From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [RFC v1 0/3] *spi-mem: adding setup and callback function Date: Tue, 30 Jul 2019 20:04:10 +0200 Message-ID: <20190730200410.72b2f7d3@collabora.com> References: <20190729142504.188336-1-tmaimon77@gmail.com> <20190729172859.4374a2ad@collabora.com> <20190730085438.6fe0480b@collabora.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Tomer Maimon , Sergei Shtylyov , bbrezillon@kernel.org, richard@nod.at, tudor.ambarus@microchip.com, Schrempf Frieder , linux-spi@vger.kernel.org, broonie@kernel.org, linux-mtd@lists.infradead.org, miquel.raynal@bootlin.com To: Vignesh Raghavendra Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+gldm-linux-mtd-36=gmane.org@lists.infradead.org List-Id: linux-spi.vger.kernel.org On Tue, 30 Jul 2019 23:18:25 +0530 Vignesh Raghavendra wrote: > On 30-Jul-19 12:24 PM, Boris Brezillon wrote: > > Trimmed the recipient list a bit and used Frieder's new address. > > +Sergey > > > > On Mon, 29 Jul 2019 23:55:05 +0300 > > Tomer Maimon wrote: > > > >> Hi Boris, > >> > >> Thanks for the prompt reply, > >> > >> > >> > >> On Mon, 29 Jul 2019 at 18:29, Boris Brezillon > >> wrote: > >> > >>> Hi Tomer, > >>> > >>> On Mon, 29 Jul 2019 17:25:01 +0300 > >>> Tomer Maimon wrote: > >>> > >>>> Lately we have working on Flash interface unit (FIU) SPI driver that > >>>> using spi-mem interface, Our FIU HW module support direct Flash Rd//Wr. > >>>> > >>>> In our SOC (32 bit dual core ARM) we have 3 FIU's that using memory > >>> mapping as follow: > >>>> > >>>> FIU0 - have 2 chip select and each one have 128MB memory mapping (total > >>> 256MB memory mapping) > >>>> FIU1 - have 4 chip select and each one have 128MB memory mapping (total > >>> 512MB memory mapping) > >>>> FIU2 - have 4 chip select and each one have 16MB memory mapping (total > >>> 32MB memory mapping) > >>>> > >>>> Totally 800MB memory mapping. > >>>> > >>>> When the FIU driver probe it don't know the size of each Flash that > >>>> connected to the FIU, so the entire memory mapping is allocated for each > >>> FIU > >>>> according the FIU device tree memory map parameters. > >>> > >>> Do you need those mappings to be active to support simple reg accesses? > >>> > >>>> It means, if we enable all three FIU's the drivers will try to allocate > >>> totally 800MB. > >>>> > >>>> In 32bit system it is problematic because the kernel have only 1GB > >>>> of memory allocation so the vmalloc cannot take 800MB. > >>>> > >>>> When implementing the FIU driver in the mtd/spi-nor we allocating memory > >>> address only > >>>> for detected Flash with exact size (usually we are not using 128MB > >>> Flash), and in that case usually we allocating much less memory. > >>>> > >>>> To solve this issue we needed to overcome two things: > >>>> > >>>> 1. Get argument from the upper layer (spi-mem layer) > >>>> 2. Calling the get argument function after SPI_NOR_SCAN function. > >>> (the MTD Flash size filled in SPI_NOR_SCAN function) > >>> > >>> That's clearly breaking the layering we've tried to restore with the > >>> spi-nor/spi-mem split, and I don't see why this is needed since we now > >>> have a way to create direct mappings dynamically (with the dirmap API). > >>> Have you tried implementing the dirmap hooks in your driver? > >> > >> > >> Sorry but I wasn't familiar with the direct mapping in the spi-mem, it > >> seems it needed to implemented in the m25p80 driver as well, am I correct? > > > > There's this patch [1] floating around. IIRC, Sergey was waiting for > > the m25p80 -> spi-nor merge to send a v5. Vignesh, any updates on that > > one? If you don't have time to work on that, maybe Sergey could send a > > v5. > > > > I did send an updated series of merging m25p80 to spi-nor last week and > have received few comments. Will respin one more version this week > (mostly by tomorrow). Okay, great! ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/