Christian Gmeiner (christian.gmeiner@gmail.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3322
-gerrit
commit f0bd4644a8255ba6feb8f33ce863ce46dd6504f1 Author: Christian Gmeiner christian.gmeiner@gmail.com Date: Wed May 29 11:20:37 2013 +0200
AMD Geode LX: add get_top_of_ram()
get_top_of_ram() is needed for EARLY_CBMEM_INIT. We are reading the RCONF_DEFAULT_MSR (0x1808) msr. It contains SYSTOP [27:8], which is the top of system memory that is available for general processor use.
Here is a short calucation demo: CPU_RCONF_DEFAULT (1808): 0x25FFFC02:0x10FFDF00
0x25FFFC0210FFDF00 & 0xFFFFF00 = 0xFFDF00 0xFFDF00 << 8 = 0xFFDF0000
Change-Id: Iadde6aab85ab2adc526f1ef3c5fc22e0f5b06d51 Signed-off-by: Christian Gmeiner christian.gmeiner@gmail.com --- src/northbridge/amd/lx/raminit.c | 7 +++++++ src/northbridge/amd/lx/raminit.h | 1 + 2 files changed, 8 insertions(+)
diff --git a/src/northbridge/amd/lx/raminit.c b/src/northbridge/amd/lx/raminit.c index 9a53e9e..db9fa61 100644 --- a/src/northbridge/amd/lx/raminit.c +++ b/src/northbridge/amd/lx/raminit.c @@ -774,3 +774,10 @@ static void sdram_enable(int controllers, const struct mem_controller *ctrl) print_info("RAM DLL lock\n");
} + +unsigned long get_top_of_ram(void) +{ + msr_t msr = rdmsr(CPU_RCONF_DEFAULT); + uint32_t systop = (msr.lo & 0xFFFFF00) << 8; + return (unsigned long)systop; +} diff --git a/src/northbridge/amd/lx/raminit.h b/src/northbridge/amd/lx/raminit.h index 3d4d4c6..8c11525 100644 --- a/src/northbridge/amd/lx/raminit.h +++ b/src/northbridge/amd/lx/raminit.h @@ -28,5 +28,6 @@ struct mem_controller { };
void sdram_initialize(int controllers, const struct mem_controller *ctrl); +unsigned long get_top_of_ram(void);
#endif