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net: bcmgenet: Add support for adaptive RX coalescing
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Unlike the moder modern SYSTEMPORT hardware, we do not have a
configurable TDMA timeout, which limits us to implement adaptive RX
interrupt coalescing only. We have each of our RX rings implement a
bcmgenet_net_dim structure which holds an interrupt counter, number of
packets, bytes, and a container for a net_dim instance.

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 Mar 26, 2018
1 parent b6e0e87 commit 9f4ca05
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Showing 2 changed files with 103 additions and 18 deletions.
109 changes: 91 additions & 18 deletions drivers/net/ethernet/broadcom/genet/bcmgenet.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -603,6 +603,8 @@ static int bcmgenet_get_coalesce(struct net_device *dev,
struct ethtool_coalesce *ec)
{
struct bcmgenet_priv *priv = netdev_priv(dev);
struct bcmgenet_rx_ring *ring;
unsigned int i;

ec->tx_max_coalesced_frames =
bcmgenet_tdma_ring_readl(priv, DESC_INDEX,
Expand All @@ -613,15 +615,37 @@ static int bcmgenet_get_coalesce(struct net_device *dev,
ec->rx_coalesce_usecs =
bcmgenet_rdma_readl(priv, DMA_RING16_TIMEOUT) * 8192 / 1000;

for (i = 0; i < priv->hw_params->rx_queues; i++) {
ring = &priv->rx_rings[i];
ec->use_adaptive_rx_coalesce |= ring->dim.use_dim;
}
ring = &priv->rx_rings[DESC_INDEX];
ec->use_adaptive_rx_coalesce |= ring->dim.use_dim;

return 0;
}

static void bcmgenet_set_rx_coalesce(struct bcmgenet_rx_ring *ring)
{
struct bcmgenet_priv *priv = ring->priv;
unsigned int i = ring->index;
u32 reg;

bcmgenet_rdma_ring_writel(priv, i, ring->dim.coal_pkts,
DMA_MBUF_DONE_THRESH);

reg = bcmgenet_rdma_readl(priv, DMA_RING0_TIMEOUT + i);
reg &= ~DMA_TIMEOUT_MASK;
reg |= DIV_ROUND_UP(ring->dim.coal_usecs * 1000, 8192);
bcmgenet_rdma_writel(priv, reg, DMA_RING0_TIMEOUT + i);
}

static int bcmgenet_set_coalesce(struct net_device *dev,
struct ethtool_coalesce *ec)
{
struct bcmgenet_priv *priv = netdev_priv(dev);
struct bcmgenet_rx_ring *ring;
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
Expand All @@ -641,7 +665,8 @@ static int bcmgenet_set_coalesce(struct net_device *dev,
* transmitted, or when the ring is empty.
*/
if (ec->tx_coalesce_usecs || ec->tx_coalesce_usecs_high ||
ec->tx_coalesce_usecs_irq || ec->tx_coalesce_usecs_low)
ec->tx_coalesce_usecs_irq || ec->tx_coalesce_usecs_low ||
ec->use_adaptive_tx_coalesce)
return -EOPNOTSUPP;

/* Program all TX queues with the same values, as there is no
Expand All @@ -656,24 +681,26 @@ static int bcmgenet_set_coalesce(struct net_device *dev,
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);
ring = &priv->rx_rings[i];
ring->dim.coal_usecs = ec->rx_coalesce_usecs;
ring->dim.coal_pkts = ec->rx_max_coalesced_frames;
if (!ec->use_adaptive_rx_coalesce && ring->dim.use_dim) {
ring->dim.coal_pkts = 1;
ring->dim.coal_usecs = 0;
}
ring->dim.use_dim = ec->use_adaptive_rx_coalesce;
bcmgenet_set_rx_coalesce(ring);
}

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);
ring = &priv->rx_rings[DESC_INDEX];
ring->dim.coal_usecs = ec->rx_coalesce_usecs;
ring->dim.coal_pkts = ec->rx_max_coalesced_frames;
if (!ec->use_adaptive_rx_coalesce && ring->dim.use_dim) {
ring->dim.coal_pkts = 1;
ring->dim.coal_usecs = 0;
}
ring->dim.use_dim = ec->use_adaptive_rx_coalesce;
bcmgenet_set_rx_coalesce(ring);

return 0;
}
Expand Down Expand Up @@ -1713,6 +1740,7 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_rx_ring *ring,
unsigned long dma_flag;
int len;
unsigned int rxpktprocessed = 0, rxpkttoprocess;
unsigned int bytes_processed = 0;
unsigned int p_index, mask;
unsigned int discards;
unsigned int chksum_ok = 0;
Expand Down Expand Up @@ -1832,6 +1860,8 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_rx_ring *ring,
len -= ETH_FCS_LEN;
}

bytes_processed += len;

/*Finish setting up the received SKB and send it to the kernel*/
skb->protocol = eth_type_trans(skb, priv->dev);
ring->packets++;
Expand All @@ -1854,6 +1884,9 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_rx_ring *ring,
bcmgenet_rdma_ring_writel(priv, ring->index, ring->c_index, RDMA_CONS_INDEX);
}

ring->dim.bytes = bytes_processed;
ring->dim.packets = rxpktprocessed;

return rxpktprocessed;
}

Expand All @@ -1862,6 +1895,7 @@ static int bcmgenet_rx_poll(struct napi_struct *napi, int budget)
{
struct bcmgenet_rx_ring *ring = container_of(napi,
struct bcmgenet_rx_ring, napi);
struct net_dim_sample dim_sample;
unsigned int work_done;

work_done = bcmgenet_desc_rx(ring, budget);
Expand All @@ -1871,9 +1905,32 @@ static int bcmgenet_rx_poll(struct napi_struct *napi, int budget)
ring->int_enable(ring);
}

if (ring->dim.use_dim) {
net_dim_sample(ring->dim.event_ctr, ring->dim.packets,
ring->dim.bytes, &dim_sample);
net_dim(&ring->dim.dim, dim_sample);
}

return work_done;
}

static void bcmgenet_dim_work(struct work_struct *work)
{
struct net_dim *dim = container_of(work, struct net_dim, work);
struct bcmgenet_net_dim *ndim =
container_of(dim, struct bcmgenet_net_dim, dim);
struct bcmgenet_rx_ring *ring =
container_of(ndim, struct bcmgenet_rx_ring, dim);
struct net_dim_cq_moder cur_profile =
net_dim_get_profile(dim->mode, dim->profile_ix);

ring->dim.coal_usecs = cur_profile.usec;
ring->dim.coal_pkts = cur_profile.pkts;

bcmgenet_set_rx_coalesce(ring);
dim->state = NET_DIM_START_MEASURE;
}

/* Assign skb to RX DMA descriptor. */
static int bcmgenet_alloc_rx_buffers(struct bcmgenet_priv *priv,
struct bcmgenet_rx_ring *ring)
Expand Down Expand Up @@ -2022,6 +2079,16 @@ static void init_umac(struct bcmgenet_priv *priv)
dev_dbg(kdev, "done init umac\n");
}

static void bcmgenet_init_dim(struct bcmgenet_net_dim *dim,
void (*cb)(struct work_struct *work))
{
INIT_WORK(&dim->dim.work, cb);
dim->dim.mode = NET_DIM_CQ_PERIOD_MODE_START_FROM_EQE;
dim->event_ctr = 0;
dim->packets = 0;
dim->bytes = 0;
}

/* Initialize a Tx ring along with corresponding hardware registers */
static void bcmgenet_init_tx_ring(struct bcmgenet_priv *priv,
unsigned int index, unsigned int size,
Expand Down Expand Up @@ -2111,6 +2178,8 @@ static int bcmgenet_init_rx_ring(struct bcmgenet_priv *priv,
if (ret)
return ret;

bcmgenet_init_dim(&ring->dim, bcmgenet_dim_work);

/* Initialize Rx NAPI */
netif_napi_add(priv->dev, &ring->napi, bcmgenet_rx_poll,
NAPI_POLL_WEIGHT);
Expand Down Expand Up @@ -2276,10 +2345,12 @@ static void bcmgenet_disable_rx_napi(struct bcmgenet_priv *priv)
for (i = 0; i < priv->hw_params->rx_queues; ++i) {
ring = &priv->rx_rings[i];
napi_disable(&ring->napi);
cancel_work_sync(&ring->dim.dim.work);
}

ring = &priv->rx_rings[DESC_INDEX];
napi_disable(&ring->napi);
cancel_work_sync(&ring->dim.dim.work);
}

static void bcmgenet_fini_rx_napi(struct bcmgenet_priv *priv)
Expand Down Expand Up @@ -2557,6 +2628,7 @@ static irqreturn_t bcmgenet_isr1(int irq, void *dev_id)
continue;

rx_ring = &priv->rx_rings[index];
rx_ring->dim.event_ctr++;

if (likely(napi_schedule_prep(&rx_ring->napi))) {
rx_ring->int_disable(rx_ring);
Expand Down Expand Up @@ -2601,6 +2673,7 @@ static irqreturn_t bcmgenet_isr0(int irq, void *dev_id)

if (status & UMAC_IRQ_RXDMA_DONE) {
rx_ring = &priv->rx_rings[DESC_INDEX];
rx_ring->dim.event_ctr++;

if (likely(napi_schedule_prep(&rx_ring->napi))) {
rx_ring->int_disable(rx_ring);
Expand Down
12 changes: 12 additions & 0 deletions drivers/net/ethernet/broadcom/genet/bcmgenet.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
#include <linux/mii.h>
#include <linux/if_vlan.h>
#include <linux/phy.h>
#include <linux/net_dim.h>

/* total number of Buffer Descriptors, same for Rx/Tx */
#define TOTAL_DESC 256
Expand Down Expand Up @@ -572,6 +573,16 @@ struct bcmgenet_tx_ring {
struct bcmgenet_priv *priv;
};

struct bcmgenet_net_dim {
u16 use_dim;
u16 event_ctr;
unsigned long packets;
unsigned long bytes;
u32 coal_usecs;
u32 coal_pkts;
struct net_dim dim;
};

struct bcmgenet_rx_ring {
struct napi_struct napi; /* Rx NAPI struct */
unsigned long bytes;
Expand All @@ -586,6 +597,7 @@ struct bcmgenet_rx_ring {
unsigned int cb_ptr; /* Rx ring initial CB ptr */
unsigned int end_ptr; /* Rx ring end CB ptr */
unsigned int old_discards;
struct bcmgenet_net_dim dim;
void (*int_enable)(struct bcmgenet_rx_ring *);
void (*int_disable)(struct bcmgenet_rx_ring *);
struct bcmgenet_priv *priv;
Expand Down

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