From e45c98decbb16e58a79c7ec6fbe4374320e814f1 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Fri, 10 Sep 2021 17:20:45 +0100
Subject: [PATCH] net: macb: Also set DMA coherent mask

macb: Add device tree properties that allow configuration of the AXI max pipeline register

net: macb: add support for ethtool interrupt moderation configuration

Only global throttling of rx or tx by time quanta is supported.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>

macb: add platform device shutdown function. Prevents AXI master over PCIE from hanging when the host is rebooted.

net: macb: increase polling interval for MDIO completion

MDIO is a slow bus (single-digit MHz). Polling at 1us intervals
is a bit aggressive, so increase to 100us as the transaction
usually takes 100-200us to complete.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>

net: macb: Several patches for RP1

64-bit RX fix

Also set DMA coherent mask

Add device tree properties that allow configuration of the AXI max
pipeline register

Add support for ethtool interrupt moderation configuration

Only global throttling of rx or tx by time quanta is supported.

Add platform device shutdown function. Prevents AXI master over PCIE
from hanging when the host is rebooted.

Increase polling interval for MDIO completion

MDIO is a slow bus (single-digit MHz). Polling at 1us intervals
is a bit aggressive, so increase to 100us as the transaction
usually takes 100-200us to complete.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>

net: macb: Support the phy-reset-gpios property

Allow a PHY to be reset with an optional GPIO. The reset duration can
be specified in milliseconds - the default is 10ms.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

drivers: net: macb: close device on driver shutdown

Fix some suspicious locking and instead call into macb_close, which
deregisters and frees all resources the corresponding macb_open
claimed.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>

net: macb: add hack to prevent TX stalls in a quiet system

See https://github.com/raspberrypi/linux-2712/issues/89

There is some critical window during TX where a further write to the
TSTART bit while TX is active does not cause newly queued TX descriptors
to be consumed.

For now "wait a bit, then try anyway" seems to work.

Requires further investigation, but this unsticks NFS reliably.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>

net: macb: set default interrupt moderation for GEM hardware

Defaulting to intmod = 0 is antisocial, as the MAC can generate over
130,000 interrupts per second. 50us is a sensible default.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
---
 drivers/net/ethernet/cadence/macb.h      |  25 ++++
 drivers/net/ethernet/cadence/macb_main.c | 152 ++++++++++++++++++++++-
 2 files changed, 175 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -86,6 +86,8 @@
 #define GEM_PBUFRXCUT		0x0044 /* RX Partial Store and Forward */
 #define GEM_JML			0x0048 /* Jumbo Max Length */
 #define GEM_HS_MAC_CONFIG	0x0050 /* GEM high speed config */
+#define GEM_AMP			0x0054 /* AXI Max Pipeline */
+#define GEM_INTMOD		0x005c /* Interrupt moderation */
 #define GEM_HRB			0x0080 /* Hash Bottom */
 #define GEM_HRT			0x0084 /* Hash Top */
 #define GEM_SA1B		0x0088 /* Specific1 Bottom */
@@ -348,6 +350,21 @@
 #define GEM_ADDR64_OFFSET	30 /* Address bus width - 64b or 32b */
 #define GEM_ADDR64_SIZE		1
 
+/* Bitfields in AMP */
+#define GEM_AR2R_MAX_PIPE_OFFSET	0  /* Maximum number of outstanding AXI read requests */
+#define GEM_AR2R_MAX_PIPE_SIZE		8
+#define GEM_AW2W_MAX_PIPE_OFFSET	8  /* Maximum number of outstanding AXI write requests */
+#define GEM_AW2W_MAX_PIPE_SIZE		8
+#define GEM_AW2B_FILL_OFFSET		16 /* Select wether the max AW2W transactions operates between: */
+#define GEM_AW2B_FILL_AW2W		0  /*   0: the AW to W AXI channel */
+#define GEM_AW2B_FILL_AW2B		1  /*   1: AW to B channel */
+#define GEM_AW2B_FILL_SIZE              1
+
+/* Bitfields in INTMOD */
+#define GEM_RX_MODERATION_OFFSET	0  /* RX interrupt moderation */
+#define GEM_RX_MODERATION_SIZE		8
+#define GEM_TX_MODERATION_OFFSET	16 /* TX interrupt moderation */
+#define GEM_TX_MODERATION_SIZE		8
 
 /* Bitfields in PBUFRXCUT */
 #define GEM_ENCUTTHRU_OFFSET	31 /* Enable RX partial store and forward */
@@ -813,6 +830,7 @@
 	})
 
 #define MACB_READ_NSR(bp)	macb_readl(bp, NSR)
+#define MACB_READ_TSR(bp)	macb_readl(bp, TSR)
 
 /* struct macb_dma_desc - Hardware DMA descriptor
  * @addr: DMA address of data buffer
@@ -1229,6 +1247,7 @@ struct macb_queue {
 	dma_addr_t		tx_ring_dma;
 	struct work_struct	tx_error_task;
 	bool			txubr_pending;
+	bool			tx_pending;
 	struct napi_struct	napi_tx;
 
 	dma_addr_t		rx_ring_dma;
@@ -1296,9 +1315,15 @@ struct macb {
 
 	u32			caps;
 	unsigned int		dma_burst_length;
+	u8			aw2w_max_pipe;
+	u8			ar2r_max_pipe;
+	bool			use_aw2b_fill;
 
 	phy_interface_t		phy_interface;
 
+	struct gpio_desc	*phy_reset_gpio;
+	int			phy_reset_ms;
+
 	/* AT91RM9200 transmit queue (1 on wire + 1 queued) */
 	struct macb_tx_skb	rm9200_txq[2];
 	unsigned int		max_tx_length;
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -41,6 +41,9 @@
 #include <linux/inetdevice.h>
 #include "macb.h"
 
+static unsigned int txdelay = 35;
+module_param(txdelay, uint, 0644);
+
 /* This structure is only used for MACB on SiFive FU540 devices */
 struct sifive_fu540_macb_mgmt {
 	void __iomem *reg;
@@ -334,7 +337,7 @@ static int macb_mdio_wait_for_idle(struc
 	u32 val;
 
 	return readx_poll_timeout(MACB_READ_NSR, bp, val, val & MACB_BIT(IDLE),
-				  1, MACB_MDIO_TIMEOUT);
+				  100, MACB_MDIO_TIMEOUT);
 }
 
 static int macb_mdio_read_c22(struct mii_bus *bus, int mii_id, int regnum)
@@ -493,6 +496,19 @@ mdio_pm_exit:
 	return status;
 }
 
+static int macb_mdio_reset(struct mii_bus *bus)
+{
+	struct macb *bp = bus->priv;
+
+	if (bp->phy_reset_gpio) {
+		gpiod_set_value_cansleep(bp->phy_reset_gpio, 1);
+		msleep(bp->phy_reset_ms);
+		gpiod_set_value_cansleep(bp->phy_reset_gpio, 0);
+	}
+
+	return 0;
+}
+
 static void macb_init_buffers(struct macb *bp)
 {
 	struct macb_queue *queue;
@@ -976,6 +992,7 @@ static int macb_mii_init(struct macb *bp
 	bp->mii_bus->write = &macb_mdio_write_c22;
 	bp->mii_bus->read_c45 = &macb_mdio_read_c45;
 	bp->mii_bus->write_c45 = &macb_mdio_write_c45;
+	bp->mii_bus->reset = &macb_mdio_reset;
 	snprintf(bp->mii_bus->id, MII_BUS_ID_SIZE, "%s-%x",
 		 bp->pdev->name, bp->pdev->id);
 	bp->mii_bus->priv = bp;
@@ -1641,6 +1658,11 @@ static int macb_rx(struct macb_queue *qu
 
 		macb_init_rx_ring(queue);
 		queue_writel(queue, RBQP, queue->rx_ring_dma);
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+		if (bp->hw_dma_cap & HW_DMA_CAP_64B)
+			macb_writel(bp, RBQPH,
+				    upper_32_bits(queue->rx_ring_dma));
+#endif
 
 		macb_writel(bp, NCR, ctrl | MACB_BIT(RE));
 
@@ -1943,8 +1965,9 @@ static irqreturn_t macb_interrupt(int ir
 				queue_writel(queue, ISR, MACB_BIT(TCOMP) |
 							 MACB_BIT(TXUBR));
 
-			if (status & MACB_BIT(TXUBR)) {
+			if (status & MACB_BIT(TXUBR) || queue->tx_pending) {
 				queue->txubr_pending = true;
+				queue->tx_pending = 0;
 				wmb(); // ensure softirq can see update
 			}
 
@@ -2400,6 +2423,11 @@ static netdev_tx_t macb_start_xmit(struc
 	skb_tx_timestamp(skb);
 
 	spin_lock(&bp->lock);
+
+	/* TSTART write might get dropped, so make the IRQ retrigger a buffer read */
+	if (macb_readl(bp, TSR) & MACB_BIT(TGO))
+		queue->tx_pending = 1;
+
 	macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TSTART));
 	spin_unlock(&bp->lock);
 
@@ -2806,6 +2834,37 @@ static void macb_configure_dma(struct ma
 	}
 }
 
+static void gem_init_axi(struct macb *bp)
+{
+	u32 amp;
+
+	/* AXI pipeline setup - don't touch values unless specified in device
+	 * tree. Some hardware could have reset values > 1.
+	 */
+	amp = gem_readl(bp, AMP);
+
+	if (bp->use_aw2b_fill)
+		amp = GEM_BFINS(AW2B_FILL, bp->use_aw2b_fill, amp);
+	if (bp->aw2w_max_pipe)
+		amp = GEM_BFINS(AW2W_MAX_PIPE, bp->aw2w_max_pipe, amp);
+	if (bp->ar2r_max_pipe)
+		amp = GEM_BFINS(AR2R_MAX_PIPE, bp->ar2r_max_pipe, amp);
+
+	gem_writel(bp, AMP, amp);
+}
+
+static void gem_init_intmod(struct macb *bp)
+{
+	unsigned int throttle;
+	u32 intmod = 0;
+
+	/* Use sensible interrupt moderation thresholds (50us rx and tx) */
+	throttle = (1000 * 50) / 800;
+	intmod = GEM_BFINS(TX_MODERATION, throttle, intmod);
+	intmod = GEM_BFINS(RX_MODERATION, throttle, intmod);
+	gem_writel(bp, INTMOD, intmod);
+}
+
 static void macb_init_hw(struct macb *bp)
 {
 	u32 config;
@@ -2834,6 +2893,11 @@ static void macb_init_hw(struct macb *bp
 	if (bp->caps & MACB_CAPS_JUMBO)
 		bp->rx_frm_len_mask = MACB_RX_JFRMLEN_MASK;
 
+	if (macb_is_gem(bp)) {
+		gem_init_axi(bp);
+		gem_init_intmod(bp);
+	}
+
 	macb_configure_dma(bp);
 
 	/* Enable RX partial store and forward and set watermark */
@@ -3200,6 +3264,52 @@ static void gem_get_ethtool_strings(stru
 	}
 }
 
+static int gem_set_coalesce(struct net_device *dev,
+			    struct ethtool_coalesce *ec,
+			    struct kernel_ethtool_coalesce *kernel_coal,
+			    struct netlink_ext_ack *extack)
+{
+	struct macb *bp = netdev_priv(dev);
+	unsigned int tx_throttle;
+	unsigned int rx_throttle;
+	u32 intmod = 0;
+
+	/* GEM has simple IRQ throttling support. RX and TX interrupts
+	 * are separately moderated on 800ns quantums, with no support
+	 * for frame coalescing.
+	 */
+
+	/* Max is 255 * 0.8us = 204us. Zero implies no moderation. */
+	if (ec->rx_coalesce_usecs > 204 || ec->tx_coalesce_usecs > 204)
+		return -EINVAL;
+
+	tx_throttle = (1000 * ec->tx_coalesce_usecs) / 800;
+	rx_throttle = (1000 * ec->rx_coalesce_usecs) / 800;
+
+	intmod = GEM_BFINS(TX_MODERATION, tx_throttle, intmod);
+	intmod = GEM_BFINS(RX_MODERATION, rx_throttle, intmod);
+
+	gem_writel(bp, INTMOD, intmod);
+
+	return 0;
+}
+
+static int gem_get_coalesce(struct net_device *dev,
+			    struct ethtool_coalesce *ec,
+			    struct kernel_ethtool_coalesce *kernel_coal,
+			    struct netlink_ext_ack *extack)
+{
+	struct macb *bp = netdev_priv(dev);
+	u32 intmod;
+
+	intmod = gem_readl(bp, INTMOD);
+
+	ec->tx_coalesce_usecs = (GEM_BFEXT(TX_MODERATION, intmod) * 800) / 1000;
+	ec->rx_coalesce_usecs = (GEM_BFEXT(RX_MODERATION, intmod) * 800) / 1000;
+
+	return 0;
+}
+
 static struct net_device_stats *macb_get_stats(struct net_device *dev)
 {
 	struct macb *bp = netdev_priv(dev);
@@ -3784,6 +3894,8 @@ static const struct ethtool_ops macb_eth
 };
 
 static const struct ethtool_ops gem_ethtool_ops = {
+	.supported_coalesce_params = ETHTOOL_COALESCE_RX_USECS |
+				     ETHTOOL_COALESCE_TX_USECS,
 	.get_regs_len		= macb_get_regs_len,
 	.get_regs		= macb_get_regs,
 	.get_wol		= macb_get_wol,
@@ -3793,6 +3905,8 @@ static const struct ethtool_ops gem_etht
 	.get_ethtool_stats	= gem_get_ethtool_stats,
 	.get_strings		= gem_get_ethtool_strings,
 	.get_sset_count		= gem_get_sset_count,
+	.get_coalesce		= gem_get_coalesce,
+	.set_coalesce		= gem_set_coalesce,
 	.get_link_ksettings     = macb_get_link_ksettings,
 	.set_link_ksettings     = macb_set_link_ksettings,
 	.get_ringparam		= macb_get_ringparam,
@@ -5114,6 +5228,11 @@ static int macb_probe(struct platform_de
 			}
 		}
 	}
+
+	device_property_read_u8(&pdev->dev, "cdns,aw2w-max-pipe", &bp->aw2w_max_pipe);
+	device_property_read_u8(&pdev->dev, "cdns,ar2r-max-pipe", &bp->ar2r_max_pipe);
+	bp->use_aw2b_fill = device_property_read_bool(&pdev->dev, "cdns,use-aw2b-fill");
+
 	spin_lock_init(&bp->lock);
 	spin_lock_init(&bp->stats_lock);
 
@@ -5174,6 +5293,21 @@ static int macb_probe(struct platform_de
 	else
 		bp->phy_interface = interface;
 
+	/* optional PHY reset-related properties */
+	bp->phy_reset_gpio = devm_gpiod_get_optional(&pdev->dev, "phy-reset",
+						     GPIOD_OUT_LOW);
+	if (IS_ERR(bp->phy_reset_gpio)) {
+		dev_err(&pdev->dev, "Failed to obtain phy-reset gpio\n");
+		err = PTR_ERR(bp->phy_reset_gpio);
+		goto err_out_free_netdev;
+	}
+
+	bp->phy_reset_ms = 10;
+	of_property_read_u32(np, "phy-reset-duration", &bp->phy_reset_ms);
+	/* A sane reset duration should not be longer than 1s */
+	if (bp->phy_reset_ms > 1000)
+		bp->phy_reset_ms = 1000;
+
 	/* IP specific init */
 	err = init(pdev);
 	if (err)
@@ -5245,6 +5379,19 @@ static void macb_remove(struct platform_
 	}
 }
 
+static void macb_shutdown(struct platform_device *pdev)
+{
+	struct net_device *dev;
+
+	dev = platform_get_drvdata(pdev);
+
+	rtnl_lock();
+	netif_device_detach(dev);
+	if (netif_running(dev))
+		dev_close(dev);
+	rtnl_unlock();
+}
+
 static int __maybe_unused macb_suspend(struct device *dev)
 {
 	struct net_device *netdev = dev_get_drvdata(dev);
@@ -5498,6 +5645,7 @@ static const struct dev_pm_ops macb_pm_o
 static struct platform_driver macb_driver = {
 	.probe		= macb_probe,
 	.remove_new	= macb_remove,
+	.shutdown	= macb_shutdown,
 	.driver		= {
 		.name		= "macb",
 		.of_match_table	= of_match_ptr(macb_dt_ids),
