in musb/musb_host.c [1189:1454]
void musb_host_tx(struct musb *musb, u8 epnum)
{
int pipe;
bool done = false;
u16 tx_csr;
size_t length = 0;
size_t offset = 0;
struct musb_hw_ep *hw_ep = musb->endpoints + epnum;
void __iomem *epio = hw_ep->regs;
struct musb_qh *qh = hw_ep->out_qh;
struct urb *urb = next_urb(qh);
u32 status = 0;
void __iomem *mbase = musb->mregs;
struct dma_channel *dma;
bool transfer_pending = false;
musb_ep_select(mbase, epnum);
tx_csr = musb_readw(epio, MUSB_TXCSR);
/* with CPPI, DMA sometimes triggers "extra" irqs */
if (!urb) {
musb_dbg(musb, "extra TX%d ready, csr %04x", epnum, tx_csr);
return;
}
pipe = urb->pipe;
dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
trace_musb_urb_tx(musb, urb);
musb_dbg(musb, "OUT/TX%d end, csr %04x%s", epnum, tx_csr,
dma ? ", dma" : "");
/* check for errors */
if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
/* dma was disabled, fifo flushed */
musb_dbg(musb, "TX end %d stall", epnum);
/* stall; record URB status */
status = -EPIPE;
} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
/* (NON-ISO) dma was disabled, fifo flushed */
musb_dbg(musb, "TX 3strikes on ep=%d", epnum);
status = -ETIMEDOUT;
} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
if (USB_ENDPOINT_XFER_BULK == qh->type && qh->mux == 1
&& !list_is_singular(&musb->out_bulk)) {
musb_dbg(musb, "NAK timeout on TX%d ep", epnum);
musb_bulk_nak_timeout(musb, hw_ep, 0);
} else {
musb_dbg(musb, "TX ep%d device not responding", epnum);
/* NOTE: this code path would be a good place to PAUSE a
* transfer, if there's some other (nonperiodic) tx urb
* that could use this fifo. (dma complicates it...)
* That's already done for bulk RX transfers.
*
* if (bulk && qh->ring.next != &musb->out_bulk), then
* we have a candidate... NAKing is *NOT* an error
*/
musb_ep_select(mbase, epnum);
musb_writew(epio, MUSB_TXCSR,
MUSB_TXCSR_H_WZC_BITS
| MUSB_TXCSR_TXPKTRDY);
}
return;
}
done:
if (status) {
if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
dma->status = MUSB_DMA_STATUS_CORE_ABORT;
musb->dma_controller->channel_abort(dma);
}
/* do the proper sequence to abort the transfer in the
* usb core; the dma engine should already be stopped.
*/
musb_h_tx_flush_fifo(hw_ep);
tx_csr &= ~(MUSB_TXCSR_AUTOSET
| MUSB_TXCSR_DMAENAB
| MUSB_TXCSR_H_ERROR
| MUSB_TXCSR_H_RXSTALL
| MUSB_TXCSR_H_NAKTIMEOUT
);
musb_ep_select(mbase, epnum);
musb_writew(epio, MUSB_TXCSR, tx_csr);
/* REVISIT may need to clear FLUSHFIFO ... */
musb_writew(epio, MUSB_TXCSR, tx_csr);
musb_writeb(epio, MUSB_TXINTERVAL, 0);
done = true;
}
/* second cppi case */
if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
musb_dbg(musb, "extra TX%d ready, csr %04x", epnum, tx_csr);
return;
}
if (is_dma_capable() && dma && !status) {
/*
* DMA has completed. But if we're using DMA mode 1 (multi
* packet DMA), we need a terminal TXPKTRDY interrupt before
* we can consider this transfer completed, lest we trash
* its last packet when writing the next URB's data. So we
* switch back to mode 0 to get that interrupt; we'll come
* back here once it happens.
*/
if (tx_csr & MUSB_TXCSR_DMAMODE) {
/*
* We shouldn't clear DMAMODE with DMAENAB set; so
* clear them in a safe order. That should be OK
* once TXPKTRDY has been set (and I've never seen
* it being 0 at this moment -- DMA interrupt latency
* is significant) but if it hasn't been then we have
* no choice but to stop being polite and ignore the
* programmer's guide... :-)
*
* Note that we must write TXCSR with TXPKTRDY cleared
* in order not to re-trigger the packet send (this bit
* can't be cleared by CPU), and there's another caveat:
* TXPKTRDY may be set shortly and then cleared in the
* double-buffered FIFO mode, so we do an extra TXCSR
* read for debouncing...
*/
tx_csr &= musb_readw(epio, MUSB_TXCSR);
if (tx_csr & MUSB_TXCSR_TXPKTRDY) {
tx_csr &= ~(MUSB_TXCSR_DMAENAB |
MUSB_TXCSR_TXPKTRDY);
musb_writew(epio, MUSB_TXCSR,
tx_csr | MUSB_TXCSR_H_WZC_BITS);
}
tx_csr &= ~(MUSB_TXCSR_DMAMODE |
MUSB_TXCSR_TXPKTRDY);
musb_writew(epio, MUSB_TXCSR,
tx_csr | MUSB_TXCSR_H_WZC_BITS);
/*
* There is no guarantee that we'll get an interrupt
* after clearing DMAMODE as we might have done this
* too late (after TXPKTRDY was cleared by controller).
* Re-read TXCSR as we have spoiled its previous value.
*/
tx_csr = musb_readw(epio, MUSB_TXCSR);
}
/*
* We may get here from a DMA completion or TXPKTRDY interrupt.
* In any case, we must check the FIFO status here and bail out
* only if the FIFO still has data -- that should prevent the
* "missed" TXPKTRDY interrupts and deal with double-buffered
* FIFO mode too...
*/
if (tx_csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY)) {
musb_dbg(musb,
"DMA complete but FIFO not empty, CSR %04x",
tx_csr);
return;
}
}
if (!status || dma || usb_pipeisoc(pipe)) {
if (dma)
length = dma->actual_len;
else
length = qh->segsize;
qh->offset += length;
if (usb_pipeisoc(pipe)) {
struct usb_iso_packet_descriptor *d;
d = urb->iso_frame_desc + qh->iso_idx;
d->actual_length = length;
d->status = status;
if (++qh->iso_idx >= urb->number_of_packets) {
done = true;
} else {
d++;
offset = d->offset;
length = d->length;
}
} else if (dma && urb->transfer_buffer_length == qh->offset) {
done = true;
} else {
/* see if we need to send more data, or ZLP */
if (qh->segsize < qh->maxpacket)
done = true;
else if (qh->offset == urb->transfer_buffer_length
&& !(urb->transfer_flags
& URB_ZERO_PACKET))
done = true;
if (!done) {
offset = qh->offset;
length = urb->transfer_buffer_length - offset;
transfer_pending = true;
}
}
}
/* urb->status != -EINPROGRESS means request has been faulted,
* so we must abort this transfer after cleanup
*/
if (urb->status != -EINPROGRESS) {
done = true;
if (status == 0)
status = urb->status;
}
if (done) {
/* set status */
urb->status = status;
urb->actual_length = qh->offset;
musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
return;
} else if ((usb_pipeisoc(pipe) || transfer_pending) && dma) {
if (musb_tx_dma_program(musb->dma_controller, hw_ep, qh, urb,
offset, length)) {
if (is_cppi_enabled(musb) || tusb_dma_omap(musb))
musb_h_tx_dma_start(hw_ep);
return;
}
} else if (tx_csr & MUSB_TXCSR_DMAENAB) {
musb_dbg(musb, "not complete, but DMA enabled?");
return;
}
/*
* PIO: start next packet in this URB.
*
* REVISIT: some docs say that when hw_ep->tx_double_buffered,
* (and presumably, FIFO is not half-full) we should write *two*
* packets before updating TXCSR; other docs disagree...
*/
if (length > qh->maxpacket)
length = qh->maxpacket;
/* Unmap the buffer so that CPU can use it */
usb_hcd_unmap_urb_for_dma(musb->hcd, urb);
/*
* We need to map sg if the transfer_buffer is
* NULL.
*/
if (!urb->transfer_buffer) {
/* sg_miter_start is already done in musb_ep_program */
if (!sg_miter_next(&qh->sg_miter)) {
dev_err(musb->controller, "error: sg list empty\n");
sg_miter_stop(&qh->sg_miter);
status = -EINVAL;
goto done;
}
length = min_t(u32, length, qh->sg_miter.length);
musb_write_fifo(hw_ep, length, qh->sg_miter.addr);
qh->sg_miter.consumed = length;
sg_miter_stop(&qh->sg_miter);
} else {
musb_write_fifo(hw_ep, length, urb->transfer_buffer + offset);
}
qh->segsize = length;
musb_ep_select(mbase, epnum);
musb_writew(epio, MUSB_TXCSR,
MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
}