lkml.org 
[lkml]   [2022]   [Oct]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH v3 2/2] soc: renesas: Add L2 cache management for RZ/Five SoC
On Wed, Oct 19, 2022 at 11:02:42PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> On the AX45MP core, cache coherency is a specification option so it may
> not be supported. In this case DMA will fail. As a workaround, firstly we
> allocate a global dma coherent pool from which DMA allocations are taken
> and marked as non-cacheable + bufferable using the PMA region as specified
> in the device tree. Synchronization callbacks are implemented to
> synchronize when doing DMA transactions.
>
> 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
>
> This patch adds support to configure the memory attributes of the memory
> regions as passed from the l2 cache node and exposes the cache management
> ops.
>
> More info about PMA (section 10.3):
> http://www.andestech.com/wp-content/uploads/AX45MP-1C-Rev.-5.0.0-Datasheet.pdf
>
> This feature is based on the work posted [0] by Vincent Chen
> <vincentc@andestech.com> for the Andes AndeStart RISC-V CPU.
>
> [0] https://lore.kernel.org/lkml/1540982130-28248-1-git-send-email-vincentc@andestech.com/
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
> arch/riscv/include/asm/cacheflush.h | 8 +
> arch/riscv/include/asm/errata_list.h | 2 +
> arch/riscv/mm/dma-noncoherent.c | 20 ++
> drivers/soc/renesas/Kconfig | 5 +
> drivers/soc/renesas/Makefile | 4 +
> drivers/soc/renesas/rzf/Kconfig | 6 +
> drivers/soc/renesas/rzf/Makefile | 3 +
> drivers/soc/renesas/rzf/ax45mp_cache.c | 431 +++++++++++++++++++++++++

How many cache drivers do we have around now? I've seen a few bindings
go by. I'm guessing it is time to stop putting the drivers in the
drivers/soc/ dumping ground.

> drivers/soc/renesas/rzf/ax45mp_sbi.h | 29 ++
> 9 files changed, 508 insertions(+)
> create mode 100644 drivers/soc/renesas/rzf/Kconfig
> create mode 100644 drivers/soc/renesas/rzf/Makefile
> create mode 100644 drivers/soc/renesas/rzf/ax45mp_cache.c
> create mode 100644 drivers/soc/renesas/rzf/ax45mp_sbi.h
>
> diff --git a/arch/riscv/include/asm/cacheflush.h b/arch/riscv/include/asm/cacheflush.h
> index 8a5c246b0a21..40aa790be9a3 100644
> --- a/arch/riscv/include/asm/cacheflush.h
> +++ b/arch/riscv/include/asm/cacheflush.h
> @@ -65,6 +65,14 @@ static inline void riscv_noncoherent_supported(void) {}
> #define SYS_RISCV_FLUSH_ICACHE_LOCAL 1UL
> #define SYS_RISCV_FLUSH_ICACHE_ALL (SYS_RISCV_FLUSH_ICACHE_LOCAL)
>
> +#ifdef CONFIG_AX45MP_L2_CACHE
> +void ax45mp_cpu_dma_inval_range(void *vaddr, size_t end);
> +void ax45mp_cpu_dma_wb_range(void *vaddr, size_t end);
> +
> +#define ALT_CMO_OP(_op, _start, _size, _cachesize) \
> + _op(_start, _size)
> +#endif
> +
> #include <asm-generic/cacheflush.h>
>
> #endif /* _ASM_RISCV_CACHEFLUSH_H */
> diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h
> index 19a771085781..d9cbf60c3b65 100644
> --- a/arch/riscv/include/asm/errata_list.h
> +++ b/arch/riscv/include/asm/errata_list.h
> @@ -89,6 +89,7 @@ asm volatile(ALTERNATIVE( \
> #define ALT_THEAD_PMA(_val)
> #endif
>
> +#ifdef CONFIG_ERRATA_THEAD_CMO
> /*
> * dcache.ipa rs1 (invalidate, physical address)
> * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
> @@ -143,5 +144,6 @@ asm volatile(ALTERNATIVE_2( \
> : "a0")
>
> #endif /* __ASSEMBLY__ */
> +#endif
>
> #endif
> diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
> index b0add983530a..5270acca6766 100644
> --- a/arch/riscv/mm/dma-noncoherent.c
> +++ b/arch/riscv/mm/dma-noncoherent.c
> @@ -24,13 +24,25 @@ void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
>
> switch (dir) {
> case DMA_TO_DEVICE:
> +#ifdef CONFIG_ERRATA_THEAD_CMO
> ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size);
> +#elif CONFIG_AX45MP_L2_CACHE
> + ALT_CMO_OP(ax45mp_cpu_dma_wb_range, vaddr, size, 0x0);
> +#endif

How do you support more than one platform in a build?

Rob

\
 
 \ /
  Last update: 2022-10-21 04:06    [W:0.156 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site