From d34599bcd2e4e93a28d5904bf94bc7dafc511f04 Mon Sep 17 00:00:00 2001 From: Lad Prabhakar Date: Fri, 18 Aug 2023 14:57:22 +0100 Subject: cache: Add L2 cache management for Andes AX45MP RISC-V core 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 due to this reason IP blocks using DMA will fail. The Andes AX45MP core has a Programmable Physical Memory Attributes (PMA) block that allows dynamic adjustment of memory attributes in the runtime. It contains a configurable amount of PMA entries implemented as CSR registers to control the attributes of memory locations in interest. Below are the memory attributes supported: * Device, Non-bufferable * Device, bufferable * Memory, Non-cacheable, Non-bufferable * Memory, Non-cacheable, Bufferable * Memory, Write-back, No-allocate * Memory, Write-back, Read-allocate * Memory, Write-back, Write-allocate * Memory, Write-back, Read and Write-allocate More info about PMA (section 10.3): Link: http://www.andestech.com/wp-content/uploads/AX45MP-1C-Rev.-5.0.0-Datasheet.pdf 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. Example PMA region passes as a DT node from OpenSBI: 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 Reviewed-by: Conor Dooley Tested-by: Conor Dooley # tyre-kicking on a d1 Link: https://lore.kernel.org/r/20230818135723.80612-6-prabhakar.mahadev-lad.rj@bp.renesas.com Signed-off-by: Palmer Dabbelt --- drivers/cache/Makefile | 3 +++ 1 file changed, 3 insertions(+) create mode 100644 drivers/cache/Makefile (limited to 'drivers/cache/Makefile') diff --git a/drivers/cache/Makefile b/drivers/cache/Makefile new file mode 100644 index 000000000000..2012e7fb978d --- /dev/null +++ b/drivers/cache/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-$(CONFIG_AX45MP_L2_CACHE) += ax45mp_cache.o -- cgit v1.2.3