From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Anholt Subject: Re: [PATCH 0/3] dmaengine: bcm2835: support dma channel 11 to 14 Date: Fri, 08 Apr 2016 11:37:23 -0700 Message-ID: <87zit4ymjg.fsf@eliezer.anholt.net> References: <1458228273-15591-1-git-send-email-kernel@martin.sperl.org> <20160405170336.GB5392@vkoul-mobl.iind.intel.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Return-path: In-Reply-To: <20160405170336.GB5392-bQVUxfxUtC13uc1i7fC1zK2pdiUAq4bhAL8bYrjMMd8@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Vinod Koul , kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org Cc: Rob Herring , Mark Rutland , Stephen Warren , Lee Jones , Russell King , Dan Williams , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Vinod Koul writes: > On Thu, Mar 17, 2016 at 03:24:30PM +0000, kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org wrote: >> From: Martin Sperl >>=20 >> Right now the dma engine officially supports dma channel 11 and 12. >> But the use of dma channel 12 immediately stalls the system. >>=20 >> The reason is that the interrupt assigned right now to dma channel 11 >> is actually a shared interrupt for dma channels 11 to 12. >> So whenever the dma channel 12, 13 or 14 is used, it triggers the interr= upt >> for dma 11 which only clears the interrupt flag for dma channel 11. >> This results in the interrupt 11 is triggered all the time. >>=20 >> On top the requesting dma channel12 (and the corresponding irq) triggers >> an immeditate stall of the system, because for the 12th interrupt >> any dma channel will trigger also this interrupt - even if the dma chann= el >> is controlled by the firmware. >>=20 >> As the description in the default device-tree is (for the above reasons) >> wrong a new means had to get devised that allows correct representation >> of the mapping between interrupts and dma channels. >>=20 >> For this the existing (but unused) device-tree property "interrupt-names" >> is used to define the mapping. > > This looks fine by me, need an ACK on ARM patch before this can be applie= d. This series is: Acked-by: Eric Anholt --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBCgAGBQJXB/pkAAoJELXWKTbR/J7opx8P/1UCvt+Qz/JmYx8w6o1n/hw/ 61iPwRRws1ZK+puW1oBQmMB9cXCom2W0d3OpcRuws1/+Wl+I9QuQi5+TSDUg3Yw7 NU296ydRgILCzL04J2UsIrS0zjPyRw9oHQNMd1yY+IfO8Kr72q3HkqmhI66fkSdI 3Om4irzgWYmg5DAjWnb4tZlO7dkKP0IoN927Ubh41JTRxDnLEH0nvjMO9vjiPwXh EV58zPDPzSJtX+6lgu+cidlG6JWIqR8+S1KTzYbemZ7T+adUfnzcV/y44EWJbe/k hOYW2DJsOtXqvLJ1tcg1d8FonrSYHYOAwUNY+ErUuB7hbmlwtRArUsNjPch2KE7M oOh1Y3+J8hhPKSUu63L9l2L3eN+8h3MOqRvHrD1EW8/8B1Jq4DkCqFmDTQ3HTXZ3 JI34/UGXDazVYZ7mohW7iMiZnJY0rbshk/ppgFnG1nqUU/8PV0z89kW6NQp9c9sU 5f54Ks4OxSyHh/N+MFEeKuMGl3xqdM+j7Z3rcUoAG+0J52p+g9JsV9qXRR6I+yGN SKdl1v9awyaNnRDpwA1KU2TGRxDJDpswDXdiT9HleTdo5PyrqMMJS1oeohQBv2uW NQ3xKQ2uSjWPcCOKFwDhS0KkOzGbONEE+SvJavqdZkIaQ6tHDqb+DOQ/zPxvLhye wyEpW696iqjWV1OXJ4Vz =iXfL -----END PGP SIGNATURE----- --=-=-=-- -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html