I/O Coherence Port (IOCP) provides an AXI interface for connecting
external non-caching masters, such as DMA controllers. The accesses
from IOCP are coherent with D-Caches and L2 Cache.
IOCP is a specification option and is disabled on the Renesas RZ/Five
SoC (which is based on Andes AX45MP core) due to this reason IP blocks
using DMA will fail.
As a workaround for SoCs with IOCP disabled CMO needs to be handled by
software. Firstly OpenSBI configures the memory region as
"Memory, Non-cacheable, Bufferable" and passes this region as a global
shared dma pool as a DT node. With DMA_GLOBAL_POOL enabled all DMA
allocations happen from this region and synchronization callbacks are
implemented to synchronize when doing DMA transactions.
SBI_EXT_ANDES_IOCP_SW_WORKAROUND checks if the IOCP errata should be
applied to handle cache management.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
On the Renesas RZ/Five SoC by default we want to configure 128MiB of memory
ranging from 0x58000000 as a non-cacheable + bufferable region in the PMA
and populate this region as PMA reserve DT node with shared DMA pool and
no-map flags set so that Linux drivers requesting any DMA'able memory go
through this region.
PMA node passed to the above stack:
reserved-memory {
#address-cells = <2>;
#size-cells = <2>;
ranges;
pma_resv0@58000000 {
compatible = "shared-dma-pool";
reg = <0x0 0x58000000 0x0 0x08000000>;
no-map;
linux,dma-default;
};
};
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Renesas RZ/Five RISC-V SoC has Instruction local memory and Data local
memory (ILM & DLM) mapped between region 0x30000 - 0x4FFFF. When a
virtual address falls within this range, the MMU doesn't trigger a page
fault; it assumes the virtual address is a physical address which can
cause undesired behaviours for statically linked applications/libraries.
To avoid this, add the ILM/DLM memory regions to the root domain region
of the PMPU with permissions set to 0x0 for S/U modes so that any access
to these regions gets blocked and for M-mode we grant full access (R/W/X).
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
