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Message-ID: <Pine.LNX.4.44L0.1303201024190.1701-100000@iolanthe.rowland.org>
Date: Wed, 20 Mar 2013 10:26:09 -0400 (EDT)
From: Alan Stern <stern@...land.harvard.edu>
To: Yuan-Hsin Chen <yuanlmm@...il.com>
cc: Felipe Balbi <balbi@...com>, <gregkh@...uxfoundation.org>,
<sarah.a.sharp@...ux.intel.com>, <Julia.Lawall@...6.fr>,
<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
Yuan-Hsin Chen <yhchen@...aday-tech.com>,
<john453@...aday-tech.com>
Subject: Re: [PATCH] usb host: Faraday FUSBH200 HCD driver.
On Wed, 20 Mar 2013, Yuan-Hsin Chen wrote:
> Hi,
>
> On Tue, Mar 19, 2013 at 11:48 PM, Alan Stern <stern@...land.harvard.edu> wrote:
> > On Tue, 19 Mar 2013, Yuan-Hsin Chen wrote:
> >
> >> > What about the port_status registers? They're not between command and
> >> > async_next. If they aren't consistent with EHCI, it makes things a lot
> >> > more complicated.
> >>
> >> fusbh200 has only one port_status register with different offset,
> >> 0x30, and the position of some bits are different from EHCI.
>
> How about adding kernel configuration to adjust offset for FUSBH200 in
> ehci_def.h? So port_status would be in offset 0x20 from ehci_regs.
>
> For example,
>
> /* ASYNCLISTADDR: offset 0x18 */
> u32 async_next; /* address of next async queue head */
>
> #ifndef CONFIG_USB_EHCI_HCD_FUSBH200
> u32 reserved1[2];
>
> /* TXFILLTUNING: offset 0x24 */
> u32 txfill_tuning; /* TX FIFO Tuning register */
> #define TXFIFO_DEFAULT (8<<16) /* FIFO burst threshold 8 */
>
> u32 reserved2[6];
>
> /* CONFIGFLAG: offset 0x40 */
> u32 configured_flag;
> #define FLAG_CF (1<<0) /* true: we'll support "high speed" */
>
> #else
> u32 reserved1;
> #endif
> /* PORTSC: offset 0x44 */
> u32 port_status[0]; /* up to N_PORTS */
This is acceptable _only_ if it is not possible to use an FUSBH200
controller in the same computer as a normal EHCI controller.
> Furthermore, there are PORT_POWER, PORT_OWNER, PORT_LED_XXX,
> PORT_TEST, PORT_WKCONN_E, PORT_WKDISC_E, PORT_WKOC_E absent in
> port_status of FUSBH200. Also PORT_OC and PORT_OCC are in another
> register. Is it ok to use quirk flag also?
Yes, those can be handled by a quirk flag. Does the FUSBH200 have a
built-in Transaction Translator?
Alan Stern
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