gve: Add basic driver framework for Compute Engine Virtual NIC

Add a driver framework for the Compute Engine Virtual NIC that will be
available in the future.

At this point the only functionality is loading the driver.

Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Jon Olson <jonolson@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 249 insertions, 0 deletions

diff --git a/drivers/net/ethernet/google/gve/gve_adminq.c b/drivers/net/ethernet/google/gve/gve_adminq.c
new file mode 100644
index 000000000000..4bf32e4e2810
--- /dev/null
+++ b/drivers/net/ethernet/google/gve/gve_adminq.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/* Google virtual Ethernet (gve) driver
+ *
+ * Copyright (C) 2015-2019 Google, Inc.
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/pci.h>
+#include "gve.h"
+#include "gve_adminq.h"
+#include "gve_register.h"
+
+#define GVE_MAX_ADMINQ_RELEASE_CHECK	500
+#define GVE_ADMINQ_SLEEP_LEN		20
+#define GVE_MAX_ADMINQ_EVENT_COUNTER_CHECK	100
+
+int gve_adminq_alloc(struct device *dev, struct gve_priv *priv)
+{
+	priv->adminq = dma_alloc_coherent(dev, PAGE_SIZE,
+					  &priv->adminq_bus_addr, GFP_KERNEL);
+	if (unlikely(!priv->adminq))
+		return -ENOMEM;
+
+	priv->adminq_mask = (PAGE_SIZE / sizeof(union gve_adminq_command)) - 1;
+	priv->adminq_prod_cnt = 0;
+
+	/* Setup Admin queue with the device */
+	iowrite32be(priv->adminq_bus_addr / PAGE_SIZE,
+		    &priv->reg_bar0->adminq_pfn);
+
+	gve_set_admin_queue_ok(priv);
+	return 0;
+}
+
+void gve_adminq_release(struct gve_priv *priv)
+{
+	int i = 0;
+
+	/* Tell the device the adminq is leaving */
+	iowrite32be(0x0, &priv->reg_bar0->adminq_pfn);
+	while (ioread32be(&priv->reg_bar0->adminq_pfn)) {
+		/* If this is reached the device is unrecoverable and still
+		 * holding memory. Continue looping to avoid memory corruption,
+		 * but WARN so it is visible what is going on.
+		 */
+		if (i == GVE_MAX_ADMINQ_RELEASE_CHECK)
+			WARN(1, "Unrecoverable platform error!");
+		i++;
+		msleep(GVE_ADMINQ_SLEEP_LEN);
+	}
+	gve_clear_device_rings_ok(priv);
+	gve_clear_device_resources_ok(priv);
+	gve_clear_admin_queue_ok(priv);
+}
+
+void gve_adminq_free(struct device *dev, struct gve_priv *priv)
+{
+	if (!gve_get_admin_queue_ok(priv))
+		return;
+	gve_adminq_release(priv);
+	dma_free_coherent(dev, PAGE_SIZE, priv->adminq, priv->adminq_bus_addr);
+	gve_clear_admin_queue_ok(priv);
+}
+
+static void gve_adminq_kick_cmd(struct gve_priv *priv, u32 prod_cnt)
+{
+	iowrite32be(prod_cnt, &priv->reg_bar0->adminq_doorbell);
+}
+
+static bool gve_adminq_wait_for_cmd(struct gve_priv *priv, u32 prod_cnt)
+{
+	int i;
+
+	for (i = 0; i < GVE_MAX_ADMINQ_EVENT_COUNTER_CHECK; i++) {
+		if (ioread32be(&priv->reg_bar0->adminq_event_counter)
+		    == prod_cnt)
+			return true;
+		msleep(GVE_ADMINQ_SLEEP_LEN);
+	}
+
+	return false;
+}
+
+static int gve_adminq_parse_err(struct device *dev, u32 status)
+{
+	if (status != GVE_ADMINQ_COMMAND_PASSED &&
+	    status != GVE_ADMINQ_COMMAND_UNSET)
+		dev_err(dev, "AQ command failed with status %d\n", status);
+
+	switch (status) {
+	case GVE_ADMINQ_COMMAND_PASSED:
+		return 0;
+	case GVE_ADMINQ_COMMAND_UNSET:
+		dev_err(dev, "parse_aq_err: err and status both unset, this should not be possible.\n");
+		return -EINVAL;
+	case GVE_ADMINQ_COMMAND_ERROR_ABORTED:
+	case GVE_ADMINQ_COMMAND_ERROR_CANCELLED:
+	case GVE_ADMINQ_COMMAND_ERROR_DATALOSS:
+	case GVE_ADMINQ_COMMAND_ERROR_FAILED_PRECONDITION:
+	case GVE_ADMINQ_COMMAND_ERROR_UNAVAILABLE:
+		return -EAGAIN;
+	case GVE_ADMINQ_COMMAND_ERROR_ALREADY_EXISTS:
+	case GVE_ADMINQ_COMMAND_ERROR_INTERNAL_ERROR:
+	case GVE_ADMINQ_COMMAND_ERROR_INVALID_ARGUMENT:
+	case GVE_ADMINQ_COMMAND_ERROR_NOT_FOUND:
+	case GVE_ADMINQ_COMMAND_ERROR_OUT_OF_RANGE:
+	case GVE_ADMINQ_COMMAND_ERROR_UNKNOWN_ERROR:
+		return -EINVAL;
+	case GVE_ADMINQ_COMMAND_ERROR_DEADLINE_EXCEEDED:
+		return -ETIME;
+	case GVE_ADMINQ_COMMAND_ERROR_PERMISSION_DENIED:
+	case GVE_ADMINQ_COMMAND_ERROR_UNAUTHENTICATED:
+		return -EACCES;
+	case GVE_ADMINQ_COMMAND_ERROR_RESOURCE_EXHAUSTED:
+		return -ENOMEM;
+	case GVE_ADMINQ_COMMAND_ERROR_UNIMPLEMENTED:
+		return -ENOTSUPP;
+	default:
+		dev_err(dev, "parse_aq_err: unknown status code %d\n", status);
+		return -EINVAL;
+	}
+}
+
+/* This function is not threadsafe - the caller is responsible for any
+ * necessary locks.
+ */
+int gve_adminq_execute_cmd(struct gve_priv *priv,
+			   union gve_adminq_command *cmd_orig)
+{
+	union gve_adminq_command *cmd;
+	u32 status = 0;
+	u32 prod_cnt;
+
+	cmd = &priv->adminq[priv->adminq_prod_cnt & priv->adminq_mask];
+	priv->adminq_prod_cnt++;
+	prod_cnt = priv->adminq_prod_cnt;
+
+	memcpy(cmd, cmd_orig, sizeof(*cmd_orig));
+
+	gve_adminq_kick_cmd(priv, prod_cnt);
+	if (!gve_adminq_wait_for_cmd(priv, prod_cnt)) {
+		dev_err(&priv->pdev->dev, "AQ command timed out, need to reset AQ\n");
+		return -ENOTRECOVERABLE;
+	}
+
+	memcpy(cmd_orig, cmd, sizeof(*cmd));
+	status = be32_to_cpu(READ_ONCE(cmd->status));
+	return gve_adminq_parse_err(&priv->pdev->dev, status);
+}
+
+/* The device specifies that the management vector can either be the first irq
+ * or the last irq. ntfy_blk_msix_base_idx indicates the first irq assigned to
+ * the ntfy blks. It if is 0 then the management vector is last, if it is 1 then
+ * the management vector is first.
+ *
+ * gve arranges the msix vectors so that the management vector is last.
+ */
+#define GVE_NTFY_BLK_BASE_MSIX_IDX	0
+int gve_adminq_configure_device_resources(struct gve_priv *priv,
+					  dma_addr_t counter_array_bus_addr,
+					  u32 num_counters,
+					  dma_addr_t db_array_bus_addr,
+					  u32 num_ntfy_blks)
+{
+	union gve_adminq_command cmd;
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = cpu_to_be32(GVE_ADMINQ_CONFIGURE_DEVICE_RESOURCES);
+	cmd.configure_device_resources =
+		(struct gve_adminq_configure_device_resources) {
+		.counter_array = cpu_to_be64(counter_array_bus_addr),
+		.num_counters = cpu_to_be32(num_counters),
+		.irq_db_addr = cpu_to_be64(db_array_bus_addr),
+		.num_irq_dbs = cpu_to_be32(num_ntfy_blks),
+		.irq_db_stride = cpu_to_be32(sizeof(priv->ntfy_blocks[0])),
+		.ntfy_blk_msix_base_idx =
+					cpu_to_be32(GVE_NTFY_BLK_BASE_MSIX_IDX),
+	};
+
+	return gve_adminq_execute_cmd(priv, &cmd);
+}
+
+int gve_adminq_deconfigure_device_resources(struct gve_priv *priv)
+{
+	union gve_adminq_command cmd;
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = cpu_to_be32(GVE_ADMINQ_DECONFIGURE_DEVICE_RESOURCES);
+
+	return gve_adminq_execute_cmd(priv, &cmd);
+}
+
+int gve_adminq_describe_device(struct gve_priv *priv)
+{
+	struct gve_device_descriptor *descriptor;
+	union gve_adminq_command cmd;
+	dma_addr_t descriptor_bus;
+	int err = 0;
+	u8 *mac;
+	u16 mtu;
+
+	memset(&cmd, 0, sizeof(cmd));
+	descriptor = dma_alloc_coherent(&priv->pdev->dev, PAGE_SIZE,
+					&descriptor_bus, GFP_KERNEL);
+	if (!descriptor)
+		return -ENOMEM;
+	cmd.opcode = cpu_to_be32(GVE_ADMINQ_DESCRIBE_DEVICE);
+	cmd.describe_device.device_descriptor_addr =
+						cpu_to_be64(descriptor_bus);
+	cmd.describe_device.device_descriptor_version =
+			cpu_to_be32(GVE_ADMINQ_DEVICE_DESCRIPTOR_VERSION);
+	cmd.describe_device.available_length = cpu_to_be32(PAGE_SIZE);
+
+	err = gve_adminq_execute_cmd(priv, &cmd);
+	if (err)
+		goto free_device_descriptor;
+
+	mtu = be16_to_cpu(descriptor->mtu);
+	if (mtu < ETH_MIN_MTU) {
+		netif_err(priv, drv, priv->dev, "MTU %d below minimum MTU\n",
+			  mtu);
+		err = -EINVAL;
+		goto free_device_descriptor;
+	}
+	priv->dev->max_mtu = mtu;
+	priv->num_event_counters = be16_to_cpu(descriptor->counters);
+	ether_addr_copy(priv->dev->dev_addr, descriptor->mac);
+	mac = descriptor->mac;
+	netif_info(priv, drv, priv->dev, "MAC addr: %pM\n", mac);
+
+free_device_descriptor:
+	dma_free_coherent(&priv->pdev->dev, sizeof(*descriptor), descriptor,
+			  descriptor_bus);
+	return err;
+}
+
+int gve_adminq_set_mtu(struct gve_priv *priv, u64 mtu)
+{
+	union gve_adminq_command cmd;
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = cpu_to_be32(GVE_ADMINQ_SET_DRIVER_PARAMETER);
+	cmd.set_driver_param = (struct gve_adminq_set_driver_parameter) {
+		.parameter_type = cpu_to_be32(GVE_SET_PARAM_MTU),
+		.parameter_value = cpu_to_be64(mtu),
+	};
+
+	return gve_adminq_execute_cmd(priv, &cmd);
+}