From: Christoph Hellwig <hch@lst.de>
To: Ralf Baechle <ralf@linux-mips.org>,
Paul Burton <paul.burton@mips.com>,
James Hogan <jhogan@kernel.org>, Ley Foon Tan <lftan@altera.com>,
Michal Simek <monstr@monstr.eu>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-mips@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org
Subject: [PATCH 4/7] dma-direct: provide generic support for uncached kernel segments
Date: Tue, 30 Apr 2019 07:00:29 -0400 [thread overview]
Message-ID: <20190430110032.25301-5-hch@lst.de> (raw)
In-Reply-To: <20190430110032.25301-1-hch@lst.de>
A few architectures support uncached kernel segments. In that case we get
an uncached mapping for a given physica address by using an offset in the
uncached segement. Implement support for this scheme in the generic
dma-direct code instead of duplicating it in arch hooks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/Kconfig | 8 ++++++++
include/linux/dma-noncoherent.h | 3 +++
kernel/dma/direct.c | 18 ++++++++++++++++--
3 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 33687dddd86a..ea22a8c894ec 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -249,6 +249,14 @@ config ARCH_HAS_FORTIFY_SOURCE
config ARCH_HAS_SET_MEMORY
bool
+#
+# Select if arch has an uncached kernel segment and provides the
+# uncached_kernel_address / cached_kernel_address symbols to use it
+#
+config ARCH_HAS_UNCACHED_SEGMENT
+ select ARCH_HAS_DMA_PREP_COHERENT
+ bool
+
# Select if arch init_task must go in the __init_task_data section
config ARCH_TASK_STRUCT_ON_STACK
bool
diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h
index 9741767e400f..7e0126a04e02 100644
--- a/include/linux/dma-noncoherent.h
+++ b/include/linux/dma-noncoherent.h
@@ -80,4 +80,7 @@ static inline void arch_dma_prep_coherent(struct page *page, size_t size)
}
#endif /* CONFIG_ARCH_HAS_DMA_PREP_COHERENT */
+void *uncached_kernel_address(void *addr);
+void *cached_kernel_address(void *addr);
+
#endif /* _LINUX_DMA_NONCOHERENT_H */
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 2c2772e9702a..d15a535c3e67 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -164,6 +164,13 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
}
ret = page_address(page);
+
+ if (IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
+ !dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_NON_CONSISTENT)) {
+ arch_dma_prep_coherent(page, size);
+ ret = uncached_kernel_address(ret);
+ }
+
if (force_dma_unencrypted()) {
set_memory_decrypted((unsigned long)ret, 1 << get_order(size));
*dma_handle = __phys_to_dma(dev, page_to_phys(page));
@@ -171,6 +178,7 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
*dma_handle = phys_to_dma(dev, page_to_phys(page));
}
memset(ret, 0, size);
+
return ret;
}
@@ -189,13 +197,18 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
if (force_dma_unencrypted())
set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
+
+ if (IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
+ !dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_NON_CONSISTENT))
+ cpu_addr = cached_kernel_address(cpu_addr);
__dma_direct_free_pages(dev, size, virt_to_page(cpu_addr));
}
void *dma_direct_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
- if (!dev_is_dma_coherent(dev))
+ if (!IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
+ !dev_is_dma_coherent(dev))
return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
return dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
}
@@ -203,7 +216,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
void dma_direct_free(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
{
- if (!dev_is_dma_coherent(dev))
+ if (!IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
+ !dev_is_dma_coherent(dev))
arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
else
dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs);
--
2.20.1
next prev parent reply other threads:[~2019-04-30 11:01 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-30 11:00 provide generic support for uncached segements in dma-direct Christoph Hellwig
2019-04-30 11:00 ` [PATCH 1/7] MIPS: remove the _dma_cache_wback_inv export Christoph Hellwig
2019-04-30 11:00 ` [PATCH 2/7] au1100fb: fix DMA API abuse Christoph Hellwig
2019-05-06 13:49 ` Bartlomiej Zolnierkiewicz
2019-05-07 6:36 ` Christoph Hellwig
2019-06-03 6:49 ` Christoph Hellwig
2019-04-30 11:00 ` [PATCH 3/7] dma-mapping: add a Kconfig symbol to indicate arch_dma_prep_coherent presence Christoph Hellwig
2019-04-30 11:00 ` Christoph Hellwig [this message]
2019-05-01 17:18 ` [PATCH 4/7] dma-direct: provide generic support for uncached kernel segments Paul Burton
2019-05-01 17:29 ` Christoph Hellwig
2019-05-01 17:40 ` Paul Burton
2019-05-01 17:49 ` Christoph Hellwig
2019-05-02 0:08 ` Paul Burton
2019-05-02 13:11 ` Christoph Hellwig
2019-04-30 11:00 ` [PATCH 5/7] MIPS: use the generic uncached segment support in dma-direct Christoph Hellwig
2019-04-30 20:10 ` Paul Burton
2019-04-30 20:29 ` Christoph Hellwig
2019-04-30 21:11 ` Paul Burton
2019-04-30 21:15 ` Christoph Hellwig
2019-05-01 13:13 ` [PATCH 5/7 v2] " Christoph Hellwig
2019-05-01 17:13 ` Paul Burton
2019-06-03 6:48 ` Christoph Hellwig
2019-07-03 8:54 ` Arnd Bergmann
2019-07-03 12:13 ` Christoph Hellwig
2019-04-30 11:00 ` [PATCH 6/7] nios2: " Christoph Hellwig
2019-04-30 11:00 ` [PATCH 7/7] microblaze: " Christoph Hellwig
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