From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Ferre Subject: Re: [RFC PATCH 0/7] add at91sam9 LCDC DRM driver Date: Mon, 13 Aug 2018 16:47:26 +0200 Message-ID: <264d51a0-7e41-6c27-d438-9ae337e6dcf0@microchip.com> References: <20180812184152.GA22343@ravnborg.org> <20180812195536.GA29811@ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180812195536.GA29811@ravnborg.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Sam Ravnborg , Boris Brezillon , Rob Herring , Mark Rutland , Lee Jones , Alexandre Belloni , Joshua Henderson Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-pwm@vger.kernel.org List-Id: devicetree@vger.kernel.org On 12/08/2018 at 21:55, Sam Ravnborg wrote: > The at91sam9263 has a few interesting "GPU" features: > > - 2D memory addressing > Data sheet says: > The LCDC can be configured to work on a frame buffer > larger than the actual screen size. By changing the > values in a few registers, it is easy to move the > displayed area along the frame buffer width and height > > - 2D Graphics controller > Data sheet says: > The Two D Graphics Controller (TDGC) features a > hardware accelerator which highly simplifies drawing > tasks and graphic management operations. > The hardware accelerator makes it easy to draw lines > and complex polygons and to perform block transfers > within the frame buffer. > The TDGC also features a draw command queue that > automatically executes a more complex drawing function > that is composed of several register accesses. > > The datasheet text is from: chapter 43.9 + chapter 44: > http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-6249-32-bit-ARM926EJ-S-Embedded-Microprocessor-SAM9263_Datasheet.pdf > (No NDA required) (old memories) this 2D engine prove itself of being quite limited as the fill polygon and clipping functions are not working. > Based on the above, would it be possible to utilise some > of these features without any dedicated userspace (mesa) support? > Any other driver that has something similar that can be used > for inspiration? This is really an interesting question indeed. > Or is this in reality a simple GPU that requires a > dedicated GPU driver? > > Sam > -- Nicolas Ferre