soc/cavium/cn81xx: Fix minor things

* Move cbmem.c to cn81xx folder
* Store CBMEM below 4 GiB
* Make sure CBMEM doesn't overlap with ATF scratchpad
* Fix ATF scratchpad not marked as reserved due to wrong calculation
* The scratchpad is the last 1 MiB at the end of DRAM.

Tested on Cavium CN81xx EVB:
The ATF scratchpad is now marked reserved and the configuration tables
are located below 4 GiB. Linux still boots.

Change-Id: Ibbc8b586f04bd6867c045f5546b32a77c057ac74
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/27955
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/cavium/cn81xx/Makefile.inc

@@ -39,16 +39,11 @@ romstage-y += timer.c
 romstage-y += spi.c
 romstage-y += uart.c
 romstage-$(CONFIG_DRIVERS_UART) += uart.c
-romstage-< += cpu.c
+romstage-y += cbmem.c
 
 romstage-y += sdram.c
 romstage-y += mmu.c
 
-romstage-y += ../common/cbmem.c
-# BDK coreboot interface
-romstage-y += ../common/bdk-coreboot.c
-
-
 ################################################################################
 # ramstage
 
@@ -64,12 +59,10 @@ ramstage-y += soc.c
 ramstage-y += cpu.c
 ramstage-y += cpu_secondary.S
 ramstage-y += ecam0.c
+ramstage-y += cbmem.c
 
 ramstage-$(CONFIG_ARM64_USE_ARM_TRUSTED_FIRMWARE) += bl31_plat_params.c
 
-# BDK coreboot interface
-ramstage-y += ../common/bdk-coreboot.c
-
 BL31_MAKEARGS += PLAT=t81 M0_CROSS_COMPILE="$(CROSS_COMPILE_arm)" ENABLE_SPE_FOR_LOWER_ELS=0
 
 CPPFLAGS_common += -Isrc/soc/cavium/cn81xx/include

src/soc/cavium/cn81xx/cbmem.c

@@ -21,6 +21,7 @@
 
 void *cbmem_top(void)
 {
-	return (void *)min((uintptr_t)_dram + sdram_size_mb() * MiB,
-			   MAX_DRAM_ADDRESS);
+	/* Make sure not to overlap with reserved ATF scratchpad */
+	return (void *)min((uintptr_t)_dram + (sdram_size_mb() - 1) * MiB,
+			   4ULL * GiB);
 }

src/soc/cavium/cn81xx/soc.c

@@ -309,7 +309,8 @@ void bootmem_platform_add_ranges(void)
 			  BM_MEM_RESERVED);
 
 	/* Scratchpad for ATF SATA quirks */
-	bootmem_add_range(sdram_size_mb() * KiB, 1 * MiB, BM_MEM_RESERVED);
+	bootmem_add_range((sdram_size_mb() - 1) * MiB, 1 * MiB,
+			  BM_MEM_RESERVED);
 }
 
 static void soc_read_resources(device_t dev)

src/soc/cavium/common/Makefile.inc

@@ -22,13 +22,12 @@ bootblock-$(CONFIG_BOOTBLOCK_CUSTOM) += bootblock.c
 ################################################################################
 # romstage
 
-romstage-y += cbmem.c
 romstage-y += bdk-coreboot.c
 
 ################################################################################
 # ramstage
 
-ramstage-y += cbmem.c
+ramstage-y += bdk-coreboot.c
 
 CPPFLAGS_common += -Isrc/soc/cavium/common/include