tsnep: Use page pool for RX

Use page pool for RX buffer handling. Makes RX path more efficient and
is required prework for future XDP support.

Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/engleder/Kconfig b/drivers/net/ethernet/engleder/Kconfig
index f4e2b11..3df6bf4 100644 (file)
--- a/drivers/net/ethernet/engleder/Kconfig
+++ b/drivers/net/ethernet/engleder/Kconfig
@@ -21,6 +21,7 @@ config TSNEP
        depends on HAS_IOMEM && HAS_DMA
        depends on PTP_1588_CLOCK_OPTIONAL
        select PHYLIB
+       select PAGE_POOL
        help
          Support for the Engleder TSN endpoint Ethernet MAC IP Core.
 

diff --git a/drivers/net/ethernet/engleder/tsnep.h b/drivers/net/ethernet/engleder/tsnep.h
index 2ca34ae..09a723b 100644 (file)
--- a/drivers/net/ethernet/engleder/tsnep.h
+++ b/drivers/net/ethernet/engleder/tsnep.h
@@ -96,9 +96,9 @@ struct tsnep_rx_entry {
 
        u32 properties;
 
-       struct sk_buff *skb;
+       struct page *page;
        size_t len;
-       DEFINE_DMA_UNMAP_ADDR(dma);
+       dma_addr_t dma;
 };
 
 struct tsnep_rx {
@@ -113,6 +113,7 @@ struct tsnep_rx {
        int read;
        u32 owner_counter;
        int increment_owner_counter;
+       struct page_pool *page_pool;
 
        u32 packets;
        u32 bytes;

diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
index 5ed4f69..48fb391 100644 (file)
--- a/drivers/net/ethernet/engleder/tsnep_main.c
+++ b/drivers/net/ethernet/engleder/tsnep_main.c
@@ -27,10 +27,10 @@
 #include <linux/phy.h>
 #include <linux/iopoll.h>
 
-#define RX_SKB_LENGTH (round_up(TSNEP_RX_INLINE_METADATA_SIZE + ETH_HLEN + \
-                               TSNEP_MAX_FRAME_SIZE + ETH_FCS_LEN, 4))
-#define RX_SKB_RESERVE ((16 - TSNEP_RX_INLINE_METADATA_SIZE) + NET_IP_ALIGN)
-#define RX_SKB_ALLOC_LENGTH (RX_SKB_RESERVE + RX_SKB_LENGTH)
+#define TSNEP_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
+#define TSNEP_HEADROOM ALIGN(TSNEP_SKB_PAD, 4)
+#define TSNEP_MAX_RX_BUF_SIZE (PAGE_SIZE - TSNEP_HEADROOM - \
+                              SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
 
 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
 #define DMA_ADDR_HIGH(dma_addr) ((u32)(((dma_addr) >> 32) & 0xFFFFFFFF))
@@ -587,14 +587,15 @@ static void tsnep_rx_ring_cleanup(struct tsnep_rx *rx)
 
        for (i = 0; i < TSNEP_RING_SIZE; i++) {
                entry = &rx->entry[i];
-               if (dma_unmap_addr(entry, dma))
-                       dma_unmap_single(dmadev, dma_unmap_addr(entry, dma),
-                                        dma_unmap_len(entry, len),
-                                        DMA_FROM_DEVICE);
-               if (entry->skb)
-                       dev_kfree_skb(entry->skb);
+               if (entry->page)
+                       page_pool_put_full_page(rx->page_pool, entry->page,
+                                               false);
+               entry->page = NULL;
        }
 
+       if (rx->page_pool)
+               page_pool_destroy(rx->page_pool);
+
        memset(rx->entry, 0, sizeof(rx->entry));
 
        for (i = 0; i < TSNEP_RING_PAGE_COUNT; i++) {
@@ -607,31 +608,19 @@ static void tsnep_rx_ring_cleanup(struct tsnep_rx *rx)
        }
 }
 
-static int tsnep_rx_alloc_and_map_skb(struct tsnep_rx *rx,
-                                     struct tsnep_rx_entry *entry)
+static int tsnep_rx_alloc_buffer(struct tsnep_rx *rx,
+                                struct tsnep_rx_entry *entry)
 {
-       struct device *dmadev = rx->adapter->dmadev;
-       struct sk_buff *skb;
-       dma_addr_t dma;
+       struct page *page;
 
-       skb = __netdev_alloc_skb(rx->adapter->netdev, RX_SKB_ALLOC_LENGTH,
-                                GFP_ATOMIC | GFP_DMA);
-       if (!skb)
+       page = page_pool_dev_alloc_pages(rx->page_pool);
+       if (unlikely(!page))
                return -ENOMEM;
 
-       skb_reserve(skb, RX_SKB_RESERVE);
-
-       dma = dma_map_single(dmadev, skb->data, RX_SKB_LENGTH,
-                            DMA_FROM_DEVICE);
-       if (dma_mapping_error(dmadev, dma)) {
-               dev_kfree_skb(skb);
-               return -ENOMEM;
-       }
-
-       entry->skb = skb;
-       entry->len = RX_SKB_LENGTH;
-       dma_unmap_addr_set(entry, dma, dma);
-       entry->desc->rx = __cpu_to_le64(dma);
+       entry->page = page;
+       entry->len = TSNEP_MAX_RX_BUF_SIZE;
+       entry->dma = page_pool_get_dma_addr(entry->page);
+       entry->desc->rx = __cpu_to_le64(entry->dma + TSNEP_SKB_PAD);
 
        return 0;
 }
@@ -640,6 +629,7 @@ static int tsnep_rx_ring_init(struct tsnep_rx *rx)
 {
        struct device *dmadev = rx->adapter->dmadev;
        struct tsnep_rx_entry *entry;
+       struct page_pool_params pp_params = { 0 };
        struct tsnep_rx_entry *next_entry;
        int i, j;
        int retval;
@@ -661,12 +651,28 @@ static int tsnep_rx_ring_init(struct tsnep_rx *rx)
                        entry->desc_dma = rx->page_dma[i] + TSNEP_DESC_SIZE * j;
                }
        }
+
+       pp_params.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV;
+       pp_params.order = 0;
+       pp_params.pool_size = TSNEP_RING_SIZE;
+       pp_params.nid = dev_to_node(dmadev);
+       pp_params.dev = dmadev;
+       pp_params.dma_dir = DMA_FROM_DEVICE;
+       pp_params.max_len = TSNEP_MAX_RX_BUF_SIZE;
+       pp_params.offset = TSNEP_SKB_PAD;
+       rx->page_pool = page_pool_create(&pp_params);
+       if (IS_ERR(rx->page_pool)) {
+               retval = PTR_ERR(rx->page_pool);
+               rx->page_pool = NULL;
+               goto failed;
+       }
+
        for (i = 0; i < TSNEP_RING_SIZE; i++) {
                entry = &rx->entry[i];
                next_entry = &rx->entry[(i + 1) % TSNEP_RING_SIZE];
                entry->desc->next = __cpu_to_le64(next_entry->desc_dma);
 
-               retval = tsnep_rx_alloc_and_map_skb(rx, entry);
+               retval = tsnep_rx_alloc_buffer(rx, entry);
                if (retval)
                        goto failed;
        }
@@ -682,7 +688,7 @@ static void tsnep_rx_activate(struct tsnep_rx *rx, int index)
 {
        struct tsnep_rx_entry *entry = &rx->entry[index];
 
-       /* RX_SKB_LENGTH is a multiple of 4 */
+       /* TSNEP_MAX_RX_BUF_SIZE is a multiple of 4 */
        entry->properties = entry->len & TSNEP_DESC_LENGTH_MASK;
        entry->properties |= TSNEP_DESC_INTERRUPT_FLAG;
        if (index == rx->increment_owner_counter) {
@@ -705,19 +711,52 @@ static void tsnep_rx_activate(struct tsnep_rx *rx, int index)
        entry->desc->properties = __cpu_to_le32(entry->properties);
 }
 
+static struct sk_buff *tsnep_build_skb(struct tsnep_rx *rx, struct page *page,
+                                      int length)
+{
+       struct sk_buff *skb;
+
+       skb = napi_build_skb(page_address(page), PAGE_SIZE);
+       if (unlikely(!skb))
+               return NULL;
+
+       /* update pointers within the skb to store the data */
+       skb_reserve(skb, TSNEP_SKB_PAD + TSNEP_RX_INLINE_METADATA_SIZE);
+       __skb_put(skb, length - TSNEP_RX_INLINE_METADATA_SIZE - ETH_FCS_LEN);
+
+       if (rx->adapter->hwtstamp_config.rx_filter == HWTSTAMP_FILTER_ALL) {
+               struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
+               struct tsnep_rx_inline *rx_inline =
+                       (struct tsnep_rx_inline *)(page_address(page) +
+                                                  TSNEP_SKB_PAD);
+
+               skb_shinfo(skb)->tx_flags |=
+                       SKBTX_HW_TSTAMP_NETDEV;
+               memset(hwtstamps, 0, sizeof(*hwtstamps));
+               hwtstamps->netdev_data = rx_inline;
+       }
+
+       skb_record_rx_queue(skb, rx->queue_index);
+       skb->protocol = eth_type_trans(skb, rx->adapter->netdev);
+
+       return skb;
+}
+
 static int tsnep_rx_poll(struct tsnep_rx *rx, struct napi_struct *napi,
                         int budget)
 {
        struct device *dmadev = rx->adapter->dmadev;
        int done = 0;
+       enum dma_data_direction dma_dir;
        struct tsnep_rx_entry *entry;
+       struct page *page;
        struct sk_buff *skb;
-       size_t len;
-       dma_addr_t dma;
        int length;
        bool enable = false;
        int retval;
 
+       dma_dir = page_pool_get_dma_dir(rx->page_pool);
+
        while (likely(done < budget)) {
                entry = &rx->entry[rx->read];
                if ((__le32_to_cpu(entry->desc_wb->properties) &
@@ -730,43 +769,34 @@ static int tsnep_rx_poll(struct tsnep_rx *rx, struct napi_struct *napi,
                 */
                dma_rmb();
 
-               skb = entry->skb;
-               len = dma_unmap_len(entry, len);
-               dma = dma_unmap_addr(entry, dma);
+               prefetch(page_address(entry->page) + TSNEP_SKB_PAD);
+               length = __le32_to_cpu(entry->desc_wb->properties) &
+                        TSNEP_DESC_LENGTH_MASK;
+               dma_sync_single_range_for_cpu(dmadev, entry->dma, TSNEP_SKB_PAD,
+                                             length, dma_dir);
+               page = entry->page;
 
                /* forward skb only if allocation is successful, otherwise
-                * skb is reused and frame dropped
+                * page is reused and frame dropped
                 */
-               retval = tsnep_rx_alloc_and_map_skb(rx, entry);
+               retval = tsnep_rx_alloc_buffer(rx, entry);
                if (!retval) {
-                       dma_unmap_single(dmadev, dma, len, DMA_FROM_DEVICE);
-
-                       length = __le32_to_cpu(entry->desc_wb->properties) &
-                                TSNEP_DESC_LENGTH_MASK;
-                       skb_put(skb, length - ETH_FCS_LEN);
-                       if (rx->adapter->hwtstamp_config.rx_filter ==
-                           HWTSTAMP_FILTER_ALL) {
-                               struct skb_shared_hwtstamps *hwtstamps =
-                                       skb_hwtstamps(skb);
-                               struct tsnep_rx_inline *rx_inline =
-                                       (struct tsnep_rx_inline *)skb->data;
-
-                               skb_shinfo(skb)->tx_flags |=
-                                       SKBTX_HW_TSTAMP_NETDEV;
-                               memset(hwtstamps, 0, sizeof(*hwtstamps));
-                               hwtstamps->netdev_data = rx_inline;
-                       }
-                       skb_pull(skb, TSNEP_RX_INLINE_METADATA_SIZE);
-                       skb_record_rx_queue(skb, rx->queue_index);
-                       skb->protocol = eth_type_trans(skb,
-                                                      rx->adapter->netdev);
+                       skb = tsnep_build_skb(rx, page, length);
+                       if (skb) {
+                               page_pool_release_page(rx->page_pool, page);
+
+                               rx->packets++;
+                               rx->bytes += length -
+                                            TSNEP_RX_INLINE_METADATA_SIZE;
+                               if (skb->pkt_type == PACKET_MULTICAST)
+                                       rx->multicast++;
 
-                       rx->packets++;
-                       rx->bytes += length - TSNEP_RX_INLINE_METADATA_SIZE;
-                       if (skb->pkt_type == PACKET_MULTICAST)
-                               rx->multicast++;
+                               napi_gro_receive(napi, skb);
+                       } else {
+                               page_pool_recycle_direct(rx->page_pool, page);
 
-                       napi_gro_receive(napi, skb);
+                               rx->dropped++;
+                       }
                        done++;
                } else {
                        rx->dropped++;