[U-Boot] Targets with xHCI but without DM_USB

[Vignesh R]

Hi Bin,

On Monday 03 July 2017 06:49 PM, Bin Meng wrote:
> Hi Vignesh,
> 
> On Thu, Jun 29, 2017 at 2:41 PM, Vignesh R <vigneshr at ti.com> wrote:
>> Hi Stefan,
>>
>> On Thursday 29 June 2017 11:15 AM, Stefan Roese wrote:
>>> Hi,
>>>
>>> as you might have noticed, Bin Meng is currently greatly improving
>>> the U-Boot xHCI support. While doing this, he noticed that some
>>> additions are more complex and especially ugly to add, since some
>>> users of the xHCI support have not enabled CONFIG_DM_USB. This
>>> adds ugly #ifdef's, which we really would like to avoid. Because
>>> of this we checked, which boards exactly are using xHCI without
>>> DM_USB enabled. Here a complete list of all the boards:
>>>
>>> ls1012ardb_qspi_SECURE_BOOT
>>> ls1021atwr_nor_SECURE_BOOT
>>> am43xx_hs_evm
>>> am57xx_hs_evm
>>> ls1021aqds_nand
>>> ls1021atwr_nor
>>> ls1021atwr_qspi
>>> cm_t43
>>> ls1021atwr_nor_lpuart
>>> ls1021aqds_sdcard_qspi
>>> k2hk_hs_evm
>>> am43xx_evm
>>> ls1021aqds_qspi
>>> am57xx_evm_nodt
>>> k2g_hs_evm
>>> ls1021atwr_sdcard_qspi
>>> am43xx_evm_ethboot
>>> ls1021aqds_sdcard_ifc
>>> k2l_evm
>>> am43xx_evm_usbhost_boot
>>> am43xx_evm_qspiboot
>>> k2g_evm
>>> am57xx_evm
>>> ls1021atwr_sdcard_ifc
>>> cl-som-am57x
>>> k2hk_evm
>>> k2e_evm
>>> ls1021atwr_sdcard_ifc_SECURE_BOOT
>>> ls1021aqds_nor_SECURE_BOOT
>>> k2e_hs_evm
>>
>> For TI platforms, there is some work needed to convert xhci-dwc3,
>> xhci-omap and xhci-keystone to DM (under drivers/usb/host)
>>
>> But the bigger concern of enabling DM_USB is with gadget framework,
>> which is not DM compliant yet. There is a significant amount work[1][2]
>> there before dwc3 gadget can be moved to DM and we can enable DM_USB.
>>
>> [1]https://lists.denx.de/pipermail/u-boot/2017-June/296081.html
>> [2]https://lists.denx.de/pipermail/u-boot/2017-June/295370.html
> 
> I thought gadget and host support are separate, so host support like
> xHCI can be moved to DM without affecting gadget support, no? Are they
> sharing some codes?
> 

Right now, the assumption is if DM_USB is enabled, then both host and
gadget frameworks use DM along with DT. If, DM_USB is enabled, then
board specific registration of gadget drivers don't happen. Also, I see
couple of gadget drivers like ether.c. ci_udc.c (and everything under
musb_new) seem use DM_USB already, making it hard for DM based host and
non DM gadget to exist.

Some work would be needed to remove dependency b/w DM_USB and gadget
support.

-- 
Regards
Vignesh