RE: [PATCH net-next v10 5/7] r8169: add support and enable rss

>
>On Mon, 3 Aug 2026 10:13:03 +0800 javen wrote:
>> From: Javen Xu <[email protected]>
>>
>> This patch adds support and enable rss for RTL8127.
>>
>> Signed-off-by: Javen Xu <[email protected]>
>> ---
>> Changes in v2:
>>  - some changes moved from Patch 2/7
>>
>> Changes in v3:
>>  - add struct rtl8169_rss_data. Allocate it dynamically when needed.
>>  - define rss_key as an u32 array
>>  - replace some magic bit numbers in rtl8169_set_rss_hash_opt() and
>>    rtl8125_set_rx_q_num()
>>  - use union to combine different rx descriptor, refactor struct
>> RxDesc
>>  - remove dead code from rtl8169_double_check_rss_support()
>>
>> Changes in v4:
>>  - rename macro definition, e.g R8127_MAX_IRQ to
>R8127_MAX_NUM_IRQVEC
>>  - change hw_supp_indir_tbl_entries type to unsigned int
>>  - change init_rx_desc_type type to enum
>>  - remove rtl_check_rss_support(), add helper function
>>    rtl_hw_support_rss()
>>  - remove hw_curr_isr_ver, use irq_nvecs to judge whether we should
>>    enable vector interrupt mapping, use tp->num_rx_ring to judge whether
>>    we should enable rss
>>  - remove function rtl8169_double_check_rss_support(), use
>>    rtl8169_set_rx_ring_num() to set num_rx_ring according to
>> tp->irq_nvecs
>>
>> Changes in v5:
>>  - no changes
>>
>> Changes in v6:
>>  - change rss_queue_num type from u8 to unsigned int
>>  - fix rx desc clear in rtl8169_rx_clear() for different desc type
>>  - clamping num_rx_ring with rounddown_pow_of_two()
>>
>> Changes in v7:
>>  - remove unused macro
>>  - change unfixed type in rtl8169_store_reta
>>
>> Changes in v8:
>>  - refill desc->addr when rx_desc reset
>>  - rtl8169_set_channels fixed in patch 7/7
>>
>> Changes in v9:
>>  - remove rtl8169_set_desc_dma_addr, only set desc dma addr for
>>    RX_DESC_TYPE_RSS desc
>>
>> Changes in v10:
>> - Change rss_key to u8 array and write rss_key_reg as u32 values.
>>    Use get_unaligned_le32() to keep behavior consistent on big-endian
>>    and little-endian
>> ---
>>  drivers/net/ethernet/realtek/r8169_main.c | 379
>> ++++++++++++++++++++--
>>  1 file changed, 346 insertions(+), 33 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c
>> b/drivers/net/ethernet/realtek/r8169_main.c
>> index 31f6d0c2e3d1..4e571fcea092 100644
>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>> @@ -88,6 +88,19 @@
>>  #define R8127_MAX_TX_QUEUES  8
>>  #define R8169_DEFAULT_RX_QUEUES      1
>>  #define R8169_MAX_TX_QUEUES  1
>> +#define R8127_MAX_NUM_IRQVEC 32
>> +#define R8127_MIN_NUM_IRQVEC 30
>> +#define R8169_IRQ_DEFAULT    1
>> +#define RTL_RSS_KEY_SIZE     40
>> +#define RSS_CPU_NUM_MASK     GENMASK(18, 16)
>> +#define RSS_HASH_MASK                GENMASK(10, 8)
>> +#define RTL_MAX_INDIRECTION_TABLE_ENTRIES 128
>> +#define RXS_RSS_UDP          BIT(27)
>> +#define RXS_RSS_IPV4         BIT(28)
>> +#define RXS_RSS_IPV6         BIT(29)
>> +#define RXS_RSS_TCP          BIT(30)
>> +#define RXS_RSS_L3_TYPE_MASK (RXS_RSS_IPV4 | RXS_RSS_IPV6) #define
>> +RXS_RSS_L4_TYPE_MASK (RXS_RSS_TCP | RXS_RSS_UDP)
>>
>>  #define OCP_STD_PHY_BASE     0xa400
>>
>> @@ -595,6 +608,20 @@ enum rtl_register_content {
>>  #define      ISRIMR_LINKCHG  BIT(29)
>>  #define      ISRIMR_TOK_Q0   BIT(8)
>>  #define      ISRIMR_ROK_Q0   BIT(0)
>> +#define RTL_DESC_TYPE_CTRL           0xd8
>> +#define RSS_KEY_REG                  0x4600
>> +#define RSS_INDIRECTION_TBL_REG              0x4700
>> +#define RSS_CTRL_TCP_IPV4_SUPP               BIT(0)
>> +#define RTL_DESC_TYPE_RSS            BIT(1)
>> +#define RSS_CTRL_IPV4_SUPP           BIT(1)
>> +#define RSS_CTRL_TCP_IPV6_SUPP               BIT(2)
>> +#define RSS_CTRL_IPV6_SUPP           BIT(3)
>> +#define RSS_CTRL_IPV6_EXT_SUPP               BIT(4)
>> +#define RSS_CTRL_TCP_IPV6_EXT_SUPP   BIT(5)
>> +#define      RX_RES_RSS                      BIT(22)
>> +#define      RX_RUNT_RSS                     BIT(21)
>> +#define      RX_CRC_RSS                      BIT(20)
>> +#define RTL_RX_Q_NUM_MASK            GENMASK(4, 2)
>>  };
>>
>>  enum rtl_desc_bit {
>> @@ -652,6 +679,11 @@ enum rtl_rx_desc_bit {
>>  #define RxProtoIP    (PID1 | PID0)
>>  #define RxProtoMask  RxProtoIP
>>
>> +#define      RX_UDPT_DESC_RSS        BIT(19)
>> +#define      RX_TCPT_DESC_RSS        BIT(18)
>> +#define      RX_UDPF_DESC_RSS        BIT(16) /* UDP/IP checksum failed */
>> +#define      RX_TCPF_DESC_RSS        BIT(15) /* TCP/IP checksum failed */
>> +
>>       IPFail          = (1 << 16), /* IP checksum failed */
>>       UDPFail         = (1 << 15), /* UDP/IP checksum failed */
>>       TCPFail         = (1 << 14), /* TCP/IP checksum failed */
>> @@ -673,9 +705,27 @@ struct TxDesc {
>>  };
>>
>>  struct RxDesc {
>> -     __le32 opts1;
>> -     __le32 opts2;
>> -     __le64 addr;
>> +     union {
>> +             /* RX_DESC_TYPE_DEFAULT */
>> +             struct {
>> +                     __le32 opts1;
>> +                     __le32 opts2;
>> +                     __le64 addr;
>> +             };
>> +
>> +             /* RX_DESC_TYPE_RSS */
>> +             struct {
>> +                     union {
>> +                             __le64 rss_addr;
>> +                             struct {
>> +                                     __le32 rss_info;
>> +                                     __le32 rss_result;
>> +                             } rss_dword;
>> +                     };
>> +                     __le32 rss_opts2;
>> +                     __le32 rss_opts1;
>> +             };
>> +     };
>>  };
>>
>>  struct ring_info {
>> @@ -747,6 +797,11 @@ enum rtl_dash_type {
>>       RTL_DASH_25_BP,
>>  };
>>
>> +enum rx_desc_type {
>> +     RX_DESC_TYPE_DEFAULT,
>> +     RX_DESC_TYPE_RSS,
>> +};
>> +
>>  struct rtl8169_rx_ring {
>>       u32 cur_rx;                                     /* Index of next Rx pkt. */
>>       u32 dirty_rx;                                   /* Index for recycling. */
>> @@ -756,6 +811,12 @@ struct rtl8169_rx_ring {
>>       struct page *rx_databuff[NUM_RX_DESC];          /* Rx data buffers */
>>  };
>>
>> +struct rtl8169_rss_data {
>> +     u8 rss_key[RTL_RSS_KEY_SIZE];
>> +     u8 rss_indir_tbl[RTL_MAX_INDIRECTION_TABLE_ENTRIES];
>> +     unsigned int hw_supp_indir_tbl_entries; };
>> +
>>  struct rtl8169_private {
>>       void __iomem *mmio_addr;        /* memory map physical address */
>>       struct pci_dev *pci_dev;
>> @@ -775,7 +836,9 @@ struct rtl8169_private {
>>       u16 tx_lpi_timer;
>>       u32 irq_mask;
>>       unsigned int hw_supp_num_rx_queues;
>> +     struct rtl8169_rss_data *rss_data;
>>       unsigned int irq_nvecs;
>> +     enum rx_desc_type init_rx_desc_type;
>>       struct clk *clk;
>>
>>       struct {
>> @@ -1605,6 +1668,11 @@ static bool rtl_dash_is_enabled(struct
>rtl8169_private *tp)
>>       }
>>  }
>>
>> +static bool rtl_hw_support_rss(struct rtl8169_private *tp) {
>> +     return tp->mac_version == RTL_GIGA_MAC_VER_80; }
>> +
>>  static enum rtl_dash_type rtl_get_dash_type(struct rtl8169_private
>> *tp)  {
>>       switch (tp->mac_version) {
>> @@ -1906,9 +1974,20 @@ static inline u32 rtl8169_tx_vlan_tag(struct
>sk_buff *skb)
>>               TxVlanTag | swab16(skb_vlan_tag_get(skb)) : 0x00;  }
>>
>> -static void rtl8169_rx_vlan_tag(struct RxDesc *desc, struct sk_buff
>> *skb)
>> +static void rtl8169_rx_vlan_tag(struct rtl8169_private *tp,
>> +                             struct RxDesc *desc,
>> +                             struct sk_buff *skb)
>>  {
>> -     u32 opts2 = le32_to_cpu(desc->opts2);
>> +     u32 opts2;
>> +
>> +     switch (tp->init_rx_desc_type) {
>> +     case RX_DESC_TYPE_RSS:
>> +             opts2 = le32_to_cpu(desc->rss_opts2);
>> +             break;
>> +     default:
>> +             opts2 = le32_to_cpu(desc->opts2);
>> +             break;
>> +     }
>>
>>       if (opts2 & RxVlanTag)
>>               __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
>> swab16(opts2 & 0xffff)); @@ -2736,17 +2815,27 @@ static void
>rtl_hw_reset(struct rtl8169_private *tp)
>>       rtl_loop_wait_low(tp, &rtl_chipcmd_cond, 100, 100);  }
>>
>> +static void rtl8169_init_rss(struct rtl8169_private *tp) {
>> +     for (int i = 0; i < tp->rss_data->hw_supp_indir_tbl_entries; i++)
>> +             tp->rss_data->rss_indir_tbl[i] =
>> +ethtool_rxfh_indir_default(i, tp->num_rx_rings);
>> +
>> +     netdev_rss_key_fill(tp->rss_data->rss_key, RTL_RSS_KEY_SIZE); }
>> +
>>  static void rtl_setup_rx_params(struct rtl8169_private *tp)  {
>>       tp->num_rx_rings = 1;
>>       switch (tp->mac_version) {
>>       case RTL_GIGA_MAC_VER_80:
>>               tp->hw_supp_num_rx_queues = R8169_MAX_RX_QUEUES;
>> +             tp->rss_data->hw_supp_indir_tbl_entries =
>> + RTL_MAX_INDIRECTION_TABLE_ENTRIES;
>>               break;
>>       default:
>>               tp->hw_supp_num_rx_queues = R8169_DEFAULT_RX_QUEUES;
>>               break;
>>       }
>> +     tp->init_rx_desc_type = RX_DESC_TYPE_DEFAULT;
>>  }
>>
>>  static void rtl_request_firmware(struct rtl8169_private *tp) @@
>> -2871,6 +2960,58 @@ static void rtl_set_rx_max_size(struct rtl8169_private
>*tp)
>>       RTL_W16(tp, RxMaxSize, R8169_RX_BUF_SIZE + 1);  }
>>
>> +static void rtl8169_store_rss_key(struct rtl8169_private *tp) {
>> +     u8 *rss_key = tp->rss_data->rss_key;
>> +     const u16 rss_key_reg = RSS_KEY_REG;
>> +
>> +     /* Write redirection table to HW */
>> +     for (int i = 0; i < RTL_RSS_KEY_SIZE; i += sizeof(u32))
>> +             RTL_W32(tp, rss_key_reg + i, get_unaligned_le32(rss_key
>> + + i));
>
>you fetched packed word of the key with get_unaligned_le32()..
>
>> +}
>> +
>> +static void rtl8169_store_reta(struct rtl8169_private *tp) {
>> +     u8 *indir_tbl = tp->rss_data->rss_indir_tbl;
>> +     unsigned int i;
>> +
>> +     /* Write redirection table to HW */
>> +     for (i = 0; i < tp->rss_data->hw_supp_indir_tbl_entries; i += 4) {
>> +             u32 reta = (u32)indir_tbl[i] |
>> +                        (u32)indir_tbl[i + 1] << 8 |
>> +                        (u32)indir_tbl[i + 2] << 16 |
>> +                        (u32)indir_tbl[i + 3] << 24;
>
>.. but the indir table you pack manually, why?
>
>> +             RTL_W32(tp, RSS_INDIRECTION_TBL_REG + i, reta);
>> +     }
>> +}
>> +
>> +static void rtl8169_set_rss_hash_opt(struct rtl8169_private *tp) {
>> +     u32 rss_ctrl;
>> +
>> +     rss_ctrl = FIELD_PREP(RSS_CPU_NUM_MASK,
>> + ilog2(tp->num_rx_rings));
>> +
>> +     /* Perform hash on these packet types */
>> +     rss_ctrl |= RSS_CTRL_TCP_IPV4_SUPP
>> +              | RSS_CTRL_IPV4_SUPP
>> +              | RSS_CTRL_IPV6_SUPP
>> +              | RSS_CTRL_IPV6_EXT_SUPP
>> +              | RSS_CTRL_TCP_IPV6_SUPP
>> +              | RSS_CTRL_TCP_IPV6_EXT_SUPP;
>
>| should be at the end of the lines
>
>> +     rss_ctrl |= FIELD_PREP(RSS_HASH_MASK,
>> +
>> + ilog2(tp->rss_data->hw_supp_indir_tbl_entries));
>> +
>> +     RTL_W32(tp, RSS_CTRL_8125, rss_ctrl); }
>> +
>> +static void rtl_set_rss_config(struct rtl8169_private *tp) {
>> +     rtl8169_set_rss_hash_opt(tp);
>> +     rtl8169_store_reta(tp);
>> +     rtl8169_store_rss_key(tp);
>> +}
>
>> +     /* enable rx descriptor type v4 and set queue num for rss*/
>
>nit: missing space at the end of the comment
>
>
>> -     nvecs = pci_alloc_irq_vectors(pdev, 1, 1, flags);
>> +     nvecs = pci_alloc_irq_vectors(pdev, get_min_irq_nvecs(tp),
>> + get_max_irq_nvecs(tp), flags);
>> +
>> +     if (nvecs < 0)
>> +             nvecs = pci_alloc_irq_vectors(pdev, 1, 1, flags);
>
>Why the two calls to pci_alloc_irq_vectors() ?
>It should select the best number of IRQs it can, so why not just call
>
>        pci_alloc_irq_vectors(pdev, 1, get_max_irq_nvecs(tp), flags);
>

Hardware limitation. When we try to enable rss, we should use new interrupt mapping. New interrupt 0-7 is used for rx, 8-15 is used for tx, and linkchg interrupt is fixed at 29. So the min irq number for RTL8127 to enable rss is 30, not 1.
I will add this explanation in the code.

Thanks,
Javen

>note: please review the submission for unnecessarily going over 80 chars, we
>still prefer <=80 lines in netdev
>
>>       if (nvecs < 0)
>>               return nvecs;