As documented in dwc2_calculate_dynamic_fifo(), host_rx_fifo_size should
really be:
2 * ((Largest Packet size / 4) + 1 + 1) + n
with n = number of host channel.
We have 9 host channels, so
2 * ((1024/4) + 2) + 9 = 516 + 9 = 525
We've got 960 / 972 total_fifo_size on rk3288 (and presumably on
rk3066) and 525 + 128 + 256 = 909 so we're still under on both ports
even when we increment by 5.
In the future, it would be nice if dwc2_calculate_dynamic_fifo() could
handle the "too small" FIFO case and come up with something more
dynamically. When we do that we can figure out how to allocate the
extra 48 / 60 bytes of FIFO that we're currently wasting.
NOTE: no known bugs are fixed by this patch, but it seems like a simple
fix and ought to fix someone.
Signed-off-by: Douglas Anderson <diand...@chromium.org>
Reviewed-by: Kever Yang <kever.y...@rock-chips.com>
Tested-by: Heiko Stuebner <he...@sntech.de>
---
Changes in v6:
- Back to 525 dwords, not 528.
- Add Kever's Reviewed-by.
- Add Heiko's Tested-by.
Changes in v5: None
Changes in v4:
- Set host_rx_fifo_size to 528 for rk3066 new for v4.
Changes in v3: None
Changes in v2: None
drivers/usb/dwc2/platform.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index 5008a467ce06..b277e521a311 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -126,7 +126,7 @@ static const struct dwc2_core_params params_rk3066 = {
.speed = -1,
.enable_dynamic_fifo = 1,
.en_multiple_tx_fifo = -1,
- .host_rx_fifo_size = 520, /* 520 DWORDs */
+ .host_rx_fifo_size = 525, /* 525 DWORDs */
.host_nperio_tx_fifo_size = 128, /* 128 DWORDs */
.host_perio_tx_fifo_size = 256, /* 256 DWORDs */
.max_transfer_size = -1,
--
2.7.0.rc3.207.g0ac5344
--
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