From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felipe Balbi Subject: Re: [RFC PATCH 3/4] tty: omap-serial: use threaded interrupt handler Date: Tue, 19 Aug 2014 13:57:02 -0500 Message-ID: <20140819185701.GC22003@saruman.home> References: <1406645577-18620-1-git-send-email-frans.klaver@xsens.com> <1408450488-4083-1-git-send-email-frans.klaver@xsens.com> <1408450488-4083-4-git-send-email-frans.klaver@xsens.com> Reply-To: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Pk6IbRAofICFmK5e" Return-path: Content-Disposition: inline In-Reply-To: <1408450488-4083-4-git-send-email-frans.klaver@xsens.com> Sender: linux-serial-owner@vger.kernel.org To: Frans Klaver Cc: Felipe Balbi , Tony Lindgren , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Greg Kroah-Hartman , Alexey Pelykh , Jiri Slaby , Frans Klaver , linux-serial@vger.kernel.org, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org --Pk6IbRAofICFmK5e Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Aug 19, 2014 at 02:14:47PM +0200, Frans Klaver wrote: > At 3.6Mbaud, with slightly over 2Mbit/s data coming in, we see 1600 uart > rx buffer overflows within 30 seconds. Threading the interrupt handling r= educes > this to about 170 overflows in 10 minutes. Can you try Sebastian Siewior's patches for 8250_omap and 8250 dma support ? That should help you a lot. > In practice this therefore reduces the need for hardware flow control, > meaning the sending side doesn't have to buffer as much either. >=20 > Signed-off-by: Frans Klaver > --- > drivers/tty/serial/omap-serial.c | 31 ++++++++++++++++++++++++------- > 1 file changed, 24 insertions(+), 7 deletions(-) >=20 > diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-s= erial.c > index 14a0167..57664b9 100644 > --- a/drivers/tty/serial/omap-serial.c > +++ b/drivers/tty/serial/omap-serial.c > @@ -575,6 +575,21 @@ static void serial_omap_rdi(struct uart_omap_port *u= p, unsigned int lsr) > } > =20 > /** > + * serial_omap_fast_irq() - schedule interrupt handling > + */ > +static irqreturn_t serial_omap_fast_irq(int irq, void *dev_id) > +{ > + struct uart_omap_port *up =3D dev_id; > + unsigned int iir =3D serial_in(up, UART_IIR); > + > + if (iir & UART_IIR_NO_INT) > + return IRQ_NONE; > + > + disable_irq_nosync(up->port.irq); NAK. Either use IRQF_ONESHOT or actually mask the IRQs at the device's registers (basically clearing IER). --=20 balbi --Pk6IbRAofICFmK5e Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJT8539AAoJEIaOsuA1yqREubgP/i6HM/lzaIpLIB+pnvyrvQCs 11MLkMLKSa8ORfkapcUr/lCSbZPsvrJwzyMNWTrVF3grSQyPKRpPykJYEkJkrwQ+ BUUqrSt5VlJkgdvhhY1KVoqPLonFUrBKEnPsgmv59tMC9dc+4oPA0ZZD8EIT5vjf RNh+ZKmi0jrtLLuAkwIPpe4LmglFqKLVEwiIWS2RmuWWnEOGwcGEEa4fzv21EV3b dexziU0ZhrvoBU6pM5j8U5xsF02iXHcFjfeva87Rwb13bZRSPzVZ56C2k0U+3oT9 p1Vp82yzW089huJKH6//02cWbOevb7r0bs1gJCFVO8T8x+h5jFdbwBb+elaL0xbR VnTclc3YeyP31nve5JeYUSfMog9zGoa03gz3Yr+M4ChxcuvCvOt71cVG8q5jF/yg s6AXiBNqUhFFgQr7j3JnybLhI3rigkX7SdwRU/WfjJflS9dwpJimPwPd1v4okIry OfxPBglxTTMQjPS+LwW2Wkxj/PSvKS5NJ8NOry6FaJT5eOJAysxo1mAT4yvrBjn5 4KhDBiPuXlD0vpu5TFTt6OKNsb2gqNt2qe3EHpDGrqcAfNMLLMwLad1npST++43b KIobmrTDuivGZNPNZ1qXBZh5T5xZzConhtNzcB4FAQOATp3l/XjjpsiZV4oQonCB Eto7ADF0v4uStCOhOoyd =aLFS -----END PGP SIGNATURE----- --Pk6IbRAofICFmK5e--