Date: Sun, 04 Jun 2006 10:07:13 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: avalonwallace@gmail.com Cc: freebsd-hackers@freebsd.org Subject: Re: misc questions about the device&driver arch Message-ID: <20060604.100713.-552478981.imp@bsdimp.com> In-Reply-To: <87ab37ab0606040823k73cf27b1q787d544ce19a9687@mail.gmail.com> References: <87ab37ab0606040029u67edc35ende0b34e39e80bd37@mail.gmail.com> <20060604.043725.778152499.imp@bsdimp.com> <87ab37ab0606040823k73cf27b1q787d544ce19a9687@mail.gmail.com>
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In message: <87ab37ab0606040823k73cf27b1q787d544ce19a9687@mail.gmail.com>
"william wallace" <avalonwallace@gmail.com> writes:
: now i am dealing with the pciexpress resource release and allocation
: i found it hard to distinguish between the bus_alloc_resource
: familiy(type rid and flag) and the rman_get/set_***** family(struct
: rman and resource ) ,i have heard that memory resource which alloc by
: the bus_alloc_resource should not be refer to by rid ,
: " SYS_RES_MEMORY
: Memory-access is done with the bus_space_(read,write)_(1,2,3,4)
: functions (depends on how many bytes you want to read/write).
: u_int8_t old;
: old = bus_space_read_1(sc->bst, sc->bsh, 0);
: bus_space_write_1(sc->bst, sc->bsh, 0, old); "
: is that true?
bus_alloc_resources is how you get resources from your parent device.
It will return a struct resource * that the rman* rouintes can access
the insides of (let's call it r).
bus_space_read_1(rman_get_bustag(r), rman_get_bushandle(r), 0);
or the newer
bus_read_1(r, 0);
: the second question ,if i do hot swap and donot release the hot remove
: card 's resource ,how can i attach it to the newly add-in card ?
You must release the resource whent he card exits the system.
: shall i do a
: pci_write_config(child, rle->rid, rle->start, 4);to pin the resource
: to the pci space ?
No. The pci code should already handle things correctly.
: i wonder if there 's a find document for the freebsd resource topology,
There's not a centralized document outside of the source.
Warner
: thank you ,sir .
: On 6/4/06, M. Warner Losh <imp@bsdimp.com> wrote:
: > In message: <87ab37ab0606040029u67edc35ende0b34e39e80bd37@mail.gmail.com>
: > "william wallace" <avalonwallace@gmail.com> writes:
: > : On 5/20/06, Warner Losh <imp@bsdimp.com> wrote:
: > : > From: "william wallace" <avalonwallace@gmail.com>
: > : > Subject: Re: misc questions about the device&driver arch
: > : > Date: Sat, 20 May 2006 13:39:08 +0800
: > : >
: > : > > comparing the method array of pci_pci and cardbusbridge:
: > : > > what losts in pci bridge but exist in cardbusbridge:
: > : > > 1 card interface
: > : > > 2 power interface
: > : > > 3 some functions :
: > : > > 3ain bus interface
: > : > > (bus_driver_added, cbb_driver_added),
: > : > > (bus_child_detached, cbb_child_detached),
: > : > > (bus_child_present, cbb_child_present),
: > : > > 3b in device interface
: > : > > (device_detach, cbb_detach),
: > : > > what exists in pci bridge but losts in cardbusbridge:
: > : > > (pcib_route_interrupt, pcib_route_interrupt),
: > : > >
: > : > > not only that ,functions r very different eventhough they realize the
: > : > > same interface function template
: > : > > wooo，so long to go to hotplug pci
: > : >
: > : > Yes. The hardest part would be to create a pci hot swap bridge
: > : > driver. The interface for them tend to be underdocumented.
: > : >
: > : > The bus_child_present is important for detaching.
: > : >
: > : > Also, I think that we may need to start implementing a quiess method
: > : > to tell the drivers they are about to be removed. For hot plug PCI,
: > : > the model is that you quess the driver, the os tells you somehow it is
: > : > safe, and then you remove the card. The details vary (some system are
: > : > all in software, while others have a complicated interlock and LEDs),
: > : > but they are similar. Cardbus is harder in some ways because cards
: > : > leave unannounced (in fact, there's not a good way to announce a card
: > : > leaving, but there should be).
: > : >
: > : > Warner
: > : >
: > : > > On 5/20/06, Warner Losh <imp@bsdimp.com> wrote:
: > : > >
: > : > > > Busses create devices to represent hardware in the system. The bus
: > : > > > then causes these devices to be probed and attached. This latter
: > : > > > usage is for those cases. As drivers are loaded these devices are
: > : > > > offered to the new (and old) drivers in the system.
: > : > > >
: > : > > > FreeBSD inherently dynamic in its device system. The hardest part of
: > : > > > adding hotplug support is programming the bridge. Adding new devices
: > : > > > to the tree is easy, but knowing when to add them is hard since you
: > : > > > have to write a bridge driver...
: > : > > >
: > : > > > Warner
: > : Prior to removing a card from the system, two things must occur:
: > :
: > : The device's driver must cease accessing the card.
: > :
: > : The card must cease generation transaction and interrupts.
: > :
: > : How this is accomplished is OS-specific, but the following must take place:
: > :
: > : The OS must stop issuing new requests to the device's driver or must
: > : instruct the driver to stop accepting new requests.
: > :
: > : The driver must terminate or complete all outstanding requests.
: > :
: > : The card must be disabled from generating interrupts or transactions.
: > :
: > : When the OS commands the driver to quiesce itself and its device, the
: > : OS must not expect the device to remain in the system (in other words,
: > : it could be removed and not replaced with a similar card).
: > :
: > : How to design and implement quiescing in freebsd?
: >
: > device_quiesce? I have it in a p4 tree right now. Specifically, it
: > hooks up to the MOD_UNLOAD with a QUIESCE flag. The driver's
: > device_quiesce routine gets called, the driver sleeps there until it
: > knows that it is good, then returns to the caller. Then the driver's
: > detach routine can be called.
: >
: > Warner
: >
:
:
: --
: we who r about to die,salute u!
:
:
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