Re: [PATCH] usb: gadget: renesas_usb3: add support for Renesas USB3.0 peripheral controller

[Arnd Bergmann <arnd@arndb.de>]

On Tuesday 15 December 2015 15:54:32 Yoshihiro Shimoda wrote:
> R-Car H3 has USB3.0 peripheral controllers. This controller's has the
> following features:
>  - Supports super, high and full speed
>  - Contains 30 pipes for bulk or interrupt transfer
>  - Contains dedicated DMA controller
> 
> This driver doesn't support the dedicated DMAC for now.
> 
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> ---
>  This patch is based on the latest Felipe's usb.git / testing/next branch.
>  (commit id = e9284de9fae69f1d5e57a4817bfc36dc5f3adf71)

Looks good overall, I've found a few small details:

>  .../devicetree/bindings/usb/renesas_usb3.txt       |   23 +
>  drivers/usb/gadget/udc/Kconfig                     |   11 +
>  drivers/usb/gadget/udc/Makefile                    |    1 +
>  drivers/usb/gadget/udc/renesas_usb3.c              | 1720 ++++++++++++++++++++
>  drivers/usb/gadget/udc/renesas_usb3.h              |  284 ++++

The header file is only used by one .c file, so just merge it all into that
file.

> +Required properties:
> +  - compatible: Must contain one of the following:
> +	- "renesas,usb3-peri-r8a7795"
> +  - reg: Base address and length of the register for the USB3.0 Peripheral
> +  - interrupts: Interrupt specifier for the USB3.0 Peripheral
> +  - clocks: A list of phandle + clock specifier pairs

The clock specifier contains the phandle, please rephrase the last line

> diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
> new file mode 100644
> index 0000000..f302c89
> --- /dev/null
> +++ b/drivers/usb/gadget/udc/renesas_usb3.c
> @@ -0,0 +1,1720 @@
> +/*
> + * Renesas USB3.0 Peripheral driver (USB gadget)
> + *
> + * Copyright (C) 2015  Renesas Electronics Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; version 2 of the License.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/slab.h>
> +#include <linux/usb/ch9.h>
> +#include <linux/usb/gadget.h>

As the 0-say bot found, this needs #include <linux/sizes.h>

> +static int renesas_usb3_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
> +				 gfp_t gfp_flags);
> +static void usb3_start_pipen(struct renesas_usb3_ep *usb3_ep,
> +			     struct renesas_usb3_request *usb3_req);

Can you try to reorder the functions so you don't need forward declarations?

> +static void usb3_write(struct renesas_usb3 *usb3, u32 data, u32 offs)
> +{
> +	iowrite32(data, usb3->reg + offs);
> +}
> +
> +static u32 usb3_read(struct renesas_usb3 *usb3, u32 offs)
> +{
> +	return ioread32(usb3->reg + offs);
> +}

I think using readl() is more common than ioread32() if the driver cannot
use IORESOURCE_IO but only IORESOURCE_MEM.

On ARM, the two are the same, but on some architectures ioread32 is more
expensive, so using the former is preferred.

> +	for (i = 0; i < USB3_WAIT_NS; i++) {
> +		if ((usb3_read(usb3, reg) & mask) == expected)
> +			return 0;
> +		ndelay(1);
> +	}

ndelay(1) is unusual, maybe use cpu_relax() instead, or document why
you call ndelay()?

> +static void usb3_init_phy(struct renesas_usb3 *usb3)
> +{
> +}

If the function is empty, don't add or call it, it's easy to add if you
need it later.

> +static struct platform_driver renesas_usb3_driver = {
> +	.remove =	__exit_p(renesas_usb3_remove),
> +	.driver		= {
> +		.name =	(char *)udc_name,
> +		.of_match_table = of_match_ptr(usb3_of_match),
> +	},
> +};
> +module_platform_driver_probe(renesas_usb3_driver, renesas_usb3_probe);

module_platform_driver_probe() won't work if you get into deferred probing,
I'd suggest using module_platform_driver() and not marking the remove
function as __exit

> +struct renesas_usb3;
> +struct renesas_usb3_request {
> +	struct usb_request	req;
> +	struct list_head	queue;
> +};

There is already a list_head in struct usb_request. Could you use that?
(I don't know, just asking because this looks odd)

> +#define USB3_EP_NAME_SIZE	8
> +struct renesas_usb3_ep {
> +	struct usb_ep ep;
> +	struct renesas_usb3 *usb3;
> +	int num;
> +	char ep_name[USB3_EP_NAME_SIZE];
> +	struct list_head queue;
> +	u32 rammap_val;
> +	bool dir_in;
> +	bool halt;
> +	bool wedge;
> +	bool started;
> +};
> +
> +struct renesas_usb3_priv {
> +	int ramsize_per_ramif;		/* unit = bytes */
> +	int num_ramif;
> +	int ramsize_per_pipe;		/* unit = bytes */
> +	unsigned workaround_for_vbus:1;	/* if 1, don't check vbus signal */
> +};

You use 'bool' in one structure, and bit fields in the other.
Maybe pick one of the two styles consistently.

	Arnd