mbox series

[v12,0/6] Add non-coherent DMA support for AX45MP

Message ID 20230818135723.80612-1-prabhakar.mahadev-lad.rj@bp.renesas.com (mailing list archive)
Headers show
Series Add non-coherent DMA support for AX45MP | expand

Message

Lad, Prabhakar Aug. 18, 2023, 1:57 p.m. UTC
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Hi All,

non-coherent DMA support for AX45MP
====================================

On the Andes AX45MP core, cache coherency is a specification option so it
may not be supported. In this case DMA will fail. To get around with this
issue this patch series does the below:

1] Andes alternative ports is implemented as errata which checks if the
IOCP is missing and only then applies to CMO errata. One vendor specific
SBI EXT (ANDES_SBI_EXT_IOCP_SW_WORKAROUND) is implemented as part of
errata.

Below are the configs which Andes port provides (and are selected by
RZ/Five):
      - ERRATA_ANDES
      - ERRATA_ANDES_CMO

OpenSBI patch supporting ANDES_SBI_EXT_IOCP_SW_WORKAROUND SBI is now
part v1.3 release.

2] 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.
OpenSBI configures the PMA regions as required and creates a reserve memory
node and propagates it to the higher boot stack.

Currently OpenSBI (upstream) configures the required PMA region and passes
this a shared DMA pool to Linux.

    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;
        };
    };

The above shared DMA pool gets appended to Linux DTB so the DMA memory
requests go through this region.

3] We provide callbacks to synchronize specific content between memory and
cache.

4] RZ/Five SoC selects the below configs
        - AX45MP_L2_CACHE
        - DMA_GLOBAL_POOL
        - ERRATA_ANDES
        - ERRATA_ANDES_CMO

----------x---------------------x--------------------x---------------x----

Note,
- Ive used GCC 12.2.0 for compilation
- Tested all the IP blocks on RZ/Five which use DMA
- Patch series is dependent on the series from Arnd,
  https://patchwork.kernel.org/project/linux-renesas-soc/cover/20230816232336.164413-1-prabhakar.mahadev-lad.rj@bp.renesas.com/.
- Patches applies on top of palmer/master (25aa0bebba72) +
  palmer/for-next (174e8ac0272d5) + palmer/fixes (7e3811521dc39)
- Ive pushed the complete tree here https://github.com/prabhakarlad/linux/tree/rzfive-cmo-v12

v11 -> v12
* Renamed struct riscv_cache_ops -> struct riscv_nonstd_cache_ops

v10 -> v11
* Changed data type of size from unsigned long to size_t
* Reworded doc for struct riscv_cache_ops
* Marked ax45mp_cmo_ops as __initdata

v9 -> v10
* Included RB/TB tags from Conor
* Fixed review comments pointed by Geert to rename cache callbacks
* Dropped preserving the cache lines in ax45mp_dma_cache_inv() callback

v8 -> v9
* Dropped adding ALTERNATIVE_3
* Implemented function pointer support for nonstandard noncoherent systems
* Added a new config option CONFIG_RISCV_NONSTANDARD_CACHE_OPS
* Updated Andes errata code to drop patching the calls as we no more use
  ALTERNATIVE_X() macro.
* Updated Andes CMO code to use function pointer for doing cache management.

v7 -> v8
* Dropped using function pointers and switched to ALTERNATIVE_X()
* Added new patches (#1, #2)

v6 -> v7
* Reworked the code based on Arnd's work
* Fixed review comments pointed by Arnd
* Fixed review comments pointed by Conor

v5.1 -> v6
* Dropped use of ALTERNATIVE_x() macro
* Now switched to used function pointers for CMO
* Moved driver to drivers/cache folder

v5 -> v5.1
* https://patchwork.kernel.org/project/linux-riscv/list/?series=708610&state=%2A&archive=both

v4 -> v5
* Rebased ALTERNATIVE_3() macro on top of Andrew's patches
* Rebased the changes on top of Heiko's alternative call patches
* Dropped configuring the PMA from Linux
* Dropped configuring the L2 cache from Linux and dropped the binding for same
* Now using runtime patching mechanism instead of compile time config

RFC v3 -> v4
* Implemented ALTERNATIVE_3() macro
* Now using runtime patching mechanism instead of compile time config
* Added Andes CMO as and errata
* Fixed comments pointed by Geert

RFC v2-> RFC v3
* Fixed review comments pointed by Conor
* Move DT binding into cache folder
* Fixed DT binding check issue
* Added andestech,ax45mp-cache.h header file
* Now passing the flags for the PMA setup as part of andestech,pma-regions
  property.
* Added andestech,inst/data-prefetch and andestech,tag/data-ram-ctl
  properties to configure the L2 cache.
* Registered the cache driver as platform driver

RFC v1-> RFC v2
* Moved out the code from arc/riscv to drivers/soc/renesas
* Now handling the PMA setup as part of the L2 cache
* Now making use of dma-noncoherent.c instead SoC specific implementation.
* Dropped arch_dma_alloc() and arch_dma_free()
* Switched to RISCV_DMA_NONCOHERENT
* Included DT binding doc

RFC v2: https://patchwork.kernel.org/project/linux-renesas-soc/cover/20221003223222.448551-1-prabhakar.mahadev-lad.rj@bp.renesas.com/
RFC v1: https://patchwork.kernel.org/project/linux-renesas-soc/cover/20220906102154.32526-1-prabhakar.mahadev-lad.rj@bp.renesas.com/

Cheers,
Prabhakar

Lad Prabhakar (6):
  riscv: asm: vendorid_list: Add Andes Technology to the vendors list
  riscv: errata: Add Andes alternative ports
  riscv: mm: dma-noncoherent: nonstandard cache operations support
  dt-bindings: cache: andestech,ax45mp-cache: Add DT binding
    documentation for L2 cache controller
  cache: Add L2 cache management for Andes AX45MP RISC-V core
  soc: renesas: Kconfig: Select the required configs for RZ/Five SoC

 .../cache/andestech,ax45mp-cache.yaml         |  81 +++++++
 MAINTAINERS                                   |   7 +
 arch/riscv/Kconfig                            |   7 +
 arch/riscv/Kconfig.errata                     |  21 ++
 arch/riscv/errata/Makefile                    |   1 +
 arch/riscv/errata/andes/Makefile              |   1 +
 arch/riscv/errata/andes/errata.c              |  66 ++++++
 arch/riscv/include/asm/alternative.h          |   3 +
 arch/riscv/include/asm/dma-noncoherent.h      |  28 +++
 arch/riscv/include/asm/errata_list.h          |   5 +
 arch/riscv/include/asm/vendorid_list.h        |   1 +
 arch/riscv/kernel/alternative.c               |   5 +
 arch/riscv/mm/dma-noncoherent.c               |  43 ++++
 arch/riscv/mm/pmem.c                          |  13 ++
 drivers/Kconfig                               |   2 +
 drivers/Makefile                              |   1 +
 drivers/cache/Kconfig                         |  11 +
 drivers/cache/Makefile                        |   3 +
 drivers/cache/ax45mp_cache.c                  | 213 ++++++++++++++++++
 drivers/soc/renesas/Kconfig                   |   4 +
 20 files changed, 516 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/cache/andestech,ax45mp-cache.yaml
 create mode 100644 arch/riscv/errata/andes/Makefile
 create mode 100644 arch/riscv/errata/andes/errata.c
 create mode 100644 arch/riscv/include/asm/dma-noncoherent.h
 create mode 100644 drivers/cache/Kconfig
 create mode 100644 drivers/cache/Makefile
 create mode 100644 drivers/cache/ax45mp_cache.c

Comments

patchwork-bot+linux-riscv@kernel.org Aug. 30, 2023, 8:30 p.m. UTC | #1
Hello:

This series was applied to riscv/linux.git (for-next)
by Palmer Dabbelt <palmer@rivosinc.com>:

On Fri, 18 Aug 2023 14:57:17 +0100 you wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Hi All,
> 
> non-coherent DMA support for AX45MP
> ====================================
> 
> [...]

Here is the summary with links:
  - [v12,1/6] riscv: asm: vendorid_list: Add Andes Technology to the vendors list
    https://git.kernel.org/riscv/c/93e0e2419b65
  - [v12,2/6] riscv: errata: Add Andes alternative ports
    https://git.kernel.org/riscv/c/f2863f30d1b0
  - [v12,3/6] riscv: mm: dma-noncoherent: nonstandard cache operations support
    https://git.kernel.org/riscv/c/30bc090f40f8
  - [v12,4/6] dt-bindings: cache: andestech,ax45mp-cache: Add DT binding documentation for L2 cache controller
    https://git.kernel.org/riscv/c/555dd72bc06e
  - [v12,5/6] cache: Add L2 cache management for Andes AX45MP RISC-V core
    https://git.kernel.org/riscv/c/f508b0175578
  - [v12,6/6] soc: renesas: Kconfig: Select the required configs for RZ/Five SoC
    https://git.kernel.org/riscv/c/ed1a8872ff83

You are awesome, thank you!