Hi Paul,
On Mon, Apr 25, 2022 at 11:23 AM Rasmus Villemoes rasmus.villemoes@prevas.dk wrote:
I was trying to employ lpddr4_mr_read() to something similar to what the imx8mm-cl-iot-gate board is doing for auto-detecting the RAM type. However, the version in drivers/ddr/imx/imx8m/ddrphy_utils.c differs from the private one used by that board in how it extracts the byte value, and I was only getting zeroes. Adding a bit of debug printf'ing gives me
tmp = 0x00ffff00 tmp = 0x00070700 tmp = 0x00000000 tmp = 0x00101000
and indeed I was expecting a (combined) value of 0xff070010 (0xff being Manufacturer ID for Micron). I can't find any documentation that says how the values are supposed to be read, but clearly the iot-gate definition is the right one, both for its use case as well as my imx8mp-based board.
So lift the private definition of lpddr4_mr_read() from the imx8mm-cl-iot-gate board code to ddrphy_utils.c, and add a declaration in the ddr.h header where e.g. get_trained_CDD() is already declared.
This has only been compile-tested for the imx8mm-cl-iot-gate board (since I don't have the hardware), but since I've merely moved its definition of lpddr4_mr_read(), I'd be surprised if it changed anything for that board.
Signed-off-by: Rasmus Villemoes rasmus.villemoes@prevas.dk
Could you please test this patch?
I only have remote access to this board.