Subject: Re: [PATCH v9 net-next 02/14] pds_core: add devcmd device interfaces

From: Leon Romanovsky <[email-masked]>
Date: Sun, 9 Apr 2023 14:46:08 +0300

On Thu, Apr 06, 2023 at 04:41:31PM -0700, Shannon Nelson wrote:
> The devcmd interface is the basic connection to the device through the
> PCI BAR for low level identification and command services.  This does
> the early device initialization and finds the identity data, and adds
> devcmd routines to be used by later driver bits.
> 
> Signed-off-by: Shannon Nelson <[email-masked]>
> ---
>  drivers/net/ethernet/amd/pds_core/Makefile  |   4 +-
>  drivers/net/ethernet/amd/pds_core/core.c    |  36 ++
>  drivers/net/ethernet/amd/pds_core/core.h    |  52 +++
>  drivers/net/ethernet/amd/pds_core/debugfs.c |  68 ++++
>  drivers/net/ethernet/amd/pds_core/dev.c     | 349 ++++++++++++++++++++
>  drivers/net/ethernet/amd/pds_core/main.c    |  33 +-
>  include/linux/pds/pds_common.h              |  61 ++++
>  include/linux/pds/pds_intr.h                | 163 +++++++++
>  8 files changed, 763 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/net/ethernet/amd/pds_core/core.c
>  create mode 100644 drivers/net/ethernet/amd/pds_core/dev.c
>  create mode 100644 include/linux/pds/pds_intr.h

<...>

> +int pdsc_setup(struct pdsc *pdsc, bool init)
> +{
> +	int err = 0;

You don't need to set value as you overwrite it immediately.

> +
> +	if (init)
> +		err = pdsc_dev_init(pdsc);
> +	else
> +		err = pdsc_dev_reinit(pdsc);
> +	if (err)
> +		return err;
> +
> +	clear_bit(PDSC_S_FW_DEAD, &pdsc->state);
> +	return 0;
> +}

<...>

> +static int irqs_show(struct seq_file *seq, void *v)
> +{
> +	struct pdsc *pdsc = seq->private;
> +	struct pdsc_intr_info *intr_info;
> +	int i;
> +
> +	seq_printf(seq, "index  vector  name (nintrs %d)\n", pdsc->nintrs);
> +
> +	if (!pdsc->intr_info)
> +		return 0;
> +
> +	for (i = 0; i < pdsc->nintrs; i++) {
> +		intr_info = &pdsc->intr_info[i];
> +		if (!intr_info->vector)
> +			continue;
> +
> +		seq_printf(seq, "% 3d    % 3d     %s\n",
> +			   i, intr_info->vector, intr_info->name);
> +	}
> +
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(irqs);

I'm curious why existing IRQ core support is not enough?

> +
> +void pdsc_debugfs_add_irqs(struct pdsc *pdsc)
> +{
> +	debugfs_create_file("irqs", 0400, pdsc->dentry, pdsc, &irqs_fops);
> +}
> +
>  #endif /* CONFIG_DEBUG_FS */
> diff --git a/drivers/net/ethernet/amd/pds_core/dev.c b/drivers/net/ethernet/amd/pds_core/dev.c
> new file mode 100644
> index 000000000000..52385a72246d
> --- /dev/null
> +++ b/drivers/net/ethernet/amd/pds_core/dev.c
> @@ -0,0 +1,349 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright(c) 2023 Advanced Micro Devices, Inc */
> +
> +#include <linux/errno.h>
> +#include <linux/pci.h>
> +#include <linux/utsname.h>
> +
> +#include "core.h"
> +
> +int pdsc_err_to_errno(enum pds_core_status_code code)

All users of this function, call to pdsc_devcmd_status() first. Probably
they need to be combined.

> +{
> +	switch (code) {
> +	case PDS_RC_SUCCESS:
> +		return 0;
> +	case PDS_RC_EVERSION:
> +	case PDS_RC_EQTYPE:
> +	case PDS_RC_EQID:
> +	case PDS_RC_EINVAL:
> +	case PDS_RC_ENOSUPP:
> +		return -EINVAL;
> +	case PDS_RC_EPERM:
> +		return -EPERM;
> +	case PDS_RC_ENOENT:
> +		return -ENOENT;
> +	case PDS_RC_EAGAIN:
> +		return -EAGAIN;
> +	case PDS_RC_ENOMEM:
> +		return -ENOMEM;
> +	case PDS_RC_EFAULT:
> +		return -EFAULT;
> +	case PDS_RC_EBUSY:
> +		return -EBUSY;
> +	case PDS_RC_EEXIST:
> +		return -EEXIST;
> +	case PDS_RC_EVFID:
> +		return -ENODEV;
> +	case PDS_RC_ECLIENT:
> +		return -ECHILD;
> +	case PDS_RC_ENOSPC:
> +		return -ENOSPC;
> +	case PDS_RC_ERANGE:
> +		return -ERANGE;
> +	case PDS_RC_BAD_ADDR:
> +		return -EFAULT;
> +	case PDS_RC_EOPCODE:
> +	case PDS_RC_EINTR:
> +	case PDS_RC_DEV_CMD:
> +	case PDS_RC_ERROR:
> +	case PDS_RC_ERDMA:
> +	case PDS_RC_EIO:
> +	default:
> +		return -EIO;
> +	}
> +}

<...>

> +static u8 pdsc_devcmd_status(struct pdsc *pdsc)
> +{
> +	return ioread8(&pdsc->cmd_regs->comp.status);
> +}

<...>

> +int pdsc_devcmd_init(struct pdsc *pdsc)
> +{
> +	union pds_core_dev_comp comp = { 0 };

There is no need to put 0 while using {} initialization.

> +	union pds_core_dev_cmd cmd = {
> +		.opcode = PDS_CORE_CMD_INIT,
> +	};
> +
> +	return pdsc_devcmd(pdsc, &cmd, &comp, pdsc->devcmd_timeout);
> +}

<...>

> +	/* Get intr_info struct array for tracking */
> +	pdsc->intr_info = kcalloc(nintrs, sizeof(*pdsc->intr_info), GFP_KERNEL);
> +	if (!pdsc->intr_info) {
> +		err = -ENOSPC;

The general convention is to return -ENOMEM for memorly allocation failures.

> +		goto err_out;
> +	}

<...>

> +/*
> + * enum pds_core_status_code - Device command return codes
> + */
> +enum pds_core_status_code {
> +	PDS_RC_SUCCESS	= 0,	/* Success */
> +	PDS_RC_EVERSION	= 1,	/* Incorrect version for request */
> +	PDS_RC_EOPCODE	= 2,	/* Invalid cmd opcode */
> +	PDS_RC_EIO	= 3,	/* I/O error */
> +	PDS_RC_EPERM	= 4,	/* Permission denied */
> +	PDS_RC_EQID	= 5,	/* Bad qid */
> +	PDS_RC_EQTYPE	= 6,	/* Bad qtype */
> +	PDS_RC_ENOENT	= 7,	/* No such element */
> +	PDS_RC_EINTR	= 8,	/* operation interrupted */
> +	PDS_RC_EAGAIN	= 9,	/* Try again */
> +	PDS_RC_ENOMEM	= 10,	/* Out of memory */
> +	PDS_RC_EFAULT	= 11,	/* Bad address */
> +	PDS_RC_EBUSY	= 12,	/* Device or resource busy */
> +	PDS_RC_EEXIST	= 13,	/* object already exists */
> +	PDS_RC_EINVAL	= 14,	/* Invalid argument */
> +	PDS_RC_ENOSPC	= 15,	/* No space left or alloc failure */
> +	PDS_RC_ERANGE	= 16,	/* Parameter out of range */
> +	PDS_RC_BAD_ADDR	= 17,	/* Descriptor contains a bad ptr */
> +	PDS_RC_DEV_CMD	= 18,	/* Device cmd attempted on AdminQ */
> +	PDS_RC_ENOSUPP	= 19,	/* Operation not supported */
> +	PDS_RC_ERROR	= 29,	/* Generic error */
> +	PDS_RC_ERDMA	= 30,	/* Generic RDMA error */
> +	PDS_RC_EVFID	= 31,	/* VF ID does not exist */
> +	PDS_RC_BAD_FW	= 32,	/* FW file is invalid or corrupted */
> +	PDS_RC_ECLIENT	= 33,   /* No such client id */
> +};

We asked from Intel to remove custom error codes and we would like to
ask it here too. Please use standard in-kernel errors.

> +
> +enum pds_core_driver_type {
> +	PDS_DRIVER_LINUX   = 1,

This is only relevant here, everything else is not applicable.

> +	PDS_DRIVER_WIN     = 2,
> +	PDS_DRIVER_DPDK    = 3,
> +	PDS_DRIVER_FREEBSD = 4,
> +	PDS_DRIVER_IPXE    = 5,
> +	PDS_DRIVER_ESXI    = 6,
> +};
> +

Thanks