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Three content changes:

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1) Use the new c99 initialization in the pci driver example.  Also,
	   don't claim this device is a tty.
	2) Add notes about caution needed during detach routine wrt interrupts
	   and locking.
	3) Add note that vtophys is deprecated and to use busdma instead.
	   Since the busdma API isn't completely settled for 5.x yet,
	   don't document it.  I'll leave that to others when the API is
	   done being frobbed.
This commit is contained in:
Warner Losh 2003-07-03 22:30:10 +00:00
parent 1c722a4f22
commit 6891feb81d
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=17467
2 changed files with 46 additions and 28 deletions
en_US.ISO8859-1/books
arch-handbook/pci
chapter.sgml
developers-handbook/pci
chapter.sgml

37
en_US.ISO8859-1/books/arch-handbook/pci/chapter.sgml
View file

@ -47,20 +47,11 @@ d_write_t mypci_write;
/* Character device entry points */
static struct cdevsw mypci_cdevsw = {
mypci_open,
mypci_close,
mypci_read,
mypci_write,
noioctl,
nopoll,
nommap,
nostrategy,
"mypci",
36, /* reserved for lkms - /usr/src/sys/conf/majors */
nodump,
nopsize,
D_TTY,
-1
.d_open = mypci_open,
.d_close = mypci_close,
.d_read = mypci_read,
.d_write = mypci_write,
.d_name = "mypci",
};
/* vars */
@ -325,10 +316,28 @@ board_write(struct ni_softc *sc, uint16_t address, uint16_t value) {
sc->irq_bh = rman_get_bushandle(sc->irqres);
</programlisting>
<para>Some care must be taken in the detach routine of the
driver. You must quiess the device's interrupt stream, and
remove the interrupt hanlder. Once
<function>bus_space_teardown_intr()</function> has returned, you
know that your interrupt handler will no longer be called, and
that all threads that might have been this interrupt handler
have returned. Depending on the locking strategy of your
driver, you will also need to be careful with what locks you
hold when you do this to avoid deadlock.</para>
</sect2>
<sect2>
<title>DMA</title>
<para>This section is obsolete, and present only for historical
reasons. The proper methods for dealing with these issues is to
use the <function>bus_space_dma*()</function> functions instead.
This paragraph can be removed when this section is updated to reflect
that usage. However, at the moment, the API is in a bit of
flux, so once that settles down, it would be good to update this
section to reflect that.</para>
<para>On the PC, peripherals that want to do bus-mastering DMA
must deal with physical addresses. This is a problem since
FreeBSD uses virtual memory and deals almost exclusively with

37
en_US.ISO8859-1/books/developers-handbook/pci/chapter.sgml
View file

@ -47,20 +47,11 @@ d_write_t mypci_write;
/* Character device entry points */
static struct cdevsw mypci_cdevsw = {
mypci_open,
mypci_close,
mypci_read,
mypci_write,
noioctl,
nopoll,
nommap,
nostrategy,
"mypci",
36, /* reserved for lkms - /usr/src/sys/conf/majors */
nodump,
nopsize,
D_TTY,
-1
.d_open = mypci_open,
.d_close = mypci_close,
.d_read = mypci_read,
.d_write = mypci_write,
.d_name = "mypci",
};
/* vars */
@ -325,10 +316,28 @@ board_write(struct ni_softc *sc, uint16_t address, uint16_t value) {
sc->irq_bh = rman_get_bushandle(sc->irqres);
</programlisting>
<para>Some care must be taken in the detach routine of the
driver. You must quiess the device's interrupt stream, and
remove the interrupt hanlder. Once
<function>bus_space_teardown_intr()</function> has returned, you
know that your interrupt handler will no longer be called, and
that all threads that might have been this interrupt handler
have returned. Depending on the locking strategy of your
driver, you will also need to be careful with what locks you
hold when you do this to avoid deadlock.</para>
</sect2>
<sect2>
<title>DMA</title>
<para>This section is obsolete, and present only for historical
reasons. The proper methods for dealing with these issues is to
use the <function>bus_space_dma*()</function> functions instead.
This paragraph can be removed when this section is updated to reflect
that usage. However, at the moment, the API is in a bit of
flux, so once that settles down, it would be good to update this
section to reflect that.</para>
<para>On the PC, peripherals that want to do bus-mastering DMA
must deal with physical addresses. This is a problem since
FreeBSD uses virtual memory and deals almost exclusively with