diff options
Diffstat (limited to 'drivers/net/ethernet/intel/i40e/i40e_txrx.h')
| -rw-r--r-- | drivers/net/ethernet/intel/i40e/i40e_txrx.h | 45 |
1 files changed, 42 insertions, 3 deletions
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h index a9bd70537d65..6b2b1913527d 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h @@ -146,10 +146,39 @@ enum i40e_dyn_idx_t { #define I40E_MAX_BUFFER_TXD 8 #define I40E_MIN_TX_LEN 17 -#define I40E_MAX_DATA_PER_TXD 8192 + +/* The size limit for a transmit buffer in a descriptor is (16K - 1). + * In order to align with the read requests we will align the value to + * the nearest 4K which represents our maximum read request size. + */ +#define I40E_MAX_READ_REQ_SIZE 4096 +#define I40E_MAX_DATA_PER_TXD (16 * 1024 - 1) +#define I40E_MAX_DATA_PER_TXD_ALIGNED \ + (I40E_MAX_DATA_PER_TXD & ~(I40E_MAX_READ_REQ_SIZE - 1)) + +/* This ugly bit of math is equivalent to DIV_ROUNDUP(size, X) where X is + * the value I40E_MAX_DATA_PER_TXD_ALIGNED. It is needed due to the fact + * that 12K is not a power of 2 and division is expensive. It is used to + * approximate the number of descriptors used per linear buffer. Note + * that this will overestimate in some cases as it doesn't account for the + * fact that we will add up to 4K - 1 in aligning the 12K buffer, however + * the error should not impact things much as large buffers usually mean + * we will use fewer descriptors then there are frags in an skb. + */ +static inline unsigned int i40e_txd_use_count(unsigned int size) +{ + const unsigned int max = I40E_MAX_DATA_PER_TXD_ALIGNED; + const unsigned int reciprocal = ((1ull << 32) - 1 + (max / 2)) / max; + unsigned int adjust = ~(u32)0; + + /* if we rounded up on the reciprocal pull down the adjustment */ + if ((max * reciprocal) > adjust) + adjust = ~(u32)(reciprocal - 1); + + return (u32)((((u64)size * reciprocal) + adjust) >> 32); +} /* Tx Descriptors needed, worst case */ -#define TXD_USE_COUNT(S) DIV_ROUND_UP((S), I40E_MAX_DATA_PER_TXD) #define DESC_NEEDED (MAX_SKB_FRAGS + 4) #define I40E_MIN_DESC_PENDING 4 @@ -377,7 +406,7 @@ static inline int i40e_xmit_descriptor_count(struct sk_buff *skb) int count = 0, size = skb_headlen(skb); for (;;) { - count += TXD_USE_COUNT(size); + count += i40e_txd_use_count(size); if (!nr_frags--) break; @@ -423,4 +452,14 @@ static inline bool i40e_chk_linearize(struct sk_buff *skb, int count) /* we can support up to 8 data buffers for a single send */ return count != I40E_MAX_BUFFER_TXD; } + +/** + * i40e_rx_is_fcoe - returns true if the Rx packet type is FCoE + * @ptype: the packet type field from Rx descriptor write-back + **/ +static inline bool i40e_rx_is_fcoe(u16 ptype) +{ + return (ptype >= I40E_RX_PTYPE_L2_FCOE_PAY3) && + (ptype <= I40E_RX_PTYPE_L2_FCOE_VFT_FCOTHER); +} #endif /* _I40E_TXRX_H_ */ |