Patches for 3c59x and vortex-diag

Note: The Scyld driver has VLAN support since 2002.

This patch adds support for variable MTU and VLAN to the 3c59x driver for kernel 2.4.18 (version LK 1.1.16). The patched driver can be downloaded here. Some remarks:

• VLAN support is enabled through a module option called vlan. So far there is no support for enabling/disabling it at run-time. Setting it to a positive number will enable VLAN support, while setting it to zero or a negative number (as well as not setting it at all) disables VLAN support. Example:
  

  	insmod 3c59x vlan=1		# enables VLAN support
  

  A routine to enable/disable VLAN at run-time should set vp->vlan then call the run-time MTU changing function.
• There is no support so far for changing MTU at run-time - this involves deallocating the whole Rx ring and allocating a new one with the new Rx packet size. The current version of the patch tries to test the functional support; if/when it will be proven to work OK, I will add run-time support. Until then a larger MTU can be set in the driver source (followed by recompilation) or by deleting the line
  

  	dev->mtu = mtu;
  

  from vortex_probe1() and let the upper levels take care of it. A routine to change MTU at run-time should call vortex_set_MacControl() then vortex_set_MaxPktSize() (see below) after setting dev->mtu.
• The support offered for large frames and VLAN is different among the chipsets that this driver supports:
  
  1. Boomerang (and probably ealier ones): there is only a bit which enables receving frames for up to FDDI size (4500 bytes). Any check for oversized frames and/or VLAN tagging has to be done in software.
  2. Cyclone: adds a MaxPktSize register which defines when the frames are to be flagged as oversized. Checking for VLAN tagging still has to be done in software (to differentiate between a n bytes VLAN frame and n+4 bytes non-VLAN frame).
  3. Tornado: adds a vlanOversizeEn bit to the MacControl register which if set allows packets with VLAN tagging to be 4 bytes larger than the MaxPktSize value before flagging the packet as oversized. No software checking for VLAN tagging is needed.
• For chipsets that support it (Cyclone and Tornado), the recognition of VLAN frames (magic 0x8100) is set unconditionally. I can't think of any side-effect...
• A new inline function called vortex_set_MacControl was introduced to be used everytime modifications to the MacControl register are required. My feeling is that every modification of this register should be done by reading the existing value, masking some bits and writting back; however, I preferred to just leave the existing form in the driver. For the replacement in vortex_up(), the dependence on vp->info1 (which keeps full duplex) info was removed; this dependence is taken care of earlier in the driver. The caller must switch to Window 3 before calling this function.
• A new inline function called vortex_set_MaxPktSize was introduced to set the MaxPktSize register for chipsets that support it (Cyclone and Tornado). The function contains a test for chipset type (the hardware VLAN support is different), so that it's safe to call it for all types of chipsets. It has to be called after each RxReset command, as the register is reset based on the allowLargePackets bit from the MacControl register. The caller must switch to Window 3 before calling this function.
• A pointer to net_device is added to vortex_private structure. I need to access dev->mtu...
• For Boomerang and earlier chipsets, some Tx related thresholds have to be set based on the packet size. Although I don't really like it, I did it by replacing PKT_BUF_SZ with vp->rx_buf_sz. Even more, these chipsets have a variable Rx/Tx FIFO size - what if the packet size specified by a larger MTU does not fit in?

Note: Setting the default media is available in recent versions (starting sometimes in 2002) of the original vortex-diag from Scyld.

This patch adds support to vortex-diag 2.05 for enabling/disabling the Boot PROM and setting a default media. The values used to rewrite the EEPROM have been obtained from the documentation as well as from watching what modifications are done by 3Com's DOS based 3c90xcfg.exe tool.

WARNING: By modifying the EEPROM, the card can be brought in a state where it is not able to start its operation properly. Because of this, vortex-diag does not write EEPROM by default, instead it shows what are the differences between the new and the old (already existent) content. To force vortex-diag to write the new values, the -w command line option has to be used.

Boot PROM (on cards that contain it - usually name ending in "M" from Manageable) may contain executable code (like PXE) to enable booting over network. If this feature is present, during the boot process connection to a network needs to be present; if one is not present or no suitable server (DHCP and PXE for example) is found, the booting process is slowed down while waiting for a timeout after which either the booting process continues from other boot devices (like disks) or it is restarted, effectively creating a loop. Using this patch, the Boot PROM can be disabled or enabled at will.

	Usage:

	vortex-diag -P 0 -w		# to disable the Boot PROM

	vortex-diag -P 1 -w		# to enable the Boot PROM

Default media is the media type (Autonegotiate/NWAY or a combination of speed - 10 or 100 MBit/s - and duplex - half or full) that is used when the card finishes the reset sequence; when the driver starts, it can use this media type or choose another one. When no module options are specified, the Linux driver honours this default media.
This patch contains however only the core code but not the user interface as that raised some problems that I didn't know how to solve: the *-diag family shares code and command line options and I didn't want to have vortex-diag diverge from the others (and probably Don wouldn't have liked it anyway 8-)).
The patch operates based on several variables that have to be set by the user interface code:

• set_ee_media - if non-zero, changing default media was requested
• set_ee_media_auto - if equal to 1, Autonegotiate/NWAY was requested
• set_ee_media_speed - if set to 100, 100baseTx was requested, otherwise 10baseT was requested
• set_ee_media_duplex - if equal to 1, full-duplex was requested, otherwise half-duplex was requested