linux-kernel - Re: [PATCH v3] of: reserved_mem: Restructure call site for dma_contiguous_early

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Message-ID: <4becbced-8e88-4588-9de6-06f98eae0736@oss.qualcomm.com>
Date: Mon, 4 Aug 2025 12:37:39 -0700
From: Oreoluwa Babatunde <oreoluwa.babatunde@....qualcomm.com>
To: Rob Herring <robh@...nel.org>
Cc: m.szyprowski@...sung.com, robin.murphy@....com, saravanak@...gle.com,
        quic_obabatun@...cinc.com, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, iommu@...ts.linux.dev,
        william.zhang@...adcom.com, kernel@....qualcomm.com, will@...nel.org,
        djakov@...nel.org
Subject: Re: [PATCH v3] of: reserved_mem: Restructure call site for
 dma_contiguous_early_fixup()



On 7/30/2025 3:41 PM, Rob Herring wrote:
> On Tue, Jul 29, 2025 at 05:29:56PM -0700, Oreoluwa Babatunde wrote:
>> Restructure the call site for dma_contiguous_early_fixup() to
>> where the reserved_mem nodes are being parsed from the DT so that
>> dma_mmu_remap[] is populated before dma_contiguous_remap() is called.
>>
>> Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed")
>> Signed-off-by: Oreoluwa Babatunde <oreoluwa.babatunde@....qualcomm.com>
>> Tested-by: William Zhang <william.zhang@...adcom.com>
>> ---
>> v3: Wrap the call to dma_contiguous_early_fixup() with a check for
>>     CONFIG_DMA_CMA to fix compile error seen on x86. The __weak function
>>     definition introduced in v2 was not sufficient to prevent the issue,
>>     so remove that as well.
>>     Also add Tested-by tag from William Zhang.
>>
>> v2: Add a check for the "reusable" property to narrow things down to
>>     only cma regions.
>>     Also add __weak function definition for dma_contiguous_early_fixup()
>>     to avoid compile errors on architectures that do not define the
>>     function.
>>
>>  drivers/of/of_reserved_mem.c | 20 ++++++++++++++++----
>>  kernel/dma/contiguous.c      |  2 --
>>  2 files changed, 16 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
>> index 77016c0cc296..cfffecb91c3a 100644
>> --- a/drivers/of/of_reserved_mem.c
>> +++ b/drivers/of/of_reserved_mem.c
>> @@ -25,6 +25,7 @@
>>  #include <linux/memblock.h>
>>  #include <linux/kmemleak.h>
>>  #include <linux/cma.h>
>> +#include <linux/dma-map-ops.h>
>>  
>>  #include "of_private.h"
>>  
>> @@ -175,13 +176,19 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
>>  		base = dt_mem_next_cell(dt_root_addr_cells, &prop);
>>  		size = dt_mem_next_cell(dt_root_size_cells, &prop);
>>  
>> -		if (size &&
>> -		    early_init_dt_reserve_memory(base, size, nomap) == 0)
>> +		if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
>> +			/* Architecture specific contiguous memory fixup. */
>> +#ifdef CONFIG_DMA_CMA
>> +			if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
>> +			    of_get_flat_dt_prop(node, "reusable", NULL))
>> +				dma_contiguous_early_fixup(base, size);
>> +#endif
> 
> Add a static inline for dma_contiguous_early_fixup() instead of having 
> an #ifdef.

ACK.

Thanks!