[PATCH v2 0/2] net: Add LiteETH network driver

[PATCH v2 0/2] net: Add LiteETH network driver

[Joel Stanley]

This adds a driver for the LiteX network device, LiteEth.

v2 Addresses feedback from Jakub, with detailed changes in each patch.

It also moves to the litex register accessors so the system works on big
endian litex platforms. I tested with mor1k on an Arty A7-100T.

I have removed the mdio aspects of the driver as they are not needed for
basic operation. I will continue to work on adding support in the
future, but I don't think it needs to block the mac driver going in.

The binding describes the mdio registers, and has been fixed to not show
any warnings against dtschema master.

LiteEth is a simple driver for the FPGA based Ethernet device used in various
RISC-V, PowerPC's microwatt, OpenRISC's mor1k and other FPGA based
systems on chip.

Joel Stanley (2):
  dt-bindings: net: Add bindings for LiteETH
  net: Add driver for LiteX's LiteETH network interface

 .../bindings/net/litex,liteeth.yaml           |  79 +++++
 drivers/net/ethernet/Kconfig                  |   1 +
 drivers/net/ethernet/Makefile                 |   1 +
 drivers/net/ethernet/litex/Kconfig            |  27 ++
 drivers/net/ethernet/litex/Makefile           |   5 +
 drivers/net/ethernet/litex/litex_liteeth.c    | 327 ++++++++++++++++++
 6 files changed, 440 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/litex,liteeth.yaml
 create mode 100644 drivers/net/ethernet/litex/Kconfig
 create mode 100644 drivers/net/ethernet/litex/Makefile
 create mode 100644 drivers/net/ethernet/litex/litex_liteeth.c

-- 
2.32.0

[PATCH v2 1/2] dt-bindings: net: Add bindings for LiteETH

[Joel Stanley]

LiteETH is a small footprint and configurable Ethernet core for FPGA
based system on chips.

Signed-off-by: Joel Stanley <joel@jms.id.au>
---
v2:
 - Fix dtschema check warning relating to registers
 - Add names to the registers to make it easier to distinguish which is
   what region
 - Add mdio description
 - Includ ethernet-controller parent description

 .../bindings/net/litex,liteeth.yaml           | 79 +++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/litex,liteeth.yaml

diff --git a/Documentation/devicetree/bindings/net/litex,liteeth.yaml b/Documentation/devicetree/bindings/net/litex,liteeth.yaml
new file mode 100644
index 000000000000..30f8f8b0b657
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/litex,liteeth.yaml
@@ -0,0 +1,79 @@
+# SPDX-License-Identifier: GPL-2.0-or-later OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/litex,liteeth.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: LiteX LiteETH ethernet device
+
+maintainers:
+  - Joel Stanley <joel@jms.id.au>
+
+description: |
+  LiteETH is a small footprint and configurable Ethernet core for FPGA based
+  system on chips.
+
+  The hardware source is Open Source and can be found on at
+  https://github.com/enjoy-digital/liteeth/.
+
+allOf:
+  - $ref: ethernet-controller.yaml#
+
+properties:
+  compatible:
+    const: litex,liteeth
+
+  reg:
+    minItems: 3
+    items:
+      - description: MAC registers
+      - description: MDIO registers
+      - description: Packet buffer
+
+  reg-names:
+    minItems: 3
+
+  interrupts:
+    maxItems: 1
+
+  rx-fifo-depth: true
+  tx-fifo-depth: true
+  mac-address: true
+  local-mac-address: true
+  phy-handle: true
+
+  mdio:
+    $ref: mdio.yaml#
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    mac: ethernet@8020000 {
+        compatible = "litex,liteeth";
+        reg = <0x8021000 0x100>,
+              <0x8020800 0x100>,
+              <0x8030000 0x2000>;
+        reg-names = "mac", "mdio", "buffer";
+        rx-fifo-depth = <1024>;
+        tx-fifo-depth = <1024>;
+        interrupts = <0x11 0x1>;
+        phy-handle = <&eth_phy>;
+
+        mdio {
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          eth_phy: ethernet-phy@0 {
+            reg = <0>;
+          };
+        };
+    };
+...
+
+#  vim: set ts=2 sw=2 sts=2 tw=80 et cc=80 ft=yaml :
-- 
2.32.0

Re: [PATCH v2 1/2] dt-bindings: net: Add bindings for LiteETH

[Andrew Lunn]

On Fri, Aug 20, 2021 at 05:17:25PM +0930, Joel Stanley wrote:
> LiteETH is a small footprint and configurable Ethernet core for FPGA
> based system on chips.

Hi Joel

Just an FYI.

DT is considered ABI. Once released, you should not be making changes
which are not backwards compatible.

All the PHY and MDIO properties you are adding here are unused in the
driver. They all look sensible, and you should be able to make it
work. But when you do come to make that implementation, this
definition is the base of what you have to work with.

	   Andrew

Re: [PATCH v2 1/2] dt-bindings: net: Add bindings for LiteETH

[Rob Herring]

On Fri, Aug 20, 2021 at 05:17:25PM +0930, Joel Stanley wrote:
> LiteETH is a small footprint and configurable Ethernet core for FPGA
> based system on chips.
> 
> Signed-off-by: Joel Stanley <joel@jms.id.au>
> ---
> v2:
>  - Fix dtschema check warning relating to registers
>  - Add names to the registers to make it easier to distinguish which is
>    what region
>  - Add mdio description
>  - Includ ethernet-controller parent description
> 
>  .../bindings/net/litex,liteeth.yaml           | 79 +++++++++++++++++++
>  1 file changed, 79 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/net/litex,liteeth.yaml
> 
> diff --git a/Documentation/devicetree/bindings/net/litex,liteeth.yaml b/Documentation/devicetree/bindings/net/litex,liteeth.yaml
> new file mode 100644
> index 000000000000..30f8f8b0b657
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/litex,liteeth.yaml
> @@ -0,0 +1,79 @@
> +# SPDX-License-Identifier: GPL-2.0-or-later OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/net/litex,liteeth.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: LiteX LiteETH ethernet device
> +
> +maintainers:
> +  - Joel Stanley <joel@jms.id.au>
> +
> +description: |
> +  LiteETH is a small footprint and configurable Ethernet core for FPGA based
> +  system on chips.
> +
> +  The hardware source is Open Source and can be found on at
> +  https://github.com/enjoy-digital/liteeth/.
> +
> +allOf:
> +  - $ref: ethernet-controller.yaml#
> +
> +properties:
> +  compatible:
> +    const: litex,liteeth
> +
> +  reg:
> +    minItems: 3
> +    items:
> +      - description: MAC registers
> +      - description: MDIO registers
> +      - description: Packet buffer
> +
> +  reg-names:
> +    minItems: 3

Need to define the names here.

> +
> +  interrupts:
> +    maxItems: 1
> +

> +  rx-fifo-depth: true
> +  tx-fifo-depth: true

Needs a vendor prefix, type, description and constraints.

> +  mac-address: true
> +  local-mac-address: true
> +  phy-handle: true
> +
> +  mdio:
> +    $ref: mdio.yaml#
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    mac: ethernet@8020000 {
> +        compatible = "litex,liteeth";
> +        reg = <0x8021000 0x100>,
> +              <0x8020800 0x100>,
> +              <0x8030000 0x2000>;
> +        reg-names = "mac", "mdio", "buffer";
> +        rx-fifo-depth = <1024>;
> +        tx-fifo-depth = <1024>;
> +        interrupts = <0x11 0x1>;
> +        phy-handle = <&eth_phy>;
> +
> +        mdio {
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +
> +          eth_phy: ethernet-phy@0 {
> +            reg = <0>;
> +          };
> +        };
> +    };
> +...
> +
> +#  vim: set ts=2 sw=2 sts=2 tw=80 et cc=80 ft=yaml :
> -- 
> 2.32.0
> 
> 

Re: [PATCH v2 1/2] dt-bindings: net: Add bindings for LiteETH

[Joel Stanley]

On Mon, 23 Aug 2021 at 18:44, Rob Herring <robh@kernel.org> wrote:
>
> On Fri, Aug 20, 2021 at 05:17:25PM +0930, Joel Stanley wrote:

> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
>
> > +  rx-fifo-depth: true
> > +  tx-fifo-depth: true
>
> Needs a vendor prefix, type, description and constraints.

These are the standard properties from the ethernet-controller.yaml. I
switched the driver to using those once I discovered they existed (v1
defined these in terms of slots, whereas the ethernet-controller
bindings use bytes).

Cheers,

Joel

Re: [PATCH v2 1/2] dt-bindings: net: Add bindings for LiteETH

[Rob Herring]

On Mon, Aug 23, 2021 at 10:52 PM Joel Stanley <joel@jms.id.au> wrote:
>
> On Mon, 23 Aug 2021 at 18:44, Rob Herring <robh@kernel.org> wrote:
> >
> > On Fri, Aug 20, 2021 at 05:17:25PM +0930, Joel Stanley wrote:
>
> > > +
> > > +  interrupts:
> > > +    maxItems: 1
> > > +
> >
> > > +  rx-fifo-depth: true
> > > +  tx-fifo-depth: true
> >
> > Needs a vendor prefix, type, description and constraints.
>
> These are the standard properties from the ethernet-controller.yaml. I
> switched the driver to using those once I discovered they existed (v1
> defined these in terms of slots, whereas the ethernet-controller
> bindings use bytes).

Indeed (grepping the wrong repo didn't work too well :) ).

Still, I'd assume there's some valid range for this h/w you can
define? Or 0 - 2^32 is valid?

Rob

Re: [PATCH v2 1/2] dt-bindings: net: Add bindings for LiteETH

[Joel Stanley]

On Tue, 24 Aug 2021 at 11:52, Rob Herring <robh@kernel.org> wrote:
>
> On Mon, Aug 23, 2021 at 10:52 PM Joel Stanley <joel@jms.id.au> wrote:
> >
> > On Mon, 23 Aug 2021 at 18:44, Rob Herring <robh@kernel.org> wrote:
> > >
> > > On Fri, Aug 20, 2021 at 05:17:25PM +0930, Joel Stanley wrote:
> >
> > > > +
> > > > +  interrupts:
> > > > +    maxItems: 1
> > > > +
> > >
> > > > +  rx-fifo-depth: true
> > > > +  tx-fifo-depth: true
> > >
> > > Needs a vendor prefix, type, description and constraints.
> >
> > These are the standard properties from the ethernet-controller.yaml. I
> > switched the driver to using those once I discovered they existed (v1
> > defined these in terms of slots, whereas the ethernet-controller
> > bindings use bytes).
>
> Indeed (grepping the wrong repo didn't work too well :) ).
>
> Still, I'd assume there's some valid range for this h/w you can
> define? Or 0 - 2^32 is valid?

0 would be problematic, but there's not really any bound on it.

I'll send a v3 with the reg-names documented. Thanks for the review.

Cheers,

Joel

[PATCH v2 2/2] net: Add driver for LiteX's LiteEth network interface

[Joel Stanley]

LiteX is a soft system-on-chip that targets FPGAs. LiteEth is a basic
network device that is commonly used in LiteX designs.

The driver was first written in 2017 and has been maintained by the
LiteX community in various trees. Thank you to all who have contributed.

Co-developed-by: Gabriel Somlo <gsomlo@gmail.com>
Co-developed-by: David Shah <dave@ds0.me>
Co-developed-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
---
v2:
 - check for bad len in liteeth_rx before getting skb
 - use netdev_alloc_skb_ip_align
 - remove unused duplex/speed and mii_bus variables
 - set carrier off when stopping device
 - increment packet count in the same place as bytes
 - fix error return code when irq could not be found
 - remove request of mdio base address until it is used
 - fix of_property_read line wrapping/alignment
 - only check that reader isn't busy, and then send off next packet
 - drop phy reset, it was incorrect (wrong address)
 - Add an description to the kconfig text
 - stop tx queue when busy and re-start after tx complete irq fires
 - use litex accessors to support big endian socs
 - clean up unused includes
 - use standard fifo-depth properties, which are in bytes

 drivers/net/ethernet/Kconfig               |   1 +
 drivers/net/ethernet/Makefile              |   1 +
 drivers/net/ethernet/litex/Kconfig         |  27 ++
 drivers/net/ethernet/litex/Makefile        |   5 +
 drivers/net/ethernet/litex/litex_liteeth.c | 327 +++++++++++++++++++++
 5 files changed, 361 insertions(+)
 create mode 100644 drivers/net/ethernet/litex/Kconfig
 create mode 100644 drivers/net/ethernet/litex/Makefile
 create mode 100644 drivers/net/ethernet/litex/litex_liteeth.c

diff --git a/drivers/net/ethernet/Kconfig b/drivers/net/ethernet/Kconfig
index 1cdff1dca790..d796684ec9ca 100644
--- a/drivers/net/ethernet/Kconfig
+++ b/drivers/net/ethernet/Kconfig
@@ -118,6 +118,7 @@ config LANTIQ_XRX200
 	  Support for the PMAC of the Gigabit switch (GSWIP) inside the
 	  Lantiq / Intel VRX200 VDSL SoC
 
+source "drivers/net/ethernet/litex/Kconfig"
 source "drivers/net/ethernet/marvell/Kconfig"
 source "drivers/net/ethernet/mediatek/Kconfig"
 source "drivers/net/ethernet/mellanox/Kconfig"
diff --git a/drivers/net/ethernet/Makefile b/drivers/net/ethernet/Makefile
index cb3f9084a21b..aaa5078cd7d1 100644
--- a/drivers/net/ethernet/Makefile
+++ b/drivers/net/ethernet/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_JME) += jme.o
 obj-$(CONFIG_KORINA) += korina.o
 obj-$(CONFIG_LANTIQ_ETOP) += lantiq_etop.o
 obj-$(CONFIG_LANTIQ_XRX200) += lantiq_xrx200.o
+obj-$(CONFIG_NET_VENDOR_LITEX) += litex/
 obj-$(CONFIG_NET_VENDOR_MARVELL) += marvell/
 obj-$(CONFIG_NET_VENDOR_MEDIATEK) += mediatek/
 obj-$(CONFIG_NET_VENDOR_MELLANOX) += mellanox/
diff --git a/drivers/net/ethernet/litex/Kconfig b/drivers/net/ethernet/litex/Kconfig
new file mode 100644
index 000000000000..265dba414b41
--- /dev/null
+++ b/drivers/net/ethernet/litex/Kconfig
@@ -0,0 +1,27 @@
+#
+# LiteX device configuration
+#
+
+config NET_VENDOR_LITEX
+	bool "LiteX devices"
+	default y
+	help
+	  If you have a network (Ethernet) card belonging to this class, say Y.
+
+	  Note that the answer to this question doesn't directly affect the
+	  kernel: saying N will just cause the configurator to skip all
+	  the questions about LiteX devices. If you say Y, you will be asked
+	  for your specific card in the following questions.
+
+if NET_VENDOR_LITEX
+
+config LITEX_LITEETH
+	tristate "LiteX Ethernet support"
+	help
+	  If you wish to compile a kernel for hardware with a LiteX LiteEth
+	  device then you should answer Y to this.
+
+	  LiteX is a soft system-on-chip that targets FPGAs. LiteETH is a basic
+	  network device that is commonly used in LiteX designs.
+
+endif # NET_VENDOR_LITEX
diff --git a/drivers/net/ethernet/litex/Makefile b/drivers/net/ethernet/litex/Makefile
new file mode 100644
index 000000000000..9343b73b8e49
--- /dev/null
+++ b/drivers/net/ethernet/litex/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the LiteX network device drivers.
+#
+
+obj-$(CONFIG_LITEX_LITEETH) += litex_liteeth.o
diff --git a/drivers/net/ethernet/litex/litex_liteeth.c b/drivers/net/ethernet/litex/litex_liteeth.c
new file mode 100644
index 000000000000..e9c5d817e1f9
--- /dev/null
+++ b/drivers/net/ethernet/litex/litex_liteeth.c
@@ -0,0 +1,327 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * LiteX Liteeth Ethernet
+ *
+ * Copyright 2017 Joel Stanley <joel@jms.id.au>
+ *
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/interrupt.h>
+#include <linux/litex.h>
+#include <linux/module.h>
+#include <linux/of_net.h>
+#include <linux/platform_device.h>
+
+#define LITEETH_WRITER_SLOT       0x00
+#define LITEETH_WRITER_LENGTH     0x04
+#define LITEETH_WRITER_ERRORS     0x08
+#define LITEETH_WRITER_EV_STATUS  0x0C
+#define LITEETH_WRITER_EV_PENDING 0x10
+#define LITEETH_WRITER_EV_ENABLE  0x14
+#define LITEETH_READER_START      0x18
+#define LITEETH_READER_READY      0x1C
+#define LITEETH_READER_LEVEL      0x20
+#define LITEETH_READER_SLOT       0x24
+#define LITEETH_READER_LENGTH     0x28
+#define LITEETH_READER_EV_STATUS  0x2C
+#define LITEETH_READER_EV_PENDING 0x30
+#define LITEETH_READER_EV_ENABLE  0x34
+#define LITEETH_PREAMBLE_CRC      0x38
+#define LITEETH_PREAMBLE_ERRORS   0x3C
+#define LITEETH_CRC_ERRORS        0x40
+
+#define LITEETH_PHY_CRG_RESET     0x00
+#define LITEETH_MDIO_W            0x04
+#define LITEETH_MDIO_R            0x0C
+
+#define DRV_NAME	"liteeth"
+
+#define LITEETH_BUFFER_SIZE		0x800
+#define MAX_PKT_SIZE			LITEETH_BUFFER_SIZE
+
+struct liteeth {
+	void __iomem *base;
+	struct net_device *netdev;
+	struct device *dev;
+
+	/* Tx */
+	int tx_slot;
+	int num_tx_slots;
+	void __iomem *tx_base;
+
+	/* Rx */
+	int rx_slot;
+	int num_rx_slots;
+	void __iomem *rx_base;
+};
+
+static int liteeth_rx(struct net_device *netdev)
+{
+	struct liteeth *priv = netdev_priv(netdev);
+	struct sk_buff *skb;
+	unsigned char *data;
+	u8 rx_slot;
+	int len;
+
+	rx_slot = litex_read8(priv->base + LITEETH_WRITER_SLOT);
+	len = litex_read32(priv->base + LITEETH_WRITER_LENGTH);
+
+	if (len == 0 || len > 2048)
+		goto rx_drop;
+
+	skb = netdev_alloc_skb_ip_align(netdev, len);
+	if (!skb) {
+		netdev_err(netdev, "couldn't get memory\n");
+		goto rx_drop;
+	}
+
+	data = skb_put(skb, len);
+	memcpy_fromio(data, priv->rx_base + rx_slot * LITEETH_BUFFER_SIZE, len);
+	skb->protocol = eth_type_trans(skb, netdev);
+
+	netdev->stats.rx_packets++;
+	netdev->stats.rx_bytes += len;
+
+	return netif_rx(skb);
+
+rx_drop:
+	netdev->stats.rx_dropped++;
+	netdev->stats.rx_errors++;
+
+	return NET_RX_DROP;
+}
+
+static irqreturn_t liteeth_interrupt(int irq, void *dev_id)
+{
+	struct net_device *netdev = dev_id;
+	struct liteeth *priv = netdev_priv(netdev);
+	u8 reg;
+
+	reg = litex_read8(priv->base + LITEETH_READER_EV_PENDING);
+	if (reg) {
+		if (netif_queue_stopped(netdev))
+			netif_wake_queue(netdev);
+		litex_write8(priv->base + LITEETH_READER_EV_PENDING, reg);
+	}
+
+	reg = litex_read8(priv->base + LITEETH_WRITER_EV_PENDING);
+	if (reg) {
+		liteeth_rx(netdev);
+		litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, reg);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int liteeth_open(struct net_device *netdev)
+{
+	struct liteeth *priv = netdev_priv(netdev);
+	int err;
+
+	/* Clear pending events */
+	litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, 1);
+	litex_write8(priv->base + LITEETH_READER_EV_PENDING, 1);
+
+	err = request_irq(netdev->irq, liteeth_interrupt, 0, netdev->name, netdev);
+	if (err) {
+		netdev_err(netdev, "failed to request irq %d\n", netdev->irq);
+		return err;
+	}
+
+	/* Enable IRQs */
+	litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 1);
+	litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 1);
+
+	netif_carrier_on(netdev);
+	netif_start_queue(netdev);
+
+	return 0;
+}
+
+static int liteeth_stop(struct net_device *netdev)
+{
+	struct liteeth *priv = netdev_priv(netdev);
+
+	netif_stop_queue(netdev);
+	netif_carrier_off(netdev);
+
+	litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 0);
+	litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 0);
+
+	free_irq(netdev->irq, netdev);
+
+	return 0;
+}
+
+static int liteeth_start_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+	struct liteeth *priv = netdev_priv(netdev);
+	void __iomem *txbuffer;
+
+	if (!litex_read8(priv->base + LITEETH_READER_READY)) {
+		if (net_ratelimit())
+			netdev_err(netdev, "LITEETH_READER_READY not ready\n");
+
+		netif_stop_queue(netdev);
+
+		return NETDEV_TX_BUSY;
+	}
+
+	/* Reject oversize packets */
+	if (unlikely(skb->len > MAX_PKT_SIZE)) {
+		if (net_ratelimit())
+			netdev_err(netdev, "tx packet too big\n");
+
+		dev_kfree_skb_any(skb);
+		netdev->stats.tx_dropped++;
+		netdev->stats.tx_errors++;
+
+		return NETDEV_TX_OK;
+	}
+
+	txbuffer = priv->tx_base + priv->tx_slot * LITEETH_BUFFER_SIZE;
+	memcpy_toio(txbuffer, skb->data, skb->len);
+	litex_write8(priv->base + LITEETH_READER_SLOT, priv->tx_slot);
+	litex_write16(priv->base + LITEETH_READER_LENGTH, skb->len);
+	litex_write8(priv->base + LITEETH_READER_START, 1);
+
+	netdev->stats.tx_bytes += skb->len;
+	netdev->stats.tx_packets++;
+
+	priv->tx_slot = (priv->tx_slot + 1) % priv->num_tx_slots;
+	dev_kfree_skb_any(skb);
+
+	return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops liteeth_netdev_ops = {
+	.ndo_open		= liteeth_open,
+	.ndo_stop		= liteeth_stop,
+	.ndo_start_xmit         = liteeth_start_xmit,
+};
+
+int liteeth_setup_slots(struct liteeth *priv)
+{
+	struct device_node *np = priv->dev->of_node;
+	int err, depth;
+
+	err = of_property_read_u32(np, "rx-fifo-depth", &depth);
+	if (err) {
+		dev_err(priv->dev, "unable to get rx-fifo-depth\n");
+		return err;
+	}
+	if (depth < LITEETH_BUFFER_SIZE) {
+		dev_err(priv->dev, "invalid tx-fifo-depth: %d\n", depth);
+		return -EINVAL;
+	}
+	priv->num_rx_slots = depth / LITEETH_BUFFER_SIZE;
+
+	err = of_property_read_u32(np, "tx-fifo-depth", &depth);
+	if (err) {
+		dev_err(priv->dev, "unable to get tx-fifo-depth\n");
+		return err;
+	}
+	if (depth < LITEETH_BUFFER_SIZE) {
+		dev_err(priv->dev, "invalid rx-fifo-depth: %d\n", depth);
+		return -EINVAL;
+	}
+	priv->num_tx_slots = depth / LITEETH_BUFFER_SIZE;
+
+	return 0;
+}
+
+static int liteeth_probe(struct platform_device *pdev)
+{
+	struct net_device *netdev;
+	void __iomem *buf_base;
+	struct resource *res;
+	struct liteeth *priv;
+	int irq, err;
+
+	netdev = devm_alloc_etherdev(&pdev->dev, sizeof(*priv));
+	if (!netdev)
+		return -ENOMEM;
+
+	SET_NETDEV_DEV(netdev, &pdev->dev);
+	platform_set_drvdata(pdev, netdev);
+
+	priv = netdev_priv(netdev);
+	priv->netdev = netdev;
+	priv->dev = &pdev->dev;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "Failed to get IRQ %d\n", irq);
+		return irq;
+	}
+	netdev->irq = irq;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mac");
+	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "buffer");
+	buf_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(buf_base))
+		return PTR_ERR(buf_base);
+
+	err = liteeth_setup_slots(priv);
+	if (err)
+		return err;
+
+	/* Rx slots */
+	priv->rx_base = buf_base;
+	priv->rx_slot = 0;
+
+	/* Tx slots come after Rx slots */
+	priv->tx_base = buf_base + priv->num_rx_slots * LITEETH_BUFFER_SIZE;
+	priv->tx_slot = 0;
+
+	err = of_get_mac_address(pdev->dev.of_node, netdev->dev_addr);
+	if (err)
+		eth_hw_addr_random(netdev);
+
+	netdev->netdev_ops = &liteeth_netdev_ops;
+
+	err = register_netdev(netdev);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to register netdev %d\n", err);
+		return err;
+	}
+
+	netdev_info(netdev, "irq %d tx slots %d rx slots %d",
+		    netdev->irq, priv->num_tx_slots, priv->num_rx_slots);
+
+	return 0;
+}
+
+static int liteeth_remove(struct platform_device *pdev)
+{
+	struct net_device *netdev = platform_get_drvdata(pdev);
+
+	unregister_netdev(netdev);
+	free_netdev(netdev);
+
+	return 0;
+}
+
+static const struct of_device_id liteeth_of_match[] = {
+	{ .compatible = "litex,liteeth" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, liteeth_of_match);
+
+static struct platform_driver liteeth_driver = {
+	.probe = liteeth_probe,
+	.remove = liteeth_remove,
+	.driver = {
+		.name = DRV_NAME,
+		.of_match_table = liteeth_of_match,
+	},
+};
+module_platform_driver(liteeth_driver);
+
+MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
+MODULE_LICENSE("GPL");
-- 
2.32.0

Re: [PATCH v2 2/2] net: Add driver for LiteX's LiteEth network interface

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 3187 bytes --]

Hi Joel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on robh/for-next]
[also build test WARNING on net-next/master net/master linus/master v5.14-rc6 next-20210819]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Joel-Stanley/net-Add-LiteETH-network-driver/20210820-154958
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
config: sh-allmodconfig (attached as .config)
compiler: sh4-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/3355b2a96c6d9881128ebac1d3801171b988dbeb
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Joel-Stanley/net-Add-LiteETH-network-driver/20210820-154958
        git checkout 3355b2a96c6d9881128ebac1d3801171b988dbeb
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=sh 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/net/ethernet/litex/litex_liteeth.c:204:5: warning: no previous prototype for 'liteeth_setup_slots' [-Wmissing-prototypes]
     204 | int liteeth_setup_slots(struct liteeth *priv)
         |     ^~~~~~~~~~~~~~~~~~~

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for SND_ATMEL_SOC_PDC
   Depends on SOUND && !UML && SND && SND_SOC && SND_ATMEL_SOC && HAS_DMA
   Selected by
   - SND_ATMEL_SOC_SSC && SOUND && !UML && SND && SND_SOC && SND_ATMEL_SOC
   - SND_ATMEL_SOC_SSC_PDC && SOUND && !UML && SND && SND_SOC && SND_ATMEL_SOC && ATMEL_SSC


vim +/liteeth_setup_slots +204 drivers/net/ethernet/litex/litex_liteeth.c

   203	
 > 204	int liteeth_setup_slots(struct liteeth *priv)
   205	{
   206		struct device_node *np = priv->dev->of_node;
   207		int err, depth;
   208	
   209		err = of_property_read_u32(np, "rx-fifo-depth", &depth);
   210		if (err) {
   211			dev_err(priv->dev, "unable to get rx-fifo-depth\n");
   212			return err;
   213		}
   214		if (depth < LITEETH_BUFFER_SIZE) {
   215			dev_err(priv->dev, "invalid tx-fifo-depth: %d\n", depth);
   216			return -EINVAL;
   217		}
   218		priv->num_rx_slots = depth / LITEETH_BUFFER_SIZE;
   219	
   220		err = of_property_read_u32(np, "tx-fifo-depth", &depth);
   221		if (err) {
   222			dev_err(priv->dev, "unable to get tx-fifo-depth\n");
   223			return err;
   224		}
   225		if (depth < LITEETH_BUFFER_SIZE) {
   226			dev_err(priv->dev, "invalid rx-fifo-depth: %d\n", depth);
   227			return -EINVAL;
   228		}
   229		priv->num_tx_slots = depth / LITEETH_BUFFER_SIZE;
   230	
   231		return 0;
   232	}
   233	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 55043 bytes --]

Re: [PATCH v2 2/2] net: Add driver for LiteX's LiteEth network interface

[Gabriel L. Somlo]

Hi Joel,

Couple of comments below:

On Fri, Aug 20, 2021 at 05:17:26PM +0930, Joel Stanley wrote:
> LiteX is a soft system-on-chip that targets FPGAs. LiteEth is a basic
> network device that is commonly used in LiteX designs.
> 
> The driver was first written in 2017 and has been maintained by the
> LiteX community in various trees. Thank you to all who have contributed.
> 
> Co-developed-by: Gabriel Somlo <gsomlo@gmail.com>
> Co-developed-by: David Shah <dave@ds0.me>
> Co-developed-by: Stafford Horne <shorne@gmail.com>
> Signed-off-by: Joel Stanley <joel@jms.id.au>
> ---
> v2:
>  - check for bad len in liteeth_rx before getting skb
>  - use netdev_alloc_skb_ip_align
>  - remove unused duplex/speed and mii_bus variables
>  - set carrier off when stopping device
>  - increment packet count in the same place as bytes
>  - fix error return code when irq could not be found
>  - remove request of mdio base address until it is used
>  - fix of_property_read line wrapping/alignment
>  - only check that reader isn't busy, and then send off next packet
>  - drop phy reset, it was incorrect (wrong address)
>  - Add an description to the kconfig text
>  - stop tx queue when busy and re-start after tx complete irq fires
>  - use litex accessors to support big endian socs
>  - clean up unused includes
>  - use standard fifo-depth properties, which are in bytes
> 
>  drivers/net/ethernet/Kconfig               |   1 +
>  drivers/net/ethernet/Makefile              |   1 +
>  drivers/net/ethernet/litex/Kconfig         |  27 ++
>  drivers/net/ethernet/litex/Makefile        |   5 +
>  drivers/net/ethernet/litex/litex_liteeth.c | 327 +++++++++++++++++++++
>  5 files changed, 361 insertions(+)
>  create mode 100644 drivers/net/ethernet/litex/Kconfig
>  create mode 100644 drivers/net/ethernet/litex/Makefile
>  create mode 100644 drivers/net/ethernet/litex/litex_liteeth.c
> 
> diff --git a/drivers/net/ethernet/Kconfig b/drivers/net/ethernet/Kconfig
> index 1cdff1dca790..d796684ec9ca 100644
> --- a/drivers/net/ethernet/Kconfig
> +++ b/drivers/net/ethernet/Kconfig
> @@ -118,6 +118,7 @@ config LANTIQ_XRX200
>  	  Support for the PMAC of the Gigabit switch (GSWIP) inside the
>  	  Lantiq / Intel VRX200 VDSL SoC
>  
> +source "drivers/net/ethernet/litex/Kconfig"
>  source "drivers/net/ethernet/marvell/Kconfig"
>  source "drivers/net/ethernet/mediatek/Kconfig"
>  source "drivers/net/ethernet/mellanox/Kconfig"
> diff --git a/drivers/net/ethernet/Makefile b/drivers/net/ethernet/Makefile
> index cb3f9084a21b..aaa5078cd7d1 100644
> --- a/drivers/net/ethernet/Makefile
> +++ b/drivers/net/ethernet/Makefile
> @@ -51,6 +51,7 @@ obj-$(CONFIG_JME) += jme.o
>  obj-$(CONFIG_KORINA) += korina.o
>  obj-$(CONFIG_LANTIQ_ETOP) += lantiq_etop.o
>  obj-$(CONFIG_LANTIQ_XRX200) += lantiq_xrx200.o
> +obj-$(CONFIG_NET_VENDOR_LITEX) += litex/
>  obj-$(CONFIG_NET_VENDOR_MARVELL) += marvell/
>  obj-$(CONFIG_NET_VENDOR_MEDIATEK) += mediatek/
>  obj-$(CONFIG_NET_VENDOR_MELLANOX) += mellanox/
> diff --git a/drivers/net/ethernet/litex/Kconfig b/drivers/net/ethernet/litex/Kconfig
> new file mode 100644
> index 000000000000..265dba414b41
> --- /dev/null
> +++ b/drivers/net/ethernet/litex/Kconfig
> @@ -0,0 +1,27 @@
> +#
> +# LiteX device configuration
> +#
> +
> +config NET_VENDOR_LITEX
> +	bool "LiteX devices"
> +	default y
> +	help
> +	  If you have a network (Ethernet) card belonging to this class, say Y.
> +
> +	  Note that the answer to this question doesn't directly affect the
> +	  kernel: saying N will just cause the configurator to skip all
> +	  the questions about LiteX devices. If you say Y, you will be asked
> +	  for your specific card in the following questions.
> +
> +if NET_VENDOR_LITEX
> +
> +config LITEX_LITEETH
> +	tristate "LiteX Ethernet support"

Mostly cosmetic, but should there be a "depends on LITEX" statement in here?
Maybe also "select MII" and "select PHYLIB"?

> +	help
> +	  If you wish to compile a kernel for hardware with a LiteX LiteEth
> +	  device then you should answer Y to this.
> +
> +	  LiteX is a soft system-on-chip that targets FPGAs. LiteETH is a basic
> +	  network device that is commonly used in LiteX designs.
> +
> +endif # NET_VENDOR_LITEX
> diff --git a/drivers/net/ethernet/litex/Makefile b/drivers/net/ethernet/litex/Makefile
> new file mode 100644
> index 000000000000..9343b73b8e49
> --- /dev/null
> +++ b/drivers/net/ethernet/litex/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for the LiteX network device drivers.
> +#
> +
> +obj-$(CONFIG_LITEX_LITEETH) += litex_liteeth.o
> diff --git a/drivers/net/ethernet/litex/litex_liteeth.c b/drivers/net/ethernet/litex/litex_liteeth.c
> new file mode 100644
> index 000000000000..e9c5d817e1f9
> --- /dev/null
> +++ b/drivers/net/ethernet/litex/litex_liteeth.c
> @@ -0,0 +1,327 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * LiteX Liteeth Ethernet
> + *
> + * Copyright 2017 Joel Stanley <joel@jms.id.au>
> + *
> + */
> +
> +#include <linux/etherdevice.h>
> +#include <linux/interrupt.h>
> +#include <linux/litex.h>
> +#include <linux/module.h>
> +#include <linux/of_net.h>
> +#include <linux/platform_device.h>
> +
> +#define LITEETH_WRITER_SLOT       0x00
> +#define LITEETH_WRITER_LENGTH     0x04
> +#define LITEETH_WRITER_ERRORS     0x08
> +#define LITEETH_WRITER_EV_STATUS  0x0C
> +#define LITEETH_WRITER_EV_PENDING 0x10
> +#define LITEETH_WRITER_EV_ENABLE  0x14
> +#define LITEETH_READER_START      0x18
> +#define LITEETH_READER_READY      0x1C
> +#define LITEETH_READER_LEVEL      0x20
> +#define LITEETH_READER_SLOT       0x24
> +#define LITEETH_READER_LENGTH     0x28
> +#define LITEETH_READER_EV_STATUS  0x2C
> +#define LITEETH_READER_EV_PENDING 0x30
> +#define LITEETH_READER_EV_ENABLE  0x34
> +#define LITEETH_PREAMBLE_CRC      0x38
> +#define LITEETH_PREAMBLE_ERRORS   0x3C
> +#define LITEETH_CRC_ERRORS        0x40
> +
> +#define LITEETH_PHY_CRG_RESET     0x00
> +#define LITEETH_MDIO_W            0x04
> +#define LITEETH_MDIO_R            0x0C
> +
> +#define DRV_NAME	"liteeth"
> +
> +#define LITEETH_BUFFER_SIZE		0x800
> +#define MAX_PKT_SIZE			LITEETH_BUFFER_SIZE
> +
> +struct liteeth {
> +	void __iomem *base;
> +	struct net_device *netdev;
> +	struct device *dev;
> +
> +	/* Tx */
> +	int tx_slot;
> +	int num_tx_slots;
> +	void __iomem *tx_base;
> +
> +	/* Rx */
> +	int rx_slot;
> +	int num_rx_slots;
> +	void __iomem *rx_base;
> +};
> +
> +static int liteeth_rx(struct net_device *netdev)
> +{
> +	struct liteeth *priv = netdev_priv(netdev);
> +	struct sk_buff *skb;
> +	unsigned char *data;
> +	u8 rx_slot;
> +	int len;
> +
> +	rx_slot = litex_read8(priv->base + LITEETH_WRITER_SLOT);
> +	len = litex_read32(priv->base + LITEETH_WRITER_LENGTH);
> +
> +	if (len == 0 || len > 2048)
> +		goto rx_drop;
> +
> +	skb = netdev_alloc_skb_ip_align(netdev, len);
> +	if (!skb) {
> +		netdev_err(netdev, "couldn't get memory\n");
> +		goto rx_drop;
> +	}
> +
> +	data = skb_put(skb, len);
> +	memcpy_fromio(data, priv->rx_base + rx_slot * LITEETH_BUFFER_SIZE, len);
> +	skb->protocol = eth_type_trans(skb, netdev);
> +
> +	netdev->stats.rx_packets++;
> +	netdev->stats.rx_bytes += len;
> +
> +	return netif_rx(skb);
> +
> +rx_drop:
> +	netdev->stats.rx_dropped++;
> +	netdev->stats.rx_errors++;
> +
> +	return NET_RX_DROP;
> +}
> +
> +static irqreturn_t liteeth_interrupt(int irq, void *dev_id)
> +{
> +	struct net_device *netdev = dev_id;
> +	struct liteeth *priv = netdev_priv(netdev);
> +	u8 reg;
> +
> +	reg = litex_read8(priv->base + LITEETH_READER_EV_PENDING);
> +	if (reg) {
> +		if (netif_queue_stopped(netdev))
> +			netif_wake_queue(netdev);
> +		litex_write8(priv->base + LITEETH_READER_EV_PENDING, reg);
> +	}
> +
> +	reg = litex_read8(priv->base + LITEETH_WRITER_EV_PENDING);
> +	if (reg) {
> +		liteeth_rx(netdev);
> +		litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, reg);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int liteeth_open(struct net_device *netdev)
> +{
> +	struct liteeth *priv = netdev_priv(netdev);
> +	int err;
> +
> +	/* Clear pending events */
> +	litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, 1);
> +	litex_write8(priv->base + LITEETH_READER_EV_PENDING, 1);
> +
> +	err = request_irq(netdev->irq, liteeth_interrupt, 0, netdev->name, netdev);
> +	if (err) {
> +		netdev_err(netdev, "failed to request irq %d\n", netdev->irq);
> +		return err;
> +	}
> +
> +	/* Enable IRQs */
> +	litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 1);
> +	litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 1);
> +
> +	netif_carrier_on(netdev);
> +	netif_start_queue(netdev);
> +
> +	return 0;
> +}
> +
> +static int liteeth_stop(struct net_device *netdev)
> +{
> +	struct liteeth *priv = netdev_priv(netdev);
> +
> +	netif_stop_queue(netdev);
> +	netif_carrier_off(netdev);
> +
> +	litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 0);
> +	litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 0);
> +
> +	free_irq(netdev->irq, netdev);
> +
> +	return 0;
> +}
> +
> +static int liteeth_start_xmit(struct sk_buff *skb, struct net_device *netdev)
> +{
> +	struct liteeth *priv = netdev_priv(netdev);
> +	void __iomem *txbuffer;
> +
> +	if (!litex_read8(priv->base + LITEETH_READER_READY)) {
> +		if (net_ratelimit())
> +			netdev_err(netdev, "LITEETH_READER_READY not ready\n");
> +
> +		netif_stop_queue(netdev);
> +
> +		return NETDEV_TX_BUSY;
> +	}
> +
> +	/* Reject oversize packets */
> +	if (unlikely(skb->len > MAX_PKT_SIZE)) {
> +		if (net_ratelimit())
> +			netdev_err(netdev, "tx packet too big\n");
> +
> +		dev_kfree_skb_any(skb);
> +		netdev->stats.tx_dropped++;
> +		netdev->stats.tx_errors++;
> +
> +		return NETDEV_TX_OK;
> +	}
> +
> +	txbuffer = priv->tx_base + priv->tx_slot * LITEETH_BUFFER_SIZE;
> +	memcpy_toio(txbuffer, skb->data, skb->len);
> +	litex_write8(priv->base + LITEETH_READER_SLOT, priv->tx_slot);
> +	litex_write16(priv->base + LITEETH_READER_LENGTH, skb->len);
> +	litex_write8(priv->base + LITEETH_READER_START, 1);
> +
> +	netdev->stats.tx_bytes += skb->len;
> +	netdev->stats.tx_packets++;
> +
> +	priv->tx_slot = (priv->tx_slot + 1) % priv->num_tx_slots;
> +	dev_kfree_skb_any(skb);
> +
> +	return NETDEV_TX_OK;
> +}
> +
> +static const struct net_device_ops liteeth_netdev_ops = {
> +	.ndo_open		= liteeth_open,
> +	.ndo_stop		= liteeth_stop,
> +	.ndo_start_xmit         = liteeth_start_xmit,
> +};
> +
> +int liteeth_setup_slots(struct liteeth *priv)
> +{
> +	struct device_node *np = priv->dev->of_node;
> +	int err, depth;
> +
> +	err = of_property_read_u32(np, "rx-fifo-depth", &depth);
> +	if (err) {
> +		dev_err(priv->dev, "unable to get rx-fifo-depth\n");
> +		return err;
> +	}
> +	if (depth < LITEETH_BUFFER_SIZE) {

If I set depth to be *equal* to LITEETH_BUFFER_SIZE (2048) in DTS,
no traffic makes it out of my network interface (linux-on-litex-rocket
on an ecpix5 board, see github.com/litex-hub/linux-on-litex-rocket).

May I suggest rejecting if (depth / LITEETH_BUFFER_SIZE < 2) instead?
When that's enforced, the interface actually works fine for me.

> +		dev_err(priv->dev, "invalid tx-fifo-depth: %d\n", depth);

This should read "rx-fifo-depth".

> +		return -EINVAL;
> +	}
> +	priv->num_rx_slots = depth / LITEETH_BUFFER_SIZE;
> +
> +	err = of_property_read_u32(np, "tx-fifo-depth", &depth);
> +	if (err) {
> +		dev_err(priv->dev, "unable to get tx-fifo-depth\n");
> +		return err;
> +	}
> +	if (depth < LITEETH_BUFFER_SIZE) {

Ditto reject if (depth / LITEETH_BUFFER_SIZE < 2) instead.

> +		dev_err(priv->dev, "invalid rx-fifo-depth: %d\n", depth);

This should read "tx-fifo-depth".

> +		return -EINVAL;
> +	}
> +	priv->num_tx_slots = depth / LITEETH_BUFFER_SIZE;
> +
> +	return 0;
> +}
> +
> +static int liteeth_probe(struct platform_device *pdev)
> +{
> +	struct net_device *netdev;
> +	void __iomem *buf_base;
> +	struct resource *res;
> +	struct liteeth *priv;
> +	int irq, err;
> +
> +	netdev = devm_alloc_etherdev(&pdev->dev, sizeof(*priv));
> +	if (!netdev)
> +		return -ENOMEM;
> +
> +	SET_NETDEV_DEV(netdev, &pdev->dev);
> +	platform_set_drvdata(pdev, netdev);
> +
> +	priv = netdev_priv(netdev);
> +	priv->netdev = netdev;
> +	priv->dev = &pdev->dev;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "Failed to get IRQ %d\n", irq);
> +		return irq;

At this point, netdev has been dynamically allocated, and should
probably be free'd before liteeth_probe() is allowed to fail,
to avoid any potential leaks...

Something like "err = irq; goto err_free;" maybe?

> +	}
> +	netdev->irq = irq;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mac");
> +	priv->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(priv->base))
> +		return PTR_ERR(priv->base);

goto err_free instead?

> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "buffer");
> +	buf_base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(buf_base))
> +		return PTR_ERR(buf_base);

goto err_free, again?

Same for everywhere we return with an error, from here to the end of the
probe function...

> +
> +	err = liteeth_setup_slots(priv);
> +	if (err)
> +		return err;
> +
> +	/* Rx slots */
> +	priv->rx_base = buf_base;
> +	priv->rx_slot = 0;
> +
> +	/* Tx slots come after Rx slots */
> +	priv->tx_base = buf_base + priv->num_rx_slots * LITEETH_BUFFER_SIZE;
> +	priv->tx_slot = 0;
> +
> +	err = of_get_mac_address(pdev->dev.of_node, netdev->dev_addr);
> +	if (err)
> +		eth_hw_addr_random(netdev);
> +
> +	netdev->netdev_ops = &liteeth_netdev_ops;
> +
> +	err = register_netdev(netdev);
> +	if (err) {
> +		dev_err(&pdev->dev, "Failed to register netdev %d\n", err);
> +		return err;
> +	}
> +
> +	netdev_info(netdev, "irq %d tx slots %d rx slots %d",
> +		    netdev->irq, priv->num_tx_slots, priv->num_rx_slots);
> +
> +	return 0;

err_free:
	free_netdev(netdev);
	return err;

Thanks,
--Gabriel

> +}
> +
> +static int liteeth_remove(struct platform_device *pdev)
> +{
> +	struct net_device *netdev = platform_get_drvdata(pdev);
> +
> +	unregister_netdev(netdev);
> +	free_netdev(netdev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id liteeth_of_match[] = {
> +	{ .compatible = "litex,liteeth" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, liteeth_of_match);
> +
> +static struct platform_driver liteeth_driver = {
> +	.probe = liteeth_probe,
> +	.remove = liteeth_remove,
> +	.driver = {
> +		.name = DRV_NAME,
> +		.of_match_table = liteeth_of_match,
> +	},
> +};
> +module_platform_driver(liteeth_driver);
> +
> +MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
> +MODULE_LICENSE("GPL");
> -- 
> 2.32.0
> 

Re: [PATCH v2 2/2] net: Add driver for LiteX's LiteEth network interface

[Joel Stanley]

On Tue, 24 Aug 2021 at 19:43, Gabriel L. Somlo <gsomlo@gmail.com> wrote:
>
> Hi Joel,
>
> Couple of comments below:
>
> On Fri, Aug 20, 2021 at 05:17:26PM +0930, Joel Stanley wrote:

> > diff --git a/drivers/net/ethernet/litex/Kconfig b/drivers/net/ethernet/litex/Kconfig
> > new file mode 100644
> > index 000000000000..265dba414b41
> > --- /dev/null
> > +++ b/drivers/net/ethernet/litex/Kconfig

> > +
> > +config LITEX_LITEETH
> > +     tristate "LiteX Ethernet support"
>
> Mostly cosmetic, but should there be a "depends on LITEX" statement in here?

No, there's as there is no dependency on the litex soc driver.

> Maybe also "select MII" and "select PHYLIB"?

Again, there is no mii or phy code so the driver doesn't need these.

> > diff --git a/drivers/net/ethernet/litex/Makefile b/drivers/net/ethernet/litex/Makefile
> > new file mode 100644
> > index 000000000000..9343b73b8e49
> > --- /dev/null
> > +++ b/drivers/net/ethernet/litex/Makefile
> > +int liteeth_setup_slots(struct liteeth *priv)
> > +{
> > +     struct device_node *np = priv->dev->of_node;
> > +     int err, depth;
> > +
> > +     err = of_property_read_u32(np, "rx-fifo-depth", &depth);
> > +     if (err) {
> > +             dev_err(priv->dev, "unable to get rx-fifo-depth\n");
> > +             return err;
> > +     }
> > +     if (depth < LITEETH_BUFFER_SIZE) {
>
> If I set depth to be *equal* to LITEETH_BUFFER_SIZE (2048) in DTS,
> no traffic makes it out of my network interface (linux-on-litex-rocket
> on an ecpix5 board, see github.com/litex-hub/linux-on-litex-rocket).
>
> May I suggest rejecting if (depth / LITEETH_BUFFER_SIZE < 2) instead?
> When that's enforced, the interface actually works fine for me.

Yes, I was using BUFFER_SIZE as the slot size, which it is not. I'll
rework it to use the slot size I think.

I spent some time digging through the migen source and I couldn't work
out where the 1024 length comes from. If anything it should be
eth_mtu, which is 1530.

Florent, can you clear that up?

>
> > +             dev_err(priv->dev, "invalid tx-fifo-depth: %d\n", depth);
>
> This should read "rx-fifo-depth".

Thanks.

>
> > +             return -EINVAL;
> > +     }
> > +     priv->num_rx_slots = depth / LITEETH_BUFFER_SIZE;
> > +
> > +     err = of_property_read_u32(np, "tx-fifo-depth", &depth);
> > +     if (err) {
> > +             dev_err(priv->dev, "unable to get tx-fifo-depth\n");
> > +             return err;
> > +     }
> > +     if (depth < LITEETH_BUFFER_SIZE) {
>
> Ditto reject if (depth / LITEETH_BUFFER_SIZE < 2) instead.
>
> > +             dev_err(priv->dev, "invalid rx-fifo-depth: %d\n", depth);
>
> This should read "tx-fifo-depth".

Ack.

>
> > +             return -EINVAL;
> > +     }
> > +     priv->num_tx_slots = depth / LITEETH_BUFFER_SIZE;
> > +
> > +     return 0;
> > +}
> > +
> > +static int liteeth_probe(struct platform_device *pdev)
> > +{
> > +     struct net_device *netdev;
> > +     void __iomem *buf_base;
> > +     struct resource *res;
> > +     struct liteeth *priv;
> > +     int irq, err;
> > +
> > +     netdev = devm_alloc_etherdev(&pdev->dev, sizeof(*priv));
> > +     if (!netdev)
> > +             return -ENOMEM;
> > +
> > +     SET_NETDEV_DEV(netdev, &pdev->dev);
> > +     platform_set_drvdata(pdev, netdev);
> > +
> > +     priv = netdev_priv(netdev);
> > +     priv->netdev = netdev;
> > +     priv->dev = &pdev->dev;
> > +
> > +     irq = platform_get_irq(pdev, 0);
> > +     if (irq < 0) {
> > +             dev_err(&pdev->dev, "Failed to get IRQ %d\n", irq);
> > +             return irq;
>
> At this point, netdev has been dynamically allocated, and should
> probably be free'd before liteeth_probe() is allowed to fail,
> to avoid any potential leaks...

We use the managed variant of alloc_etherdev, which means the
structure is freed by the driver core when the driver is removed. This
saves having to open code the cleanup/free code.

Have a read of Documentation/driver-api/driver-model/devres.rst for
more information.

Thanks for the review Gabriel. I'll send a v3 with some fixes for the
fifo buffer handling.

Cheers,

Joel

Re: [PATCH v2 2/2] net: Add driver for LiteX's LiteEth network interface

[Joel Stanley]

On Wed, 25 Aug 2021 at 06:35, Joel Stanley <joel@jms.id.au> wrote:
>
> On Tue, 24 Aug 2021 at 19:43, Gabriel L. Somlo <gsomlo@gmail.com> wrote:
> > > diff --git a/drivers/net/ethernet/litex/Makefile b/drivers/net/ethernet/litex/Makefile
> > > new file mode 100644
> > > index 000000000000..9343b73b8e49
> > > --- /dev/null
> > > +++ b/drivers/net/ethernet/litex/Makefile
> > > +int liteeth_setup_slots(struct liteeth *priv)
> > > +{
> > > +     struct device_node *np = priv->dev->of_node;
> > > +     int err, depth;
> > > +
> > > +     err = of_property_read_u32(np, "rx-fifo-depth", &depth);
> > > +     if (err) {
> > > +             dev_err(priv->dev, "unable to get rx-fifo-depth\n");
> > > +             return err;
> > > +     }
> > > +     if (depth < LITEETH_BUFFER_SIZE) {
> >
> > If I set depth to be *equal* to LITEETH_BUFFER_SIZE (2048) in DTS,
> > no traffic makes it out of my network interface (linux-on-litex-rocket
> > on an ecpix5 board, see github.com/litex-hub/linux-on-litex-rocket).
> >
> > May I suggest rejecting if (depth / LITEETH_BUFFER_SIZE < 2) instead?
> > When that's enforced, the interface actually works fine for me.
>
> Yes, I was using BUFFER_SIZE as the slot size, which it is not. I'll
> rework it to use the slot size I think.
>
> I spent some time digging through the migen source and I couldn't work
> out where the 1024 length comes from. If anything it should be
> eth_mtu, which is 1530.
>
> Florent, can you clear that up?

Replying to myself, the 0x800 is the slot size. I will fix the maths
so the number of slots is calculated correctly.

Re: [PATCH v2 2/2] net: Add driver for LiteX's LiteEth network interface

[Gabriel L. Somlo]

On Wed, Aug 25, 2021 at 06:35:17AM +0000, Joel Stanley wrote:
> > > +
> > > +     netdev = devm_alloc_etherdev(&pdev->dev, sizeof(*priv));
> > > +     if (!netdev)
> > > +             return -ENOMEM;
> > > +
> > > +     SET_NETDEV_DEV(netdev, &pdev->dev);
> > > +     platform_set_drvdata(pdev, netdev);
> > > +
> > > +     priv = netdev_priv(netdev);
> > > +     priv->netdev = netdev;
> > > +     priv->dev = &pdev->dev;
> > > +
> > > +     irq = platform_get_irq(pdev, 0);
> > > +     if (irq < 0) {
> > > +             dev_err(&pdev->dev, "Failed to get IRQ %d\n", irq);
> > > +             return irq;
> >
> > At this point, netdev has been dynamically allocated, and should
> > probably be free'd before liteeth_probe() is allowed to fail,
> > to avoid any potential leaks...
> 
> We use the managed variant of alloc_etherdev, which means the
> structure is freed by the driver core when the driver is removed. This
> saves having to open code the cleanup/free code.
> 
> Have a read of Documentation/driver-api/driver-model/devres.rst for
> more information.

That makes sense, thanks for the link!

Cheers,
--Gabriel

Re: [PATCH v2 2/2] net: Add driver for LiteX's LiteEth network interface

[Andrew Lunn]

On Wed, Aug 25, 2021 at 06:35:17AM +0000, Joel Stanley wrote:
> On Tue, 24 Aug 2021 at 19:43, Gabriel L. Somlo <gsomlo@gmail.com> wrote:
> >
> > Hi Joel,
> >
> > Couple of comments below:
> >
> > On Fri, Aug 20, 2021 at 05:17:26PM +0930, Joel Stanley wrote:
> 
> > > diff --git a/drivers/net/ethernet/litex/Kconfig b/drivers/net/ethernet/litex/Kconfig
> > > new file mode 100644
> > > index 000000000000..265dba414b41
> > > --- /dev/null
> > > +++ b/drivers/net/ethernet/litex/Kconfig
> 
> > > +
> > > +config LITEX_LITEETH
> > > +     tristate "LiteX Ethernet support"
> >
> > Mostly cosmetic, but should there be a "depends on LITEX" statement in here?
> 
> No, there's as there is no dependency on the litex soc driver.

Which is good, you will get more build coverage that way, it will be
built of x86, arm, mips, etc...

> 
> > Maybe also "select MII" and "select PHYLIB"?
> 
> Again, there is no mii or phy code so the driver doesn't need these.

Yet.

At some point i expect you will need these, but you don't need them
now.

	Andrew