From: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org,
"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>
Subject: Re: [RFC PATCH] Avoid aliasing mappings in DMA coherent allocator
Date: Sun, 9 Jan 2011 02:06:32 +0100 [thread overview]
Message-ID: <201101090206.34096.jkrzyszt@tis.icnet.pl> (raw)
In-Reply-To: <201101031928.37091.jkrzyszt@tis.icnet.pl>
(Cc linux-omap, please refere to a copy of Russell's initial message:
http://lists.infradead.org/pipermail/linux-arm-kernel/2010-December/036463.html)
Monday 03 January 2011 19:28:36 Janusz Krzysztofik wrote:
> I'll try to prepare for review a followup patch that updates those
> <{mach,plat}/memory.h> and similiar include files which provided
> their own non-default CONSISTENT_DMA_SIZE values.
Below is an example of how a build time configuration for OMAP could
be updated.
However, more looking at this, I think that a finer control of reserved
memory area sizes, yet better selected at run time for a specific
machine or board type, could be benefitial in case of kernels intended
to run on multiple board types, like those built with omap1_defconfig,
or even on multiple machine types, like in omap2plus_defconfig case.
Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
---
--- linux-2.6.37-rc7/arch/arm/plat-omap/include/plat/memory.h.orig 2011-01-07 02:37:44.000000000 +0100
+++ linux-2.6.37-rc7/arch/arm/plat-omap/include/plat/memory.h 2011-01-07 03:01:25.000000000 +0100
@@ -86,17 +86,21 @@
#endif /* CONFIG_ARCH_OMAP15XX */
/* Override the ARM default */
-#ifdef CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE
+#ifndef CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE
+#define CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE 0
+#endif
-#if (CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE == 0)
+#if (CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE == 0) && \
+ (defined(CONFIG_SND_OMAP_SOC) || defined(CONFIG_SND_OMAP_SOC_MODULE))
#undef CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE
-#define CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE 2
+#define CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE 1
#endif
-#define CONSISTENT_DMA_SIZE \
- (((CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE + 1) & ~1) * 1024 * 1024)
+#define CONSISTENT_WC_SIZE \
+ (CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE * 1024 * 1024)
-#endif
+#define CONSISTENT_DMA_SIZE \
+ ((CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE % 2 ? 1 : 2) * 1024 * 1024)
#endif
--- linux-2.6.37-rc7/drivers/video/omap/Kconfig.orig 2010-12-24 13:42:46.000000000 +0100
+++ linux-2.6.37-rc7/drivers/video/omap/Kconfig 2011-01-07 01:56:45.000000000 +0100
@@ -85,9 +85,10 @@ config FB_OMAP_CONSISTENT_DMA_SIZE
range 1 14
default 2
help
- Increase the DMA consistent memory size according to your video
+ Increase the DMA writecombine memory size according to your video
memory needs, for example if you want to use multiple planes.
- The size must be 2MB aligned.
+ Note that 256kB can be consumed by OMAP sound driver if active.
+ Specifying an odd number reduces DMA coherent memory from 2 to 1MB.
If unsure say 1.
config FB_OMAP_DMA_TUNE
WARNING: multiple messages have this Message-ID (diff)
From: jkrzyszt@tis.icnet.pl (Janusz Krzysztofik)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH] Avoid aliasing mappings in DMA coherent allocator
Date: Sun, 9 Jan 2011 02:06:32 +0100 [thread overview]
Message-ID: <201101090206.34096.jkrzyszt@tis.icnet.pl> (raw)
In-Reply-To: <201101031928.37091.jkrzyszt@tis.icnet.pl>
(Cc linux-omap, please refere to a copy of Russell's initial message:
http://lists.infradead.org/pipermail/linux-arm-kernel/2010-December/036463.html)
Monday 03 January 2011 19:28:36 Janusz Krzysztofik wrote:
> I'll try to prepare for review a followup patch that updates those
> <{mach,plat}/memory.h> and similiar include files which provided
> their own non-default CONSISTENT_DMA_SIZE values.
Below is an example of how a build time configuration for OMAP could
be updated.
However, more looking at this, I think that a finer control of reserved
memory area sizes, yet better selected at run time for a specific
machine or board type, could be benefitial in case of kernels intended
to run on multiple board types, like those built with omap1_defconfig,
or even on multiple machine types, like in omap2plus_defconfig case.
Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
---
--- linux-2.6.37-rc7/arch/arm/plat-omap/include/plat/memory.h.orig 2011-01-07 02:37:44.000000000 +0100
+++ linux-2.6.37-rc7/arch/arm/plat-omap/include/plat/memory.h 2011-01-07 03:01:25.000000000 +0100
@@ -86,17 +86,21 @@
#endif /* CONFIG_ARCH_OMAP15XX */
/* Override the ARM default */
-#ifdef CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE
+#ifndef CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE
+#define CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE 0
+#endif
-#if (CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE == 0)
+#if (CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE == 0) && \
+ (defined(CONFIG_SND_OMAP_SOC) || defined(CONFIG_SND_OMAP_SOC_MODULE))
#undef CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE
-#define CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE 2
+#define CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE 1
#endif
-#define CONSISTENT_DMA_SIZE \
- (((CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE + 1) & ~1) * 1024 * 1024)
+#define CONSISTENT_WC_SIZE \
+ (CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE * 1024 * 1024)
-#endif
+#define CONSISTENT_DMA_SIZE \
+ ((CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE % 2 ? 1 : 2) * 1024 * 1024)
#endif
--- linux-2.6.37-rc7/drivers/video/omap/Kconfig.orig 2010-12-24 13:42:46.000000000 +0100
+++ linux-2.6.37-rc7/drivers/video/omap/Kconfig 2011-01-07 01:56:45.000000000 +0100
@@ -85,9 +85,10 @@ config FB_OMAP_CONSISTENT_DMA_SIZE
range 1 14
default 2
help
- Increase the DMA consistent memory size according to your video
+ Increase the DMA writecombine memory size according to your video
memory needs, for example if you want to use multiple planes.
- The size must be 2MB aligned.
+ Note that 256kB can be consumed by OMAP sound driver if active.
+ Specifying an odd number reduces DMA coherent memory from 2 to 1MB.
If unsure say 1.
config FB_OMAP_DMA_TUNE
next prev parent reply other threads:[~2011-01-09 1:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-24 11:11 [PATCH] Replace page_to_dma()/dma_to_page() with pfn_to_dma()/dma_to_pfn() Russell King - ARM Linux
2010-12-24 11:24 ` [RFC PATCH] Avoid aliasing mappings in DMA coherent allocator Russell King - ARM Linux
2010-12-28 21:29 ` Janusz Krzysztofik
2011-01-03 9:57 ` Russell King - ARM Linux
2011-01-03 18:28 ` Janusz Krzysztofik
2011-01-09 1:06 ` Janusz Krzysztofik [this message]
2011-01-09 1:06 ` Janusz Krzysztofik
2012-06-29 11:38 ` Hiroshi Doyu
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