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usb: dwc3: gadget: Refactor preparing last TRBs
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There are a lot of common codes for preparing SG and linear TRBs.
Refactor them for easier read.

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 30892cb commit cb1b399
Showing 1 changed file with 48 additions and 81 deletions.
129 changes: 48 additions & 81 deletions drivers/usb/dwc3/gadget.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1094,15 +1094,54 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
stream_id, short_not_ok, no_interrupt, is_last);
}

/**
* dwc3_prepare_last_sg - prepare TRBs for the last SG entry
* @dep: The endpoint that the request belongs to
* @req: The request to prepare
* @entry_length: The last SG entry size
* @node: Indicates whether this is not the first entry (for isoc only)
*
* Return the number of TRBs prepared.
*/
static int dwc3_prepare_last_sg(struct dwc3_ep *dep,
struct dwc3_request *req, unsigned int entry_length,
unsigned int node)
{
unsigned int maxp = usb_endpoint_maxp(dep->endpoint.desc);
unsigned int rem = req->request.length % maxp;
unsigned int num_trbs = 1;

if ((req->request.length && req->request.zero && !rem &&
!usb_endpoint_xfer_isoc(dep->endpoint.desc)) ||
(!req->direction && rem))
num_trbs++;

if (dwc3_calc_trbs_left(dep) < num_trbs)
return 0;

req->needs_extra_trb = num_trbs > 1;

/* Prepare a normal TRB */
if (req->direction || req->request.length)
dwc3_prepare_one_trb(dep, req, entry_length,
req->needs_extra_trb, node, false);

/* Prepare extra TRBs for ZLP and MPS OUT transfer alignment */
if ((!req->direction && !req->request.length) || req->needs_extra_trb)
dwc3_prepare_one_trb(dep, req,
req->direction ? 0 : maxp - rem,
false, 1, true);

return num_trbs;
}

static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
struct dwc3_request *req)
{
struct scatterlist *sg = req->start_sg;
struct scatterlist *s;
int i;
unsigned int length = req->request.length;
unsigned int maxp = usb_endpoint_maxp(dep->endpoint.desc);
unsigned int rem = length % maxp;
unsigned int remaining = req->request.num_mapped_sgs
- req->num_queued_sgs;
unsigned int num_trbs = req->num_trbs;
Expand All @@ -1116,7 +1155,7 @@ static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,

for_each_sg(sg, s, remaining, i) {
unsigned int trb_length;
unsigned int chain = true;
bool last_sg = false;

trb_length = min_t(unsigned int, length, sg_dma_len(s));

Expand All @@ -1130,45 +1169,16 @@ static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
* mapped sg.
*/
if ((i == remaining - 1) || !length)
chain = false;
last_sg = true;

if (!dwc3_calc_trbs_left(dep))
break;

if (rem && usb_endpoint_dir_out(dep->endpoint.desc) && !chain) {
/* prepare normal TRB */
if (req->request.length) {
if (dwc3_calc_trbs_left(dep) < 2)
goto out;

req->needs_extra_trb = true;
dwc3_prepare_one_trb(dep, req, trb_length,
true, i, false);
}

/* Now prepare one extra TRB to align transfer size */
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) {

if (dwc3_calc_trbs_left(dep) < 2)
if (last_sg) {
if (!dwc3_prepare_last_sg(dep, req, trb_length, i))
goto out;

req->needs_extra_trb = true;

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

/* Prepare one extra TRB to handle ZLP */
dwc3_prepare_one_trb(dep, req,
req->direction ? 0 : maxp,
false, 1, true);
} else {
dwc3_prepare_one_trb(dep, req, trb_length,
chain, i, false);
dwc3_prepare_one_trb(dep, req, trb_length, 1, i, false);
}

/*
Expand All @@ -1178,7 +1188,7 @@ static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
* we have free trbs we can continue queuing from where we
* previously stopped
*/
if (chain)
if (!last_sg)
req->start_sg = sg_next(s);

req->num_queued_sgs++;
Expand Down Expand Up @@ -1224,50 +1234,7 @@ static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
static int dwc3_prepare_one_trb_linear(struct dwc3_ep *dep,
struct dwc3_request *req)
{
unsigned int length = req->request.length;
unsigned int maxp = usb_endpoint_maxp(dep->endpoint.desc);
unsigned int rem = length % maxp;
unsigned int num_trbs = req->num_trbs;

if (!dwc3_calc_trbs_left(dep))
goto out;

if ((!length || rem) && usb_endpoint_dir_out(dep->endpoint.desc)) {
/* prepare normal TRB */
if (req->request.length) {
if (dwc3_calc_trbs_left(dep) < 2)
goto out;

req->needs_extra_trb = true;
dwc3_prepare_one_trb(dep, req, length, true, 0, false);
}

/* Now prepare one extra TRB to align transfer size */
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))) {

if (dwc3_calc_trbs_left(dep) < 2)
goto out;

req->needs_extra_trb = true;

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

/* Prepare one extra TRB to handle ZLP */
dwc3_prepare_one_trb(dep, req, req->direction ? 0 : maxp,
false, 1, true);
} else {
if (!dwc3_calc_trbs_left(dep))
goto out;

dwc3_prepare_one_trb(dep, req, length, false, 0, false);
}

out:
return req->num_trbs - num_trbs;
return dwc3_prepare_last_sg(dep, req, req->request.length, 0);
}

/*
Expand Down

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