From: Prabhakar <prabhakar.csengg@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>, Christoph Hellwig <hch@lst.de>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Conor Dooley <conor.dooley@microchip.com>,
Anup Patel <apatel@ventanamicro.com>,
Andrew Jones <ajones@ventanamicro.com>,
Jisheng Zhang <jszhang@kernel.org>,
linux-kernel@vger.kernel.org
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
Samuel Holland <samuel@sholland.org>,
linux-riscv@lists.infradead.org,
linux-renesas-soc@vger.kernel.org,
Prabhakar <prabhakar.csengg@gmail.com>,
Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: [PATCH v3 3/3] riscv: dma-mapping: switch over to generic implementation
Date: Thu, 17 Aug 2023 00:23:36 +0100 [thread overview]
Message-ID: <20230816232336.164413-4-prabhakar.mahadev-lad.rj@bp.renesas.com> (raw)
In-Reply-To: <20230816232336.164413-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Add helper functions for cache wback/inval/clean and use them
arch_sync_dma_for_device()/arch_sync_dma_for_cpu() functions. The proposed
changes are in preparation for switching over to generic implementation.
Reorganization of the code is based on the patch (Link[0]) from Arnd.
For now I have dropped CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU check as this
will be enabled by default upon selection of RISCV_DMA_NONCOHERENT
and also dropped arch_dma_mark_dcache_clean().
Link[0]: https://lore.kernel.org/all/20230327121317.4081816-22-arnd@kernel.org/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
Hi Arnd,
I have kept the changes minimal here as compared to your original patch and
dropped arch_dma_mark_dcache_clean() function and config checks for now as we
are currently implementing for riscv only.
Cheers, Prabhakar
v3:
* New patch
---
arch/riscv/mm/dma-noncoherent.c | 60 ++++++++++++++++++++++++++++-----
1 file changed, 51 insertions(+), 9 deletions(-)
diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
index fc6377a64c8d..06b8fea58e20 100644
--- a/arch/riscv/mm/dma-noncoherent.c
+++ b/arch/riscv/mm/dma-noncoherent.c
@@ -12,21 +12,61 @@
static bool noncoherent_supported __ro_after_init;
-void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
- enum dma_data_direction dir)
+static inline void arch_dma_cache_wback(phys_addr_t paddr, size_t size)
+{
+ void *vaddr = phys_to_virt(paddr);
+
+ ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size);
+}
+
+static inline void arch_dma_cache_inv(phys_addr_t paddr, size_t size)
+{
+ void *vaddr = phys_to_virt(paddr);
+
+ ALT_CMO_OP(inval, vaddr, size, riscv_cbom_block_size);
+}
+
+static inline void arch_dma_cache_wback_inv(phys_addr_t paddr, size_t size)
{
void *vaddr = phys_to_virt(paddr);
+ ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size);
+}
+
+static inline bool arch_sync_dma_clean_before_fromdevice(void)
+{
+ return true;
+}
+
+static inline bool arch_sync_dma_cpu_needs_post_dma_flush(void)
+{
+ return true;
+}
+
+void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
+ enum dma_data_direction dir)
+{
switch (dir) {
case DMA_TO_DEVICE:
- ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size);
+ arch_dma_cache_wback(paddr, size);
break;
+
case DMA_FROM_DEVICE:
- ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size);
- break;
+ if (!arch_sync_dma_clean_before_fromdevice()) {
+ arch_dma_cache_inv(paddr, size);
+ break;
+ }
+ fallthrough;
+
case DMA_BIDIRECTIONAL:
- ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size);
+ /* Skip the invalidate here if it's done later */
+ if (IS_ENABLED(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) &&
+ arch_sync_dma_cpu_needs_post_dma_flush())
+ arch_dma_cache_wback(paddr, size);
+ else
+ arch_dma_cache_wback_inv(paddr, size);
break;
+
default:
break;
}
@@ -35,15 +75,17 @@ void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
- void *vaddr = phys_to_virt(paddr);
-
switch (dir) {
case DMA_TO_DEVICE:
break;
+
case DMA_FROM_DEVICE:
case DMA_BIDIRECTIONAL:
- ALT_CMO_OP(inval, vaddr, size, riscv_cbom_block_size);
+ /* FROM_DEVICE invalidate needed if speculative CPU prefetch only */
+ if (arch_sync_dma_cpu_needs_post_dma_flush())
+ arch_dma_cache_inv(paddr, size);
break;
+
default:
break;
}
--
2.34.1
next prev parent reply other threads:[~2023-08-16 23:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-16 23:23 [PATCH v3 0/3] riscv: dma-mapping: unify support for cache flushes Prabhakar
2023-08-16 23:23 ` [PATCH v3 1/3] riscv: dma-mapping: only invalidate after DMA, not flush Prabhakar
2023-08-16 23:23 ` [PATCH v3 2/3] riscv: dma-mapping: skip invalidation before bidirectional DMA Prabhakar
2023-08-27 10:22 ` Jisheng Zhang
2023-08-27 19:41 ` Arnd Bergmann
2023-08-16 23:23 ` Prabhakar [this message]
2023-08-30 20:30 ` [PATCH v3 0/3] riscv: dma-mapping: unify support for cache flushes patchwork-bot+linux-riscv
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