From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vignesh Raghavendra Subject: Re: [RFC v1 0/3] *spi-mem: adding setup and callback function Date: Tue, 30 Jul 2019 23:18:25 +0530 Message-ID: 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: 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: Boris Brezillon , Tomer Maimon Return-path: In-Reply-To: <20190730085438.6fe0480b@collabora.com> Content-Language: en-US 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 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). Regards Vignesh ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/