From: grygorii.strashko@ti•com (Grygorii Strashko)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 4/7] of: configure the platform device dma parameters
Date: Tue, 22 Apr 2014 18:44:12 +0300 [thread overview]
Message-ID: <53568E4C.3050305@ti.com> (raw)
In-Reply-To: <CAL_JsqKe_L00P36UT7hizB=zAxCB0S_1kV3XEVGGbJOi27S84A@mail.gmail.com>
On 04/22/2014 05:44 PM, Rob Herring wrote:
> On Tue, Apr 22, 2014 at 10:09 AM, Grygorii Strashko
> <grygorii.strashko@ti•com> wrote:
>> Hi Rob,
>>
>> On 04/21/2014 05:58 PM, Rob Herring wrote:
>>> On Sat, Apr 19, 2014 at 9:32 AM, Santosh Shilimkar
>>> <santosh.shilimkar@ti•com> wrote:
>>>> Retrieve DMA configuration from DT and setup platform device's DMA
>>>> parameters. The DMA configuration in DT has to be specified using
>>>> "dma-ranges" and "dma-coherent" properties if supported.
>>>>
>>>> We setup dma_pfn_offset using "dma-ranges" and dma_coherent_ops
>>>> using "dma-coherent" device tree properties.
>>>>
>>>> The set_arch_dma_coherent_ops macro has to be defined by arch if
>>>> it supports coherent dma_ops. Otherwise, set_arch_dma_coherent_ops() is
>>>> declared as nop.
>
> [...]
>
>>>>
>>>> + ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
>>>> + if (ret < 0) {
>>>
>>> Perhaps an error is not the right return for the default case. The
>>> default should probably be dma_addr and paddr equal to 0 and size 4GB.
>>
>> The error code is needed here to properly distinguish the case when
>> there are no "dma-ranges" defined in DT. Also, I think, that
>> of_dma_get_range() shouldn't return any default values - It just
>> has to get data from DT. And the caller should decide what to do
>> with this data and how to handle error cases.
>>
>> So, I prefer to keep behavior as is:
>> - in case of failure of_dma_get_range() will not touch values of
>> &dma_addr, &paddr, &size.
>
> Fine, but that is not how of_dma_get_range currently behaves:
Yep. That's will be fixed as you've commented :)
>
> + *dma_addr = of_read_number(ranges, naddr);
> + *paddr = of_translate_dma_address(np, ranges);
> + if (*paddr == OF_BAD_ADDR) {
> + pr_err("%s: translation of DMA address(%pad) to CPU
> address failed node(%s)\n",
> + __func__, dma_addr, np->full_name);
> + ret = -EINVAL;
> + }
>
> Rob
>
Regards
Grygorii
next prev parent reply other threads:[~2014-04-22 15:44 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 [this message]
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
2014-04-21 15:35 ` Rob Herring
2014-04-21 15:36 ` Santosh Shilimkar
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