[U-Boot] usb: ehci: Take advantage of the new multi-controller feature for MXC

[Lucas Stach]

Am Dienstag, den 06.11.2012, 00:56 +0100 schrieb Marek Vasut:
> Dear Benoît Thébaudeau,
> 
> > Dear Marek Vasut,
> > 
> > On Monday, November 5, 2012 11:54:12 PM, Marek Vasut wrote:
> > > Dear Benoît Thébaudeau,
> > > 
> > > > Hi Marek,
> > > > 
> > > > Thanks to Lucas' series coming with commits c7e3b2b and 676ae06,
> > > > I'd like
> > > > to use the multi-controller feature on MXC since most of these SoCs
> > > > come
> > > > with a USB IP supporting an OTG controller and multiple host-only
> > > > controllers.
> > > > 
> > > > Currently the MXC code in ehci-mx{c|5|6}.c just ignores the index
> > > > passed to
> > > > ehci_hcd_init() and the like, and there are 3 port-specific configs
> > > > (CONFIG_MXC_USB_PORT, CONFIG_MXC_USB_FLAGS and
> > > > CONFIG_MXC_USB_PORTSC).
> > > > 
> > > > Not all USB ports from the USB IP will be available on each board
> > > > for a
> > > > given SoC, so we need a logical to physical USB port mapping.
> > > > 
> > > > I would suggest something like the following.
> > > > 
> > > > board.h:
> > > > #define CONFIG_MXC_USB	{ \
> > > > 
> > > > 	{ \
> > > > 	
> > > > 		0, \
> > > > 		MXC_EHCI_INTERNAL_PHY, \
> > > > 		MXC_EHCI_UTMI_16BIT | MXC_EHCI_MODE_UTMI \
> > > > 	
> > > > 	}, { \
> > > > 	
> > > > 		1, \
> > > > 		MXC_EHCI_POWER_PINS_ENABLED | MXC_EHCI_PWR_PIN_ACTIVE_HIGH | \
> > > > 		MXC_EHCI_OC_PIN_ACTIVE_LOW, \
> > > > 		MXC_EHCI_MODE_ULPI \
> > > > 	
> > > > 	}, \
> > > > 
> > > > }
> > > > 
> > > > ehci-fsl.h:
> > > > struct mxc_ehci_cfg {
> > > > 
> > > > 	int port;
> > > > 	u32 flags;
> > > > 	u32 portsc;
> > > > 
> > > > };
> > > > 
> > > > ehci-mx{c|5|6}.c:
> > > > static const struct mxc_ehci_cfg
> > > > cfg[CONFIG_USB_MAX_CONTROLLER_COUNT] =
> > > > 
> > > > 		CONFIG_MXC_USB;
> > > > 
> > > > Then, in ehci_hcd_init(), there would be the following
> > > > 
> > > > replacements:
> > > >  - CONFIG_MXC_USB_PORT -> cfg[index].port,
> > > >  - CONFIG_MXC_USB_FLAGS -> cfg[index].flags,
> > > >  - CONFIG_MXC_USB_PORTSC -> cfg[index].portsc.
> > > > 
> > > > What do you think?
> > > 
> > > What about passing port private / platform data instead of ID ?
> > 
> > The ID is already passed to ehci_hcd_init(), so we have to live with it if
> > we don't want to change the newly introduced multi-controller
> > infrastructure.
> 
> Let's change it .... remove the ID and pass some generic pdata.
> 
I don't like the idea of passing around data at this level. It's
breaking the abstraction, as we have to pass low-level usb information
around in the higher USB stack levels.

The USB driver code should be able to do the virt-to-phys controller
mapping on it's own. In the Tegra world we use the information we get
from device tree to do so, but I don't see a reason why your USB host
driver code wouldn't be able to just require an array with configuration
data from the board file.

There is really no need to pass this information through all the USB
stack interfaces.

Regards,
Lucas