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

Arnd Bergmann
2015-12-15T09:30:08Z

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