From: m.szyprowski@samsung•com (Marek Szyprowski)
To: linux-arm-kernel@lists•infradead.org
Subject: [Linaro-mm-sig] [PATCH 2/2] drivers: dma-contiguous: add initialization from device tree
Date: Fri, 15 Mar 2013 16:21:47 +0100 [thread overview]
Message-ID: <51433C8B.20607@samsung.com> (raw)
In-Reply-To: <511D586A.5060902@codeaurora.org>
Hello,
On 2/14/2013 10:34 PM, Laura Abbott wrote:
>
> On 2/14/2013 4:45 AM, Marek Szyprowski wrote:
> <snip>
>> +name: an name given to the defined region.
>> +base-address: the base address of the defined region.
>> +size: the size of the memory region.
>> +linux,contiguous-region: property indicating that the defined memory
>> + region is used for contiguous memory allocations,
>> + Linux specific (optional)
>> +linux,default-contiguous-region: property indicating that the region
>> + is the default region for all contiguous memory
>> + allocations, Linux specific (optional)
>> +
>> +
>
> I don't see any code actually implementing the
> default-contiguous-region binding. Currently on ARM systems we will
> still setup the default region based on the Kconfig. Is this intentional?
Nope, this was my fault. I've missed the fixup which added support for
default-contiguous-region (it was just a few lines more to cma_fdt_scan()
function).
>> diff --git a/drivers/base/dma-contiguous.c
>> b/drivers/base/dma-contiguous.c
>> index 085389c..5761f73 100644
>> --- a/drivers/base/dma-contiguous.c
>> +++ b/drivers/base/dma-contiguous.c
>> @@ -24,6 +24,9 @@
>>
>> #include <linux/memblock.h>
>> #include <linux/err.h>
>> +#include <linux/of.h>
>> +#include <linux/of_fdt.h>
>> +#include <linux/of_platform.h>
>> #include <linux/mm.h>
>> #include <linux/mutex.h>
>> #include <linux/page-isolation.h>
>> @@ -177,6 +180,35 @@ no_mem:
>> return ERR_PTR(ret);
>> }
>>
>> +/*****************************************************************************/
>>
>> +
>> +#ifdef CONFIG_OF
>> +int __init cma_fdt_scan(unsigned long node, const char *uname,
>> + int depth, void *data)
>> +{
>> + phys_addr_t base, size;
>> + unsigned long len;
>> + __be32 *prop;
>> +
>> + if (strncmp(uname, "region@", 7) != 0 || depth != 2 ||
>> + !of_get_flat_dt_prop(node, "contiguous-region", NULL))
>
> The documentation says "linux,contiguous-region"
>
Right, lack of another fixup. It looks that I posted an incomplete
version, I'm sorry.
I hurried that time (it was my last day in the office before going for
holidays).
>
>> +#ifdef CONFIG_OF
>> +static void cma_assign_device_from_dt(struct device *dev)
>> +{
>> + struct device_node *node;
>> + struct cma *cma;
>> + u32 value;
>> +
>> + node = of_parse_phandle(dev->of_node, "linux,contiguous-region",
>> 0);
>> + if (!node)
>> + return;
>> + if (of_property_read_u32(node, "reg", &value) && !value)
>> + return;
>> + cma = cma_get_area(value);
>> + if (!cma)
>> + return;
>> +
>> + dev_set_cma_area(dev, cma);
>> + pr_info("Assigned CMA region at %lx to %s device\n", (unsigned
>> long)value, dev_name(dev));
>> +}
>> +
>
> This scheme of associating devices with CMA regions by base does not
> work if you want to let CMA figure out where to place the region (base
> = 0). Can we use the name to associate the device with the region? I
> had been working on something similar internally and that was the only
> solution I had come up with to associate arbitrary CMA nodes with devices.
Right, support for base = 0 requires different handling, but I thought
that if
we use the device tree approach, the designer already knows the complete
memory
configuration, so providing the correct base address is not that hard.
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
next prev parent reply other threads:[~2013-03-15 15:21 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-14 12:45 [PATCH 0/2] Device Tree support for CMA (Contiguous Memory Allocator) Marek Szyprowski
2013-02-14 12:45 ` [PATCH 1/2] drivers: dma-contiguous: clean source code and prepare for device tree Marek Szyprowski
2013-02-14 21:37 ` Laura Abbott
2013-02-14 12:45 ` [PATCH 2/2] drivers: dma-contiguous: add initialization from " Marek Szyprowski
2013-02-14 21:34 ` [Linaro-mm-sig] " Laura Abbott
2013-02-15 16:12 ` Nishanth Peethambaran
2013-03-15 15:21 ` Marek Szyprowski [this message]
2013-03-19 17:54 ` Laura Abbott
2013-02-14 21:30 ` [PATCH 0/2] Device Tree support for CMA (Contiguous Memory Allocator) Sascha Hauer
2013-02-14 22:08 ` Sylwester Nawrocki
2013-02-15 8:33 ` Sascha Hauer
2013-02-15 16:24 ` Rob Herring
2013-02-17 5:18 ` [Linaro-mm-sig] " Nishanth Peethambaran
2013-02-18 21:58 ` Rob Herring
2013-02-19 9:29 ` Nishanth Peethambaran
2013-02-18 22:25 ` Sylwester Nawrocki
2013-02-19 5:03 ` Olof Johansson
2013-03-15 15:05 ` Marek Szyprowski
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