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Code Issues Releases Activity

When checking the device code in the probe routine, leave the chip in

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16-bit mode. Technically, pcn_probe() is destructive because once the
chip goes into 32-bit mode, the only way to get it out again is a
hardware reset. And once the device is in 32-bit mode, the lnc driver
won't be able to talk to it. So if pcn_probe() is called before the
lnc probe routine, and pcn_probe() rejects the chip as one it doesn't
support, the lnc driver will be SOL.

I don't like this. I think it's a design flaw that you can't switch
the chip out of 32-bit mode once it's selected. The only 'right'
solution is for the pcn driver to support all of the PCI devices
in 32-bit mode, however I don't have samples of all the PCnet series
cards for testing.
This commit is contained in:
Bill Paul 2000-11-16 19:56:09 +00:00
parent 810888e2f8
commit da6e4b77bb
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=68837
1 changed files with 22 additions and 3 deletions
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25
sys/pci/if_pcn.c
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@ -110,6 +110,7 @@ static struct pcn_type pcn_devs[] = {
};
static u_int32_t pcn_csr_read __P((struct pcn_softc *, int));
static u_int16_t pcn_csr_read16 __P((struct pcn_softc *, int));
static void pcn_csr_write __P((struct pcn_softc *, int, int));
static u_int32_t pcn_bcr_read __P((struct pcn_softc *, int));
static void pcn_bcr_write __P((struct pcn_softc *, int, int));
@ -203,6 +204,14 @@ static u_int32_t pcn_csr_read(sc, reg)
return(CSR_READ_4(sc, PCN_IO32_RDP));
}
static u_int16_t pcn_csr_read16(sc, reg)
struct pcn_softc *sc;
int reg;
{
CSR_WRITE_2(sc, PCN_IO16_RAP, reg);
return(CSR_READ_2(sc, PCN_IO16_RDP));
}
static void pcn_csr_write(sc, reg, val)
struct pcn_softc *sc;
int reg;
@ -401,10 +410,20 @@ static int pcn_probe(dev)
mtx_init(&sc->pcn_mtx,
device_get_nameunit(dev), MTX_DEF);
PCN_LOCK(sc);
pcn_reset(sc);
chip_id = pcn_csr_read(sc, PCN_CSR_CHIPID1);
/*
* Note: we can *NOT* put the chip into
* 32-bit mode yet. The lnc driver will only
* work in 16-bit mode, and once the chip
* goes into 32-bit mode, the only way to
* get it out again is with a hardware reset.
* So if pcn_probe() is called before the
* lnc driver's probe routine, the chip will
* be locked into 32-bit operation and the lnc
* driver will be unable to attach to it.
*/
chip_id = pcn_csr_read16(sc, PCN_CSR_CHIPID1);
chip_id <<= 16;
chip_id |= pcn_csr_read(sc, PCN_CSR_CHIPID0);
chip_id |= pcn_csr_read16(sc, PCN_CSR_CHIPID0);
bus_release_resource(dev, PCN_RES,
PCN_RID, sc->pcn_res);
PCN_UNLOCK(sc);