* f_mass_storage vs drivers/target @ 2019-08-21 3:38 Benjamin Herrenschmidt 2019-08-21 9:32 ` Greg KH 2019-08-21 14:25 ` Alan Stern 0 siblings, 2 replies; 11+ messages in thread From: Benjamin Herrenschmidt @ 2019-08-21 3:38 UTC (permalink / raw) To: USB list; +Cc: Alan Stern Hi folks ! It seems that f_mass_storage duplicates (well maybe predates too..) a lot of what's in drivers/target. Anybody working on implementing a new version of f_mass_storage that is layered upon drivers/target instead ? That would bring quite a lot of additional functionality. If not, I might look into it. Cheers, Ben. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-21 3:38 f_mass_storage vs drivers/target Benjamin Herrenschmidt @ 2019-08-21 9:32 ` Greg KH 2019-08-21 14:25 ` Alan Stern 1 sibling, 0 replies; 11+ messages in thread From: Greg KH @ 2019-08-21 9:32 UTC (permalink / raw) To: Benjamin Herrenschmidt; +Cc: USB list, Alan Stern On Wed, Aug 21, 2019 at 01:38:49PM +1000, Benjamin Herrenschmidt wrote: > Hi folks ! > > It seems that f_mass_storage duplicates (well maybe predates too..) a > lot of what's in drivers/target. It predates it by a long time. > Anybody working on implementing a new version of f_mass_storage that > is layered upon drivers/target instead ? That would bring quite a lot > of additional functionality. Why is that needed? What functionality is missing that it will provide? Will it make the code simpler? > If not, I might look into it. Hey, we don't refuse patches, for cleaning stuff up, you know that :) thanks, greg k-h ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-21 3:38 f_mass_storage vs drivers/target Benjamin Herrenschmidt 2019-08-21 9:32 ` Greg KH @ 2019-08-21 14:25 ` Alan Stern 2019-08-22 0:10 ` Benjamin Herrenschmidt 1 sibling, 1 reply; 11+ messages in thread From: Alan Stern @ 2019-08-21 14:25 UTC (permalink / raw) To: Benjamin Herrenschmidt; +Cc: USB list On Wed, 21 Aug 2019, Benjamin Herrenschmidt wrote: > Hi folks ! > > It seems that f_mass_storage duplicates (well maybe predates too..) a > lot of what's in drivers/target. > > Anybody working on implementing a new version of f_mass_storage that > is layered upon drivers/target instead ? That would bring quite a lot > of additional functionality. That's what f_tcm does. Alan Stern > If not, I might look into it. > > Cheers, > Ben. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-21 14:25 ` Alan Stern @ 2019-08-22 0:10 ` Benjamin Herrenschmidt 2019-08-22 4:58 ` Benjamin Herrenschmidt 0 siblings, 1 reply; 11+ messages in thread From: Benjamin Herrenschmidt @ 2019-08-22 0:10 UTC (permalink / raw) To: Alan Stern; +Cc: USB list On Wed, 2019-08-21 at 10:25 -0400, Alan Stern wrote: > On Wed, 21 Aug 2019, Benjamin Herrenschmidt wrote: > > > Hi folks ! > > > > It seems that f_mass_storage duplicates (well maybe predates too..) > a > > lot of what's in drivers/target. > > > > Anybody working on implementing a new version of f_mass_storage > that > > is layered upon drivers/target instead ? That would bring quite a > lot > > of additional functionality. > > That's what f_tcm does. > > Alan Stern Haha nice, I never noticed it :-) Cheers, Ben. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-22 0:10 ` Benjamin Herrenschmidt @ 2019-08-22 4:58 ` Benjamin Herrenschmidt 2019-08-22 5:14 ` Benjamin Herrenschmidt 0 siblings, 1 reply; 11+ messages in thread From: Benjamin Herrenschmidt @ 2019-08-22 4:58 UTC (permalink / raw) To: Alan Stern; +Cc: USB list On Thu, 2019-08-22 at 10:10 +1000, Benjamin Herrenschmidt wrote: > On Wed, 2019-08-21 at 10:25 -0400, Alan Stern wrote: > > On Wed, 21 Aug 2019, Benjamin Herrenschmidt wrote: > > > > > Hi folks ! > > > > > > It seems that f_mass_storage duplicates (well maybe predates too..) > > > > a > > > lot of what's in drivers/target. > > > > > > Anybody working on implementing a new version of f_mass_storage > > > > that > > > is layered upon drivers/target instead ? That would bring quite a > > > > lot > > > of additional functionality. > > > > That's what f_tcm does. > > > > Alan Stern > > Haha nice, I never noticed it :-) Ah lovely ... the 338x fails in EP autoconf with f_tcm, digging... While digging I found this gem: /* USB3380: use same address for usb and hardware endpoints */ snprintf(name, sizeof(name), "ep%d%s", usb_endpoint_num(desc), usb_endpoint_dir_in(desc) ? "in" : "out"); ep = gadget_find_ep_by_name(_gadget, name); if (ep && usb_gadget_ep_match_desc(_gadget, ep, desc, ep_comp)) return ep; Any idea what's that supposed to achieve ? When ep_match is called, usb_endpoint_num() hasn't been set yet so it's always 0 and always fails... or am I missing something ? Cheers, Ben. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-22 4:58 ` Benjamin Herrenschmidt @ 2019-08-22 5:14 ` Benjamin Herrenschmidt 2019-08-22 5:48 ` Benjamin Herrenschmidt 2019-08-22 17:30 ` Alan Stern 0 siblings, 2 replies; 11+ messages in thread From: Benjamin Herrenschmidt @ 2019-08-22 5:14 UTC (permalink / raw) To: Alan Stern; +Cc: USB list, Sebastian Andrzej Siewior On Thu, 2019-08-22 at 14:58 +1000, Benjamin Herrenschmidt wrote: > > Ah lovely ... the 338x fails in EP autoconf with f_tcm, digging... > > While digging I found this gem: > > /* USB3380: use same address for usb and hardware endpoints */ > snprintf(name, sizeof(name), "ep%d%s", usb_endpoint_num(desc), > usb_endpoint_dir_in(desc) ? "in" : "out"); > ep = gadget_find_ep_by_name(_gadget, name); > if (ep && usb_gadget_ep_match_desc(_gadget, ep, desc, ep_comp)) > return ep; > > Any idea what's that supposed to achieve ? > > When ep_match is called, usb_endpoint_num() hasn't been set yet so > it's always 0 and always fails... or am I missing something ? Two problems: - net2280.c doesn't set a max EP size, so autoconfig fails since f_tcm specifies one. What about this ? --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -940,12 +940,14 @@ int usb_gadget_ep_match_desc(struct usb_gadget *gadget, if (usb_endpoint_dir_out(desc) && !ep->caps.dir_out) return 0; - if (max > ep->maxpacket_limit) + if (ep->maxpacket_limit && max > ep->maxpacket_limit) return 0; (ie assume that ep->maxpacket_limit 0 means the UDC supports any legal size) - No UDC driver other than dummy sets max_streams, and f_tcm requires 4, so f_tcm will fail with *any* superspeed UDC driver as far as I can tell. Was it ever tested with USB 3 ? I'm not sure what the right fix here yet is as I yet have to learn about what those USB3 streams are :-) For now I've commented things out. It's still not working yet as configuring f_tcm seems to be a black art with no useful documentation or examples anywhere (the device shows up on the host but doesn't bind to any mass storage driver ... yet). Cheers, Ben. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-22 5:14 ` Benjamin Herrenschmidt @ 2019-08-22 5:48 ` Benjamin Herrenschmidt 2019-08-22 17:30 ` Alan Stern 1 sibling, 0 replies; 11+ messages in thread From: Benjamin Herrenschmidt @ 2019-08-22 5:48 UTC (permalink / raw) To: Alan Stern; +Cc: USB list, Sebastian Andrzej Siewior On Thu, 2019-08-22 at 15:14 +1000, Benjamin Herrenschmidt wrote: > - No UDC driver other than dummy sets max_streams, and f_tcm requires 4, > so f_tcm will fail with *any* superspeed UDC driver as far as I can tell. > > Was it ever tested with USB 3 ? Ok so I spoke too soon... dwc3 does, I didn't notice bcs it doesn't live in drivers/usb/gadget... So Sebastian, what would be the best way to "fallback" to non-stream use rather than just fail probing ? Do we really want the autoconf EP matching to enforce the stream numbers ? If we allow it to not match, then f_tcm could check after matching if enough streams were found and disable stream support if not. Another option would be to make this 2-pass, though that complicates even more: a first pass where we enforce the stream count, and if we fail, a second pass where we ignore them. Suggestions ? Cheers, Ben. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-22 5:14 ` Benjamin Herrenschmidt 2019-08-22 5:48 ` Benjamin Herrenschmidt @ 2019-08-22 17:30 ` Alan Stern 2019-08-23 0:40 ` Benjamin Herrenschmidt 1 sibling, 1 reply; 11+ messages in thread From: Alan Stern @ 2019-08-22 17:30 UTC (permalink / raw) To: Benjamin Herrenschmidt; +Cc: USB list, Sebastian Andrzej Siewior On Thu, 22 Aug 2019, Benjamin Herrenschmidt wrote: > On Thu, 2019-08-22 at 14:58 +1000, Benjamin Herrenschmidt wrote: > > > > Ah lovely ... the 338x fails in EP autoconf with f_tcm, digging... > > > > While digging I found this gem: > > > > /* USB3380: use same address for usb and hardware endpoints */ > > snprintf(name, sizeof(name), "ep%d%s", usb_endpoint_num(desc), > > usb_endpoint_dir_in(desc) ? "in" : "out"); > > ep = gadget_find_ep_by_name(_gadget, name); > > if (ep && usb_gadget_ep_match_desc(_gadget, ep, desc, ep_comp)) > > return ep; > > > > Any idea what's that supposed to achieve ? It looks like in one mode, the endpoint number has to be the value predetermined by the hardware. In the other mode, any hardware endpoint can be assigned any endpoint number. > > When ep_match is called, usb_endpoint_num() hasn't been set yet so > > it's always 0 and always fails... or am I missing something ? > > Two problems: > > - net2280.c doesn't set a max EP size, so autoconfig fails since > f_tcm specifies one. What about this ? > > --- a/drivers/usb/gadget/udc/core.c > +++ b/drivers/usb/gadget/udc/core.c > @@ -940,12 +940,14 @@ int usb_gadget_ep_match_desc(struct usb_gadget *gadget, > if (usb_endpoint_dir_out(desc) && !ep->caps.dir_out) > return 0; > > - if (max > ep->maxpacket_limit) > + if (ep->maxpacket_limit && max > ep->maxpacket_limit) > return 0; > > (ie assume that ep->maxpacket_limit 0 means the UDC supports any > legal size) That looks reasonable. > - No UDC driver other than dummy sets max_streams, and f_tcm requires 4, > so f_tcm will fail with *any* superspeed UDC driver as far as I can tell. > > Was it ever tested with USB 3 ? Note that USB 2 does not support streams at all. > I'm not sure what the right fix here yet is as I yet have to learn about > what those USB3 streams are :-) For now I've commented things out. They are for multiplexing multiple data streams over a single USB endpoint. As far as I know, the only use case for such a thing is USB Mass Storage. Alan Stern > It's still not working yet as configuring f_tcm seems to be a black art > with no useful documentation or examples anywhere (the device shows up on > the host but doesn't bind to any mass storage driver ... yet). > > Cheers, > Ben. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-22 17:30 ` Alan Stern @ 2019-08-23 0:40 ` Benjamin Herrenschmidt 2019-08-23 15:21 ` Alan Stern 0 siblings, 1 reply; 11+ messages in thread From: Benjamin Herrenschmidt @ 2019-08-23 0:40 UTC (permalink / raw) To: Alan Stern; +Cc: USB list, Sebastian Andrzej Siewior On Thu, 2019-08-22 at 13:30 -0400, Alan Stern wrote: > On Thu, 22 Aug 2019, Benjamin Herrenschmidt wrote: > > > On Thu, 2019-08-22 at 14:58 +1000, Benjamin Herrenschmidt wrote: > > > > > > Ah lovely ... the 338x fails in EP autoconf with f_tcm, digging... > > > > > > While digging I found this gem: > > > > > > /* USB3380: use same address for usb and hardware endpoints */ > > > snprintf(name, sizeof(name), "ep%d%s", usb_endpoint_num(desc), > > > usb_endpoint_dir_in(desc) ? "in" : "out"); > > > ep = gadget_find_ep_by_name(_gadget, name); > > > if (ep && usb_gadget_ep_match_desc(_gadget, ep, desc, ep_comp)) > > > return ep; > > > > > > Any idea what's that supposed to achieve ? > > It looks like in one mode, the endpoint number has to be the value > predetermined by the hardware. In the other mode, any hardware > endpoint can be assigned any endpoint number. Sure but as I wrote, this is ep_match, which when called, always has usb_endpoint_num() set to 0... this function is supposed to chose the EP number afaik. So I don't think the above ever works, it just returns NULL. Or do we ever call this again with already predetermined EP nums, for example when doing multifunction ? > > > When ep_match is called, usb_endpoint_num() hasn't been set yet so > > > it's always 0 and always fails... or am I missing something ? > > > > Two problems: > > > > - net2280.c doesn't set a max EP size, so autoconfig fails since > > f_tcm specifies one. What about this ? > > > > --- a/drivers/usb/gadget/udc/core.c > > +++ b/drivers/usb/gadget/udc/core.c > > @@ -940,12 +940,14 @@ int usb_gadget_ep_match_desc(struct usb_gadget *gadget, > > if (usb_endpoint_dir_out(desc) && !ep->caps.dir_out) > > return 0; > > > > - if (max > ep->maxpacket_limit) > > + if (ep->maxpacket_limit && max > ep->maxpacket_limit) > > return 0; > > > > (ie assume that ep->maxpacket_limit 0 means the UDC supports any > > legal size) > > That looks reasonable. I'll send a patch. > > - No UDC driver other than dummy sets max_streams, and f_tcm requires 4, > > so f_tcm will fail with *any* superspeed UDC driver as far as I can tell. > > > > Was it ever tested with USB 3 ? > > Note that USB 2 does not support streams at all. Yes, f_tcm only requires them for superspeed, but it does *require* them in that case. > > I'm not sure what the right fix here yet is as I yet have to learn about > > what those USB3 streams are :-) For now I've commented things out. > > They are for multiplexing multiple data streams over a single USB > endpoint. As far as I know, the only use case for such a thing is USB > Mass Storage. So f_tcm could operate in a degraded mode in the absence of streams easily, the problem is the mechanics of EP matching in epautoconf. It will just fail. I wonder since f_tcm is also the only user, whether we could change the matching logic to either: - Don't try to match, return streams is available. This could be problematic if the UDC supports streams on some EPs and not others however. - Do two passes: one pass trying to match the streams, and one patch without matching them if the first one fails. Then f_tcm could check whether it got EPs with streams and enable stream usage accordingly. Opinions ? Other option ? Cheers, Ben. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-23 0:40 ` Benjamin Herrenschmidt @ 2019-08-23 15:21 ` Alan Stern 2019-08-26 2:19 ` Benjamin Herrenschmidt 0 siblings, 1 reply; 11+ messages in thread From: Alan Stern @ 2019-08-23 15:21 UTC (permalink / raw) To: Benjamin Herrenschmidt; +Cc: USB list, Sebastian Andrzej Siewior On Fri, 23 Aug 2019, Benjamin Herrenschmidt wrote: > On Thu, 2019-08-22 at 13:30 -0400, Alan Stern wrote: > > On Thu, 22 Aug 2019, Benjamin Herrenschmidt wrote: > > > > > On Thu, 2019-08-22 at 14:58 +1000, Benjamin Herrenschmidt wrote: > > > > > > > > Ah lovely ... the 338x fails in EP autoconf with f_tcm, digging... > > > > > > > > While digging I found this gem: > > > > > > > > /* USB3380: use same address for usb and hardware endpoints */ > > > > snprintf(name, sizeof(name), "ep%d%s", usb_endpoint_num(desc), > > > > usb_endpoint_dir_in(desc) ? "in" : "out"); > > > > ep = gadget_find_ep_by_name(_gadget, name); > > > > if (ep && usb_gadget_ep_match_desc(_gadget, ep, desc, ep_comp)) > > > > return ep; > > > > > > > > Any idea what's that supposed to achieve ? > > > > It looks like in one mode, the endpoint number has to be the value > > predetermined by the hardware. In the other mode, any hardware > > endpoint can be assigned any endpoint number. > > Sure but as I wrote, this is ep_match, which when called, always has > usb_endpoint_num() set to 0... this function is supposed to chose the > EP number afaik. So I don't think the above ever works, it just returns > NULL. Or do we ever call this again with already predetermined EP nums, > for example when doing multifunction ? I don't know. You might try asking the person who wrote that code. > > > > When ep_match is called, usb_endpoint_num() hasn't been set yet so > > > > it's always 0 and always fails... or am I missing something ? > > > > > > Two problems: > > > > > > - net2280.c doesn't set a max EP size, so autoconfig fails since > > > f_tcm specifies one. What about this ? > > > > > > --- a/drivers/usb/gadget/udc/core.c > > > +++ b/drivers/usb/gadget/udc/core.c > > > @@ -940,12 +940,14 @@ int usb_gadget_ep_match_desc(struct usb_gadget *gadget, > > > if (usb_endpoint_dir_out(desc) && !ep->caps.dir_out) > > > return 0; > > > > > > - if (max > ep->maxpacket_limit) > > > + if (ep->maxpacket_limit && max > ep->maxpacket_limit) > > > return 0; > > > > > > (ie assume that ep->maxpacket_limit 0 means the UDC supports any > > > legal size) > > > > That looks reasonable. > > I'll send a patch. > > > > - No UDC driver other than dummy sets max_streams, and f_tcm requires 4, > > > so f_tcm will fail with *any* superspeed UDC driver as far as I can tell. > > > > > > Was it ever tested with USB 3 ? > > > > Note that USB 2 does not support streams at all. > > Yes, f_tcm only requires them for superspeed, but it does *require* > them in that case. I don't see any reason why f_tcm shouldn't fall back on Bulk-Only Transport when streams aren't available, even on a SuperSpeed connection. > > > I'm not sure what the right fix here yet is as I yet have to learn about > > > what those USB3 streams are :-) For now I've commented things out. > > > > They are for multiplexing multiple data streams over a single USB > > endpoint. As far as I know, the only use case for such a thing is USB > > Mass Storage. > > So f_tcm could operate in a degraded mode in the absence of streams > easily, the problem is the mechanics of EP matching in epautoconf. It > will just fail. > > I wonder since f_tcm is also the only user, whether we could change the > matching logic to either: > > - Don't try to match, return streams is available. This could be > problematic if the UDC supports streams on some EPs and not others > however. > > - Do two passes: one pass trying to match the streams, and one patch > without matching them if the first one fails. > > Then f_tcm could check whether it got EPs with streams and enable > stream usage accordingly. > > Opinions ? Other option ? I like the two-pass option better. Maybe Felipe will weigh in when he's back from vacation. Alan Stern ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: f_mass_storage vs drivers/target 2019-08-23 15:21 ` Alan Stern @ 2019-08-26 2:19 ` Benjamin Herrenschmidt 0 siblings, 0 replies; 11+ messages in thread From: Benjamin Herrenschmidt @ 2019-08-26 2:19 UTC (permalink / raw) To: Alan Stern; +Cc: USB list, Sebastian Andrzej Siewior On Fri, 2019-08-23 at 11:21 -0400, Alan Stern wrote: > > I wonder since f_tcm is also the only user, whether we could change > > the > > matching logic to either: > > > > - Don't try to match, return streams is available. This could be > > problematic if the UDC supports streams on some EPs and not others > > however. > > > > - Do two passes: one pass trying to match the streams, and one > > patch > > without matching them if the first one fails. > > > > Then f_tcm could check whether it got EPs with streams and enable > > stream usage accordingly. > > > > Opinions ? Other option ? > > I like the two-pass option better. Maybe Felipe will weigh in when > he's back from vacation. Yup, I prefer it too. I'll cook up something in the meantime so I have a patch to show. Cheers, Ben. ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2019-08-26 2:20 UTC | newest] Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-08-21 3:38 f_mass_storage vs drivers/target Benjamin Herrenschmidt 2019-08-21 9:32 ` Greg KH 2019-08-21 14:25 ` Alan Stern 2019-08-22 0:10 ` Benjamin Herrenschmidt 2019-08-22 4:58 ` Benjamin Herrenschmidt 2019-08-22 5:14 ` Benjamin Herrenschmidt 2019-08-22 5:48 ` Benjamin Herrenschmidt 2019-08-22 17:30 ` Alan Stern 2019-08-23 0:40 ` Benjamin Herrenschmidt 2019-08-23 15:21 ` Alan Stern 2019-08-26 2:19 ` Benjamin Herrenschmidt
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