From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D83EC433FF for ; Mon, 29 Jul 2019 15:29:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E31DE206E0 for ; Mon, 29 Jul 2019 15:29:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388042AbfG2P3F (ORCPT ); Mon, 29 Jul 2019 11:29:05 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:57430 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387854AbfG2P3E (ORCPT ); Mon, 29 Jul 2019 11:29:04 -0400 Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 65B8826D9C2; Mon, 29 Jul 2019 16:29:02 +0100 (BST) Date: Mon, 29 Jul 2019 17:28:59 +0200 From: Boris Brezillon To: Tomer Maimon Cc: broonie@kernel.org, dwmw2@infradead.org, computersforpeace@gmail.com, marek.vasut@gmail.com, miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, bbrezillon@kernel.org, yogeshnarayan.gaur@nxp.com, tudor.ambarus@microchip.com, gregkh@linuxfoundation.org, frieder.schrempf@exceet.de, tglx@linutronix.de, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org Subject: Re: [RFC v1 0/3] *spi-mem: adding setup and callback function Message-ID: <20190729172859.4374a2ad@collabora.com> In-Reply-To: <20190729142504.188336-1-tmaimon77@gmail.com> References: <20190729142504.188336-1-tmaimon77@gmail.com> Organization: Collabora X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? Regards, Boris