Re: [PATCH 3/3] Import fw-sbp2 driver.

[Kristian Høgsberg <krh@redhat.com>]

Jeff Garzik wrote:

Again, thanks for your comments, I've added patches to my git repo, will send 
out a new set on LKML before the end of this week.

> > +/* I don't know why the SCSI stack doesn't define something like 
> > this... */
> > +typedef void (*scsi_done_fn_t) (struct scsi_cmnd *);
>
> submit a patch?

Hehe, yeah, that might work.

> > +struct sbp2_status {
> > +    unsigned int orb_high:16;
>
> unsigned short?  probably generates better code than a bitfield:16

This and all other bit fields are now just u32s that I access by shifting and 
masking.

> > +struct sbp2_login_response {
> > +    u16 login_id;
> > +    u16 length;
> > +    u32 command_block_agent_high;
> > +    u32 command_block_agent_low;
> > +    u32 reconnect_hold;
> > +};
>
> __le16 and __le32?

This struct is filled in using fw_memcpy_from_be32() to copy and byteswap the 
incoming payload, so the fields here are always cpu endian.  The two u16 
fields assume little endian ordering though, I fixed that.

> > +sbp2_send_management_orb(struct fw_unit *unit, int node_id, int 
> > generation,
> > +             int function, int lun, void *response)
> > +{
> > +    struct fw_device *device = fw_device(unit->device.parent);
> > +    struct sbp2_device *sd = unit->device.driver_data;
> > +    struct sbp2_management_orb *orb;
> > +    unsigned long timeout;
> > +    int retval = -EIO;
> > +
> > +    orb = kzalloc(sizeof *orb, GFP_ATOMIC);
> > +    if (orb == NULL)
> > +        return -ENOMEM;
> > +
> > +    /* The sbp2 device is going to send a block read request to
> > +     * read out the request from host memory, so map it for
> > +     * dma. */
> > +    orb->base.request_bus =
> > +        dma_map_single(device->card->device, &orb->request,
> > +                   sizeof orb->request, DMA_TO_DEVICE);
> > +
> > +    orb->response_bus =
> > +        dma_map_single(device->card->device, &orb->response,
> > +                   sizeof orb->response, DMA_FROM_DEVICE);
>
> check for DMA mapping error

Oops, fixed.

> > +    if (sd->workarounds)
> > +        fw_notify("Workarounds for node %s: 0x%x "
> > +              "(firmware_revision 0x%06x, model_id 0x%06x)\n",
> > +              unit->device.bus_id,
> > +              sd->workarounds, firmware_revision, model);
> > +
> > +    /* FIXME: Make this work for multi-lun devices. */
> > +    lun = 0;
>
> doesn't allowing the stack to issue REPORT LUNS take care of this?

Possibly, I don't have firewire multi-LUN devices to test with here.  The LUNs 
are also discoverable from the firewire config rom, which is why I put the 
comment there.  This doesn't mean that the SCSI commands for discovering LUNs 
doesn't also work.

> > +/* SCSI stack integration */
> > +
> > +static int sbp2_scsi_queuecommand(struct scsi_cmnd *cmd, 
> > scsi_done_fn_t done)
> > +{
> > +    if (cmd->cmnd[0] == REQUEST_SENSE) {
> > +        fw_notify("request_sense");
> > +        memcpy(cmd->request_buffer, cmd->sense_buffer, 
> > cmd->request_bufflen);
> > +        memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
> > +        cmd->result = DID_OK << 16;
> > +        done(cmd);
> > +        return 0;
> > +    }
>
> this is a broken emulation.  this command is specified to not repeatedly 
> return the same sense data.

I copied it over from the old stack under the assumption that it fixed 
something for some device.  I took it out and tested with the 10 or so storage 
devices I have here and it makes no difference.  I've never seen the 
fw_notify() that I put in there trigger.  I'm taking out this workaround for 
now, unless someone can tell me why it should stay there.

Kristian
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