linux-kernel - Re: [PATCH V5 09/12] usb: xhci: Add NVIDIA Tegra xHCI host-controller driver

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Date:	Mon, 17 Nov 2014 18:33:05 -0600
From:	Felipe Balbi <balbi@...com>
To:	Andrew Bresticker <abrestic@...omium.org>
CC:	<balbi@...com>, Stephen Warren <swarren@...dotorg.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Alexandre Courbot <gnurou@...il.com>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Russell King <linux@....linux.org.uk>,
	Jassi Brar <jassisinghbrar@...il.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Mathias Nyman <mathias.nyman@...el.com>,
	Grant Likely <grant.likely@...aro.org>,
	Alan Stern <stern@...land.harvard.edu>,
	Arnd Bergmann <arnd@...db.de>, Olof Johansson <olof@...om.net>,
	Kishon Vijay Abraham I <kishon@...com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>
Subject: Re: [PATCH V5 09/12] usb: xhci: Add NVIDIA Tegra xHCI
 host-controller driver

Hi,

On Mon, Nov 17, 2014 at 03:51:29PM -0800, Andrew Bresticker wrote:
> >> +static const struct {
> >> +     const char *name;
> >> +     unsigned int num;
> >> +} tegra_xhci_phy_types[] = {
> >> +     {
> >> +             .name = "usb3",
> >> +             .num = TEGRA_XUSB_USB3_PHYS,
> >> +     }, {
> >> +             .name = "utmi",
> >> +             .num = TEGRA_XUSB_UTMI_PHYS,
> >> +     }, {
> >> +             .name = "hsic",
> >> +             .num = TEGRA_XUSB_HSIC_PHYS,
> >> +     },
> >
> > these should be using the generic PHY subsystem (drivers/phy).
> 
> This driver does use the generic PHY subsystem, see patch 7 in this series :).

true, I got misled by the fact that you added your phy provider to your
pinctrl. Odd.

> >> +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 ?

cheers

-- 
balbi

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