Notes on ssb specs and implementation
Rafał Miłecki
zajec5 at gmail.com
Wed Feb 9 15:00:04 EST 2011
Hi,
I've N-PHY card that doesn't report any scan results, so after
checking N-PHY code (it looks fine so far) I decided to dig into ssb.
Hopefully this will lead to some fixes and maybe working card.
I've dumped MMIO operations performed by wl and ssb/b43, compared
them, documented with parts from specs and noted differences.
As you should know, we have to enable wireless core twice: first time
to get basic information about hardware, second to configure it in
correct (like PHY specific) way.
ssb_device_enable_1 is for first reset
ssb_device_enable_2 is for second reset
Notes from ssb_device_enable_1:
1) There are few undocumented flushes performed by both drivers. Could
be nice to document it in specs
2) wl does not reset PHY (no B43_TMSLOW_PHYRESET and no taking it out
of reset after enabling wireless core)
3) After reset (last step in ssb_device_enable) wl doesn't leave core
specific flags
Notes from ssb_device_enable_2:
1) ssb does not implement fast disable in case clocks are not enabled
2) ssb uses different Reject bit than wl
3) ssb doesn't check for "If the Core ID Low register has the
"Initiator" bit set"
4) wl checks for "Busy" bit in IM STATE, not TM as documented in specs
5) when writing "Force Gated Clocks On", "Clock Enable", and "Reset"
both drivers keep Reject set, however specs don't mention that
6) wl checks "If the "Initiator" bit in TM State Low is set" using ff8
register which is Core ID Low, not TMSLOW
7) rest differences are duplicated from ssb_device_enable_1
Larry: could you care for specs notes I collected?
Michael: was there any reasons why we didn't implement some parts of
core-disabling code?
Michael: should we care about the way wl sets core specific flags? I
didn't dig into that moment in MMIO dumps, but as ssb_device_enable
implementation ignores flags at the end, it has to set flags somehow
differently on it's own.
--
Rafał
-------------- next part --------------
wl:
>>> ssb_device_enable start
>>> ssb_device_disable start Disable the Core to account for a core in a random state
ssb_read32(0xf98) -> 0x00000003 If the core is already in reset (the "Reset" bit in TM State Low is set) it's already disabled, return
ssb_read32(0xf98) -> 0x00000003 If the core is already in reset (the "Reset" bit in TM State Low is set) it's already disabled, return
>>> ssb_device_disable end
ssb_write32(0xf98) <- 0x00070001 (specific==B43_TMSLOW_PHYCLKEN) Write the "Force Gated Clocks On", "Clock Enable",and "Reset" bits along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x00070001 Perform a dummy read on the TM State Low register
ssb_read32(0xf9c) -> 0x100c0000 If the S Error bit is set in the TM State High register
ssb_read32(0xf90) -> 0x00000020 Unset the "In Band Error" or "Timeout" bits if the IM State register has them set
ssb_write32(0xf98) <- 0x00070000 (specific==B43_TMSLOW_PHYCLKEN) Write the "Force Gated Clocks On", "Clock Enable" bits, along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x00070000 Perform a dummy read on the TM State Low register
ssb_write32(0xf98) <- 0x00010000 (Why no B43_TMSLOW_PHYCLKEN?) Write the "Clock Enable" bit along with any device specific flags requested to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x00010000 Undocumented flush
>>> ssb_device_enable end
-------------- next part --------------
b43/ssb:
>>> ssb_device_enable start
>>> ssb_device_disable start Disable the Core to account for a core in a random state
ssb_read32(0xf98) -> 0x00000001 If the core is already in reset (the "Reset" bit in TM State Low is set) it's already disabled, return
>>> ssb_device_disable end
ssb_write32(0xf98) <- 0x000f0001 (specific==B43_TMSLOW_PHYCLKEN | B43_TMSLOW_PHYRESET) Write the "Force Gated Clocks On", "Clock Enable",and "Reset" bits along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x000f0001 Perform a dummy read on the TM State Low register
ssb_read32(0xf9c) -> 0x10080000 If the S Error bit is set in the TM State High register
ssb_read32(0xf90) -> 0x00000020 Unset the "In Band Error" or "Timeout" bits if the IM State register has them set
ssb_write32(0xf98) <- 0x000f0000 (specific==B43_TMSLOW_PHYCLKEN | B43_TMSLOW_PHYRESET) Write the "Force Gated Clocks On", "Clock Enable" bits, along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x000f0000 Perform a dummy read on the TM State Low register
ssb_write32(0xf98) <- 0x000d0000 (specific==B43_TMSLOW_PHYCLKEN | B43_TMSLOW_PHYRESET) Write the "Clock Enable" bit along with any device specific flags requested to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x000d0000 Undocumented flush
>>> ssb_device_enable end
ssb_read32(0xf98) -> 0x000d0000 Unset the PHY Reset flag and set the Force Gated Clocks flag in TM State Low Flags
ssb_write32(0xf98) <- 0x00070000 Unset the PHY Reset flag and set the Force Gated Clocks flag in TM State Low Flags
ssb_read32(0xf98) -> 0x00070000 Undocumented flush
ssb_write32(0xf98) <- 0x00050000 Unset the Force Gated Clocks flag in TM State Low Flags
ssb_read32(0xf98) -> 0x00050000 Undocumented flush
-------------- next part --------------
wl:
>>> ssb_device_enable start
>>> ssb_device_disable start Disable the Core to account for a core in a random state
ssb_read32(0xf98) -> 0x00010000 If the core is already in reset (the "Reset" bit in TM State Low is set) it's already disabled, return
ssb_read32(0xf98) -> 0x00010000 If clocks are not yet enabled (the "Clock Enabled" bit in TM State Low
ssb_write32(0xf98) <- 0x00010002 Set the "Reject" bit in TM State Low, which will cause the core to reject further input
ssb_read32(0xf98) -> 0x00010002 Perform a dummy read on the TM State Low register
ssb_read32(0xf9c) -> 0x100c0000 Wait until the "Busy" bit in TM State High is unset (or 100000 uS, checking every 10uSec)
ssb_read32(0xf9c) -> 0x100c0000 Wait until the "Busy" bit in TM State High is unset (or 100000 uS, checking every 10uSec)
read32 0xc0200ff8 -> 0x410422c5 If the Core ID Low register has the "Initiator" bit set
ssb_read32(0xf90) -> 0x00000020 Set the "Reject" bit in the IM State register
ssb_write32(0xf90) <- 0x02000020 Set the "Reject" bit in the IM State register
ssb_read32(0xf90) -> 0x02000020 Perform a dummy read on the IM State register
ssb_read32(0xf90) -> 0x02000020 (TM != IM) Wait until the "Busy" bit in TM State is unset (of 100000 uS, checking every 10uS)
ssb_write32(0xf98) <- 0x00070003 (Reject is written!) (specific==B43_TMSLOW_PHYCLKEN) Write the "Force Gated Clocks On", "Clock Enable", and "Reset" bits along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x00070003 Perform a dummy read on the TM State Low register
read32 0xc0200ff8 -> 0x410422c5 (Core ID != TMSLOW) If the "Initiator" bit in TM State Low is set
ssb_read32(0xf90) -> 0x02000020 Clear the "Reject" bit in the IM State register
ssb_write32(0xf90) <- 0x00000020 Clear the "Reject" bit in the IM State register
ssb_write32(0xf98) <- 0x00040003 (specific==B43_TMSLOW_PHYCLKEN) Write the "Reset" and "Reject" bits along with any device specific flags requested to the TM State Low register
>>> ssb_device_disable end
ssb_write32(0xf98) <- 0x00070001 (specific==B43_TMSLOW_PHYCLKEN) Write the "Force Gated Clocks On", "Clock Enable",and "Reset" bits along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x00070001 Perform a dummy read on the TM State Low register
ssb_read32(0xf9c) -> 0x100c0000 If the S Error bit is set in the TM State High register
ssb_read32(0xf90) -> 0x00000020 Unset the "In Band Error" or "Timeout" bits if the IM State register has them set
ssb_write32(0xf98) <- 0x00070000 (specific==B43_TMSLOW_PHYCLKEN) Write the "Force Gated Clocks On", "Clock Enable" bits, along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x00070000 Perform a dummy read on the TM State Low register
ssb_write32(0xf98) <- 0x00010000 (Why no B43_TMSLOW_PHYCLKEN?) Write the "Clock Enable" bit along with any device specific flags requested to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x00010000 Undocumented flush
>>> ssb_device_enable end
-------------- next part --------------
b43/ssb:
>>> ssb_device_enable start
>>> ssb_device_disable start Disable the Core to account for a core in a random state
ssb_read32(0xf98) -> 0x00050000 If the core is already in reset (the "Reset" bit in TM State Low is set) it's already disabled, return
If clocks are not yet enabled (the "Clock Enabled" bit in TM State Low
Write the "Reset" and "Reject" bits along with any device specific flags requested to the TM State Low, wait 1uS, register and return
read32 0xc0200ff8 -> 0x410422c5 ssb_tmslow_reject_bitmask
ssb_write32(0xf98) <- 0x00010004 Set the "Reject" bit in TM State Low, which will cause the core to reject further input
ssb_read32(0xf98) -> 0x00010004 Perform a dummy read on the TM State Low register
ssb_read32(0xf9c) -> 0x10080000 Wait until the "Busy" bit in TM State High is unset (or 100000 uS, checking every 10uSec)
? If the Core ID Low register has the "Initiator" bit set
ssb_write32(0xf98) <- 0x204f0005 Write the "Force Gated Clocks On", "Clock Enable", and "Reset" bits along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x204f0005 Perform a dummy read on the TM State Low register
? If the "Initiator" bit in TM State Low is set
? Clear the "Reject" bit in the IM State register
ssb_write32(0xf98) <- 0x204c0005 Write the "Reset" and "Reject" bits along with any device specific flags requested to the TM State Low register
ssb_read32(0xf98) -> 0x204c0005 Undocumented flush
>>> ssb_device_disable end
ssb_write32(0xf98) <- 0x204f0001 (specific==B43_TMSLOW_PHYCLKEN | B43_TMSLOW_PHYRESET | B43_TMSLOW_GMODE | B43_TMSLOW_PHY_BANDWIDTH_20MHZ) Write the "Force Gated Clocks On", "Clock Enable",and "Reset" bits along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x204f0001 Perform a dummy read on the TM State Low register
ssb_read32(0xf9c) -> 0x10080000 If the S Error bit is set in the TM State High register
ssb_read32(0xf90) -> 0x00000020 Unset the "In Band Error" or "Timeout" bits if the IM State register has them set
ssb_write32(0xf98) <- 0x204f0000 (specific==B43_TMSLOW_PHYCLKEN | B43_TMSLOW_PHYRESET | B43_TMSLOW_GMODE | B43_TMSLOW_PHY_BANDWIDTH_20MHZ) Write the "Force Gated Clocks On", "Clock Enable" bits, along with any device specific flags requested, to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x204f0000 Perform a dummy read on the TM State Low register
ssb_write32(0xf98) <- 0x204d0000 (specific==B43_TMSLOW_PHYCLKEN | B43_TMSLOW_PHYRESET | B43_TMSLOW_GMODE | B43_TMSLOW_PHY_BANDWIDTH_20MHZ) Write the "Clock Enable" bit along with any device specific flags requested to the TM State Low register (unset the rest)
ssb_read32(0xf98) -> 0x204d0000 Undocumented flush
>>> ssb_device_enable end
ssb_read32(0xf98) -> 0x204d0000 Unset the PHY Reset flag and set the Force Gated Clocks flag in TM State Low Flags
ssb_write32(0xf98) <- 0x20470000 Unset the PHY Reset flag and set the Force Gated Clocks flag in TM State Low Flags
ssb_read32(0xf98) -> 0x20470000 Undocumented flush
ssb_write32(0xf98) <- 0x20450000 Unset the Force Gated Clocks flag in TM State Low Flags
ssb_read32(0xf98) -> 0x20450000 Undocumented flush
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