From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [2/8,v4] Documentation: bindings: dma: Add binding for dma-channel-mask From: Vinod Koul Message-Id: <20190120110642.GT4635@vkoul-mobl> Date: Sun, 20 Jan 2019 16:36:42 +0530 To: John Stultz Cc: Manivannan Sadhasivam , lkml , Rob Herring , Mark Rutland , Tanglei Han , Zhuangluan Su , Ryan Grachek , "open list:DMA GENERIC OFFLOAD ENGINE SUBSYSTEM" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" List-ID: T24gMTctMDEtMTksIDA5OjQzLCBKb2huIFN0dWx0eiB3cm90ZToKPiBPbiBUaHUsIEphbiAxNywg MjAxOSBhdCA5OjA4IEFNIE1hbml2YW5uYW4gU2FkaGFzaXZhbQo+IDxtYW5pdmFubmFuLnNhZGhh c2l2YW1AbGluYXJvLm9yZz4gd3JvdGU6Cj4gPgo+ID4gT24gV2VkLCBKYW4gMTYsIDIwMTkgYXQg MDk6MTA6MjNBTSAtMDgwMCwgSm9obiBTdHVsdHogd3JvdGU6Cj4gPiA+IFNvbWUgZG1hIGNoYW5u ZWxzIGNhbiBiZSByZXNlcnZlZCBmb3Igc2VjdXJlIG1vZGUgb3Igb3RoZXIKPiA+ID4gaGFyZHdh cmUgb24gdGhlIFNvQywgc28gcHJvdmlkZSBhIGJpbmRpbmcgZm9yIGEgYml0bWFzawo+ID4gPiBs aXN0aW5nIHRoZSBhdmFpbGFibGUgY2hhbm5lbHMgZm9yIHRoZSBrZXJuZWwgdG8gdXNlLgo+ID4g Pgo+ID4gPiBUaGlzIGZvbGxvd3MgdGhlIHByZS1leGlzdGluZyBiY20sZG1hLWNoYW5uZWwtbWFz ayBiaW5kaW5nLgo+ID4gPgo+ID4gPiBDYzogVmlub2QgS291bCA8dmtvdWxAa2VybmVsLm9yZz4K PiA+ID4gQ2M6IFJvYiBIZXJyaW5nIDxyb2JoK2R0QGtlcm5lbC5vcmc+Cj4gPiA+IENjOiBNYXJr IFJ1dGxhbmQgPG1hcmsucnV0bGFuZEBhcm0uY29tPgo+ID4gPiBDYzogVGFuZ2xlaSBIYW4gPGhh bnRhbmdsZWlAaHVhd2VpLmNvbT4KPiA+ID4gQ2M6IFpodWFuZ2x1YW4gU3UgPHN1emh1YW5nbHVh bkBoaXNpbGljb24uY29tPgo+ID4gPiBDYzogUnlhbiBHcmFjaGVrIDxyeWFuQGVkaXRlZC51cz4K PiA+ID4gQ2M6IE1hbml2YW5uYW4gU2FkaGFzaXZhbSA8bWFuaXZhbm5hbi5zYWRoYXNpdmFtQGxp bmFyby5vcmc+Cj4gPiA+IENjOiBkbWFlbmdpbmVAdmdlci5rZXJuZWwub3JnCj4gPiA+IENjOiBk ZXZpY2V0cmVlQHZnZXIua2VybmVsLm9yZwo+ID4gPiBTaWduZWQtb2ZmLWJ5OiBKb2huIFN0dWx0 eiA8am9obi5zdHVsdHpAbGluYXJvLm9yZz4KPiA+ID4gLS0tCj4gPiA+IHYzOiBSZW5hbWVkIHRv IGhpc2ktZG1hLWF2YWlsLWNoYW4KPiA+ID4gdjQ6IFJld29ya2VkIHRvIGdlbmVyaWMgZG1hLWNo YW5uZWwtbWFzawo+ID4gPiAtLS0KPiA+ID4gIERvY3VtZW50YXRpb24vZGV2aWNldHJlZS9iaW5k aW5ncy9kbWEvZG1hLnR4dCB8IDQgKysrKwo+ID4gPiAgMSBmaWxlIGNoYW5nZWQsIDQgaW5zZXJ0 aW9ucygrKQo+ID4gPgo+ID4gPiBkaWZmIC0tZ2l0IGEvRG9jdW1lbnRhdGlvbi9kZXZpY2V0cmVl L2JpbmRpbmdzL2RtYS9kbWEudHh0IGIvRG9jdW1lbnRhdGlvbi9kZXZpY2V0cmVlL2JpbmRpbmdz L2RtYS9kbWEudHh0Cj4gPiA+IGluZGV4IDYzMTJmYjAuLmVlYjRlNGQgMTAwNjQ0Cj4gPiA+IC0t LSBhL0RvY3VtZW50YXRpb24vZGV2aWNldHJlZS9iaW5kaW5ncy9kbWEvZG1hLnR4dAo+ID4gPiAr KysgYi9Eb2N1bWVudGF0aW9uL2RldmljZXRyZWUvYmluZGluZ3MvZG1hL2RtYS50eHQKPiA+ID4g QEAgLTE2LDYgKzE2LDkgQEAgT3B0aW9uYWwgcHJvcGVydGllczoKPiA+ID4gIC0gZG1hLWNoYW5u ZWxzOiAgICAgIE51bWJlciBvZiBETUEgY2hhbm5lbHMgc3VwcG9ydGVkIGJ5IHRoZSBjb250cm9s bGVyLgo+ID4gPiAgLSBkbWEtcmVxdWVzdHM6ICAgICAgTnVtYmVyIG9mIERNQSByZXF1ZXN0IHNp Z25hbHMgc3VwcG9ydGVkIGJ5IHRoZQo+ID4gPiAgICAgICAgICAgICAgICAgICAgICAgY29udHJv bGxlci4KPiA+ID4gKy0gZG1hLWNoYW5uZWwtbWFzazogIEJpdG1hc2sgb2YgYXZhaWxhYmxlIERN QSBjaGFubmVscyBpbiBhc2NlbmRpbmcgb3JkZXIKPiA+ID4gKyAgICAgICAgICAgICAgICAgICAg IHRoYXQgYXJlIG5vdCByZXNlcnZlZCBieSBmaXJtd2FyZSBhbmQgYXJlIGF2YWlsYWJsZSB0bwo+ ID4gPiArICAgICAgICAgICAgICAgICAgICAgdGhlIGtlcm5lbC4gaS5lLiBmaXJzdCBjaGFubmVs IGNvcnJlc3BvbmRzIHRvIExTQi4KPiA+Cj4gPiBBIGdlbmVyYWwgYXNzdW1wdGlvbiBpcywgImRt YS1jaGFubmVsLW1hc2siIHJlZmVycyB0byB0aGUgYml0IGZpZWxkcyBvZgo+ID4gdGhlIGNoYW5u ZWxzIHdoaWNoIG5lZWRzIHRvIGJlIG1hc2tlZC4gQnV0IGhlcmUsIGl0IHJlZmVycyB0byB0aGUg Y2hhbm5lbHMKPiA+IHdoaWNoIGFyZSBhdmFpbGFibGUuIERvZXNuJ3QgaXQgY29udHJhZGljdD8K PiAKPiBIcm0uIFNvIHdoaWxlIEkgY2FuIHNvcnQgb2YgdW5kZXJzdGFuZCB0aGUgY29tbW9uIHVz YWdlIG9mICJtYXNrIiBhcwo+IHRvICJoaWRlIiwgdGh1cyB0aGUgZGVzaXJlIHRvIGhhdmUgYSBi aXRmaWVsZCBtZWFuICJ0aGUgY2hhbm5lbHMgd2UKPiBoaWRlIiBvciAiZG9uJ3QgdXNlIiwgYnV0 IGluIG15IGV4cGVyaWVuY2UgYml0bWFza2luZyBpcyBtb3JlIGNvbW1vbmx5Cj4gdXNlZCB0byBr ZWVwIG9ubHkgYSBwb3J0aW9uIG9mIHRoZSB0aGUgYml0cywgc28gZnJvbSB0aGF0IHBlcnNwZWN0 aXZlCj4gaXRzIG1vcmUgaW50dWl0aXZlIHRoYXQgYSBtYXNrIGJlIHRoZSBjaGFubmVscyB3ZSBr ZWVwIHRvIHVzZS4gU28gSSdtCj4gbm90IHN1cmUgaWYgeW91ciBzdWdnZXN0aW9uIG1ha2VzIGl0 IG1vcmUgY2xlYXIuCj4gCj4gQnV0IEknbSBub3QgdmVyeSBwYXJ0aWN1bGFyIGhlcmUsIHNvIEkn bGwgZGVmZXIgdG8gb3RoZXJzIG9uIHRoaXMuCgpHaXZlbiB0aGUgY29udGV4dCBhbmQgZG9jdW1l bnRhdGlvbiB3aGljaCBleHBsaWNpdGx5IHNheXMgaXQgaXMgYml0bWFzawpvZiBhdmFpbGFibGUg Y2hhbm5lbHMsIGkgdGhpbmsgd2UgYXJlIGZpbmUgOikK From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [PATCH 2/8 v4] Documentation: bindings: dma: Add binding for dma-channel-mask Date: Sun, 20 Jan 2019 16:36:42 +0530 Message-ID: <20190120110642.GT4635@vkoul-mobl> References: <1547658629-25378-1-git-send-email-john.stultz@linaro.org> <1547658629-25378-3-git-send-email-john.stultz@linaro.org> <20190117170829.GJ5283@Mani-XPS-13-9360> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: John Stultz Cc: Manivannan Sadhasivam , lkml , Rob Herring , Mark Rutland , Tanglei Han , Zhuangluan Su , Ryan Grachek , "open list:DMA GENERIC OFFLOAD ENGINE SUBSYSTEM" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" List-Id: devicetree@vger.kernel.org On 17-01-19, 09:43, John Stultz wrote: > On Thu, Jan 17, 2019 at 9:08 AM Manivannan Sadhasivam > wrote: > > > > On Wed, Jan 16, 2019 at 09:10:23AM -0800, John Stultz wrote: > > > Some dma channels can be reserved for secure mode or other > > > hardware on the SoC, so provide a binding for a bitmask > > > listing the available channels for the kernel to use. > > > > > > This follows the pre-existing bcm,dma-channel-mask binding. > > > > > > Cc: Vinod Koul > > > Cc: Rob Herring > > > Cc: Mark Rutland > > > Cc: Tanglei Han > > > Cc: Zhuangluan Su > > > Cc: Ryan Grachek > > > Cc: Manivannan Sadhasivam > > > Cc: dmaengine@vger.kernel.org > > > Cc: devicetree@vger.kernel.org > > > Signed-off-by: John Stultz > > > --- > > > v3: Renamed to hisi-dma-avail-chan > > > v4: Reworked to generic dma-channel-mask > > > --- > > > Documentation/devicetree/bindings/dma/dma.txt | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > diff --git a/Documentation/devicetree/bindings/dma/dma.txt b/Documentation/devicetree/bindings/dma/dma.txt > > > index 6312fb0..eeb4e4d 100644 > > > --- a/Documentation/devicetree/bindings/dma/dma.txt > > > +++ b/Documentation/devicetree/bindings/dma/dma.txt > > > @@ -16,6 +16,9 @@ Optional properties: > > > - dma-channels: Number of DMA channels supported by the controller. > > > - dma-requests: Number of DMA request signals supported by the > > > controller. > > > +- dma-channel-mask: Bitmask of available DMA channels in ascending order > > > + that are not reserved by firmware and are available to > > > + the kernel. i.e. first channel corresponds to LSB. > > > > A general assumption is, "dma-channel-mask" refers to the bit fields of > > the channels which needs to be masked. But here, it refers to the channels > > which are available. Doesn't it contradict? > > Hrm. So while I can sort of understand the common usage of "mask" as > to "hide", thus the desire to have a bitfield mean "the channels we > hide" or "don't use", but in my experience bitmasking is more commonly > used to keep only a portion of the the bits, so from that perspective > its more intuitive that a mask be the channels we keep to use. So I'm > not sure if your suggestion makes it more clear. > > But I'm not very particular here, so I'll defer to others on this. Given the context and documentation which explicitly says it is bitmask of available channels, i think we are fine :) -- ~Vinod