* [PATCH net-next v2 2/2] net: ethernet: mtk_eth_soc: add 9K jumbo
2026-11-05 23:53 [PATCH net-next v2 0/2] net: ethernet: mtk_eth_soc: 9K jumbo frame support Sandeep Haemoon
2026-11-05 23:52 ` [PATCH net-next v2 1/2] net: ethernet: mtk_eth_soc: skip page_pool Sandeep Haemoon
@ 2026-11-05 23:53 ` Sandeep Haemoon
1 sibling, 0 replies; 3+ messages in thread
From: Sandeep Haemoon @ 2026-11-05 23:53 UTC (permalink / raw)
To: netdev
Cc: Felix Fietkau, Lorenzo Bianconi, Andrew Lunn, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Matthias Brugger,
AngeloGioacchino Del Regno, Russell King, Mason Chang,
Frank Wunderlich, linux-mediatek, linux-arm-kernel, linux-kernel
The driver caps max_mtu at 2030 bytes and programs the MAC max-rx field
for at most 2048-byte frames, so MTU > 2K is rejected and 9K jumbo
frames are not usable on the 10G XGMII MACs.
Add a MTK_NETSYS_RX_9K capability for MT7988 and:
- advertise 9K max_mtu on XGMII MACs, derived from the DT phy_mode at
probe time so DSA can raise the conduit MTU before the netdev is
opened;
- program XMAC_RX_CFG2 on the XGMII MACs;
- derive the shared RX buffer length from the largest MTU and size the
RX rings from it;
- program the PDMA RX SDL max frame so the DMA engine accepts jumbo
frames;
- reject a runtime MTU change that would need a different ring buffer
size while DMA is running; the rings are sized at the next open.
The RX rings and their buffers are sized for the largest MTU of any MAC,
so the MTU limits of the MACs are now written from mtk_mac_config() and
mtk_change_mtu() with eth->rx_buf_len rather than a fixed 2K.
This is a forward-port of the MediaTek downstream jumbo series:
Mason Chang's "change default rx buffer length", "add 9k jumbo frame
support" and "add dynamic rx buffer adjustment support" (MediaTek
OpenWrt feed 999-eth-30/31/33, carried in
frank-w/BPI-Router-Linux 92bfdbdd4de1/b4c6cb1d5532/ca4c976dce22),
plus Frank Wunderlich's "try to fix crash the right way"
(a3207a383794).
Link: https://github.com/frank-w/BPI-Router-Linux/commit/b4c6cb1d5532
Link: https://github.com/mediatek/mtk-openwrt-feeds
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Sandeep Haemoon <sandeeph@loljews.com>
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 178 ++++++++++++++------
drivers/net/ethernet/mediatek/mtk_eth_soc.h | 9 +-
2 files changed, 138 insertions(+), 49 deletions(-)
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 29370376f..38d402c5e 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -171,6 +171,7 @@ static const struct mtk_reg_map mt7988_reg_map = {
.glo_cfg = 0x6a04,
.rst_idx = 0x6a08,
.delay_irq = 0x6a0c,
+ .rx_cfg = 0x6a10,
.irq_status = 0x6a20,
.irq_mask = 0x6a28,
.adma_rx_dbg0 = 0x6a38,
@@ -554,6 +555,43 @@ static int mtk_mac_prepare(struct phylink_config *config, unsigned int mode,
return 0;
}
+static void mtk_set_mcr_max_rx(struct mtk_mac *mac, u32 val)
+{
+ struct mtk_eth *eth = mac->hw;
+ u32 mcr_cur, mcr_new;
+
+ if (MTK_HAS_CAPS(eth->soc->caps, MTK_SOC_MT7628))
+ return;
+
+ if (!mtk_interface_mode_is_xgmii(eth, mac->interface)) {
+ mcr_cur = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id));
+ mcr_new = mcr_cur & ~MAC_MCR_MAX_RX_MASK;
+
+ if (val <= 1518)
+ mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1518);
+ else if (val <= 1536)
+ mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1536);
+ else if (val <= 1552)
+ mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1552);
+ else
+ mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_2048);
+
+ if (mcr_new != mcr_cur)
+ mtk_w32(mac->hw, mcr_new, MTK_MAC_MCR(mac->id));
+ } else if (mtk_is_netsys_v3_or_greater(mac->hw) &&
+ mac->id != MTK_GMAC1_ID) {
+ mcr_cur = mtk_r32(mac->hw, MTK_XMAC_RX_CFG2(mac->id));
+
+ if (val < MTK_MAX_RX_LENGTH_9K)
+ mcr_new = FIELD_PREP(MTK_XMAC_MAX_RX_MASK, val);
+ else
+ mcr_new = MTK_MAX_RX_LENGTH_9K;
+
+ if (mcr_new != mcr_cur)
+ mtk_w32(mac->hw, mcr_new, MTK_XMAC_RX_CFG2(mac->id));
+ }
+}
+
static void mtk_mac_config(struct phylink_config *config, unsigned int mode,
const struct phylink_link_state *state)
{
@@ -647,6 +685,7 @@ static void mtk_mac_config(struct phylink_config *config, unsigned int mode,
regmap_write(eth->ethsys, ETHSYS_SYSCFG0, val);
mac->interface = state->interface;
+ mtk_set_mcr_max_rx(mac, eth->rx_buf_len);
}
/* SGMII */
@@ -1242,22 +1281,22 @@ static void mtk_get_stats64(struct net_device *dev,
storage->tx_dropped = dev->stats.tx_dropped;
}
-static inline int mtk_max_frag_size(int mtu)
+static inline int mtk_max_frag_size(struct mtk_eth *eth, int mtu)
{
- /* make sure buf_size will be at least MTK_MAX_RX_LENGTH */
- if (mtu + MTK_RX_ETH_HLEN < MTK_MAX_RX_LENGTH_2K)
- mtu = MTK_MAX_RX_LENGTH_2K - MTK_RX_ETH_HLEN;
+ /* make sure buf_size will be at least max rx buffer length */
+ if (mtu + MTK_RX_ETH_HLEN < eth->rx_buf_len)
+ mtu = eth->rx_buf_len - MTK_RX_ETH_HLEN;
return SKB_DATA_ALIGN(MTK_RX_HLEN + mtu) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
}
-static inline int mtk_max_buf_size(int frag_size)
+static inline int mtk_max_buf_size(struct mtk_eth *eth, int frag_size)
{
int buf_size = frag_size - NET_SKB_PAD - NET_IP_ALIGN -
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
- WARN_ON(buf_size < MTK_MAX_RX_LENGTH_2K);
+ WARN_ON(buf_size < eth->rx_buf_len);
return buf_size;
}
@@ -1280,9 +1319,8 @@ static bool mtk_rx_get_desc(struct mtk_eth *eth, struct mtk_rx_dma_v2 *rxd,
return true;
}
-static void *mtk_max_lro_buf_alloc(gfp_t gfp_mask)
+static void *mtk_max_buf_alloc(unsigned int size, gfp_t gfp_mask)
{
- unsigned int size = mtk_max_frag_size(MTK_MAX_LRO_RX_LENGTH);
unsigned long data;
data = __get_free_pages(gfp_mask | __GFP_COMP | __GFP_NOWARN,
@@ -2310,7 +2348,8 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
if (ring->frag_size <= PAGE_SIZE)
new_data = napi_alloc_frag(ring->frag_size);
else
- new_data = mtk_max_lro_buf_alloc(GFP_ATOMIC);
+ new_data = mtk_max_buf_alloc(ring->frag_size,
+ GFP_ATOMIC);
if (unlikely(!new_data)) {
netdev->stats.rx_dropped++;
@@ -2812,8 +2851,8 @@ static int mtk_rx_alloc(struct mtk_eth *eth, int ring_no, int rx_flag)
rx_dma_size = soc->rx.dma_size;
}
- ring->frag_size = mtk_max_frag_size(rx_data_len);
- ring->buf_size = mtk_max_buf_size(ring->frag_size);
+ ring->frag_size = mtk_max_frag_size(eth, rx_data_len);
+ ring->buf_size = mtk_max_buf_size(eth, ring->frag_size);
ring->data = kcalloc(rx_dma_size, sizeof(*ring->data),
GFP_KERNEL);
if (!ring->data)
@@ -2857,7 +2896,8 @@ static int mtk_rx_alloc(struct mtk_eth *eth, int ring_no, int rx_flag)
if (ring->frag_size <= PAGE_SIZE)
data = netdev_alloc_frag(ring->frag_size);
else
- data = mtk_max_lro_buf_alloc(GFP_KERNEL);
+ data = mtk_max_buf_alloc(ring->frag_size,
+ GFP_KERNEL);
if (!data)
return -ENOMEM;
@@ -3253,6 +3293,35 @@ static int mtk_dma_busy_wait(struct mtk_eth *eth)
return ret;
}
+static int mtk_max_gmac_mtu(struct mtk_eth *eth)
+{
+ int i, max_mtu = ETH_DATA_LEN;
+
+ for (i = 0; i < ARRAY_SIZE(eth->netdev); i++)
+ if (eth->netdev[i] && eth->netdev[i]->mtu > max_mtu)
+ max_mtu = eth->netdev[i]->mtu;
+
+ return max_mtu;
+}
+
+static u32 mtk_rx_buf_len_from_mtu(int max_mtu)
+{
+ int length = max_mtu + MTK_RX_ETH_HLEN;
+
+ if (length <= MTK_MAX_RX_LENGTH)
+ return MTK_MAX_RX_LENGTH;
+
+ return DIV_ROUND_UP(length, 1024) * 1024;
+}
+
+/* The rx rings are shared by every MAC, so their buffers are sized for the
+ * largest MTU configured on any of them.
+ */
+static u32 mtk_rx_buf_len(struct mtk_eth *eth)
+{
+ return mtk_rx_buf_len_from_mtu(mtk_max_gmac_mtu(eth));
+}
+
static int mtk_dma_init(struct mtk_eth *eth)
{
int err;
@@ -3261,6 +3330,12 @@ static int mtk_dma_init(struct mtk_eth *eth)
if (mtk_dma_busy_wait(eth))
return -EBUSY;
+ /* Derived here, at ring allocation, so eth->rx_buf_len always describes
+ * the buffers the rings actually hold and mtk_mac_config() never lets
+ * a MAC accept a frame the rings cannot take.
+ */
+ eth->rx_buf_len = mtk_rx_buf_len(eth);
+
if (MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA)) {
/* QDMA needs scratch memory for internal reordering of the
* descriptors
@@ -3304,6 +3379,17 @@ static int mtk_dma_init(struct mtk_eth *eth)
mtk_w32(eth, 0x0, eth->soc->reg_map->qdma.hred);
}
+ /* Program the PDMA max RX frame (SDL) from rx_buf_len so jumbo
+ * frames up to it are accepted by the DMA engine.
+ */
+ if (mtk_is_netsys_v3_or_greater(eth)) {
+ u32 val = mtk_r32(eth, eth->soc->reg_map->pdma.rx_cfg);
+
+ mtk_w32(eth, val | ((MTK_PDMA_LRO_SDL + eth->rx_buf_len) <<
+ MTK_RX_CFG_SDL_OFFSET),
+ eth->soc->reg_map->pdma.rx_cfg);
+ }
+
return 0;
}
@@ -3594,17 +3680,6 @@ static int mtk_device_event(struct notifier_block *n, unsigned long event, void
return NOTIFY_DONE;
}
-static int mtk_max_gmac_mtu(struct mtk_eth *eth)
-{
- int i, max_mtu = ETH_DATA_LEN;
-
- for (i = 0; i < ARRAY_SIZE(eth->netdev); i++)
- if (eth->netdev[i] && eth->netdev[i]->mtu > max_mtu)
- max_mtu = eth->netdev[i]->mtu;
-
- return max_mtu;
-}
-
static int mtk_open(struct net_device *dev)
{
struct mtk_mac *mac = netdev_priv(dev);
@@ -3921,29 +3996,6 @@ static void mtk_dim_tx(struct work_struct *work)
dim->state = DIM_START_MEASURE;
}
-static void mtk_set_mcr_max_rx(struct mtk_mac *mac, u32 val)
-{
- struct mtk_eth *eth = mac->hw;
- u32 mcr_cur, mcr_new;
-
- if (MTK_HAS_CAPS(eth->soc->caps, MTK_SOC_MT7628))
- return;
-
- mcr_cur = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id));
- mcr_new = mcr_cur & ~MAC_MCR_MAX_RX_MASK;
-
- if (val <= 1518)
- mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1518);
- else if (val <= 1536)
- mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1536);
- else if (val <= 1552)
- mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1552);
- else
- mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_2048);
-
- if (mcr_new != mcr_cur)
- mtk_w32(mac->hw, mcr_new, MTK_MAC_MCR(mac->id));
-}
static void mtk_hw_reset(struct mtk_eth *eth)
{
@@ -4354,6 +4406,7 @@ static int mtk_change_mtu(struct net_device *dev, int new_mtu)
int length = new_mtu + MTK_RX_ETH_HLEN;
struct mtk_mac *mac = netdev_priv(dev);
struct mtk_eth *eth = mac->hw;
+ u32 rx_buf_len;
int max_mtu, i;
if (rcu_access_pointer(eth->prog) &&
@@ -4362,6 +4415,17 @@ static int mtk_change_mtu(struct net_device *dev, int new_mtu)
return -EINVAL;
}
+ /* The RX rings are shared and cannot be resized in place while DMA is
+ * running. Until the reallocation worker lands, reject a runtime MTU
+ * change that would need a different ring buffer size.
+ */
+ max_mtu = mtk_max_gmac_mtu(eth);
+ if (new_mtu > max_mtu)
+ max_mtu = new_mtu;
+ rx_buf_len = mtk_rx_buf_len_from_mtu(max_mtu);
+ if (refcount_read(ð->dma_refcnt) && rx_buf_len != eth->rx_buf_len)
+ return -EBUSY;
+
mtk_set_mcr_max_rx(mac, length);
WRITE_ONCE(dev->mtu, new_mtu);
@@ -4369,6 +4433,15 @@ static int mtk_change_mtu(struct net_device *dev, int new_mtu)
for (i = 0; i < ARRAY_SIZE(eth->ppe); i++)
mtk_ppe_update_mtu(eth->ppe[i], max_mtu);
+ eth->rx_buf_len = rx_buf_len;
+ if (mtk_is_netsys_v3_or_greater(eth)) {
+ u32 val = mtk_r32(eth, eth->soc->reg_map->pdma.rx_cfg);
+
+ mtk_w32(eth, val | ((MTK_PDMA_LRO_SDL + eth->rx_buf_len) <<
+ MTK_RX_CFG_SDL_OFFSET),
+ eth->soc->reg_map->pdma.rx_cfg);
+ }
+
return 0;
}
@@ -5014,8 +5087,15 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
eth->netdev[id]->irq = eth->irq[MTK_FE_IRQ_SHARED];
eth->netdev[id]->dev.of_node = np;
- if (MTK_HAS_CAPS(eth->soc->caps, MTK_SOC_MT7628))
- eth->netdev[id]->max_mtu = MTK_MAX_RX_LENGTH - MTK_RX_ETH_HLEN;
+ /* DSA sets the conduit MTU (user MTU + tag) before the netdev is
+ * opened, so max_mtu must already be final here. Deriving it only
+ * in mtk_open() leaves the conduit at its 1504 default and blocks
+ * 9K frames on the DSA user ports.
+ */
+ if (MTK_HAS_CAPS(eth->soc->caps, MTK_NETSYS_RX_9K) &&
+ mtk_interface_mode_is_xgmii(eth, phy_mode))
+ eth->netdev[id]->max_mtu =
+ MTK_MAX_RX_LENGTH_9K - MTK_RX_ETH_HLEN;
else
eth->netdev[id]->max_mtu = MTK_MAX_RX_LENGTH_2K - MTK_RX_ETH_HLEN;
@@ -5156,6 +5236,8 @@ static int mtk_probe(struct platform_device *pdev)
spin_lock_init(ð->rx_irq_lock);
spin_lock_init(ð->dim_lock);
+ eth->rx_buf_len = MTK_MAX_RX_LENGTH;
+
eth->rx_dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE;
INIT_WORK(ð->rx_dim.work, mtk_dim_rx);
INIT_DELAYED_WORK(ð->reset.monitor_work, mtk_hw_reset_monitor_work);
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 88a9b3b23..9aad21ea3 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -29,6 +29,7 @@
#define MTK_QDMA_PAGE_SIZE 2048
#define MTK_MAX_RX_LENGTH 1536
#define MTK_MAX_RX_LENGTH_2K 2048
+#define MTK_MAX_RX_LENGTH_9K 9216
#define MTK_TX_DMA_BUF_LEN 0x3fff
#define MTK_TX_DMA_BUF_LEN_V2 0xffff
#define MTK_QDMA_RING_SIZE 2048
@@ -530,6 +531,8 @@
/* XFI Mac control registers */
#define MTK_XMAC_BASE(x) (0x12000 + (((x) - 1) * 0x1000))
#define MTK_XMAC_MCR(x) (MTK_XMAC_BASE(x))
+#define MTK_XMAC_RX_CFG2(x) (MTK_XMAC_MCR(x) + 0xd0)
+#define MTK_XMAC_MAX_RX_MASK GENMASK(13, 0)
#define XMAC_MCR_TRX_DISABLE 0xf
#define XMAC_MCR_FORCE_TX_FC BIT(5)
#define XMAC_MCR_FORCE_RX_FC BIT(4)
@@ -985,6 +988,7 @@ enum mkt_eth_capabilities {
MTK_INFRA_BIT,
MTK_SHARED_SGMII_BIT,
MTK_HWLRO_BIT,
+ MTK_NETSYS_RX_9K_BIT,
MTK_SHARED_INT_BIT,
MTK_TRGMII_MT7621_CLK_BIT,
MTK_QDMA_BIT,
@@ -1026,6 +1030,7 @@ enum mkt_eth_capabilities {
#define MTK_INFRA BIT_ULL(MTK_INFRA_BIT)
#define MTK_SHARED_SGMII BIT_ULL(MTK_SHARED_SGMII_BIT)
#define MTK_HWLRO BIT_ULL(MTK_HWLRO_BIT)
+#define MTK_NETSYS_RX_9K BIT_ULL(MTK_NETSYS_RX_9K_BIT)
#define MTK_SHARED_INT BIT_ULL(MTK_SHARED_INT_BIT)
#define MTK_TRGMII_MT7621_CLK BIT_ULL(MTK_TRGMII_MT7621_CLK_BIT)
#define MTK_QDMA BIT_ULL(MTK_QDMA_BIT)
@@ -1127,7 +1132,7 @@ enum mkt_eth_capabilities {
#define MT7988_CAPS (MTK_36BIT_DMA | MTK_GDM1_ESW | MTK_GMAC2_2P5GPHY | \
MTK_MUX_GMAC2_TO_2P5GPHY | MTK_QDMA | MTK_RSTCTRL_PPE1 | \
- MTK_RSTCTRL_PPE2 | MTK_SRAM)
+ MTK_RSTCTRL_PPE2 | MTK_SRAM | MTK_NETSYS_RX_9K)
struct mtk_tx_dma_desc_info {
dma_addr_t addr;
@@ -1151,6 +1156,7 @@ struct mtk_reg_map {
u32 glo_cfg; /* global configuration */
u32 rst_idx; /* reset index */
u32 delay_irq; /* delay interrupt */
+ u32 rx_cfg; /* rx dma configuration */
u32 irq_status; /* interrupt status */
u32 irq_mask; /* interrupt mask */
u32 adma_rx_dbg0;
@@ -1314,6 +1320,7 @@ struct mtk_eth {
struct mtk_tx_ring tx_ring;
struct mtk_rx_ring rx_ring[MTK_MAX_RX_RING_NUM];
struct mtk_rx_ring rx_ring_qdma;
+ u32 rx_buf_len;
struct napi_struct tx_napi;
struct napi_struct rx_napi;
void *scratch_ring;
--
2.53.0
^ permalink raw reply [flat|nested] 3+ messages in thread