Re: [PATCH] net: Linn Ethernet Packet Sniffer driver

From: James Hogan
Date: Fri Jan 23 2015 - 14:13:24 EST


Hi,

A few general things below (I'll leave the actual networking bits for
others to comment about).

On Friday 23 January 2015 10:07:01 Stathis Voukelatos wrote:
> ---
> .../bindings/net/linn-ether-packet-sniffer.txt | 27 ++
> .../devicetree/bindings/vendor-prefixes.txt | 1 +
> MAINTAINERS | 7 +
> drivers/net/Kconfig | 2 +
> drivers/net/Makefile | 1 +
> drivers/net/pkt-sniffer/Kconfig | 23 ++
> drivers/net/pkt-sniffer/Makefile | 8 +
> drivers/net/pkt-sniffer/backends/ether/channel.c | 366 ++++++++++++++++++
> drivers/net/pkt-sniffer/backends/ether/channel.h | 76 ++++
> drivers/net/pkt-sniffer/backends/ether/hw.h | 46 +++
> drivers/net/pkt-sniffer/backends/ether/platform.c | 231 +++++++++++
> drivers/net/pkt-sniffer/core/dev_table.c | 124 ++++++
> drivers/net/pkt-sniffer/core/module.c | 37 ++
> drivers/net/pkt-sniffer/core/nl.c | 427 +++++++++++++++++++++
> drivers/net/pkt-sniffer/core/nl.h | 34 ++
> drivers/net/pkt-sniffer/core/snf_core.h | 64 +++
> include/linux/pkt_sniffer.h | 89 +++++

Probably worth splitting this up a bit into a series of multiple
logically separate patches. E.g. the vendor prefix, the core, the ether
backend and dt bindings.

> diff --git a/drivers/net/pkt-sniffer/Kconfig b/drivers/net/pkt-sniffer/Kconfig
> new file mode 100644
> index 0000000..26b4f98
> --- /dev/null
> +++ b/drivers/net/pkt-sniffer/Kconfig
> @@ -0,0 +1,23 @@
> +menuconfig PKT_SNIFFER
> + tristate "Linn packet sniffer support"

Should the kconfig symbol have linn in the name, or should the prompt
not have lin in the name?

> + ---help---
> + Say Y to add support for Linn packet sniffer drivers.
> +
> + The core driver can also be built as a module. If so, the module
> + will be called snf_core.
> +
> +if PKT_SNIFFER

Just make PKT_SNIFFER_ETHER depend first on PKT_SNIFFER, then it'll
appear nested within it in menuconfig.

> +
> +config PKT_SNIFFER_ETHER
> + tristate "Ethernet packet sniffer"
> + depends on MIPS

worth adding || COMPILE_TEST to get compile coverage on x86 allmodconfig
builds, or does it have hard dependencies on the MIPS arch?

> + default n

No need, n is default

> + help
> + Say Y here if you want to use the Linn Ethernet packet sniffer
> + module. It can be found in the upcoming Pistachio SoC by
> + Imagination Technologies.
> +
> + The driver can also be built as a module. If so, the module
> + will be called snf_ether.
> +
> +endif # PKT_SNIFFER


> +/* Called when the packet sniffer device is bound with the driver */
> +static int esnf_driver_probe(struct platform_device *pdev)
> +{
> + struct ether_snf *esnf;
> + struct resource *res;
> + int ret, irq;
> + u32 fifo_blk_words;
> + void __iomem *regs;
> + struct device_node *ofn = pdev->dev.of_node;
> +
> + /* Allocate the device data structure */
> + esnf = devm_kzalloc(&pdev->dev, sizeof(*esnf), GFP_KERNEL);
> + if (!esnf)
> + return -ENOMEM;
> +
> + /* Retrieve and remap register memory space */
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
> + if (!res)
> + return -ENODEV;

No need for this check. devm_ioremap_resource does it for you.

> +
> + regs = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(regs))
> + return PTR_ERR(regs);
> +


> +static const struct of_device_id esnf_of_match_table[] = {
> + { .compatible = "linn,eth-sniffer", .data = NULL },

Nit: not strictly necessary to initialise .data since it's static.

Cheers
James

> + {},
> +};
> +MODULE_DEVICE_TABLE(of, esnf_of_match_table);
> +
> +static struct platform_driver esnf_platform_driver = {
> + .driver = {
> + .name = esnf_driver_name,
> + .of_match_table = esnf_of_match_table,
> + },
> + .probe = esnf_driver_probe,
> + .remove = esnf_driver_remove,
> +};
> +
> +module_platform_driver(esnf_platform_driver);
> +
> +MODULE_DESCRIPTION("Linn Ethernet Packet Sniffer");
> +MODULE_AUTHOR("Linn Products Ltd");
> +MODULE_LICENSE("GPL v2");

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