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net: bcmgenet: Implement RX coalescing control knobs
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Add support for the ethtool rx-frames coalescing parameter which allows
defining the number of RX interrupts per frames received. The RDMA
engine supports a configurable timeout with a resolution of
approximately 8.192 us.

We can no longer enable the BDONE/PDONE interrupts as those would
fire for each packet/buffer received, which would defeat the MBDONE
interrupt purpose. The MBDONE interrupt is guaranteed to correspond to a
PDONE/BDONE interrupt when the threshold is set to 1.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Florian Fainelli authored and David S. Miller committed Sep 18, 2015
1 parent 2f91307 commit 4a29645
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Showing 2 changed files with 105 additions and 3 deletions.
105 changes: 104 additions & 1 deletion drivers/net/ethernet/broadcom/genet/bcmgenet.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -205,6 +205,23 @@ enum dma_reg {
DMA_INDEX2RING_5,
DMA_INDEX2RING_6,
DMA_INDEX2RING_7,
DMA_RING0_TIMEOUT,
DMA_RING1_TIMEOUT,
DMA_RING2_TIMEOUT,
DMA_RING3_TIMEOUT,
DMA_RING4_TIMEOUT,
DMA_RING5_TIMEOUT,
DMA_RING6_TIMEOUT,
DMA_RING7_TIMEOUT,
DMA_RING8_TIMEOUT,
DMA_RING9_TIMEOUT,
DMA_RING10_TIMEOUT,
DMA_RING11_TIMEOUT,
DMA_RING12_TIMEOUT,
DMA_RING13_TIMEOUT,
DMA_RING14_TIMEOUT,
DMA_RING15_TIMEOUT,
DMA_RING16_TIMEOUT,
};

static const u8 bcmgenet_dma_regs_v3plus[] = {
Expand All @@ -216,6 +233,23 @@ static const u8 bcmgenet_dma_regs_v3plus[] = {
[DMA_PRIORITY_0] = 0x30,
[DMA_PRIORITY_1] = 0x34,
[DMA_PRIORITY_2] = 0x38,
[DMA_RING0_TIMEOUT] = 0x2C,
[DMA_RING1_TIMEOUT] = 0x30,
[DMA_RING2_TIMEOUT] = 0x34,
[DMA_RING3_TIMEOUT] = 0x38,
[DMA_RING4_TIMEOUT] = 0x3c,
[DMA_RING5_TIMEOUT] = 0x40,
[DMA_RING6_TIMEOUT] = 0x44,
[DMA_RING7_TIMEOUT] = 0x48,
[DMA_RING8_TIMEOUT] = 0x4c,
[DMA_RING9_TIMEOUT] = 0x50,
[DMA_RING10_TIMEOUT] = 0x54,
[DMA_RING11_TIMEOUT] = 0x58,
[DMA_RING12_TIMEOUT] = 0x5c,
[DMA_RING13_TIMEOUT] = 0x60,
[DMA_RING14_TIMEOUT] = 0x64,
[DMA_RING15_TIMEOUT] = 0x68,
[DMA_RING16_TIMEOUT] = 0x6C,
[DMA_INDEX2RING_0] = 0x70,
[DMA_INDEX2RING_1] = 0x74,
[DMA_INDEX2RING_2] = 0x78,
Expand All @@ -235,6 +269,23 @@ static const u8 bcmgenet_dma_regs_v2[] = {
[DMA_PRIORITY_0] = 0x34,
[DMA_PRIORITY_1] = 0x38,
[DMA_PRIORITY_2] = 0x3C,
[DMA_RING0_TIMEOUT] = 0x2C,
[DMA_RING1_TIMEOUT] = 0x30,
[DMA_RING2_TIMEOUT] = 0x34,
[DMA_RING3_TIMEOUT] = 0x38,
[DMA_RING4_TIMEOUT] = 0x3c,
[DMA_RING5_TIMEOUT] = 0x40,
[DMA_RING6_TIMEOUT] = 0x44,
[DMA_RING7_TIMEOUT] = 0x48,
[DMA_RING8_TIMEOUT] = 0x4c,
[DMA_RING9_TIMEOUT] = 0x50,
[DMA_RING10_TIMEOUT] = 0x54,
[DMA_RING11_TIMEOUT] = 0x58,
[DMA_RING12_TIMEOUT] = 0x5c,
[DMA_RING13_TIMEOUT] = 0x60,
[DMA_RING14_TIMEOUT] = 0x64,
[DMA_RING15_TIMEOUT] = 0x68,
[DMA_RING16_TIMEOUT] = 0x6C,
};

static const u8 bcmgenet_dma_regs_v1[] = {
Expand All @@ -245,6 +296,23 @@ static const u8 bcmgenet_dma_regs_v1[] = {
[DMA_PRIORITY_0] = 0x34,
[DMA_PRIORITY_1] = 0x38,
[DMA_PRIORITY_2] = 0x3C,
[DMA_RING0_TIMEOUT] = 0x2C,
[DMA_RING1_TIMEOUT] = 0x30,
[DMA_RING2_TIMEOUT] = 0x34,
[DMA_RING3_TIMEOUT] = 0x38,
[DMA_RING4_TIMEOUT] = 0x3c,
[DMA_RING5_TIMEOUT] = 0x40,
[DMA_RING6_TIMEOUT] = 0x44,
[DMA_RING7_TIMEOUT] = 0x48,
[DMA_RING8_TIMEOUT] = 0x4c,
[DMA_RING9_TIMEOUT] = 0x50,
[DMA_RING10_TIMEOUT] = 0x54,
[DMA_RING11_TIMEOUT] = 0x58,
[DMA_RING12_TIMEOUT] = 0x5c,
[DMA_RING13_TIMEOUT] = 0x60,
[DMA_RING14_TIMEOUT] = 0x64,
[DMA_RING15_TIMEOUT] = 0x68,
[DMA_RING16_TIMEOUT] = 0x6C,
};

/* Set at runtime once bcmgenet version is known */
Expand Down Expand Up @@ -506,6 +574,11 @@ static int bcmgenet_get_coalesce(struct net_device *dev,
ec->tx_max_coalesced_frames =
bcmgenet_tdma_ring_readl(priv, DESC_INDEX,
DMA_MBUF_DONE_THRESH);
ec->rx_max_coalesced_frames =
bcmgenet_rdma_ring_readl(priv, DESC_INDEX,
DMA_MBUF_DONE_THRESH);
ec->rx_coalesce_usecs =
bcmgenet_rdma_readl(priv, DMA_RING16_TIMEOUT) * 8192 / 1000;

return 0;
}
Expand All @@ -515,9 +588,19 @@ static int bcmgenet_set_coalesce(struct net_device *dev,
{
struct bcmgenet_priv *priv = netdev_priv(dev);
unsigned int i;
u32 reg;

/* Base system clock is 125Mhz, DMA timeout is this reference clock
* divided by 1024, which yields roughly 8.192us, our maximum value
* has to fit in the DMA_TIMEOUT_MASK (16 bits)
*/
if (ec->tx_max_coalesced_frames > DMA_INTR_THRESHOLD_MASK ||
ec->tx_max_coalesced_frames == 0)
ec->tx_max_coalesced_frames == 0 ||
ec->rx_max_coalesced_frames > DMA_INTR_THRESHOLD_MASK ||
ec->rx_coalesce_usecs > (DMA_TIMEOUT_MASK * 8) + 1)
return -EINVAL;

if (ec->rx_coalesce_usecs == 0 && ec->rx_max_coalesced_frames == 0)
return -EINVAL;

/* GENET TDMA hardware does not support a configurable timeout, but will
Expand All @@ -540,6 +623,26 @@ static int bcmgenet_set_coalesce(struct net_device *dev,
ec->tx_max_coalesced_frames,
DMA_MBUF_DONE_THRESH);

for (i = 0; i < priv->hw_params->rx_queues; i++) {
bcmgenet_rdma_ring_writel(priv, i,
ec->rx_max_coalesced_frames,
DMA_MBUF_DONE_THRESH);

reg = bcmgenet_rdma_readl(priv, DMA_RING0_TIMEOUT + i);
reg &= ~DMA_TIMEOUT_MASK;
reg |= DIV_ROUND_UP(ec->rx_coalesce_usecs * 1000, 8192);
bcmgenet_rdma_writel(priv, reg, DMA_RING0_TIMEOUT + i);
}

bcmgenet_rdma_ring_writel(priv, DESC_INDEX,
ec->rx_max_coalesced_frames,
DMA_MBUF_DONE_THRESH);

reg = bcmgenet_rdma_readl(priv, DMA_RING16_TIMEOUT);
reg &= ~DMA_TIMEOUT_MASK;
reg |= DIV_ROUND_UP(ec->rx_coalesce_usecs * 1000, 8192);
bcmgenet_rdma_writel(priv, reg, DMA_RING16_TIMEOUT);

return 0;
}

Expand Down
3 changes: 1 addition & 2 deletions drivers/net/ethernet/broadcom/genet/bcmgenet.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -304,8 +304,7 @@ struct bcmgenet_mib_counters {
#define UMAC_IRQ_RXDMA_MBDONE (1 << 13)
#define UMAC_IRQ_RXDMA_PDONE (1 << 14)
#define UMAC_IRQ_RXDMA_BDONE (1 << 15)
#define UMAC_IRQ_RXDMA_DONE (UMAC_IRQ_RXDMA_PDONE | \
UMAC_IRQ_RXDMA_BDONE)
#define UMAC_IRQ_RXDMA_DONE UMAC_IRQ_RXDMA_MBDONE
#define UMAC_IRQ_TXDMA_MBDONE (1 << 16)
#define UMAC_IRQ_TXDMA_PDONE (1 << 17)
#define UMAC_IRQ_TXDMA_BDONE (1 << 18)
Expand Down

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