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 08:54:38 +0200 Message-ID: <20190730085438.6fe0480b@collabora.com> References: <20190729142504.188336-1-tmaimon77@gmail.com> <20190729172859.4374a2ad@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: Tomer Maimon , vigneshr@ti.com 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 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. [1]https://www.spinics.net/lists/linux-mtd/msg07358.html ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/