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2019-02-27riscv: generic: Ensure that U-Boot runs within 4GB for 64bit systemsAnup Patel
On 64bit systems, the DRAM top can be easily beyond 4GB and U-Boot DMA mapping APIs will generate DMA addresses beyond 4GB. This breaks DMA programming in 32bit DMA capable devices (such as Cadence MACB ethernet). For example, If DRAM is more then 2GB on QEMU sifive_u machine then Cadence MACB ethernet stops working for U-Boot because it is a 32bit DMA capable device. To handle 32bit DMA capable devices on 64bit systems, we provide custom implementation of board_get_usable_ram_top() which ensures that usable ram top is not more then 4GB. This in-turn ensures that U-Boot always runs within 4GB hence DMA addresses generated by DMA mapping APIs will be within 4GB too. Signed-off-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Alexander Graf <agraf@suse.de> Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2019-02-27riscv: Rename cpu/qemu to cpu/genericAnup Patel
The QEMU CPU support under arch/riscv is pretty much generic and works fine for SiFive Unleashed as well. In fact, there will be quite a few RISC-V SOCs for which QEMU CPU support will work fine. This patch renames cpu/qemu to cpu/generic to indicate the above fact. If there are SOC specific errata workarounds required in cpu/generic then those can be done at runtime in cpu/generic based on CPU vendor specific DT compatible string. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Alexander Graf <agraf@suse.de> Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>