Fix two errors in transfer len calculation, move loop invariant code out
of loop.
If xfer_len is equal to CONFIG_DWC2_MAX_TRANSFER_SIZE (or slightly
smaller), the xfer_len will be to large, e.g.:
xfer_len = MAX_TRANSFER_SIZE = 65535
max packet size = 512
=> num_packets = 128
=> IN xfer_len = 65536
For OUT transactions larger than (65536 - mps) bytes, the xfer_len
determination is quite awkward, it is only correct due to:
- max_packet_size for control/bulk/interrupt is required to be
power-of-two.
- (CONFIG_DWC2_MAX_TRANSFER_SIZE + 1) % max-packet-size is zero
for all allowed (2^3 ... 2^9) packet sizes
As the max xfer len is loop invariant, it can be moved out of the loop.
Signed-off-by: Stefan Brüns <stefan.bru...@rwth-aachen.de>
---
drivers/usb/host/dwc2.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
index 5ef6deb..d317104 100644
--- a/drivers/usb/host/dwc2.c
+++ b/drivers/usb/host/dwc2.c
@@ -786,34 +786,34 @@ int chunk_msg(struct dwc2_priv *priv, struct usb_device
*dev,
uint32_t xfer_len;
uint32_t num_packets;
int stop_transfer = 0;
+ uint32_t max_xfer_len;
debug("%s: msg: pipe %lx pid %d in %d len %d\n", __func__, pipe, *pid,
in, len);
+ max_xfer_len = CONFIG_DWC2_MAX_PACKET_COUNT * max;
+ if (max_xfer_len > CONFIG_DWC2_MAX_TRANSFER_SIZE)
+ max_xfer_len = CONFIG_DWC2_MAX_TRANSFER_SIZE;
+ if (max_xfer_len > DWC2_DATA_BUF_SIZE)
+ max_xfer_len = DWC2_DATA_BUF_SIZE;
+
+ /* Make sure that max_xfer_len is a multiple of max packet size. */
+ num_packets = max_xfer_len / max;
+ max_xfer_len = num_packets * max;
+
do {
/* Initialize channel */
dwc_otg_hc_init(regs, DWC2_HC_CHANNEL, dev, devnum, ep, in,
eptype, max);
xfer_len = len - done;
- if (xfer_len > CONFIG_DWC2_MAX_TRANSFER_SIZE)
- xfer_len = CONFIG_DWC2_MAX_TRANSFER_SIZE - max + 1;
- if (xfer_len > DWC2_DATA_BUF_SIZE)
- xfer_len = DWC2_DATA_BUF_SIZE - max + 1;
- /* Make sure that xfer_len is a multiple of max packet size. */
- if (xfer_len > 0) {
+ if (xfer_len > max_xfer_len)
+ xfer_len = max_xfer_len;
+ else if (xfer_len > max)
num_packets = (xfer_len + max - 1) / max;
- if (num_packets > CONFIG_DWC2_MAX_PACKET_COUNT) {
- num_packets = CONFIG_DWC2_MAX_PACKET_COUNT;
- xfer_len = num_packets * max;
- }
- } else {
+ else
num_packets = 1;
- }
-
- if (in)
- xfer_len = num_packets * max;
debug("%s: chunk: pid %d xfer_len %u pkts %u\n", __func__,
*pid, xfer_len, num_packets);
--
2.1.4
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