From: santosh.shilimkar@ti•com (Santosh Shilimkar)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 5/7] ARM: dma: Use dma_pfn_offset for dma address translation
Date: Mon, 21 Apr 2014 09:38:01 -0400 [thread overview]
Message-ID: <53551F39.90908@ti.com> (raw)
In-Reply-To: <20140419194334.GL24070@n2100.arm.linux.org.uk>
On Saturday 19 April 2014 03:43 PM, Russell King - ARM Linux wrote:
> On Sat, Apr 19, 2014 at 10:32:50AM -0400, Santosh Shilimkar wrote:
>> From: Grygorii Strashko <grygorii.strashko@ti•com>
>>
>> In most of cases DMA addresses can be performed using offset value of
>> Bus address space relatively to physical address space as following:
>>
>> PFN->DMA:
>> __pfn_to_phys(pfn + [-]dma_pfn_offset)
>>
>> DMA->PFN:
>> __phys_to_pfn(dma_addr) + [-]dma_pfn_offset
>>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation•org>
>> Cc: Russell King <linux@arm•linux.org.uk>
>> Cc: Arnd Bergmann <arnd@arndb•de>
>> Cc: Olof Johansson <olof@lixom•net>
>> Cc: Grant Likely <grant.likely@linaro•org>
>> Cc: Rob Herring <robh+dt@kernel•org>
>> Cc: Catalin Marinas <catalin.marinas@arm•com>
>> Cc: Linus Walleij <linus.walleij@linaro•org>
>> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti•com>
>> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti•com>
>> ---
>> arch/arm/include/asm/dma-mapping.h | 17 +++++++++++++----
>> 1 file changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
>> index e701a4d..8c12149 100644
>> --- a/arch/arm/include/asm/dma-mapping.h
>> +++ b/arch/arm/include/asm/dma-mapping.h
>> @@ -58,22 +58,31 @@ static inline int dma_set_mask(struct device *dev, u64 mask)
>> #ifndef __arch_pfn_to_dma
>> static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
>> {
>> - return (dma_addr_t)__pfn_to_bus(pfn);
>> + if (!dev)
>> + return DMA_ERROR_CODE;
>> + return (dma_addr_t)__pfn_to_bus(pfn - dev->dma_pfn_offset);
>
> How do ISA devices (iow, those which pass a NULL device) work with this?
> This looks to me like it ends up breaking some drivers.
>
> I've also seen some drivers (such as the Freescale FEC driver) which
> perform DMA coherent allocations with a NULL device - technically, that's
> a bug in the driver, but the above change will cause them to regress.
>
Good point. We can keep the NULL case working as well...
static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
{
if (!dev)
return (dma_addr_t)__pfn_to_bus(pfn);
else
return (dma_addr_t)__pfn_to_bus(pfn - dev->dma_pfn_offset);
}
I will update the patch accordingly.
Regards,
Santosh
next prev parent reply other threads:[~2014-04-21 13:38 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-19 14:32 [PATCH v2 0/7] of: setup dma parameters using dma-ranges and dma-coherent Santosh Shilimkar
2014-04-19 14:32 ` [PATCH v2 1/7] device: introduce per device dma_pfn_offset Santosh Shilimkar
2014-04-19 14:32 ` [PATCH v2 2/7] of: introduce of_dma_get_range() helper Santosh Shilimkar
2014-04-21 15:29 ` Rob Herring
2014-04-22 14:56 ` Grygorii Strashko
2014-04-22 4:09 ` Joel Fernandes
2014-04-19 14:32 ` [PATCH v2 3/7] of: introduce of_dma_is_coherent() helper Santosh Shilimkar
2014-04-19 14:32 ` [PATCH v2 4/7] of: configure the platform device dma parameters Santosh Shilimkar
2014-04-21 14:58 ` Rob Herring
2014-04-22 15:09 ` Grygorii Strashko
2014-04-22 14:44 ` Rob Herring
2014-04-22 15:44 ` Grygorii Strashko
2014-04-19 14:32 ` [PATCH v2 5/7] ARM: dma: Use dma_pfn_offset for dma address translation Santosh Shilimkar
2014-04-19 19:43 ` Russell King - ARM Linux
2014-04-21 13:38 ` Santosh Shilimkar [this message]
2014-04-19 14:32 ` [PATCH v2 6/7] ARM: dma: implement set_arch_dma_coherent_ops() Santosh Shilimkar
2014-04-19 14:32 ` [PATCH v2 7/7] ARM: mm: use phys_addr_t in __dma_page_[cpu_to_dev/dev_to_cpu] Santosh Shilimkar
2014-04-21 13:39 ` Santosh Shilimkar
2014-04-19 16:25 ` [PATCH v2 0/7] of: setup dma parameters using dma-ranges and dma-coherent Thomas Petazzoni
2014-04-21 13:35 ` Santosh Shilimkar
2014-04-21 18:19 ` Thomas Petazzoni
2014-04-21 19:17 ` Santosh Shilimkar
2014-04-22 14:54 ` Catalin Marinas
2014-04-22 15:02 ` Arnd Bergmann
2014-04-22 15:15 ` Santosh Shilimkar
2014-04-22 15:25 ` Catalin Marinas
2014-04-22 15:30 ` Rob Herring
2014-04-22 16:01 ` Catalin Marinas
2014-04-21 14:37 ` Rob Herring
2014-04-21 15:13 ` Santosh Shilimkar
2014-04-21 15:35 ` Rob Herring
2014-04-21 15:36 ` Santosh Shilimkar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=53551F39.90908@ti.com \
--to=santosh.shilimkar@ti$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox