document ddr and bus clock limits / add bus-speed build-time option

Signed-off-by: Josua Mayer <[email protected]>

README.md

@@ -79,8 +79,8 @@ DDR Clock can be configured in local.conf using `LX2160A_DDR_SPEED`, supported v
 
 - `2400`
 - `2600`
-- `2900`
-- `3200` (default)
+- `2900` only for LX2162A, and LX2160A binned 2GHz and higher (default)
+- `3200` only for LX2160A binned 2.2GHz
 
 ### CPU Clock
 
@@ -89,6 +89,12 @@ CPU (Cortex A72) Clock can be configured in local.conf using `LX2160A_CPU_SPEED`
 - `2000` (default, recommended)
 - `2200` (for over-clocking, or for specifically purchased 2.2GHz binned SoC)
 
+### Bus Clock
+
+Bus clock can be configured in local.conf using `LX2160A_BUS_SPEED`, supported values are:
+
+- `700` only for LX2160A binned 2GHz and higher (default)
+
 ## Maintainer Notes
 
 ### Patching Linux / U-Boot / ATF / RCW / DPL / DPC / etc.:

conf/machine/lx2160acex7.conf

@@ -29,14 +29,15 @@ KERNEL_DEFCONFIG ?= "defconfig"
 SERIAL_CONSOLES ?= "115200;ttyS0 115200;ttyS1 115200;ttyAMA0"
 SERIAL_CONSOLES_CHECK ?= "${SERIAL_CONSOLES}"
 
+LX2160A_BUS_SPEED ?= "700"
 LX2160A_CPU_SPEED ?= "2000"
-LX2160A_DDR_SPEED ?= "3200"
+LX2160A_DDR_SPEED ?= "2900"
 
 UEFI_XSPIBOOT ?= "LX2160ARDB_EFI_NORBOOT.fd"
 BOOTTYPE ?= "flexspi_nor sd emmc"
-RCWXSPI ?= "clearfog-cx/rcw_${LX2160A_CPU_SPEED}_700_${LX2160A_DDR_SPEED}_8_5_2"
-RCWSD ?= "clearfog-cx/rcw_${LX2160A_CPU_SPEED}_700_${LX2160A_DDR_SPEED}_8_5_2"
-RCWEMMC ?= "clearfog-cx/rcw_${LX2160A_CPU_SPEED}_700_${LX2160A_DDR_SPEED}_8_5_2"
+RCWXSPI ?= "clearfog-cx/rcw_${LX2160A_CPU_SPEED}_${LX2160A_BUS_SPEED}_${LX2160A_DDR_SPEED}_8_5_2"
+RCWSD ?= "clearfog-cx/rcw_${LX2160A_CPU_SPEED}_${LX2160A_BUS_SPEED}_${LX2160A_DDR_SPEED}_8_5_2"
+RCWEMMC ?= "clearfog-cx/rcw_${LX2160A_CPU_SPEED}_${LX2160A_BUS_SPEED}_${LX2160A_DDR_SPEED}_8_5_2"
 
 EXTRA_IMAGEDEPENDS += "management-complex mc-utils rcw ls2-phy ddr-phy uefi qoriq-atf inphi"
 USE_VT = "0"