Date: Thu, 16 Jan 2003 17:52:22 -0500 From: Hiten Pandya <hiten@unixdaemons.com> To: Thomas Moestl <tmoestl@gmx.net> Cc: Josef Karthauser <joe@FreeBSD.ORG>, Maxime Henrion <mux@FreeBSD.ORG>, current@FreeBSD.ORG Subject: Re: Bus DMA for USB - compilation problems. Message-ID: <20030116225222.GB24866@unixdaemons.com> In-Reply-To: <20030115215804.GA286@crow.dom2ip.de> References: <20030115195607.GA13076@genius.tao.org.uk> <20030115200519.GH16775@elvis.mu.org> <20030115202033.GA13368@genius.tao.org.uk> <20030115215804.GA286@crow.dom2ip.de>
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On Wed, Jan 15, 2003 at 10:58:04PM +0100, Thomas Moestl wrote the words in effect of:
> On Wed, 2003/01/15 at 20:20:33 +0000, Josef Karthauser wrote:
> > On Wed, Jan 15, 2003 at 12:05:20PM -0800, Maxime Henrion wrote:
> > > Josef Karthauser wrote:
> > > > I've partially ported the NetBSD busdma code for USB to FreeBSD, but
> > > > it doesn't compile, probably for a trivial reason.
> > > >
> > > > Anyone fancy helping me out?
> > >
> > > I didn't look at the patches yet, but could you give me the compilation
> > > error you are getting ?
> > >
> >
> > cc -c -O -pipe -march=pentium3 -Wall -Wredundant-decls -Wnested-externs
> > -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith -Winline
> > -Wcast-qual -fformat-extensions -ansi -g -nostdinc -I- -I.
> > -I/usr/src/sys -I/usr/src/sys/dev -I/usr/src/sys/contrib/dev/acpica
> > -I/usr/src/sys/contrib/ipfilter -D_KERNEL -include opt_global.h
> > -fno-common -mno-align-long-strings -mpreferred-stack-boundary=2
> > -ffreestanding -Werror /usr/src/sys/dev/usb/uhci.c
> > /usr/src/sys/dev/usb/uhci.c: In function `uhci_init':
> > /usr/src/sys/dev/usb/uhci.c:425: dereferencing pointer to incomplete type
> > /usr/src/sys/dev/usb/uhci.c: In function `uhci_power':
> > /usr/src/sys/dev/usb/uhci.c:714: dereferencing pointer to incomplete type
> > /usr/src/sys/dev/usb/uhci.c: In function `uhci_alloc_std':
> >
> > It's failing at lines like:
> >
> > UWRITE4(sc, UHCI_FLBASEADDR, DMAADDR(&sc->sc_dma, 0)); /* set frame list */
> >
> > The problematic is DMAADDR, and it's because the sc->sc_dma, which is
> > defined as usb_dma_t. This is defined in usb_port.h, and it uses
> > usb_dma_block which is defined in usb_mem.h. I think that it's the
> > usb_dma_block that is coming up as incomplete, but I'm not sure.
>
> DMAADDR is:
>
> #define DMAADDR(dma, o) ((dma)->block->map->dm_segs[0].ds_addr + (dma)->offs + (o))
>
> struct usb_dma_block starts like:
>
> typedef struct usb_dma_block {
> bus_dma_tag_t tag;
> bus_dmamap_t map;
>
> However, bus_dmamap_t (like bus_dma_tag_t) is supposed to be opaque to
> users of the busdma interface on FreeBSD. Our implementations enforce
> this by defining it as:
>
> typedef struct bus_dmamap *bus_dmamap_t;
>
> , and by not exporting struct bus_dmamap in public headers.
>
> The DMA addresses are obtained by writing an appropriate callback
> routine to process them and passing it to bus_dmamap_load().
> The usb_mem.c will need some other changes to work on FreeBSD, since
> our busdma code has diverged from NetBSD's quite a bit.
Hiya Joe!
The caller has to specify a routine to receive the DMA segment list, and
for processing any errors occured during this period. If the operation
is delayed, than EINPROGRESS is returned. If you specify
BUS_DMA_NOWAIT, then the bus dma interface allows you to fail the
request rather the delay (no sleep) it. Neccessary prep. must be done
if you don't want bus_dmamap_load_*() to block, by setting the
BUS_DMA_ALLOCNOW flag at dma tag and map creation time.
You must also note, that the lifetime of the callback routine, should be
about the same as that of the bus_dma_segment_t array passed.
As defered from the NetBSD bus_dma interface, you can provide a filter
routine, at dma tag creation time (bus_dma_tag_create) to DMA to an
address range not accesilbe to the interface -- i.e. if such thing
happens, the routine is asked to take over the task.
The BusLogic driver is a very good driver to read for bus_dma related
things. I personally found it good, as it covers many cases. JFYI.
HTH.
Cheers.
--
Hiten Pandya (hiten@unixdaemons.com, hiten@uk.FreeBSD.org)
http://www.unixdaemons.com/~hiten/
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