Re: [net-next 01/11] igc: Add skeletal frame for Intel(R) 2.5G Ethernet Controller support

[Jakub Kicinski <jakub.kicinski@netronome.com>]

On Wed, 17 Oct 2018 15:23:12 -0700, Jeff Kirsher wrote:
> From: Sasha Neftin <sasha.neftin@intel.com>
> 
> This patch adds the beginning framework onto which I am going to add
> the igc driver which supports the Intel(R) I225-LM/I225-V 2.5G
> Ethernet Controller.
> 
> Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
> Tested-by: Aaron Brown <aaron.f.brown@intel.com>
> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

bunch of minor nit picks

> diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
> new file mode 100644
> index 000000000000..afe595cfcf63
> --- /dev/null
> +++ b/drivers/net/ethernet/intel/igc/igc.h
> @@ -0,0 +1,29 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright (c)  2018 Intel Corporation */
> +
> +#ifndef _IGC_H_
> +#define _IGC_H_
> +
> +#include <linux/kobject.h>
> +
> +#include <linux/pci.h>
> +#include <linux/netdevice.h>
> +#include <linux/vmalloc.h>
> +
> +#include <linux/ethtool.h>
> +
> +#include <linux/sctp.h>
> +
> +#define IGC_ERR(args...) pr_err("igc: " args)

Looks like you're reimplementing pr_fmt()

> +#define PFX "igc: "
> +
> +#include <linux/timecounter.h>
> +#include <linux/net_tstamp.h>
> +#include <linux/ptp_clock_kernel.h>

Splitting the includes looks fairly weird.  Also, you're not using any
of them here.

> +/* main */
> +extern char igc_driver_name[];
> +extern char igc_driver_version[];
> +
> +#endif /* _IGC_H_ */
> diff --git a/drivers/net/ethernet/intel/igc/igc_hw.h b/drivers/net/ethernet/intel/igc/igc_hw.h
> new file mode 100644
> index 000000000000..aa68b4516700
> --- /dev/null
> +++ b/drivers/net/ethernet/intel/igc/igc_hw.h
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright (c)  2018 Intel Corporation */
> +
> +#ifndef _IGC_HW_H_
> +#define _IGC_HW_H_
> +
> +#define IGC_DEV_ID_I225_LM			0x15F2
> +#define IGC_DEV_ID_I225_V			0x15F3
> +
> +#endif /* _IGC_HW_H_ */
> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
> new file mode 100644
> index 000000000000..753749ce5ae0
> --- /dev/null
> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> @@ -0,0 +1,146 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c)  2018 Intel Corporation */
> +
> +#include <linux/module.h>
> +#include <linux/types.h>
> +
> +#include "igc.h"
> +#include "igc_hw.h"
> +
> +#define DRV_VERSION	"0.0.1-k"

You can just use the kernel version, it works pretty well in presence
of backports.

> +#define DRV_SUMMARY	"Intel(R) 2.5G Ethernet Linux Driver"
> +
> +MODULE_AUTHOR("Intel Corporation, <linux.nics@intel.com>");
> +MODULE_DESCRIPTION(DRV_SUMMARY);
> +MODULE_LICENSE("GPL v2");
> +MODULE_VERSION(DRV_VERSION);
> +
> +char igc_driver_name[] = "igc";
> +char igc_driver_version[] = DRV_VERSION;
> +static const char igc_driver_string[] = DRV_SUMMARY;
> +static const char igc_copyright[] =
> +	"Copyright(c) 2018 Intel Corporation.";
> +
> +static const struct pci_device_id igc_pci_tbl[] = {
> +	{ PCI_VDEVICE(INTEL, IGC_DEV_ID_I225_LM) },
> +	{ PCI_VDEVICE(INTEL, IGC_DEV_ID_I225_V) },
> +	/* required last entry */
> +	{0, }
> +};
> +
> +MODULE_DEVICE_TABLE(pci, igc_pci_tbl);
> +
> +/**
> + * igc_probe - Device Initialization Routine
> + * @pdev: PCI device information struct
> + * @ent: entry in igc_pci_tbl
> + *
> + * Returns 0 on success, negative on failure
> + *
> + * igc_probe initializes an adapter identified by a pci_dev structure.
> + * The OS initialization, configuring the adapter private structure,
> + * and a hardware reset occur.
> + */
> +static int igc_probe(struct pci_dev *pdev,
> +		     const struct pci_device_id *ent)
> +{
> +	int err, pci_using_dac;
> +
> +	err = pci_enable_device_mem(pdev);
> +	if (err)
> +		return err;
> +
> +	pci_using_dac = 0;
> +	err = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
> +	if (!err) {
> +		err = dma_set_coherent_mask(&pdev->dev,
> +					    DMA_BIT_MASK(64));
> +		if (!err)
> +			pci_using_dac = 1;

You never use this pci_using_dac.  dma_set_mask_and_coherent() maybe?

> +	} else {
> +		err = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
> +		if (err) {
> +			err = dma_set_coherent_mask(&pdev->dev,
> +						    DMA_BIT_MASK(32));
> +			if (err) {
> +				IGC_ERR("Wrong DMA configuration, aborting\n");
> +				goto err_dma;
> +			}
> +		}
> +	}
> +
> +	err = pci_request_selected_regions(pdev,
> +					   pci_select_bars(pdev,
> +							   IORESOURCE_MEM),
> +					   igc_driver_name);
> +	if (err)
> +		goto err_pci_reg;
> +
> +	pci_set_master(pdev);
> +	err = pci_save_state(pdev);

And you never look at err?

> +	return 0;
> +
> +err_pci_reg:
> +err_dma:

The error label should be named after what it points to, not where it's
coming from.

> +	pci_disable_device(pdev);
> +	return err;
> +}
> +
> +/**
> + * igc_remove - Device Removal Routine
> + * @pdev: PCI device information struct
> + *
> + * igc_remove is called by the PCI subsystem to alert the driver
> + * that it should release a PCI device.  This could be caused by a
> + * Hot-Plug event, or because the driver is going to be removed from
> + * memory.
> + */
> +static void igc_remove(struct pci_dev *pdev)
> +{
> +	pci_release_selected_regions(pdev,
> +				     pci_select_bars(pdev, IORESOURCE_MEM));
> +
> +	pci_disable_device(pdev);
> +}
> +
> +static struct pci_driver igc_driver = {
> +	.name     = igc_driver_name,
> +	.id_table = igc_pci_tbl,
> +	.probe    = igc_probe,
> +	.remove   = igc_remove,
> +};
> +
> +/**
> + * igc_init_module - Driver Registration Routine
> + *
> + * igc_init_module is the first routine called when the driver is
> + * loaded. All it does is register with the PCI subsystem.
> + */
> +static int __init igc_init_module(void)
> +{
> +	int ret;
> +
> +	pr_info("%s - version %s\n",
> +		igc_driver_string, igc_driver_version);
> +
> +	pr_info("%s\n", igc_copyright);
> +
> +	ret = pci_register_driver(&igc_driver);
> +	return ret;

Why the variable?

> +}
> +
> +module_init(igc_init_module);
> +
> +/**
> + * igc_exit_module - Driver Exit Cleanup Routine
> + *
> + * igc_exit_module is called just before the driver is removed
> + * from memory.
> + */
> +static void __exit igc_exit_module(void)
> +{
> +	pci_unregister_driver(&igc_driver);
> +}
> +
> +module_exit(igc_exit_module);
> +/* igc_main.c */

I'd argue most editors make it fairly clear which file one is
editing, hence making this sort of comments entirely superfluous :)