| Message ID | 1453486736-15358-4-git-send-email-dianders@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Doug, On 01/23/2016 02:18 AM, Douglas Anderson wrote: > 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. > > Since we have space, Kever Yang suggests bumping by 8. He says this > will meet INCR16 access and next fifo type can start with a aligned > address. I have double check this feature, the INCR16 is actually a burst 16 on to the bus, the aligned problem only happen on the DRAM access, and it's OK for internal RAM access via internal DMA. Bump to 8 looks much better when we check the FIFO setting if we have enough memory, right? :) rk3066/rk3188/rk3288 have the same hw config for dwc2 controller, so this patch should works on those files. Reviewed-by: Kever Yang <kever.yang@rock-chips.com> > > ...so let's bump up by 8. 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 <dianders@chromium.org> > --- > 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..b6d7666e715c 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 = 528, /* 528 DWORDs */ > .host_nperio_tx_fifo_size = 128, /* 128 DWORDs */ > .host_perio_tx_fifo_size = 256, /* 256 DWORDs */ > .max_transfer_size = -1,
Kever, On Wed, Jan 27, 2016 at 2:13 AM, Kever Yang <kever.yang@rock-chips.com> wrote: > Hi Doug, > > On 01/23/2016 02:18 AM, Douglas Anderson wrote: >> >> 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. >> >> Since we have space, Kever Yang suggests bumping by 8. He says this >> will meet INCR16 access and next fifo type can start with a aligned >> address. > > I have double check this feature, the INCR16 is actually a burst 16 > on to the bus, the aligned problem only happen on the DRAM > access, and it's OK for internal RAM access via internal DMA. > > Bump to 8 looks much better when we check the FIFO setting if we > have enough memory, right? :) > > rk3066/rk3188/rk3288 have the same hw config for dwc2 controller, > so this patch should works on those files. > > Reviewed-by: Kever Yang <kever.yang@rock-chips.com> Thanks for double-checking and thanks for the review! If it's all the same to you, I'll probably change it back to 525 and then increase the periodic FIFO size by 3 DWORDS in the next patch. 12 bytes may not be much, but might as well make use of them to improve performance / compatibility? Presumably you're also OK with the next patch in the series: ("usb: dwc2: host: Set host_perio_tx_fifo_size to 304 for rk3066")? Note to anyone who may be thinking of applying patches in this series: * You can skip both this and the next patch if you wish and any other patches in the series are unaffected. * You can request that I spin just these two patches and I will do it ASAP. Otherwise I'll add that fix to the next spin of the whole series. * You can make the changes yourself to this patch and the next one (this patch should be 525 and the next should increase host_perio_tx_fifo_size to 307). I'm OK with any of those 3 things. ;) -Doug
Hi Doug, On 01/28/2016 03:44 AM, Doug Anderson wrote: > If it's all the same to you, I'll probably change it back to 525 and > then increase the periodic FIFO size by 3 DWORDS in the next patch. > 12 bytes may not be much, but might as well make use of them to > improve performance / compatibility? > > Presumably you're also OK with the next patch in the series: ("usb: > dwc2: host: Set host_perio_tx_fifo_size to 304 for rk3066")? I'm OK for change in this patch, but I think we don't need next patch, pls see the reply in another mail. Thank, - Kever
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c index 5008a467ce06..b6d7666e715c 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 = 528, /* 528 DWORDs */ .host_nperio_tx_fifo_size = 128, /* 128 DWORDs */ .host_perio_tx_fifo_size = 256, /* 256 DWORDs */ .max_transfer_size = -1,
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. Since we have space, Kever Yang suggests bumping by 8. He says this will meet INCR16 access and next fifo type can start with a aligned address. ...so let's bump up by 8. 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 <dianders@chromium.org> --- 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(-)