[Bug 203385] [patch] Add support for BCM57765 Card Reader

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=203385

            Bug ID: 203385
           Summary: [patch] Add support for BCM57765 Card Reader
           Product: Base System
           Version: 11.0-CURRENT
          Hardware: Any
                OS: Any
            Status: New
          Keywords: patch
          Severity: Affects Many People
          Priority: ---
         Component: kern
          Assignee: freebsd-bugs at FreeBSD.org
          Reporter: landon at landonf.org
          Keywords: patch

Created attachment 161446
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=161446&action=edit
BCM57765 support patch

This patch adds support for the BCM57765[2] card reader function included in
Broadcom's BCM57766 ethernet/sd3.0 controller. This controller is commonly
found in laptops and Apple hardware (MBP, iMac, etc).

The BCM57765 chipset is almost fully compatible with the SD3.0 spec, but does
not support deriving a frequency below 781KHz from its default base clock via
the standard SD3.0-configured 10-bit clock divisor.

If such a divisor is set, card identification (which requires a 400KHz clock
frequency) will time out[1].

As a work-around, I've made use of an undocumented device-specific clock
control register to switch the controller to a 63MHz clock source when
targeting clock speeds below 781KHz; the clock source is likewise switched back
to the 200MHz clock when targeting speeds greater than 781KHz.

Additionally, this patch fixes a small sdhci_pci bug; the
sdhci_pci_softc->quirks flag was not copied to the sdhci_slot, resulting in
`quirk` behavior not being applied by sdhci.c.

[1] A number of Linux/FreeBSD users have noted that bringing up the chipsets'
associated ethernet interface will allow SD cards to enumerate (slowly). This
is a controller implementation side-effect triggered by the ethernet driver's
reading of the hardware statistics registers.

[2] This may also fix card detection when using the BCM57785 chipset, but I
don't have access to the BCM57785 chipset and can't verify.

-- 
You are receiving this mail because:
You are the assignee for the bug.