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From: Joel Stanley <joel@jms.id.au>
To: Ryan Chen <ryan_chen@aspeedtech.com>,
	 Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: BMC-SW <BMC-SW@aspeedtech.com>,
	linux-aspeed <linux-aspeed@lists.ozlabs.org>,
	Felipe Balbi <balbi@kernel.org>, Andrew Jeffery <andrew@aj.id.au>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-usb@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/1] usb: gadget: aspeed: fix stop dma register setting.
Date: Mon, 11 Jan 2021 02:24:27 +0000	[thread overview]
Message-ID: <CACPK8XdWKY4QmuojaZ13tmKR3MVEzU8MOV=bmqyTiotScaGfRA@mail.gmail.com> (raw)
In-Reply-To: <20210108081238.10199-2-ryan_chen@aspeedtech.com>

On Fri, 8 Jan 2021 at 08:13, Ryan Chen <ryan_chen@aspeedtech.com> wrote:
>
> The vhub engine has two dma mode, one is descriptor list, another
> is single stage DMA. Each mode has different stop register setting.
> Descriptor list operation (bit2) : 0 disable reset, 1: enable reset
> Single mode operation (bit0) : 0 : disable, 1: enable
>
> Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
> ---
>  drivers/usb/gadget/udc/aspeed-vhub/epn.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/gadget/udc/aspeed-vhub/epn.c b/drivers/usb/gadget/udc/aspeed-vhub/epn.c
> index 0bd6b20435b8..02d8bfae58fb 100644
> --- a/drivers/usb/gadget/udc/aspeed-vhub/epn.c
> +++ b/drivers/usb/gadget/udc/aspeed-vhub/epn.c
> @@ -420,7 +420,10 @@ static void ast_vhub_stop_active_req(struct ast_vhub_ep *ep,
>         u32 state, reg, loops;
>
>         /* Stop DMA activity */
> -       writel(0, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
> +       if (ep->epn.desc_mode)
> +               writel(VHUB_EP_DMA_CTRL_RESET, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
> +       else
> +               writel(0, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);

This looks correct, as whenever the driver re-enables DMA it uses
ep->epn.dma_conf for the value of this register. So we're not losing
any configuration by setting it to 0.

Acked-by: Joel Stanley <joel@jms.id.au>
Fixes: 7ecca2a4080c ("usb/gadget: Add driver for Aspeed SoC virtual hub")

I've cc'd Ben for his ack too.

Cheers,

Joel

>
>         /* Wait for it to complete */
>         for (loops = 0; loops < 1000; loops++) {
> --
> 2.17.1
>

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      parent reply	other threads:[~2021-01-11  2:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-08  8:12 [PATCH 0/1] Fix vhub engine stop dma register setting Ryan Chen
2021-01-08  8:12 ` [PATCH 1/1] usb: gadget: aspeed: fix " Ryan Chen
2021-01-08 12:21   ` Felipe Balbi
2021-01-11  2:24   ` Joel Stanley [this message]

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