Commit b3cf53e9 authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
Browse files

can: flexcan: add support for timestamp based rx-offload 



The flexcan IP core has 64 mailboxes. For now they are configured for
RX as a hardware FIFO. This FIFO has a fixed depth of 6 CAN frames. In
some high load scenarios it turns out thas this buffer is too small.

In order to have a buffer larger than the 6 frames FIFO, this patch adds
support for timestamp based offloading via the generic rx-offload
infrastructure.

Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 9eb7aa89

drivers/net/can/flexcan.c

+129 −29
Original line number Diff line number Diff line
@@ -3,7 +3,8 @@ 
 *

 * Copyright (c) 2005-2006 Varma Electronics Oy

 * Copyright (c) 2009 Sascha Hauer, Pengutronix

 * Copyright (c) 2010 Marc Kleine-Budde, Pengutronix

 * Copyright (c) 2010-2017 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>

 * Copyright (c) 2014 David Jander, Protonic Holland

 *

 * Based on code originally by Andrey Volkov <avolkov@varma-el.com>

 *
@@ -59,6 +60,7 @@ 
#define FLEXCAN_MCR_IRMQ		BIT(16)

#define FLEXCAN_MCR_LPRIO_EN		BIT(13)

#define FLEXCAN_MCR_AEN			BIT(12)

/* MCR_MAXMB: maximum used MBs is MAXMB + 1 */

#define FLEXCAN_MCR_MAXMB(x)		((x) & 0x7f)

#define FLEXCAN_MCR_IDAM_A		(0x0 << 8)

#define FLEXCAN_MCR_IDAM_B		(0x1 << 8)
@@ -146,12 +148,18 @@ 
/* Errata ERR005829 step7: Reserve first valid MB */

#define FLEXCAN_TX_MB_RESERVED_OFF_FIFO	8

#define FLEXCAN_TX_MB_OFF_FIFO		9

#define FLEXCAN_TX_MB_RESERVED_OFF_TIMESTAMP	0

#define FLEXCAN_TX_MB_OFF_TIMESTAMP		1

#define FLEXCAN_RX_MB_OFF_TIMESTAMP_FIRST	(FLEXCAN_TX_MB_OFF_TIMESTAMP + 1)

#define FLEXCAN_RX_MB_OFF_TIMESTAMP_LAST	63

#define FLEXCAN_IFLAG_MB(x)		BIT(x)

#define FLEXCAN_IFLAG_RX_FIFO_OVERFLOW	BIT(7)

#define FLEXCAN_IFLAG_RX_FIFO_WARN	BIT(6)

#define FLEXCAN_IFLAG_RX_FIFO_AVAILABLE	BIT(5)



/* FLEXCAN message buffers */

#define FLEXCAN_MB_CODE_MASK		(0xf << 24)

#define FLEXCAN_MB_CODE_RX_BUSY_BIT	(0x1 << 24)

#define FLEXCAN_MB_CODE_RX_INACTIVE	(0x0 << 24)

#define FLEXCAN_MB_CODE_RX_EMPTY	(0x4 << 24)

#define FLEXCAN_MB_CODE_RX_FULL		(0x2 << 24)
@@ -189,6 +197,7 @@ 
#define FLEXCAN_QUIRK_DISABLE_RXFG	BIT(2) /* Disable RX FIFO Global mask */

#define FLEXCAN_QUIRK_ENABLE_EACEN_RRS	BIT(3) /* Enable EACEN and RRS bit in ctrl2 */

#define FLEXCAN_QUIRK_DISABLE_MECR	BIT(4) /* Disble Memory error detection */

#define FLEXCAN_QUIRK_USE_OFF_TIMESTAMP	BIT(5) /* Use timestamp based offloading */



/* Structure of the message buffer */

struct flexcan_mb {
@@ -263,6 +272,7 @@ struct flexcan_priv { 
	u8 tx_mb_idx;

	u32 reg_ctrl_default;

	u32 reg_imask1_default;

	u32 reg_imask2_default;



	struct clk *clk_ipg;

	struct clk *clk_per;
@@ -624,11 +634,32 @@ static unsigned int flexcan_mailbox_read(struct can_rx_offload *offload, 
	struct flexcan_mb __iomem *mb = &regs->mb[n];

	u32 reg_ctrl, reg_id, reg_iflag1;



	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {

		u32 code;



		do {

			reg_ctrl = flexcan_read(&mb->can_ctrl);

		} while (reg_ctrl & FLEXCAN_MB_CODE_RX_BUSY_BIT);



		/* is this MB empty? */

		code = reg_ctrl & FLEXCAN_MB_CODE_MASK;

		if ((code != FLEXCAN_MB_CODE_RX_FULL) &&

		    (code != FLEXCAN_MB_CODE_RX_OVERRUN))

			return 0;



		if (code == FLEXCAN_MB_CODE_RX_OVERRUN) {

			/* This MB was overrun, we lost data */

			offload->dev->stats.rx_over_errors++;

			offload->dev->stats.rx_errors++;

		}

	} else {

		reg_iflag1 = flexcan_read(&regs->iflag1);

		if (!(reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE))

			return 0;



		reg_ctrl = flexcan_read(&mb->can_ctrl);

	}



	/* increase timstamp to full 32 bit */

	*timestamp = reg_ctrl << 16;
@@ -646,12 +677,33 @@ static unsigned int flexcan_mailbox_read(struct can_rx_offload *offload, 
	*(__be32 *)(cf->data + 4) = cpu_to_be32(flexcan_read(&mb->data[1]));



	/* mark as read */

	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {

		/* Clear IRQ */

		if (n < 32)

			flexcan_write(BIT(n), &regs->iflag1);

		else

			flexcan_write(BIT(n - 32), &regs->iflag2);

	} else {

		flexcan_write(FLEXCAN_IFLAG_RX_FIFO_AVAILABLE, &regs->iflag1);

		flexcan_read(&regs->timer);

	}



	return 1;

}





static inline u64 flexcan_read_reg_iflag_rx(struct flexcan_priv *priv)

{

	struct flexcan_regs __iomem *regs = priv->regs;

	u32 iflag1, iflag2;



	iflag2 = flexcan_read(&regs->iflag2) & priv->reg_imask2_default;

	iflag1 = flexcan_read(&regs->iflag1) & priv->reg_imask1_default &

		~FLEXCAN_IFLAG_MB(priv->tx_mb_idx);



	return (u64)iflag2 << 32 | iflag1;

}



static irqreturn_t flexcan_irq(int irq, void *dev_id)

{

	struct net_device *dev = dev_id;
@@ -664,6 +716,18 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id) 
	reg_iflag1 = flexcan_read(&regs->iflag1);



	/* reception interrupt */

	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {

		u64 reg_iflag;

		int ret;



		while ((reg_iflag = flexcan_read_reg_iflag_rx(priv))) {

			handled = IRQ_HANDLED;

			ret = can_rx_offload_irq_offload_timestamp(&priv->offload,

								   reg_iflag);

			if (!ret)

				break;

		}

	} else {

		if (reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE) {

			handled = IRQ_HANDLED;

			can_rx_offload_irq_offload_fifo(&priv->offload);
@@ -676,6 +740,7 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id) 
			dev->stats.rx_over_errors++;

			dev->stats.rx_errors++;

		}

	}



	/* transmission complete interrupt */

	if (reg_iflag1 & FLEXCAN_IFLAG_MB(priv->tx_mb_idx)) {
@@ -787,10 +852,17 @@ static int flexcan_chip_start(struct net_device *dev) 
	 */

	reg_mcr = flexcan_read(&regs->mcr);

	reg_mcr &= ~FLEXCAN_MCR_MAXMB(0xff);

	reg_mcr |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_FEN | FLEXCAN_MCR_HALT |

		FLEXCAN_MCR_SUPV | FLEXCAN_MCR_WRN_EN | FLEXCAN_MCR_SRX_DIS |

		FLEXCAN_MCR_IRMQ | FLEXCAN_MCR_IDAM_C |

	reg_mcr |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT | FLEXCAN_MCR_SUPV |

		FLEXCAN_MCR_WRN_EN | FLEXCAN_MCR_SRX_DIS | FLEXCAN_MCR_IRMQ |

		FLEXCAN_MCR_IDAM_C;



	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {

		reg_mcr &= ~FLEXCAN_MCR_FEN;

		reg_mcr |= FLEXCAN_MCR_MAXMB(priv->offload.mb_last);

	} else {

		reg_mcr |= FLEXCAN_MCR_FEN |

			FLEXCAN_MCR_MAXMB(priv->tx_mb_idx);

	}

	netdev_dbg(dev, "%s: writing mcr=0x%08x", __func__, reg_mcr);

	flexcan_write(reg_mcr, &regs->mcr);
@@ -839,6 +911,12 @@ static int flexcan_chip_start(struct net_device *dev) 
			      &regs->mb[i].can_ctrl);

	}



	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {

		for (i = priv->offload.mb_first; i <= priv->offload.mb_last; i++)

			flexcan_write(FLEXCAN_MB_CODE_RX_EMPTY,

				      &regs->mb[i].can_ctrl);

	}



	/* Errata ERR005829: mark first TX mailbox as INACTIVE */

	flexcan_write(FLEXCAN_MB_CODE_TX_INACTIVE,

		      &priv->tx_mb_reserved->can_ctrl);
@@ -897,6 +975,7 @@ static int flexcan_chip_start(struct net_device *dev) 
	disable_irq(dev->irq);

	flexcan_write(priv->reg_ctrl_default, &regs->ctrl);

	flexcan_write(priv->reg_imask1_default, &regs->imask1);

	flexcan_write(priv->reg_imask2_default, &regs->imask2);

	enable_irq(dev->irq);



	/* print chip status */
@@ -926,6 +1005,7 @@ static void flexcan_chip_stop(struct net_device *dev) 
	flexcan_chip_disable(priv);



	/* Disable all interrupts */

	flexcan_write(0, &regs->imask2);

	flexcan_write(0, &regs->imask1);

	flexcan_write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,

		      &regs->ctrl);
@@ -1058,8 +1138,9 @@ static int register_flexcandev(struct net_device *dev) 
	flexcan_write(reg, &regs->mcr);



	/* Currently we only support newer versions of this core

	 * featuring a RX FIFO. Older cores found on some Coldfire

	 * derivates are not yet supported.

	 * featuring a RX hardware FIFO (although this driver doesn't

	 * make use of it on some cores). Older cores, found on some

	 * Coldfire derivates are not tested.

	 */

	reg = flexcan_read(&regs->mcr);

	if (!(reg & FLEXCAN_MCR_FEN)) {
@@ -1183,17 +1264,36 @@ static int flexcan_probe(struct platform_device *pdev) 
	priv->devtype_data = devtype_data;

	priv->reg_xceiver = reg_xceiver;



	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {

		priv->tx_mb_idx = FLEXCAN_TX_MB_OFF_TIMESTAMP;

		priv->tx_mb_reserved = &regs->mb[FLEXCAN_TX_MB_RESERVED_OFF_TIMESTAMP];

	} else {

		priv->tx_mb_idx = FLEXCAN_TX_MB_OFF_FIFO;

		priv->tx_mb_reserved = &regs->mb[FLEXCAN_TX_MB_RESERVED_OFF_FIFO];

	}

	priv->tx_mb = &regs->mb[priv->tx_mb_idx];



	priv->reg_imask1_default = FLEXCAN_IFLAG_RX_FIFO_OVERFLOW |

		FLEXCAN_IFLAG_RX_FIFO_AVAILABLE |

		FLEXCAN_IFLAG_MB(priv->tx_mb_idx);

	priv->reg_imask1_default = FLEXCAN_IFLAG_MB(priv->tx_mb_idx);

	priv->reg_imask2_default = 0;



	priv->offload.mailbox_read = flexcan_mailbox_read;



	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {

		u64 imask;



		priv->offload.mb_first = FLEXCAN_RX_MB_OFF_TIMESTAMP_FIRST;

		priv->offload.mb_last = FLEXCAN_RX_MB_OFF_TIMESTAMP_LAST;



		imask = GENMASK_ULL(priv->offload.mb_last, priv->offload.mb_first);

		priv->reg_imask1_default |= imask;

		priv->reg_imask2_default |= imask >> 32;



		err = can_rx_offload_add_timestamp(dev, &priv->offload);

	} else {

		priv->reg_imask1_default |= FLEXCAN_IFLAG_RX_FIFO_OVERFLOW |

			FLEXCAN_IFLAG_RX_FIFO_AVAILABLE;

		err = can_rx_offload_add_fifo(dev, &priv->offload, FLEXCAN_NAPI_WEIGHT);

	}

	if (err)

		goto failed_offload;

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