Files
opensbi/platform/generic/Kconfig
Lad Prabhakar c10095132a platform: generic: renesas: rzfive: Add support to configure the PMA
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 passed 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 <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-02-27 11:35:01 +05:30

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# SPDX-License-Identifier: BSD-2-Clause
config PLATFORM_GENERIC
bool
select FDT
select FDT_DOMAIN
select FDT_PMU
default y
if PLATFORM_GENERIC
config PLATFORM_GENERIC_NAME
string "Platform default name"
default "Generic"
config PLATFORM_GENERIC_MAJOR_VER
int "Platform major version"
range 0 65535
default 0
config PLATFORM_GENERIC_MINOR_VER
int "Platform minor version"
range 0 65535
default 1
config PLATFORM_ALLWINNER_D1
bool "Allwinner D1 support"
depends on FDT_IRQCHIP_PLIC
default n
config PLATFORM_ANDES_AE350
bool "Andes AE350 support"
select SYS_ATCSMU
default n
config PLATFORM_RENESAS_RZFIVE
bool "Renesas RZ/Five support"
default n
config PLATFORM_SIFIVE_FU540
bool "SiFive FU540 support"
default n
config PLATFORM_SIFIVE_FU740
bool "SiFive FU740 support"
depends on FDT_RESET && FDT_I2C
default n
config PLATFORM_STARFIVE_JH7110
bool "StarFive JH7110 support"
default n
source "$(OPENSBI_SRC_DIR)/platform/generic/andes/Kconfig"
endif