From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-bl2nam02on0093.outbound.protection.outlook.com ([104.47.38.93] helo=NAM02-BL2-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1eUz0i-0000pb-Ur for linux-mtd@lists.infradead.org; Fri, 29 Dec 2017 18:04:02 +0000 From: Trent Piepho To: "linux-mtd@lists.infradead.org" , "linux@armlinux.org.uk" , "broonie@kernel.org" , "cyrille.pitchen@wedev4u.fr" , "dwmw2@infradead.org" , "computersforpeace@gmail.com" , "vigneshr@ti.com" , "boris.brezillon@free-electrons.com" , "richard@nod.at" , "marek.vasut@gmail.com" CC: "linux-spi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "nicolas.ferre@microchip.com" , "radu.pirea@microchip.com" , "robh@kernel.org" , "devicetree@vger.kernel.org" Subject: Re: [PATCH 1/3] mtd: spi-nor: add optional DMA-safe bounce buffer for data transfer Date: Fri, 29 Dec 2017 18:03:47 +0000 Message-ID: <1514570627.26695.114.camel@impinj.com> References: <1514317385.26695.39.camel@impinj.com> <1a7dc424-1ce0-6c64-fc52-bb88ec7db8fa@wedev4u.fr> <1514487276.26695.94.camel@impinj.com> <08be8b42-732a-bf28-40c4-f46bf9d71c80@ti.com> In-Reply-To: <08be8b42-732a-bf28-40c4-f46bf9d71c80@ti.com> Content-Language: en-US Content-Type: text/plain; charset="utf-8" Content-ID: <51651E7A11DB4D408180A3F356864551@namprd06.prod.outlook.com> Content-Transfer-Encoding: base64 MIME-Version: 1.0 List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , T24gRnJpLCAyMDE3LTEyLTI5IGF0IDE1OjQ2ICswNTMwLCBWaWduZXNoIFIgd3JvdGU6DQo+IE9u IEZyaWRheSAyOSBEZWNlbWJlciAyMDE3IDEyOjI0IEFNLCBUcmVudCBQaWVwaG8gd3JvdGU6DQo+ ID4gDQo+ID4gPiBWaWduZXNoIGhhcyBzdWdnZXN0ZWQgdG8gY2FsbCB2aXJ0X2FkZHJfdmFsaWQo KSBpbnN0ZWFkLg0KPiA+ID4gSSB0aGluayBCb3JpcyBoYXMgYWxzbyB0b2xkIG1lIGFib3V0IHRo aXMgZnVuY3Rpb24uDQo+ID4gPiBTbyBpdCBtaWdodCBiZSB0aGUgcmlnaHQgc29sdXRpb24uIFdo YXQgZG8geW91IHRoaW5rIGFib3V0IHRoZWlyIHByb3Bvc2FsPw0KPiA+IA0KPiA+IE5vdCBzdXJl IHdoYXQgZXhhY3RseSB0aGUgZGlmZmVyZW5jZXMgYXJlIGJldHdlZW4gdGhlc2UgbWV0aG9kcy4g IFRoZQ0KPiA+IGZhY3QgdGhhdCBlYWNoIG9mIHRoZSBtYW55IGV4aXN0aW5nIERNQSBmaXhlcyB1 c2VzIHNsaWdodGx5IGRpZmZlcmVudA0KPiA+IGNvZGUgdG8gZGV0ZWN0IHdoYXQgaXMgdW5zYWZl IHNwZWFrcyB0byB0aGUgZGlmZmljdWx0eSBvZiB0aGlzIHByb2JsZW0hDQo+IA0KPiBNeSB1bmRl cnN0YW5kaW5nIGJhc2VkIG9uIERvY3VtZW50YXRpb24vRE1BLUFQSS1IT1dUTy50eHQgYW5kDQo+ IERvY3VtZW50YXRpb24vYXJtL21lbW9yeS50eHQgaXMgdGhhdA0KPiB2aXJ0X2FkZHJfdmFsaWQo KSB3aWxsIGd1YXJhbnRlZSB0aGF0IGFkZHJlc3MgaXMgaW4gcmFuZ2Ugb2YNCj4gUEFHRV9PRkZT RVQgdG8gaGlnaF9tZW1vcnktMSAoS2VybmVsIGRpcmVjdC1tYXBwZWQgUkFNIHJlZ2lvbikgd2hp Y2ggaXMNCj4gYWRkcmVzcyByYW5nZSBvZiBidWZmZXJzIHRoYXQgYXJlIERNQSdhYmxlLg0KDQpU aGVyZSdzIGNvZGUgaW4gZ3BtaS1uYW5kLmMgdGhhdCBkb2VzOg0KDQogICAgICAgIC8qIGZpcnN0 IHRyeSB0byBtYXAgdGhlIHVwcGVyIGJ1ZmZlciBkaXJlY3RseSAqLw0KICAgICAgICBpZiAodmly dF9hZGRyX3ZhbGlkKHRoaXMtPnVwcGVyX2J1ZikgJiYNCiAgICAgICAgICAgICAgICAhb2JqZWN0 X2lzX29uX3N0YWNrKHRoaXMtPnVwcGVyX2J1ZikpIHsNCiAgICAgICAgICAgICAgICBzZ19pbml0 X29uZShzZ2wsIHRoaXMtPnVwcGVyX2J1ZiwgdGhpcy0+dXBwZXJfbGVuKTsNCg0KU28gd2hvZXZl ciB3cm90ZSB0aGF0IHRob3VnaHQgdGhhdCBzdGFjayBvYmplY3RzIG5lZWRlZCBhbiBhZGRpdGlv bmFsDQp0ZXN0IGJleW9uZCB2aXJ0X2FkZHJfdmFsaWQuICBCdXQgaXQgZG9lcyBhcHBlYXIgdG8g YmUgZmFyIG1vcmUgY29tbW9uDQp0byBkZXBlbmQgb24ganVzdCB2aXJ0X2FkZHJfdmFsaWQsIHNv IHBlcmhhcHMgdGhlIGNvZGUgaW4gZ3BtaS1uYW5kIGlzDQppbiBlcnJvci4NCg0KPiA+ICB2aXJ0 X2FkZHJfdmFsaWQoKSBpcyBhbHJlYWR5IHVzZWQgYnkgc3BpLXRpLXFzcGkuICBzcGkgY29yZSB1 c2VzIGZvcg0KPiA+IHRoZSBidWZmZXIgbWFwIGhlbHBlciwgYnV0IHRoYXQgY29kZSBwYXRoIGlz IGZvciBidWZmZXJzIHdoaWNoIGFyZSBOT1QNCj4gPiB2bWFsbG9jIG9yIGhpZ2htZW0sIGJ1dCBh cmUgc3RpbGwgbm90IHZpcnRfYWRkcl92YWxpZCgpIGZvciBzb21lIG90aGVyDQo+ID4gcmVhc29u Lg0KPiA+IA0KPiANCj4gCWlmICh2bWFsbG9jZWRfYnVmIHx8IGttYXBfYnVmKSB7DQo+IAkJLyog SGFuZGxlIHZtYWxsb2MnZCBvciBrbWFwJ2QgYnVmZmVycyAqLw0KPiAJCS4uLg0KVGhpcyBzdHVm ZiBkb2VzIGdldCBETUFlZC4gIFNvIEkgaGF2ZSB0byB3b25kZXIsIGlmIHNwaS5jIHRoaW5rcyBp dCBjYW4NCnVzZSBETUEgd2l0aCB2bWFsbG9jIG9yIGhpZ2htZW0sIGNvdWxkbid0IHNwaS1ub3Qg ZG8gdGhlIHNhbWUgaW5zdGVhZA0Kb2YgdGhlIGJvdW5jZSBidWZmZXI/DQoNCj4gICAgICAgICB9 IGVsc2UgaWYgKHZpcnRfYWRkcl92YWxpZChidWYpKSB7DQo+IAkJLyogSGFuZGxlIGttYWxsb2Mn ZCBhbmQgc3VjaCBidWZmZXJzICovDQo+ICAgICAgICAgICAgICAgICAuLi4NCj4gCX0gZWxzZSB7 DQo+IAkJLyogRXJyb3IgaWYgbm9uZSBvZiB0aGUgYWJvdmUgKi8NCg0KU28gd2hhdCBpcyB0aGlz IGNhc2UgaGVyZSBmb3I/ICBJdCdzIHNvbWUgY2xhc3MgdGhhdCBkb2VzIG5vdCBoYXZlIGENCnZh bGlkIHZpcnR1YWwgYWRkcmVzcyBhbmQgeWV0IGlzIG5vdCB2bWFsbG9jIG9yIGhpZ2htZW0uDQoN Cj4gCQlyZXR1cm4gLUVJTlZBTDsNCj4gCX0NCj4g