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usb: dwc3: gadget: Refactor preparing extra TRB
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When the driver prepares the extra TRB, it uses bounce buffer. If we
just add a new parameter to dwc3_prepare_one_trb() to indicate this,
then we can refactor and simplify the driver quite a bit.
dwc3_prepare_one_trb() also checks if a request had been moved to the
started list. This is a prerequisite to subsequence patches improving
the handling of extra TRBs.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
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Thinh Nguyen authored and Felipe Balbi committed Oct 2, 2020
1 parent 690e5c2 commit 2b80357
Showing 1 changed file with 25 additions and 68 deletions.
93 changes: 25 additions & 68 deletions drivers/usb/dwc3/gadget.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1060,10 +1060,11 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb,
* @trb_length: buffer size of the TRB
* @chain: should this TRB be chained to the next?
* @node: only for isochronous endpoints. First TRB needs different type.
* @use_bounce_buffer: set to use bounce buffer
*/
static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
struct dwc3_request *req, unsigned int trb_length,
unsigned int chain, unsigned int node)
unsigned int chain, unsigned int node, bool use_bounce_buffer)
{
struct dwc3_trb *trb;
dma_addr_t dma;
Expand All @@ -1072,7 +1073,9 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
unsigned int no_interrupt = req->request.no_interrupt;
unsigned int is_last = req->request.is_last;

if (req->request.num_sgs > 0)
if (use_bounce_buffer)
dma = dep->dwc->bounce_addr;
else if (req->request.num_sgs > 0)
dma = sg_dma_address(req->start_sg);
else
dma = req->request.dma;
Expand Down Expand Up @@ -1129,56 +1132,35 @@ static void dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
chain = false;

if (rem && usb_endpoint_dir_out(dep->endpoint.desc) && !chain) {
struct dwc3 *dwc = dep->dwc;
struct dwc3_trb *trb;

req->needs_extra_trb = true;

/* prepare normal TRB */
dwc3_prepare_one_trb(dep, req, trb_length, true, i);
dwc3_prepare_one_trb(dep, req, trb_length,
true, i, false);

/* Now prepare one extra TRB to align transfer size */
trb = &dep->trb_pool[dep->trb_enqueue];
req->num_trbs++;
__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr,
maxp - rem, false, 1,
req->request.stream_id,
req->request.short_not_ok,
req->request.no_interrupt,
req->request.is_last);
dwc3_prepare_one_trb(dep, req, maxp - rem,
false, 1, true);
} else if (req->request.zero && req->request.length &&
!usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
!rem && !chain) {
struct dwc3 *dwc = dep->dwc;
struct dwc3_trb *trb;

req->needs_extra_trb = true;

/* Prepare normal TRB */
dwc3_prepare_one_trb(dep, req, trb_length, true, i);
dwc3_prepare_one_trb(dep, req, trb_length,
true, i, false);

/* Prepare one extra TRB to handle ZLP */
trb = &dep->trb_pool[dep->trb_enqueue];
req->num_trbs++;
__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, 0,
!req->direction, 1,
req->request.stream_id,
req->request.short_not_ok,
req->request.no_interrupt,
req->request.is_last);
dwc3_prepare_one_trb(dep, req, 0,
!req->direction, 1, true);

/* Prepare one more TRB to handle MPS alignment */
if (!req->direction) {
trb = &dep->trb_pool[dep->trb_enqueue];
req->num_trbs++;
__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, maxp,
false, 1, req->request.stream_id,
req->request.short_not_ok,
req->request.no_interrupt,
req->request.is_last);
}
if (!req->direction)
dwc3_prepare_one_trb(dep, req, maxp,
false, 1, true);
} else {
dwc3_prepare_one_trb(dep, req, trb_length, chain, i);
dwc3_prepare_one_trb(dep, req, trb_length,
chain, i, false);
}

/*
Expand Down Expand Up @@ -1216,54 +1198,29 @@ static void dwc3_prepare_one_trb_linear(struct dwc3_ep *dep,
unsigned int rem = length % maxp;

if ((!length || rem) && usb_endpoint_dir_out(dep->endpoint.desc)) {
struct dwc3 *dwc = dep->dwc;
struct dwc3_trb *trb;

req->needs_extra_trb = true;

/* prepare normal TRB */
dwc3_prepare_one_trb(dep, req, length, true, 0);
dwc3_prepare_one_trb(dep, req, length, true, 0, false);

/* Now prepare one extra TRB to align transfer size */
trb = &dep->trb_pool[dep->trb_enqueue];
req->num_trbs++;
__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, maxp - rem,
false, 1, req->request.stream_id,
req->request.short_not_ok,
req->request.no_interrupt,
req->request.is_last);
dwc3_prepare_one_trb(dep, req, maxp - rem, false, 1, true);
} else if (req->request.zero && req->request.length &&
!usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
(IS_ALIGNED(req->request.length, maxp))) {
struct dwc3 *dwc = dep->dwc;
struct dwc3_trb *trb;

req->needs_extra_trb = true;

/* prepare normal TRB */
dwc3_prepare_one_trb(dep, req, length, true, 0);
dwc3_prepare_one_trb(dep, req, length, true, 0, false);

/* Prepare one extra TRB to handle ZLP */
trb = &dep->trb_pool[dep->trb_enqueue];
req->num_trbs++;
__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, 0,
!req->direction, 1, req->request.stream_id,
req->request.short_not_ok,
req->request.no_interrupt,
req->request.is_last);
dwc3_prepare_one_trb(dep, req, 0, !req->direction, 1, true);

/* Prepare one more TRB to handle MPS alignment for OUT */
if (!req->direction) {
trb = &dep->trb_pool[dep->trb_enqueue];
req->num_trbs++;
__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, maxp,
false, 1, req->request.stream_id,
req->request.short_not_ok,
req->request.no_interrupt,
req->request.is_last);
}
if (!req->direction)
dwc3_prepare_one_trb(dep, req, maxp, false, 1, true);
} else {
dwc3_prepare_one_trb(dep, req, length, false, 0);
dwc3_prepare_one_trb(dep, req, length, false, 0, false);
}
}

Expand Down

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