diff mbox series

[v3,08/16] can: m_can: Implement transmit coalescing

Message ID 20230315110546.2518305-9-msp@baylibre.com (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series can: m_can: Optimizations for m_can/tcan part 2 | expand

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Commit Message

Markus Schneider-Pargmann March 15, 2023, 11:05 a.m. UTC
Extend the coalescing implementation for transmits.

In normal mode the chip raises an interrupt for every finished transmit.
This implementation switches to coalescing mode as soon as an interrupt
handled a transmit. For coalescing the watermark level interrupt is used
to interrupt exactly after x frames were sent. It switches back into
normal mode once there was an interrupt with no finished transmit and
the timer being inactive.

The timer is shared with receive coalescing. The time for receive and
transmit coalescing timers have to be the same for that to work. The
benefit is to have only a single running timer.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
---
 drivers/net/can/m_can/m_can.c | 33 ++++++++++++++++++++-------------
 drivers/net/can/m_can/m_can.h |  3 +++
 2 files changed, 23 insertions(+), 13 deletions(-)

Comments

Simon Horman March 16, 2023, 10:05 a.m. UTC | #1
On Wed, Mar 15, 2023 at 12:05:38PM +0100, Markus Schneider-Pargmann wrote:
> Extend the coalescing implementation for transmits.
> 
> In normal mode the chip raises an interrupt for every finished transmit.
> This implementation switches to coalescing mode as soon as an interrupt
> handled a transmit. For coalescing the watermark level interrupt is used
> to interrupt exactly after x frames were sent. It switches back into
> normal mode once there was an interrupt with no finished transmit and
> the timer being inactive.
> 
> The timer is shared with receive coalescing. The time for receive and
> transmit coalescing timers have to be the same for that to work. The
> benefit is to have only a single running timer.
> 
> Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>

Reviewed-by: Simon Horman <simon.horman@corigine.com>
diff mbox series

Patch

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index e7dc083e32e4..94c962ac6992 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -255,6 +255,7 @@  enum m_can_reg {
 #define TXESC_TBDS_64B		0x7
 
 /* Tx Event FIFO Configuration (TXEFC) */
+#define TXEFC_EFWM_MASK		GENMASK(29, 24)
 #define TXEFC_EFS_MASK		GENMASK(21, 16)
 
 /* Tx Event FIFO Status (TXEFS) */
@@ -1080,7 +1081,7 @@  static void m_can_interrupt_enable(struct m_can_classdev *cdev, u32 interrupts)
 
 static void m_can_coalescing_disable(struct m_can_classdev *cdev)
 {
-	u32 new_interrupts = cdev->active_interrupts | IR_RF0N;
+	u32 new_interrupts = cdev->active_interrupts | IR_RF0N | IR_TEFN;
 
 	hrtimer_cancel(&cdev->irq_timer);
 	m_can_interrupt_enable(cdev, new_interrupts);
@@ -1089,21 +1090,26 @@  static void m_can_coalescing_disable(struct m_can_classdev *cdev)
 static void m_can_coalescing_update(struct m_can_classdev *cdev, u32 ir)
 {
 	u32 new_interrupts = cdev->active_interrupts;
-	bool enable_timer = false;
+	bool enable_rx_timer = false;
+	bool enable_tx_timer = false;
 
 	if (cdev->rx_coalesce_usecs_irq > 0 && (ir & (IR_RF0N | IR_RF0W))) {
-		enable_timer = true;
+		enable_rx_timer = true;
 		new_interrupts &= ~IR_RF0N;
-	} else if (!hrtimer_active(&cdev->irq_timer)) {
-		new_interrupts |= IR_RF0N;
 	}
+	if (cdev->tx_coalesce_usecs_irq > 0 && (ir & (IR_TEFN | IR_TEFW))) {
+		enable_tx_timer = true;
+		new_interrupts &= ~IR_TEFN;
+	}
+	if (!enable_rx_timer && !hrtimer_active(&cdev->irq_timer))
+		new_interrupts |= IR_RF0N;
+	if (!enable_tx_timer && !hrtimer_active(&cdev->irq_timer))
+		new_interrupts |= IR_TEFN;
 
 	m_can_interrupt_enable(cdev, new_interrupts);
-	if (enable_timer) {
-		hrtimer_start(&cdev->irq_timer,
-			      ns_to_ktime(cdev->rx_coalesce_usecs_irq * NSEC_PER_USEC),
+	if (enable_rx_timer | enable_tx_timer)
+		hrtimer_start(&cdev->irq_timer, cdev->irq_timer_wait,
 			      HRTIMER_MODE_REL);
-	}
 }
 
 static irqreturn_t m_can_isr(int irq, void *dev_id)
@@ -1158,7 +1164,7 @@  static irqreturn_t m_can_isr(int irq, void *dev_id)
 			netif_wake_queue(dev);
 		}
 	} else  {
-		if (ir & IR_TEFN) {
+		if (ir & (IR_TEFN | IR_TEFW)) {
 			/* New TX FIFO Element arrived */
 			if (m_can_echo_tx_event(dev) != 0)
 				goto out_fail;
@@ -1326,9 +1332,8 @@  static int m_can_chip_config(struct net_device *dev)
 	}
 
 	/* Disable unused interrupts */
-	interrupts &= ~(IR_ARA | IR_ELO | IR_DRX | IR_TEFF | IR_TEFW | IR_TFE |
-			IR_TCF | IR_HPM | IR_RF1F | IR_RF1W | IR_RF1N |
-			IR_RF0F);
+	interrupts &= ~(IR_ARA | IR_ELO | IR_DRX | IR_TEFF | IR_TFE | IR_TCF |
+			IR_HPM | IR_RF1F | IR_RF1W | IR_RF1N | IR_RF0F);
 
 	m_can_config_endisable(cdev, true);
 
@@ -1365,6 +1370,8 @@  static int m_can_chip_config(struct net_device *dev)
 	} else {
 		/* Full TX Event FIFO is used */
 		m_can_write(cdev, M_CAN_TXEFC,
+			    FIELD_PREP(TXEFC_EFWM_MASK,
+				       cdev->tx_max_coalesced_frames_irq) |
 			    FIELD_PREP(TXEFC_EFS_MASK,
 				       cdev->mcfg[MRAM_TXE].num) |
 			    cdev->mcfg[MRAM_TXE].off);
diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
index c59099d3f5b9..d0c21eddb6ec 100644
--- a/drivers/net/can/m_can/m_can.h
+++ b/drivers/net/can/m_can/m_can.h
@@ -85,6 +85,7 @@  struct m_can_classdev {
 	struct phy *transceiver;
 
 	struct hrtimer irq_timer;
+	ktime_t irq_timer_wait;
 
 	struct m_can_ops *ops;
 
@@ -98,6 +99,8 @@  struct m_can_classdev {
 	u32 active_interrupts;
 	u32 rx_max_coalesced_frames_irq;
 	u32 rx_coalesce_usecs_irq;
+	u32 tx_max_coalesced_frames_irq;
+	u32 tx_coalesce_usecs_irq;
 
 	struct mram_cfg mcfg[MRAM_CFG_NUM];
 };