RK3588 has two known memory gaps when using 16+ GiB DRAM, [0x3fc000000, 0x3fc500000) and [0x3fff00000, 0x400000000).
Skip both gaps when initializing the DRAM on rk3588 to avoid running into an exception when running memtest on an rk3588 board with 16+ GiB DRAM. The information about the gaps is taken from a patch by Jonas Karlman to the U-Boot mailing list [0]. [0] https://lore.kernel.org/all/20250405153832.1427549-5-jo...@kwiboo.se/ Signed-off-by: Michael Tretter <m.tret...@pengutronix.de> --- The start and end addresses of the gaps probably should be put into of rockchip_dmc_drvdata and only set for the rk3588. Any suggestion how to implement this more nicely would be very welcome. --- arch/arm/mach-rockchip/dmc.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/arch/arm/mach-rockchip/dmc.c b/arch/arm/mach-rockchip/dmc.c index 86e61f311661..cf63fdb5a8bb 100644 --- a/arch/arm/mach-rockchip/dmc.c +++ b/arch/arm/mach-rockchip/dmc.c @@ -27,6 +27,12 @@ #define RK3568_INT_REG_START RK3399_INT_REG_START #define RK3588_INT_REG_START RK3399_INT_REG_START +/* RK3588 has two known memory gaps when using 16+ GiB DRAM */ +#define DRAM_GAP1_START 0x3fc000000 +#define DRAM_GAP1_END 0x3fc500000 +#define DRAM_GAP2_START 0x3fff00000 +#define DRAM_GAP2_END 0x400000000 + struct rockchip_dmc_drvdata { unsigned int os_reg2; unsigned int os_reg3; @@ -220,9 +226,19 @@ static int rockchip_dmc_probe(struct device *dev) arm_add_mem_device("ram0", membase, min_t(resource_size_t, drvdata->internal_registers_start, memsize) - membase); - /* ram1, remaining RAM beyond 32bit space */ + /* ram1, RAM beyond 32bit space up to first gap */ if (memsize > SZ_4G) - arm_add_mem_device("ram1", SZ_4G, memsize - SZ_4G); + arm_add_mem_device("ram1", SZ_4G, + min_t(resource_size_t, DRAM_GAP1_START, memsize) - SZ_4G); + + /* ram2, RAM between first and second gap */ + if (memsize > DRAM_GAP1_END) + arm_add_mem_device("ram2", DRAM_GAP1_END, + min_t(resource_size_t, DRAM_GAP2_START, memsize) - DRAM_GAP1_END); + + /* ram3, remaining RAM after second gap */ + if (memsize > DRAM_GAP2_END) + arm_add_mem_device("ram3", DRAM_GAP2_END, memsize - DRAM_GAP2_END); return 0; } -- 2.39.5
