On 03/31/2010 01:21 PM, Rafał Miłecki wrote:
> Attempting to read registers that don't exist on the SSB bus can cause
> hangs on some boxes. At least some b43 devices are 'in the wild' that
> don't have SPROMs at all. When the SSB bus support loads, it attempts
> to read these (non-existant) SPROMs and causes hard hangs on the box --
> no console output, etc.
>
> This patch adds some intelligence to determine whether or not the SPROM
> is present before attempting to read it. This avoids those hard hangs
> on those devices with no SPROM attached to their SSB bus. The
> SSB-attached devices (e.g. b43, et al.) won't work, but at least the box
> will survive to test further patches. :-)
>
> Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
> Signed-off-by: Rafał Miłecki <zajec5@xxxxxxxxx>
> Cc: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
> Cc: Michael Buesch <mb@xxxxxxxxx>
> ---
> V2: adapt to updated specs, drop some warning-causing braces
>
> Do I understand correctly this patch can be applied even without fix for
> location of SPROM? AFAIU that is separated issue and we do not support
> SPROM with recently discovered location anyway. However this should fix
> hangs on boards without SPROM, right?
It is separate from the SPROM location change.
> John: I searched for explaination of Signed-off-by and found info it shows
> people involved in creating patch. As this one is mostly based on yours, I
> have kept your S-o-b line. Is that OK? Is this also OK I added myself, even
> if my involvement is much lower than yours?
>
> Please do not irritate if I done this incorrectly :)
>
> So finally: can someone test this, please? John?
The usual way to do this is to include a From: line as the first thing
in the patch. That indicates that the patch is not from the person that
actually submitted it, and it implies a sighed-off-by.
> ---
> drivers/ssb/driver_chipcommon.c | 2 +
> drivers/ssb/pci.c | 5 ++++
> drivers/ssb/sprom.c | 30 +++++++++++++++++++++++++++++
> include/linux/ssb/ssb.h | 3 ++
> include/linux/ssb/ssb_driver_chipcommon.h | 15 ++++++++++++++
> 5 files changed, 55 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/ssb/driver_chipcommon.c b/drivers/ssb/driver_chipcommon.c
> index 59c3c0f..59ae76b 100644
> --- a/drivers/ssb/driver_chipcommon.c
> +++ b/drivers/ssb/driver_chipcommon.c
> @@ -233,6 +233,8 @@ void ssb_chipcommon_init(struct ssb_chipcommon *cc)
> {
> if (!cc->dev)
> return; /* We don't have a ChipCommon */
> + if (cc->dev->id.revision >= 11)
> + cc->status = chipco_read32(cc, SSB_CHIPCO_CHIPSTAT);
> ssb_pmu_init(cc);
> chipco_powercontrol_init(cc);
> ssb_chipco_set_clockmode(cc, SSB_CLKMODE_FAST);
> diff --git a/drivers/ssb/pci.c b/drivers/ssb/pci.c
> index 9e50896..a4b2b99 100644
> --- a/drivers/ssb/pci.c
> +++ b/drivers/ssb/pci.c
> @@ -620,6 +620,11 @@ static int ssb_pci_sprom_get(struct ssb_bus *bus,
> int err = -ENOMEM;
> u16 *buf;
>
> + if (!ssb_is_sprom_available(bus)) {
> + ssb_printk(KERN_ERR PFX "No SPROM available!\n");
> + return -ENODEV;
> + }
> +
> buf = kcalloc(SSB_SPROMSIZE_WORDS_R123, sizeof(u16), GFP_KERNEL);
> if (!buf)
> goto out;
> diff --git a/drivers/ssb/sprom.c b/drivers/ssb/sprom.c
> index d0e6762..fbaa68c 100644
> --- a/drivers/ssb/sprom.c
> +++ b/drivers/ssb/sprom.c
> @@ -175,3 +175,33 @@ const struct ssb_sprom *ssb_get_fallback_sprom(void)
> {
> return fallback_sprom;
> }
> +
> +bool ssb_is_sprom_available(struct ssb_bus *bus)
> +{
> + if (bus->bustype == SSB_BUSTYPE_PCI) {
> + if (bus->chipco.dev->id.revision >= 31)
> + return bus->chipco.capabilities & SSB_CHIPCO_CAP_SPROM;
> + } else if (bus->bustype == SSB_BUSTYPE_PCMCIA) {
> + /* status register only exists on chipcomon rev >= 11 */
> + if (bus->chipco.dev->id.revision < 11)
> + return true;
> +
I works as is, but seeing the above if caused me to revise the specs a
little. The test for chip common revision < 11 should be first.
Larry
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