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tg3: Make the TX BD DMA limit configurable
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The 57766 ASIC rev will impose a new TX BD DMA limit on the driver.
This patch prepares for 57766 support by making the tx BD DMA limit
tunable.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Reviewed-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Matt Carlson authored and David S. Miller committed Dec 15, 2011
1 parent 4f27209 commit a4cb428
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Showing 2 changed files with 9 additions and 8 deletions.
16 changes: 8 additions & 8 deletions drivers/net/ethernet/broadcom/tg3.c
Original file line number Diff line number Diff line change
Expand Up @@ -199,7 +199,7 @@ static inline void _tg3_flag_clear(enum TG3_FLAGS flag, unsigned long *bits)

/* minimum number of free TX descriptors required to wake up TX process */
#define TG3_TX_WAKEUP_THRESH(tnapi) ((tnapi)->tx_pending / 4)
#define TG3_TX_BD_DMA_MAX 4096
#define TG3_TX_BD_DMA_MAX_4K 4096

#define TG3_RAW_IP_ALIGN 2

Expand Down Expand Up @@ -6449,17 +6449,17 @@ static bool tg3_tx_frag_set(struct tg3_napi *tnapi, u32 *entry, u32 *budget,
if (tg3_40bit_overflow_test(tp, map, len))
hwbug = 1;

if (tg3_flag(tp, 4K_FIFO_LIMIT)) {
if (tp->dma_limit) {
u32 prvidx = *entry;
u32 tmp_flag = flags & ~TXD_FLAG_END;
while (len > TG3_TX_BD_DMA_MAX && *budget) {
u32 frag_len = TG3_TX_BD_DMA_MAX;
len -= TG3_TX_BD_DMA_MAX;
while (len > tp->dma_limit && *budget) {
u32 frag_len = tp->dma_limit;
len -= tp->dma_limit;

/* Avoid the 8byte DMA problem */
if (len <= 8) {
len += TG3_TX_BD_DMA_MAX / 2;
frag_len = TG3_TX_BD_DMA_MAX / 2;
len += tp->dma_limit / 2;
frag_len = tp->dma_limit / 2;
}

tnapi->tx_buffers[*entry].fragmented = true;
Expand Down Expand Up @@ -14041,7 +14041,7 @@ static int __devinit tg3_get_invariants(struct tg3 *tp)
tg3_flag_set(tp, SHORT_DMA_BUG);

if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5719)
tg3_flag_set(tp, 4K_FIFO_LIMIT);
tp->dma_limit = TG3_TX_BD_DMA_MAX_4K;

if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5717 ||
GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5719 ||
Expand Down
1 change: 1 addition & 0 deletions drivers/net/ethernet/broadcom/tg3.h
Original file line number Diff line number Diff line change
Expand Up @@ -2994,6 +2994,7 @@ struct tg3 {
/* begin "tx thread" cacheline section */
void (*write32_tx_mbox) (struct tg3 *, u32,
u32);
u32 dma_limit;

/* begin "rx thread" cacheline section */
struct tg3_napi napi[TG3_IRQ_MAX_VECS];
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