From: Nicolas Ferre <nicolas.ferre@microchip.com>
To: Claudiu Beznea <claudiu.beznea@microchip.com>,
<stern@rowland.harvard.edu>, <gregkh@linuxfoundation.org>,
<alexandre.belloni@bootlin.com>,
<ludovic.desroches@microchip.com>,
<cristian.birsan@microchip.com>
Cc: <linux-usb@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] usb: host: ohci-at91: suspend/resume ports after/before OHCI accesses
Date: Wed, 9 Jun 2021 14:40:19 +0200 [thread overview]
Message-ID: <21280c02-0dd2-461a-1baf-464f280d2f0e@microchip.com> (raw)
In-Reply-To: <20210609121027.70951-1-claudiu.beznea@microchip.com>
On 09/06/2021 at 14:10, Claudiu Beznea wrote:
> On SAMA7G5 suspending ports will cut the access to OHCI registers and
> any subsequent access to them will lead to CPU being blocked trying to
> access that memory. Same thing happens on resume: if OHCI memory is
> accessed before resuming ports the CPU will block on that access. The
> OCHI memory is accessed on suspend/resume though
> ohci_suspend()/ohci_resume().
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Claudiu,
Your patch look good to me.
In addition, I see ohci_at91_port_suspend() function also used in
ohci_at91_hub_control(). It might suffer the same problem as I see
accesses to ohci register, at first glance.
Can you please double check that we are not in such condition with calls
to ohci_at91_hub_control()?
Best regards,
Nicolas
> ---
>
> The patch was tested on SAMA7G5, SAMA5D2 and SAM9X60.
>
> Thank you,
> Claudiu Beznea
>
> drivers/usb/host/ohci-at91.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
> index b3a6a497dcb1..7c6202b05ff4 100644
> --- a/drivers/usb/host/ohci-at91.c
> +++ b/drivers/usb/host/ohci-at91.c
> @@ -666,8 +666,6 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
> if (ohci_at91->wakeup)
> enable_irq_wake(hcd->irq);
>
> - ohci_at91_port_suspend(ohci_at91, 1);
> -
> ret = ohci_suspend(hcd, ohci_at91->wakeup);
> if (ret) {
> if (ohci_at91->wakeup)
> @@ -687,7 +685,10 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
> /* flush the writes */
> (void) ohci_readl (ohci, &ohci->regs->control);
> msleep(1);
> + ohci_at91_port_suspend(ohci_at91, 1);
> at91_stop_clock(ohci_at91);
> + } else {
> + ohci_at91_port_suspend(ohci_at91, 1);
> }
>
> return ret;
> @@ -699,6 +700,8 @@ ohci_hcd_at91_drv_resume(struct device *dev)
> struct usb_hcd *hcd = dev_get_drvdata(dev);
> struct ohci_at91_priv *ohci_at91 = hcd_to_ohci_at91_priv(hcd);
>
> + ohci_at91_port_suspend(ohci_at91, 0);
> +
> if (ohci_at91->wakeup)
> disable_irq_wake(hcd->irq);
> else
> @@ -706,8 +709,6 @@ ohci_hcd_at91_drv_resume(struct device *dev)
>
> ohci_resume(hcd, false);
>
> - ohci_at91_port_suspend(ohci_at91, 0);
> -
> return 0;
> }
>
>
--
Nicolas Ferre
next prev parent reply other threads:[~2021-06-09 12:40 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 12:10 [PATCH] usb: host: ohci-at91: suspend/resume ports after/before OHCI accesses Claudiu Beznea
2021-06-09 12:40 ` Nicolas Ferre [this message]
2021-06-09 23:07 ` Alan Stern
2021-06-23 12:47 ` Claudiu.Beznea
2021-06-23 13:59 ` Alan Stern
2021-06-23 14:09 ` Claudiu.Beznea
2021-06-23 14:19 ` Alan Stern
2021-06-23 14:33 ` Claudiu.Beznea
2021-06-23 16:41 ` Alan Stern
2021-06-24 6:40 ` Claudiu.Beznea
2021-06-24 6:54 ` Claudiu.Beznea
2021-06-24 13:23 ` Alan Stern
2021-06-30 14:46 ` Claudiu.Beznea
2021-06-30 18:21 ` Alan Stern
2021-07-01 5:45 ` Claudiu.Beznea
2021-07-01 14:01 ` Alan Stern
2021-06-30 14:47 ` Claudiu.Beznea
2021-07-21 8:08 ` Greg KH
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