[PATCH net-next v2 09/15] net: ethernet: mtk_eth_soc: implement dynamic interrupt moderation

From: Ilya Lipnitskiy
Date: Fri Apr 23 2021 - 01:21:56 EST

From: Felix Fietkau <nbd@xxxxxxxx>

Reduces the number of interrupts under load

Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
[Ilya: add documentation for new struct fields]
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@xxxxxxxxx>
---
drivers/net/ethernet/mediatek/Kconfig | 1 +
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 96 +++++++++++++++++++--
drivers/net/ethernet/mediatek/mtk_eth_soc.h | 41 +++++++--
3 files changed, 124 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/Kconfig b/drivers/net/ethernet/mediatek/Kconfig
index 08c2e446d3d5..c357c193378e 100644
--- a/drivers/net/ethernet/mediatek/Kconfig
+++ b/drivers/net/ethernet/mediatek/Kconfig
@@ -11,6 +11,7 @@ config NET_MEDIATEK_SOC
tristate "MediaTek SoC Gigabit Ethernet support"
depends on NET_DSA || !NET_DSA
select PHYLINK
+ select DIMLIB
help
This driver supports the gigabit ethernet MACs in the
MediaTek SoC family.
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 645360cfdfe9..762e985fa294 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -1233,12 +1233,13 @@ static void mtk_update_rx_cpu_idx(struct mtk_eth *eth)
static int mtk_poll_rx(struct napi_struct *napi, int budget,
struct mtk_eth *eth)
{
+ struct dim_sample dim_sample = {};
struct mtk_rx_ring *ring;
int idx;
struct sk_buff *skb;
u8 *data, *new_data;
struct mtk_rx_dma *rxd, trxd;
- int done = 0;
+ int done = 0, bytes = 0;

while (done < budget) {
struct net_device *netdev;
@@ -1312,6 +1313,7 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
else
skb_checksum_none_assert(skb);
skb->protocol = eth_type_trans(skb, netdev);
+ bytes += pktlen;

if (netdev->features & NETIF_F_HW_VLAN_CTAG_RX &&
(trxd.rxd2 & RX_DMA_VTAG))
@@ -1344,6 +1346,12 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
mtk_update_rx_cpu_idx(eth);
}

+ eth->rx_packets += done;
+ eth->rx_bytes += bytes;
+ dim_update_sample(eth->rx_events, eth->rx_packets, eth->rx_bytes,
+ &dim_sample);
+ net_dim(&eth->rx_dim, dim_sample);
+
return done;
}

@@ -1436,6 +1444,7 @@ static int mtk_poll_tx_pdma(struct mtk_eth *eth, int budget,
static int mtk_poll_tx(struct mtk_eth *eth, int budget)
{
struct mtk_tx_ring *ring = &eth->tx_ring;
+ struct dim_sample dim_sample = {};
unsigned int done[MTK_MAX_DEVS];
unsigned int bytes[MTK_MAX_DEVS];
int total = 0, i;
@@ -1453,8 +1462,14 @@ static int mtk_poll_tx(struct mtk_eth *eth, int budget)
continue;
netdev_completed_queue(eth->netdev[i], done[i], bytes[i]);
total += done[i];
+ eth->tx_packets += done[i];
+ eth->tx_bytes += bytes[i];
}

+ dim_update_sample(eth->tx_events, eth->tx_packets, eth->tx_bytes,
+ &dim_sample);
+ net_dim(&eth->tx_dim, dim_sample);
+
if (mtk_queue_stopped(eth) &&
(atomic_read(&ring->free_count) > ring->thresh))
mtk_wake_queue(eth);
@@ -2129,6 +2144,7 @@ static irqreturn_t mtk_handle_irq_rx(int irq, void *_eth)
{
struct mtk_eth *eth = _eth;

+ eth->rx_events++;
if (likely(napi_schedule_prep(&eth->rx_napi))) {
__napi_schedule(&eth->rx_napi);
mtk_rx_irq_disable(eth, MTK_RX_DONE_INT);
@@ -2141,6 +2157,7 @@ static irqreturn_t mtk_handle_irq_tx(int irq, void *_eth)
{
struct mtk_eth *eth = _eth;

+ eth->tx_events++;
if (likely(napi_schedule_prep(&eth->tx_napi))) {
__napi_schedule(&eth->tx_napi);
mtk_tx_irq_disable(eth, MTK_TX_DONE_INT);
@@ -2325,6 +2342,9 @@ static int mtk_stop(struct net_device *dev)
napi_disable(&eth->tx_napi);
napi_disable(&eth->rx_napi);

+ cancel_work_sync(&eth->rx_dim.work);
+ cancel_work_sync(&eth->tx_dim.work);
+
if (MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA))
mtk_stop_dma(eth, MTK_QDMA_GLO_CFG);
mtk_stop_dma(eth, MTK_PDMA_GLO_CFG);
@@ -2377,6 +2397,64 @@ static int mtk_clk_enable(struct mtk_eth *eth)
return ret;
}

+static void mtk_dim_rx(struct work_struct *work)
+{
+ struct dim *dim = container_of(work, struct dim, work);
+ struct mtk_eth *eth = container_of(dim, struct mtk_eth, rx_dim);
+ struct dim_cq_moder cur_profile;
+ u32 val, cur;
+
+ cur_profile = net_dim_get_rx_moderation(eth->rx_dim.mode,
+ dim->profile_ix);
+ spin_lock_bh(&eth->dim_lock);
+
+ val = mtk_r32(eth, MTK_PDMA_DELAY_INT);
+ val &= MTK_PDMA_DELAY_TX_MASK;
+ val |= MTK_PDMA_DELAY_RX_EN;
+
+ cur = min_t(u32, DIV_ROUND_UP(cur_profile.usec, 20), MTK_PDMA_DELAY_PTIME_MASK);
+ val |= cur << MTK_PDMA_DELAY_RX_PTIME_SHIFT;
+
+ cur = min_t(u32, cur_profile.pkts, MTK_PDMA_DELAY_PINT_MASK);
+ val |= cur << MTK_PDMA_DELAY_RX_PINT_SHIFT;
+
+ mtk_w32(eth, val, MTK_PDMA_DELAY_INT);
+ mtk_w32(eth, val, MTK_QDMA_DELAY_INT);
+
+ spin_unlock_bh(&eth->dim_lock);
+
+ dim->state = DIM_START_MEASURE;
+}
+
+static void mtk_dim_tx(struct work_struct *work)
+{
+ struct dim *dim = container_of(work, struct dim, work);
+ struct mtk_eth *eth = container_of(dim, struct mtk_eth, tx_dim);
+ struct dim_cq_moder cur_profile;
+ u32 val, cur;
+
+ cur_profile = net_dim_get_tx_moderation(eth->tx_dim.mode,
+ dim->profile_ix);
+ spin_lock_bh(&eth->dim_lock);
+
+ val = mtk_r32(eth, MTK_PDMA_DELAY_INT);
+ val &= MTK_PDMA_DELAY_RX_MASK;
+ val |= MTK_PDMA_DELAY_TX_EN;
+
+ cur = min_t(u32, DIV_ROUND_UP(cur_profile.usec, 20), MTK_PDMA_DELAY_PTIME_MASK);
+ val |= cur << MTK_PDMA_DELAY_TX_PTIME_SHIFT;
+
+ cur = min_t(u32, cur_profile.pkts, MTK_PDMA_DELAY_PINT_MASK);
+ val |= cur << MTK_PDMA_DELAY_TX_PINT_SHIFT;
+
+ mtk_w32(eth, val, MTK_PDMA_DELAY_INT);
+ mtk_w32(eth, val, MTK_QDMA_DELAY_INT);
+
+ spin_unlock_bh(&eth->dim_lock);
+
+ dim->state = DIM_START_MEASURE;
+}
+
static int mtk_hw_init(struct mtk_eth *eth)
{
int i, val, ret;
@@ -2398,9 +2476,6 @@ static int mtk_hw_init(struct mtk_eth *eth)
goto err_disable_pm;
}

- /* enable interrupt delay for RX */
- mtk_w32(eth, MTK_PDMA_DELAY_RX_DELAY, MTK_PDMA_DELAY_INT);
-
/* disable delay and normal interrupt */
mtk_tx_irq_disable(eth, ~0);
mtk_rx_irq_disable(eth, ~0);
@@ -2439,11 +2514,11 @@ static int mtk_hw_init(struct mtk_eth *eth)
/* Enable RX VLan Offloading */
mtk_w32(eth, 1, MTK_CDMP_EG_CTRL);

- /* enable interrupt delay for RX */
- mtk_w32(eth, MTK_PDMA_DELAY_RX_DELAY, MTK_PDMA_DELAY_INT);
+ /* set interrupt delays based on current Net DIM sample */
+ mtk_dim_rx(&eth->rx_dim.work);
+ mtk_dim_tx(&eth->tx_dim.work);

/* disable delay and normal interrupt */
- mtk_w32(eth, 0, MTK_QDMA_DELAY_INT);
mtk_tx_irq_disable(eth, ~0);
mtk_rx_irq_disable(eth, ~0);

@@ -2978,6 +3053,13 @@ static int mtk_probe(struct platform_device *pdev)
spin_lock_init(&eth->page_lock);
spin_lock_init(&eth->tx_irq_lock);
spin_lock_init(&eth->rx_irq_lock);
+ spin_lock_init(&eth->dim_lock);
+
+ eth->rx_dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE;
+ INIT_WORK(&eth->rx_dim.work, mtk_dim_rx);
+
+ eth->tx_dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE;
+ INIT_WORK(&eth->tx_dim.work, mtk_dim_tx);

if (!MTK_HAS_CAPS(eth->soc->caps, MTK_SOC_MT7628)) {
eth->ethsys = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 540a5771b7bf..ceb5a4a661e6 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -16,6 +16,7 @@
#include <linux/refcount.h>
#include <linux/phylink.h>
#include <linux/rhashtable.h>
+#include <linux/dim.h>
#include "mtk_ppe.h"

#define MTK_QDMA_PAGE_SIZE 2048
@@ -137,13 +138,18 @@

/* PDMA Delay Interrupt Register */
#define MTK_PDMA_DELAY_INT 0xa0c
+#define MTK_PDMA_DELAY_RX_MASK GENMASK(15, 0)
#define MTK_PDMA_DELAY_RX_EN BIT(15)
-#define MTK_PDMA_DELAY_RX_PINT 4
#define MTK_PDMA_DELAY_RX_PINT_SHIFT 8
-#define MTK_PDMA_DELAY_RX_PTIME 4
-#define MTK_PDMA_DELAY_RX_DELAY \
- (MTK_PDMA_DELAY_RX_EN | MTK_PDMA_DELAY_RX_PTIME | \
- (MTK_PDMA_DELAY_RX_PINT << MTK_PDMA_DELAY_RX_PINT_SHIFT))
+#define MTK_PDMA_DELAY_RX_PTIME_SHIFT 0
+
+#define MTK_PDMA_DELAY_TX_MASK GENMASK(31, 16)
+#define MTK_PDMA_DELAY_TX_EN BIT(31)
+#define MTK_PDMA_DELAY_TX_PINT_SHIFT 24
+#define MTK_PDMA_DELAY_TX_PTIME_SHIFT 16
+
+#define MTK_PDMA_DELAY_PINT_MASK 0x7f
+#define MTK_PDMA_DELAY_PTIME_MASK 0xff

/* PDMA Interrupt Status Register */
#define MTK_PDMA_INT_STATUS 0xa20
@@ -225,6 +231,7 @@
/* QDMA Interrupt Status Register */
#define MTK_QDMA_INT_STATUS 0x1A18
#define MTK_RX_DONE_DLY BIT(30)
+#define MTK_TX_DONE_DLY BIT(28)
#define MTK_RX_DONE_INT3 BIT(19)
#define MTK_RX_DONE_INT2 BIT(18)
#define MTK_RX_DONE_INT1 BIT(17)
@@ -234,8 +241,7 @@
#define MTK_TX_DONE_INT1 BIT(1)
#define MTK_TX_DONE_INT0 BIT(0)
#define MTK_RX_DONE_INT MTK_RX_DONE_DLY
-#define MTK_TX_DONE_INT (MTK_TX_DONE_INT0 | MTK_TX_DONE_INT1 | \
- MTK_TX_DONE_INT2 | MTK_TX_DONE_INT3)
+#define MTK_TX_DONE_INT MTK_TX_DONE_DLY

/* QDMA Interrupt grouping registers */
#define MTK_QDMA_INT_GRP1 0x1a20
@@ -849,6 +855,7 @@ struct mtk_sgmii {
* @page_lock: Make sure that register operations are atomic
* @tx_irq__lock: Make sure that IRQ register operations are atomic
* @rx_irq__lock: Make sure that IRQ register operations are atomic
+ * @dim_lock: Make sure that Net DIM operations are atomic
* @dummy_dev: we run 2 netdevs on 1 physical DMA ring and need a
* dummy for NAPI to work
* @netdev: The netdev instances
@@ -867,6 +874,14 @@ struct mtk_sgmii {
* @rx_ring_qdma: Pointer to the memory holding info about the QDMA RX ring
* @tx_napi: The TX NAPI struct
* @rx_napi: The RX NAPI struct
+ * @rx_events: Net DIM RX event counter
+ * @rx_packets: Net DIM RX packet counter
+ * @rx_bytes: Net DIM RX byte counter
+ * @rx_dim: Net DIM RX context
+ * @tx_events: Net DIM TX event counter
+ * @tx_packets: Net DIM TX packet counter
+ * @tx_bytes: Net DIM TX byte counter
+ * @tx_dim: Net DIM TX context
* @scratch_ring: Newer SoCs need memory for a second HW managed TX ring
* @phy_scratch_ring: physical address of scratch_ring
* @scratch_head: The scratch memory that scratch_ring points to.
@@ -911,6 +926,18 @@ struct mtk_eth {

const struct mtk_soc_data *soc;

+ spinlock_t dim_lock;
+
+ u32 rx_events;
+ u32 rx_packets;
+ u32 rx_bytes;
+ struct dim rx_dim;
+
+ u32 tx_events;
+ u32 tx_packets;
+ u32 tx_bytes;
+ struct dim tx_dim;
+
u32 tx_int_mask_reg;
u32 tx_int_status_reg;
u32 rx_dma_l4_valid;
--
2.31.1