mlxsw: pci: Sync Rx buffers for device

Non-coherent architectures, like ARM, may require invalidating caches
before the device can use the DMA mapped memory, which means that before
posting pages to device, drivers should sync the memory for device.

Sync for device can be configured as page pool responsibility. Set the
relevant flag and define max_len for sync.

Cc: Jiri Pirko <[email protected]>
Fixes: b5b60bb ("mlxsw: pci: Use page pool for Rx buffers allocation")
Signed-off-by: Amit Cohen <[email protected]>
Reviewed-by: Ido Schimmel <[email protected]>
Signed-off-by: Petr Machata <[email protected]>
Link: https://patch.msgid.link/92e01f05c4f506a4f0a9b39c10175dcc01994910.1729866134.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <[email protected]>

Author: Amit Cohen

drivers/net/ethernet/mellanox/mlxsw/pci.c

@@ -996,12 +996,13 @@ static int mlxsw_pci_cq_page_pool_init(struct mlxsw_pci_queue *q,
 	if (cq_type != MLXSW_PCI_CQ_RDQ)
 		return 0;
 
-	pp_params.flags = PP_FLAG_DMA_MAP;
+	pp_params.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV;
 	pp_params.pool_size = MLXSW_PCI_WQE_COUNT * mlxsw_pci->num_sg_entries;
 	pp_params.nid = dev_to_node(&mlxsw_pci->pdev->dev);
 	pp_params.dev = &mlxsw_pci->pdev->dev;
 	pp_params.napi = &q->u.cq.napi;
 	pp_params.dma_dir = DMA_FROM_DEVICE;
+	pp_params.max_len = PAGE_SIZE;
 
 	page_pool = page_pool_create(&pp_params);
 	if (IS_ERR(page_pool))