While attempting to apply a local patch that implements
receive hardware timestamps (nice for research and intrusion
detection applications) with the syskonnect SK-9843, I
noticed that some 32-bit register operations are broken.
Most of the registers, including XM_MODE and XM_TSTAMP_READ,
must be accessed 16-bits at a time. One step in enabling
timestamps is to set the XM_MODE_TIMESTAMP bit in the XM_MODE
register but it was not possible to access the high bytes
of the register.
I developed my timestamp patch with 4.8-RELEASE using version
188.8.131.52 of if_skreg.h which defines SK_XM_READ_4() and
SK_XM_WRITE_4() macros that use sk_win_read_2() and
sk_win_read_2() to read and write 16 bits at a time, as
required by the hardware.
Version 184.108.40.206 of the include file change the macros to
use sk_win_read_4() and sk_win_write_4() which only return
the low order 16-bits.
This problem probably wasn't detected before now because
the current driver only seems to ever access bits in the
low bytes of the registers (e.g. XM_MODE_RX_PROMISC in
Fix: The appended patch (vs. 220.127.116.11 of if_skreg.h) re-enables
the 2-byte versions if the SK_XM_READ_4() and SK_XM_WRITE_4()
macros. It also protects the SK_XM_WRITE_4() macro.
After booting the new kernel, the debugging printout
shows the complete device id value:
sk0: XM_DEVID 0xe0ae20 (0xe0/0xae20)
It looks like this patch would also apply to the -current
How-To-Repeat: This patch helps demonstrate the problem:
*** if_sk.c.virgin Wed May 3 17:56:30 2006
--- if_sk.c Wed May 3 17:56:37 2006
*** 2532,2537 ****
--- 2532,2540 ----
/* Save the XMAC II revision */
sc_if->sk_xmac_rev = XM_XMAC_REV(SK_XM_READ_4(sc_if, XM_DEVID));
+ printf("sk%d: XM_DEVID 0x%x (0x%x/0x%x)\n",
+ sc_if->sk_unit, SK_XM_READ_4(sc_if, XM_DEVID),
+ SK_XM_READ_2(sc_if, XM_DEVID_HI), SK_XM_READ_2(sc_if, XM_DEVID_LO));
* Perform additional initialization for external PHYs,
After applying the patch and building and booting the kernel,
the driver reports:
skc0: <SysKonnect Gigabit Ethernet (V1.0)> port 0x3000-0x30ff mem 0xdd300000-0xd
d303fff irq 48 at device 1.0 on pci3
skc0: SysKonnect SK-NET Gigabit Ethernet Adapter SK-9843 SX rev. (0x0)
sk0: <XaQti Corp. XMAC II> on skc0
sk0: Ethernet address: 00:00:5a:9a:80:18
sk0: XM_DEVID 0xae20 (0xe0/0xae20)
Notice that SK_XM_READ_4() returned the same value as the
low bytes SK_XM_READ_2() and that the high bytes have 0xe0,
I'll handle this.
XMAC documentation says that NP(node processor) interface supports
both 16bit/32bit modes. Your results shows it uses 16bit mode only.
I don't have SysKonnect SK-NET hardware so it's hard to verify this.
As multicast filter setup uses SK_XM_WRITE_4 macros, I think
multicasting filtering didn't work on your hardware without using
two 16bit accesses.
Would you verify that the hardware really works for multicasting
packet after applying your patch?
Close(feedback timed out).
I double checked XaQti XQ11800FP 1000Mbps Gigabit Ethernet
Controller data sheet and it clearly says NP supports both 16bits
and 32bits operation. I also checked Linux and Vendor's driver and
they also used 32bits register access for Genesis controllers. The
only guess I have at this moment is you may have wrong access
pattern to the register. To access 32bits quantity with two 16bits
operation, you may have to access low address first and then high
address. Just accessing high 16bits of a 32bit register would yield
Please check data sheet to see which register supports both 16bits
and 32bits and which register supports 16bits only(pp. 40).