Subject: [PATCH 2/2] arm: mvebu: Add hardware I/O Coherency support

From: [email-masked] (Gregory CLEMENT)
Date: Wed, 24 Oct 2012 13:53:28 +0200

On 10/24/2012 01:48 PM, Gregory CLEMENT wrote:
> On 10/24/2012 01:36 PM, Arnd Bergmann wrote:
>> On Wednesday 24 October 2012, Gregory CLEMENT wrote:
>>> +void __init armada_370_xp_coherency_iocache_init(void)
>>> +{
>>> +       /* When the coherency fabric is available, the Armada XP and
>>> +        * Aramada 370 are close to a coherent architecture, so we based
>>> +        * our dma ops on the coherent one, and just changes the
>>> +        * operations which need a arch io sync */
>>> +       if (of_find_compatible_node(NULL, NULL, "marvell,coherency-fabric")) {
>>> +               struct dma_map_ops *dma_ops = &armada_xp_dma_ops;
>>> +               memcpy(dma_ops, &arm_coherent_dma_ops, sizeof(*dma_ops));
>>> +               dma_ops->map_page = armada_xp_dma_map_page;
>>> +               dma_ops->unmap_page = armada_xp_dma_unmap_page;
>>> +               dma_ops->unmap_sg = arm_dma_ops.unmap_sg;
>>> +               dma_ops->sync_single_for_cpu = armada_xp_dma_sync;
>>> +               dma_ops->sync_single_for_device = armada_xp_dma_sync;
>>> +               dma_ops->sync_sg_for_cpu = arm_dma_ops.sync_sg_for_cpu;
>>> +               dma_ops->sync_sg_for_device = arm_dma_ops.sync_sg_for_device;
>>> +       }
>>> +       bus_register_notifier(&platform_bus_type, &armada_xp_platform_nb);
>>
>> I think it would be cleaner to statically define the operations in a constant
>> structure and point directly to the functions you need. If necessary, use
>> multiple structures.
> 
> My problem was that these functions are not exposed, only arm_dma_op and
> arm_coherent_dma_ops are exported.
> Or do you think about something like this:
> 
> struct dma_map_ops *dma_ops = {
> 	.alloc			= arm_dma_ops.arm_coherent_dma_alloc,
> 	.free			= arm_dma_ops.arm_coherent_dma_free,
> 	.mmap			= arm_dma_ops.arm_dma_mmap,
> 	.get_sgtable		= arm_dma_ops.arm_dma_get_sgtable,
> 	.map_sg			= arm_dma_ops.arm_dma_map_sg,
> 	.set_dma_mask		= arm_dma_ops.arm_dma_set_mask,
> 	.map_page 		= armada_xp_dma_map_page,
> 	.unmap_page 		= armada_xp_dma_unmap_page,
> 	.unmap_sg 		= arm_dma_ops.unmap_sg,
> 	.sync_single_for_cpu 	= armada_xp_dma_sync,
> 	.sync_single_for_device = armada_xp_dma_sync,
> 	.sync_sg_for_cpu 	= arm_dma_ops.sync_sg_for_cpu,
> 	.sync_sg_for_device	= arm_dma_ops.sync_sg_for_device,
> };

I was too fast to reply this struct is wrong, it should be as this one:

struct dma_map_ops *dma_ops = {
	.alloc			= arm_coherent_dma_ops.arm_coherent_dma_alloc,
	.free			= arm_coherent_dma_ops.arm_coherent_dma_free,
	.mmap			= arm_coherent_dma_ops.arm_dma_mmap,
	.get_sgtable		= arm_coherent_dma_ops.arm_dma_get_sgtable,
	.map_sg			= arm_coherent_dma_ops.arm_dma_map_sg,
	.set_dma_mask		= arm_coherent_dma_ops.arm_dma_set_mask,
	.map_page 		= armada_xp_dma_map_page,
	.unmap_page 		= armada_xp_dma_unmap_page,
	.unmap_sg 		= arm_dma_ops.unmap_sg,
	.sync_single_for_cpu 	= armada_xp_dma_sync,
	.sync_single_for_device = armada_xp_dma_sync,
	.sync_sg_for_cpu 	= arm_dma_ops.sync_sg_for_cpu,
	.sync_sg_for_device 	= arm_dma_ops.sync_sg_for_device,
};

Thanks,
Gregory