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Date: Tue, 18 Nov 2014 09:12:58 -0800
Message-ID: <CAL1qeaFRPcTVABoEbip=Fq0nHo6aKSR7bhTo3QQYcZq2k1S3Eg@mail.gmail.com>
Subject: Re: [PATCH V5 09/12] usb: xhci: Add NVIDIA Tegra xHCI host-controller driver
From: Andrew Bresticker <abrestic@chromium.org>
To: balbi@ti.com
Cc: Stephen Warren <swarren@wwwdotorg.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Alexandre Courbot <gnurou@gmail.com>,
        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Ian Campbell <ijc+devicetree@hellion.org.uk>,
        Kumar Gala <galak@codeaurora.org>,
        Russell King <linux@arm.linux.org.uk>,
        Jassi Brar <jassisinghbrar@gmail.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mathias Nyman <mathias.nyman@intel.com>,
        Grant Likely <grant.likely@linaro.org>,
        Alan Stern <stern@rowland.harvard.edu>, Arnd Bergmann <arnd@arndb.de>,
        Olof Johansson <olof@lixom.net>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org

On Mon, Nov 17, 2014 at 4:33 PM, Felipe Balbi <balbi@ti.com> wrote:
>> >> +static int tegra_xhci_load_firmware(struct tegra_xhci_hcd *tegra)
>> >> +{
>> >> +     struct device *dev = tegra->dev;
>> >> +     struct tegra_xhci_fw_cfgtbl *cfg_tbl;
>> >> +     struct tm fw_tm;
>> >> +     u32 val, code_tag_blocks, code_size_blocks;
>> >> +     u64 fw_base;
>> >> +     time_t fw_time;
>> >> +     unsigned long timeout;
>> >> +
>> >> +     if (csb_readl(tegra, XUSB_CSB_MP_ILOAD_BASE_LO) != 0) {
>> >> +             dev_info(dev, "Firmware already loaded, Falcon state 0x%x\n",
>> >> +                      csb_readl(tegra, XUSB_FALC_CPUCTL));
>> >> +             return 0;
>> >> +     }
>> >
>> > won't this prevent rmmod && insmod from succeeding ? Maybe not, as you
>> > return 0 anyway, but if the firmware side craps out, it might be useful
>> > to reload the firmware and reset that block. I wonder if this prevents
>> > that.
>>
>> rmmod && insmod does work with the above since, as you mentioned, we
>> return successfully if the controller is already running.  Attempting
>> to re-load the firmware if the controller is already running won't
>> work - it requires a full power-gate/ungate sequence of the
>> controller.  Unfortunately, that sequence is rather complicated and I
>> haven't had a chance to implement it yet.  it will hopefully be coming
>> later, though.
>
> Alright, could you add a comment on the source code stating that ?
> Perhaps a REVISIT note or FIXME ?

Sure, will do.
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