net/mlx5: Add Crdump support

Crdump allows the driver to retrieve a dump of the FW PCI crspace.
This is useful in case of catastrophic issues which may require FW
reset. The crspace dump can be used for later debug.

Signed-off-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Reviewed-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -16,7 +16,7 @@ mlx5_core-y :=	main.o cmd.o debugfs.o fw.o eq.o uar.o pagealloc.o \
 		transobj.o vport.o sriov.o fs_cmd.o fs_core.o \
 		fs_counters.o rl.o lag.o dev.o events.o wq.o lib/gid.o \
 		lib/devcom.o lib/pci_vsc.o diag/fs_tracepoint.o \
-		diag/fw_tracer.o devlink.o
+		diag/fw_tracer.o diag/crdump.o devlink.o
 
 #
 # Netdev basic

drivers/net/ethernet/mellanox/mlx5/core/diag/crdump.c

@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/* Copyright (c) 2019 Mellanox Technologies */
+
+#include <linux/mlx5/driver.h>
+#include "mlx5_core.h"
+#include "lib/pci_vsc.h"
+#include "lib/mlx5.h"
+
+#define BAD_ACCESS			0xBADACCE5
+#define MLX5_PROTECTED_CR_SCAN_CRSPACE	0x7
+
+static bool mlx5_crdump_enabled(struct mlx5_core_dev *dev)
+{
+	return !!dev->priv.health.crdump_size;
+}
+
+static int mlx5_crdump_fill(struct mlx5_core_dev *dev, u32 *cr_data)
+{
+	u32 crdump_size = dev->priv.health.crdump_size;
+	int i, ret;
+
+	for (i = 0; i < (crdump_size / 4); i++)
+		cr_data[i] = BAD_ACCESS;
+
+	ret = mlx5_vsc_gw_read_block_fast(dev, cr_data, crdump_size);
+	if (ret <= 0) {
+		if (ret == 0)
+			return -EIO;
+		return ret;
+	}
+
+	if (crdump_size != ret) {
+		mlx5_core_warn(dev, "failed to read full dump, read %d out of %u\n",
+			       ret, crdump_size);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int mlx5_crdump_collect(struct mlx5_core_dev *dev, u32 *cr_data)
+{
+	int ret;
+
+	if (!mlx5_crdump_enabled(dev))
+		return -ENODEV;
+
+	ret = mlx5_vsc_gw_lock(dev);
+	if (ret) {
+		mlx5_core_warn(dev, "crdump: failed to lock vsc gw err %d\n",
+			       ret);
+		return ret;
+	}
+
+	ret = mlx5_vsc_gw_set_space(dev, MLX5_VSC_SPACE_SCAN_CRSPACE, NULL);
+	if (ret)
+		goto unlock;
+
+	ret = mlx5_crdump_fill(dev, cr_data);
+
+unlock:
+	mlx5_vsc_gw_unlock(dev);
+	return ret;
+}
+
+int mlx5_crdump_enable(struct mlx5_core_dev *dev)
+{
+	struct mlx5_priv *priv = &dev->priv;
+	u32 space_size;
+	int ret;
+
+	if (!mlx5_core_is_pf(dev) || !mlx5_vsc_accessible(dev) ||
+	    mlx5_crdump_enabled(dev))
+		return 0;
+
+	ret = mlx5_vsc_gw_lock(dev);
+	if (ret)
+		return ret;
+
+	/* Check if space is supported and get space size */
+	ret = mlx5_vsc_gw_set_space(dev, MLX5_VSC_SPACE_SCAN_CRSPACE,
+				    &space_size);
+	if (ret) {
+		/* Unlock and mask error since space is not supported */
+		mlx5_vsc_gw_unlock(dev);
+		return 0;
+	}
+
+	if (!space_size) {
+		mlx5_core_warn(dev, "Invalid Crspace size, zero\n");
+		mlx5_vsc_gw_unlock(dev);
+		return -EINVAL;
+	}
+
+	ret = mlx5_vsc_gw_unlock(dev);
+	if (ret)
+		return ret;
+
+	priv->health.crdump_size = space_size;
+	return 0;
+}
+
+void mlx5_crdump_disable(struct mlx5_core_dev *dev)
+{
+	dev->priv.health.crdump_size = 0;
+}

drivers/net/ethernet/mellanox/mlx5/core/lib/mlx5.h

@@ -41,6 +41,9 @@ int  mlx5_core_reserve_gids(struct mlx5_core_dev *dev, unsigned int count);
 void mlx5_core_unreserve_gids(struct mlx5_core_dev *dev, unsigned int count);
 int  mlx5_core_reserved_gid_alloc(struct mlx5_core_dev *dev, int *gid_index);
 void mlx5_core_reserved_gid_free(struct mlx5_core_dev *dev, int gid_index);
+int mlx5_crdump_enable(struct mlx5_core_dev *dev);
+void mlx5_crdump_disable(struct mlx5_core_dev *dev);
+int mlx5_crdump_collect(struct mlx5_core_dev *dev, u32 *cr_data);
 
 /* TODO move to lib/events.h */
 

drivers/net/ethernet/mellanox/mlx5/core/main.c

@@ -1313,6 +1313,10 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (err)
 		goto clean_load;
 
+	err = mlx5_crdump_enable(dev);
+	if (err)
+		dev_err(&pdev->dev, "mlx5_crdump_enable failed with error code %d\n", err);
+
 	pci_save_state(pdev);
 	return 0;
 
@@ -1334,6 +1338,7 @@ static void remove_one(struct pci_dev *pdev)
 	struct mlx5_core_dev *dev  = pci_get_drvdata(pdev);
 	struct devlink *devlink = priv_to_devlink(dev);
 
+	mlx5_crdump_disable(dev);
 	mlx5_devlink_unregister(devlink);
 	mlx5_unregister_device(dev);
 

include/linux/mlx5/driver.h

@@ -435,6 +435,7 @@ struct mlx5_core_health {
 	u32				prev;
 	int				miss_counter;
 	bool				sick;
+	u32				crdump_size;
 	/* wq spinlock to synchronize draining */
 	spinlock_t			wq_lock;
 	struct workqueue_struct	       *wq;