From: santosh.shilimkar@ti•com (Santosh Shilimkar)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 0/7] of: setup dma parameters using dma-ranges and dma-coherent
Date: Mon, 21 Apr 2014 11:13:37 -0400 [thread overview]
Message-ID: <535535A1.4020501@ti.com> (raw)
In-Reply-To: <CAL_JsqLogKfqHyw4zYBkPrYh=f6tVibtmX25oYB1Q2hO11Whcw@mail.gmail.com>
Hi Rob,
On Monday 21 April 2014 10:37 AM, Rob Herring wrote:
> On Sat, Apr 19, 2014 at 9:32 AM, Santosh Shilimkar
> <santosh.shilimkar@ti•com> wrote:
>> Here is an updated version of [2] based on discussion. Series introduces
>> support for setting up dma parameters based on device tree properties
>> like 'dma-ranges' and 'dma-coherent' and also update to ARM 32 bit port.
>> Earlier version of the same series is here [1].
>>
>> The 'dma-ranges' helps to take care of few DMAable system memory restrictions
>> by use of dma_pfn_offset which we maintain now per device. Arch code then
>> uses it for dma address translations for such cases. We update the
>> dma_pfn_offset accordingly during DT the device creation process.The
>> 'dma-coherent' property is used to setup arch's coherent dma_ops.
>>
>> After some off-list discussion with RMK and Arnd, I have now dropped the
>> controversial dma_mask setup code from the series which actually isn't blocking
>> me as such. Considering rest of the parts of the series are already aligned,
>> am hoping to get this version merged for 3.16 merge window.
>
> Can you briefly describe what the h/w looks like in terms of addresses
> for the problem you are trying to solve? Something like: Cpu view of
> RAM is X to Y address, X corresponds to DMA address Z. Max DMA address
> is ?
>
Let me try with say 8 GB RAM example
CPU view of memory : 0x0000 0008 0000 0000 to 0x0000 000a 0000 0000
>From above memory range, first 2 GB of memory has an alias 32 bit
view in the hardware. Hardware internally map the address issued within
that first 2 GB to same memory.
DMA view of first 2 GB [ 0x0000 0008 0000 0000 to 0x0000 0008 7fff ffff]
is : 0x8000 0000 to 0xffff fffff.
Regards,
Santosh
next prev parent reply other threads:[~2014-04-21 15:13 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
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 [this message]
2014-04-21 15:35 ` Rob Herring
2014-04-21 15:36 ` Santosh Shilimkar
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