emem_cfg, size_bytes;
u32 emem_cfg;phys_size_t size_bytes; emem_cfg = readl(&mc->mc_emem_cfg);#if defined(CONFIG_TEGRA20) @@ -77,6 +78,7 @@ unsigned int query_sdram_size(void) size_bytes = get_ram_size((void *)PHYS_SDRAM_1, emem_cfg * 1024); #else debug("mc->mc_emem_cfg (MEM_SIZE_MB) = 0x%08x\n", emem_cfg); +#ifndef CONFIG_PHYS_64BIT /* * If >=4GB RAM is present, the byte RAM size won't fit into 32-bits * and will wrap. Clip the reported size to the maximum that a 32-bit @@ -84,9 +86,12 @@ unsigned int query_sdram_size(void) */ if (emem_cfg >= 4096) { size_bytes = U32_MAX & ~(0x1000 - 1);
} else {
} else+#endif
{ /* RAM size EMC is programmed to. */
size_bytes = emem_cfg * 1024 * 1024;
size_bytes = (phys_size_t)emem_cfg * 1024 * 1024;+#ifndef CONFIG_ARM64 /* * If all RAM fits within 32-bits, it can be accessed without * LPAE, so go test the RAM size. Otherwise, we can't access @@ -97,6 +102,7 @@ unsigned int query_sdram_size(void) if (emem_cfg <= (0 - PHYS_SDRAM_1) / (1024 * 1024)) size_bytes = get_ram_size((void *)PHYS_SDRAM_1, size_bytes); +#endif } #endif
-- 1.9.1
You might consider using 'if IS_ENABLED()' instead of #ifdef. Or perhaps you should create a board_64.c if the code going to be so different?
Also why do you use CONFIG_ARM64 for the second one and CONFIG_PHYS_64BIT for the first?
Regards, Simon