* David Brownell <[EMAIL PROTECTED]> [2005-11-28 10:16]:
> Your original patch had TD-level hooks:
>
> > > +struct td_ops {
> > > + void (*fill)(struct ohci_hcd *ohci, u32 info, dma_addr_t data,
> > > + int len, struct urb *urb, int index);
> > > + void (*done)(struct ohci_hcd *ohci, struct urb *urb, struct td *td);
> > > +};
>
> If fill() could return fault codes, and you added some solution
> for allocating TDs without using the DMA pools, those hooks
I've added dma_pool_* hooks to allocate from a custom DMA pool.
They're in the attached, updated patch.
> might almost suffice: return ENOMEM if TD+buffer alloc+fill
> fails, and then done() would free the TD and its buffer.
Currently, td_submit_urb() has no error path for td_fill(), and
adding one would get messy quickly. Instead, I allocate
necessary kernel memory in submit_urb(), and td_fill() queues the
TDs until DMA memory is available. Other than that, they work
like you said.
> > I want to implement URB queueing
>
> When you get into that territory, I'm thinking that maybe you
> should plan on forking the OHCI code. ... Trying to make the
> OHCI driver handle DMA normally _and_ do that other stuff for
> your PIO-ish hardware would create a mess that's hard to
> maintain.
If you're okay with the td_fill() and td_done() hooks, they're
all I need.
> One issue would be resource reservation for periodic transfers.
> Right now the bus bandwidth is reserved, no buffer memory.
> It'd be possible for the resubmit to fail because its buffer
> was reused.
Yes, I'm running into that problem in testing. Right now, I'm
enqueuing TDs in the order they're submitted with td_fill().
With the default max_sectors=240, disk activity can tie up the
dma buffers for 125ms. I think the prism2_usb driver is timing
out before its URB is enqueued with the HC.
As a fix, I can prioritize TDs by endpoint and give bulk EPs a
low priority. How does this sound, or do you have a better idea?
Thanks,
Chris Humbert
Index: linux-2.6.15-rc2/drivers/usb/host/ohci.h
===================================================================
--- linux-2.6.15-rc2.orig/drivers/usb/host/ohci.h
+++ linux-2.6.15-rc2/drivers/usb/host/ohci.h
@@ -336,6 +336,23 @@ typedef struct urb_priv {
// sizeof (struct td) ~= 64 == 2^6 ...
#define TD_HASH_FUNC(td_dma) ((td_dma ^ (td_dma >> 6)) % TD_HASH_SIZE)
+struct ohci_hcd;
+
+/*
+ * Hooks to support controllers that must resort to a PIO-ish
+ * implementation because they only dma with on-chip memory.
+ */
+struct ohci_ops {
+ void* (*dma_pool_alloc) (struct dma_pool *pool, gfp_t mem_flags,
+ dma_addr_t *handle);
+ void (*dma_pool_free) (struct dma_pool *pool, void *vaddr,
+ dma_addr_t addr);
+
+ void (*td_fill) (struct ohci_hcd *ohci, u32 info, dma_addr_t data,
+ int len, struct urb *urb, int index);
+ void (*td_done) (struct ohci_hcd *ohci, struct urb *urb,
+ struct td *td);
+};
/*
* This is the full ohci controller description
@@ -346,6 +363,7 @@ typedef struct urb_priv {
struct ohci_hcd {
spinlock_t lock;
+ const struct ohci_ops *ops;
/*
* I/O memory used to communicate with the HC (dma-consistent)
Index: linux-2.6.15-rc2/drivers/usb/host/ohci-mem.c
===================================================================
--- linux-2.6.15-rc2.orig/drivers/usb/host/ohci-mem.c
+++ linux-2.6.15-rc2/drivers/usb/host/ohci-mem.c
@@ -21,10 +21,13 @@
* No memory seen by this driver is pagable.
*/
+static const struct ohci_ops ohci_ops;
+
/*-------------------------------------------------------------------------*/
static void ohci_hcd_init (struct ohci_hcd *ohci)
{
+ ohci->ops = &ohci_ops;
ohci->next_statechange = jiffies;
spin_lock_init (&ohci->lock);
INIT_LIST_HEAD (&ohci->pending);
@@ -88,7 +91,7 @@ td_alloc (struct ohci_hcd *hc, gfp_t mem
dma_addr_t dma;
struct td *td;
- td = dma_pool_alloc (hc->td_cache, mem_flags, &dma);
+ td = hc->ops->dma_pool_alloc (hc->td_cache, mem_flags, &dma);
if (td) {
/* in case hc fetches it, make it look dead */
memset (td, 0, sizeof *td);
@@ -110,7 +113,7 @@ td_free (struct ohci_hcd *hc, struct td
*prev = td->td_hash;
else if ((td->hwINFO & cpu_to_hc32(hc, TD_DONE)) != 0)
ohci_dbg (hc, "no hash for td %p\n", td);
- dma_pool_free (hc->td_cache, td, td->td_dma);
+ hc->ops->dma_pool_free (hc->td_cache, td, td->td_dma);
}
/*-------------------------------------------------------------------------*/
@@ -122,7 +125,7 @@ ed_alloc (struct ohci_hcd *hc, gfp_t mem
dma_addr_t dma;
struct ed *ed;
- ed = dma_pool_alloc (hc->ed_cache, mem_flags, &dma);
+ ed = hc->ops->dma_pool_alloc (hc->ed_cache, mem_flags, &dma);
if (ed) {
memset (ed, 0, sizeof (*ed));
INIT_LIST_HEAD (&ed->td_list);
@@ -134,6 +137,6 @@ ed_alloc (struct ohci_hcd *hc, gfp_t mem
static void
ed_free (struct ohci_hcd *hc, struct ed *ed)
{
- dma_pool_free (hc->ed_cache, ed, ed->dma);
+ hc->ops->dma_pool_free (hc->ed_cache, ed, ed->dma);
}
Index: linux-2.6.15-rc2/drivers/usb/host/ohci-q.c
===================================================================
--- linux-2.6.15-rc2.orig/drivers/usb/host/ohci-q.c
+++ linux-2.6.15-rc2/drivers/usb/host/ohci-q.c
@@ -629,7 +629,7 @@ static void td_submit_urb (
: TD_T_TOGGLE | TD_CC | TD_DP_IN;
/* TDs _could_ transfer up to 8K each */
while (data_len > 4096) {
- td_fill (ohci, info, data, 4096, urb, cnt);
+ ohci->ops->td_fill (ohci, info, data, 4096, urb, cnt);
data += 4096;
data_len -= 4096;
cnt++;
@@ -637,11 +637,11 @@ static void td_submit_urb (
/* maybe avoid ED halt on final TD short read */
if (!(urb->transfer_flags & URB_SHORT_NOT_OK))
info |= TD_R;
- td_fill (ohci, info, data, data_len, urb, cnt);
+ ohci->ops->td_fill (ohci, info, data, data_len, urb, cnt);
cnt++;
if ((urb->transfer_flags & URB_ZERO_PACKET)
&& cnt < urb_priv->length) {
- td_fill (ohci, info, 0, 0, urb, cnt);
+ ohci->ops->td_fill (ohci, info, 0, 0, urb, cnt);
cnt++;
}
/* maybe kickstart bulk list */
@@ -656,17 +656,18 @@ static void td_submit_urb (
*/
case PIPE_CONTROL:
info = TD_CC | TD_DP_SETUP | TD_T_DATA0;
- td_fill (ohci, info, urb->setup_dma, 8, urb, cnt++);
+ ohci->ops->td_fill (ohci, info, urb->setup_dma, 8, urb, cnt++);
if (data_len > 0) {
info = TD_CC | TD_R | TD_T_DATA1;
info |= is_out ? TD_DP_OUT : TD_DP_IN;
/* NOTE: mishandles transfers >8K, some >4K */
- td_fill (ohci, info, data, data_len, urb, cnt++);
+ ohci->ops->td_fill (ohci, info, data, data_len,
+ urb, cnt++);
}
info = (is_out || data_len == 0)
? TD_CC | TD_DP_IN | TD_T_DATA1
: TD_CC | TD_DP_OUT | TD_T_DATA1;
- td_fill (ohci, info, data, 0, urb, cnt++);
+ ohci->ops->td_fill (ohci, info, data, 0, urb, cnt++);
/* maybe kickstart control list */
wmb ();
ohci_writel (ohci, OHCI_CLF, &ohci->regs->cmdstatus);
@@ -685,7 +686,7 @@ static void td_submit_urb (
// a 2^16 iso range, vs other HCs max of 2^10)
frame += cnt * urb->interval;
frame &= 0xffff;
- td_fill (ohci, TD_CC | TD_ISO | frame,
+ ohci->ops->td_fill (ohci, TD_CC | TD_ISO | frame,
data + urb->iso_frame_desc [cnt].offset,
urb->iso_frame_desc [cnt].length, urb, cnt);
}
@@ -788,6 +789,14 @@ static void td_done (struct ohci_hcd *oh
}
}
+/* default operations for most HCs */
+static const struct ohci_ops ohci_ops = {
+ .dma_pool_alloc = dma_pool_alloc,
+ .dma_pool_free = dma_pool_free,
+ .td_fill = td_fill,
+ .td_done = td_done,
+};
+
/*-------------------------------------------------------------------------*/
static inline struct td *
@@ -984,7 +993,7 @@ rescan_this:
*prev = td->hwNextTD | savebits;
/* HC may have partly processed this TD */
- td_done (ohci, urb, td);
+ ohci->ops->td_done (ohci, urb, td);
urb_priv->td_cnt++;
/* if URB is done, clean up */
@@ -1079,7 +1088,7 @@ dl_done_list (struct ohci_hcd *ohci, str
struct ed *ed = td->ed;
/* update URB's length and status from TD */
- td_done (ohci, urb, td);
+ ohci->ops->td_done (ohci, urb, td);
urb_priv->td_cnt++;
/* If all this urb's TDs are done, call complete() */
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