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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 1D3E2C43381 for ; Tue, 5 Mar 2019 01:53:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFA0E206B6 for ; Tue, 5 Mar 2019 01:53:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=aj.id.au header.i=@aj.id.au header.b="i2dN4PDy"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="WzIboVZ7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726879AbfCEBxO (ORCPT ); Mon, 4 Mar 2019 20:53:14 -0500 Received: from out2-smtp.messagingengine.com ([66.111.4.26]:58579 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726066AbfCEBxN (ORCPT ); Mon, 4 Mar 2019 20:53:13 -0500 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.nyi.internal (Postfix) with ESMTP id C32AA22336; Mon, 4 Mar 2019 20:53:10 -0500 (EST) Received: from imap2 ([10.202.2.52]) by compute4.internal (MEProxy); Mon, 04 Mar 2019 20:53:10 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aj.id.au; h= message-id:in-reply-to:references:date:from:to:cc:subject :content-type; s=fm2; bh=dZM2t9sEovXIs+v6RgxkYTTDBKiKB8x7xS9NnvJ cXj0=; b=i2dN4PDyjfNhKPrUC3WzHjPNMK/ZNDWgqJnD4LLJo+D1TyOi9qsKo3X RbGl2oIdUirInABsOe6881dBHQgu0WkBgs+sYGGqXHuUSuw5CFvaBjRlGWufcf9S mb4yr6UqLNQ4uL0U6oxghTpmUUbn5K+9SO+VE06cBRp9h8KeyQFHCw6Au2ZTLWic 3HJZmAdxZGDxE6fXA8mr1bToZy+luosXqXRJxxxbQtX9ySENFIApp9qavMRFOvYr eF43tpPm4HnbjvTdq8eYMOvMEmw42lLRSh6jhbFeJeaGUMJ/pAYzJQMavqe4AZRa oOcxrCgZv2dXcWuvoaJFbRSPloScYHg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:references:subject:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=dZM2t9sEovXIs+v6R gxkYTTDBKiKB8x7xS9NnvJcXj0=; b=WzIboVZ7kINZnqZIipxa7a/R2lhRBH3J2 G1PU0C7FI6dFltRA8AT5eOJNMysbYBRvEOWsESPpGLk/LwMkohFJqk4OiFaNUonu JrQ+iuGbc2mn3tt1G+JY7lrGm/Mju5iOStg6xus3NRRadS7rTPfxkyH9p4tsEUI9 RSAnCmcZl3Th4AfQ50al+d/oP9OqfOFB4OIpSRkjppiqKYFDxNIwH4tY2hiNIWuP zwj2VcqCyXqtWXdHY+/7TYethF+a+ilX+LMB+hcfKb4C3A0TQADapXhSwzY0Bctk gXtcg3Rb+g9p/F7zDaXrS3ZAKteYZnWShQ8XI+r/slXOQdRJEnXLg== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedutddrfedvgdegtdcutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpefofgfkjghffffhvffutgesthdtredtreertdenucfhrhhomhepfdetnhgurhgv ficulfgvfhhfvghrhidfuceorghnughrvgifsegrjhdrihgurdgruheqnecurfgrrhgrmh epmhgrihhlfhhrohhmpegrnhgurhgvfiesrghjrdhiugdrrghunecuvehluhhsthgvrhfu ihiivgeptd X-ME-Proxy: Received: by mailuser.nyi.internal (Postfix, from userid 501) id 72E7D7C1EB; Mon, 4 Mar 2019 20:53:08 -0500 (EST) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.1.5-925-g644bf8c-fmstable-20190228v5 X-Me-Personality: 52947553 Message-Id: In-Reply-To: References: <20190228015223.34563-1-venture@google.com> <19097a78-7066-4fcd-aa79-aca4a8c3cb0c@www.fastmail.com> Date: Mon, 04 Mar 2019 20:53:07 -0500 From: "Andrew Jeffery" To: "Patrick Venture" Cc: "Arnd Bergmann" , "Greg Kroah-Hartman" , "Joel Stanley" , "Linux Kernel Mailing List" , linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org Subject: Re: [PATCH v5 2/2] drivers/misc: Add Aspeed P2A control driver Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 5 Mar 2019, at 05:01, Patrick Venture wrote: > On Mon, Mar 4, 2019 at 7:45 AM Patrick Venture wrote: > > > > On Sun, Mar 3, 2019 at 4:04 PM Andrew Jeffery wrote: > > > > > > Hi Patrick. > > > > > > I've got some minor comments, otherwise it looks reasonable to me. > > > > > > On Thu, 28 Feb 2019, at 12:22, Patrick Venture wrote: > > > > The ASPEED AST2400, and AST2500 in some configurations include a > > > > PCI-to-AHB MMIO bridge. This bridge allows a server to read and write > > > > in the BMC's physical address space. This feature is especially useful > > > > when using this bridge to send large files to the BMC. > > > > > > > > The host may use this to send down a firmware image by staging data at a > > > > specific memory address, and in a coordinated effort with the BMC's > > > > software stack and kernel, transmit the bytes. > > > > > > > > This driver enables the BMC to unlock the PCI bridge on demand, and > > > > configure it via ioctl to allow the host to write bytes to an agreed > > > > upon location. In the primary use-case, the region to use is known > > > > apriori on the BMC, and the host requests this information. Once this > > > > request is received, the BMC's software stack will enable the bridge and > > > > the region and then using some software flow control (possibly via IPMI > > > > packets), copy the bytes down. Once the process is complete, the BMC > > > > will disable the bridge and unset any region involved. > > > > > > > > The default behavior of this bridge when present is: enabled and all > > > > regions marked read-write. This driver will fix the regions to be > > > > read-only and then disable the bridge entirely. > > > > > > > > The memory regions protected are: > > > > * BMC flash MMIO window > > > > * System flash MMIO windows > > > > * SOC IO (peripheral MMIO) > > > > * DRAM > > > > > > > > The DRAM region itself is all of DRAM and cannot be further specified. > > > > Once the PCI bridge is enabled, the host can read all of DRAM, and if > > > > the DRAM section is write-enabled, then it can write to all of it. > > > > > > > > Signed-off-by: Patrick Venture > > > > --- > > > > Changes for v5: > > > > - Fixup missing exit condition and remove extra jump. > > > > Changes for v4: > > > > - Added ioctl for reading back the memory-region configuration. > > > > - Cleaned up some unused variables. > > > > Changes for v3: > > > > - Deleted unused read and write methods. > > > > Changes for v2: > > > > - Dropped unused reads. > > > > - Moved call to disable bridge to before registering device. > > > > - Switch from using regs to using a syscon regmap. <<< IN PROGRESS > > > > - Updated the commit message. <<< TODO > > > > - Updated the bit flipped for SCU180_ENP2A > > > > - Dropped boolean region_specified variable. > > > > - Renamed p2a_ctrl in _probe to misc_ctrl per suggestion. > > > > - Renamed aspeed_p2a_region_search to aspeed_p2a_region_acquire > > > > - Updated commit message. > > > > --- > > > > drivers/misc/Kconfig | 8 + > > > > drivers/misc/Makefile | 1 + > > > > drivers/misc/aspeed-p2a-ctrl.c | 456 +++++++++++++++++++++++++++ > > > > include/uapi/linux/aspeed-p2a-ctrl.h | 59 ++++ > > > > 4 files changed, 524 insertions(+) > > > > create mode 100644 drivers/misc/aspeed-p2a-ctrl.c > > > > create mode 100644 include/uapi/linux/aspeed-p2a-ctrl.h > > > > > > > > diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig > > > > index f417b06e11c5..9de1bafe5606 100644 > > > > --- a/drivers/misc/Kconfig > > > > +++ b/drivers/misc/Kconfig > > > > @@ -485,6 +485,14 @@ config VEXPRESS_SYSCFG > > > > bus. System Configuration interface is one of the possible means > > > > of generating transactions on this bus. > > > > > > > > +config ASPEED_P2A_CTRL > > > > + depends on (ARCH_ASPEED || COMPILE_TEST) && REGMAP && MFD_SYSCON > > > > + tristate "Aspeed ast2400/2500 HOST P2A VGA MMIO to BMC bridge control" > > > > + help > > > > + Control Aspeed ast2400/2500 HOST P2A VGA MMIO to BMC mappings > > > > through > > > > + ioctl()s, the driver also provides an interface for userspace > > > > mappings to > > > > + a pre-defined region. > > > > + > > > > config ASPEED_LPC_CTRL > > > > depends on (ARCH_ASPEED || COMPILE_TEST) && REGMAP && MFD_SYSCON > > > > tristate "Aspeed ast2400/2500 HOST LPC to BMC bridge control" > > > > diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile > > > > index e39ccbbc1b3a..57577aee354f 100644 > > > > --- a/drivers/misc/Makefile > > > > +++ b/drivers/misc/Makefile > > > > @@ -55,6 +55,7 @@ obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o > > > > obj-$(CONFIG_CXL_BASE) += cxl/ > > > > obj-$(CONFIG_ASPEED_LPC_CTRL) += aspeed-lpc-ctrl.o > > > > obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o > > > > +obj-$(CONFIG_ASPEED_P2A_CTRL) += aspeed-p2a-ctrl.o > > > > obj-$(CONFIG_PCI_ENDPOINT_TEST) += pci_endpoint_test.o > > > > obj-$(CONFIG_OCXL) += ocxl/ > > > > obj-y += cardreader/ > > > > diff --git a/drivers/misc/aspeed-p2a-ctrl.c > > > > b/drivers/misc/aspeed-p2a-ctrl.c > > > > new file mode 100644 > > > > index 000000000000..6bde4f64632d > > > > --- /dev/null > > > > +++ b/drivers/misc/aspeed-p2a-ctrl.c > > > > @@ -0,0 +1,456 @@ > > > > +/* > > > > + * Copyright 2019 Google Inc > > > > + * > > > > + * This program is free software; you can redistribute it and/or > > > > + * modify it under the terms of the GNU General Public License > > > > + * as published by the Free Software Foundation; either version > > > > + * 2 of the License, or (at your option) any later version. > > > > > > Should be a SPDX header instead. > > > > Ok, so delete the above and drop in: > > Was set straight on this. > > > > > """ > > /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ > > """ > > > > Or just add that to the top above the Google GNU copyright line? (I'm > > not a lawyer). > > > > > > > > > + * > > > > + * Provides a simple driver to control the ASPEED P2A interface which > > > > allows > > > > + * the host to read and write to various regions of the BMC's memory. > > > > + */ > > > > + > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > +#include > > > > + > > > > +#include > > > > + > > > > +#define DEVICE_NAME "aspeed-p2a-ctrl" > > > > + > > > > +/* SCU2C is a Misc. Control Register. */ > > > > +#define SCU2C 0x2c > > > > +/* SCU180 is the PCIe Configuration Setting Control Register. */ > > > > +#define SCU180 0x180 > > > > +/* Bit 1 controls the P2A bridge, while bit 0 controls the entire VGA > > > > device > > > > + * on the PCI bus. */ > > > > > > As this wraps to multiple lines the trailing `*/` should be on a separate line. > > > There are a few instances of this throughout. > > > > Can do. I will also run checkpath -- I had done it initially, but I > > forgot on later editions. > > > > > > > > > +#define SCU180_ENP2A BIT(1) > > > > + > > > > +/* The ast2400/2500 both have six ranges. */ > > > > +#define P2A_REGION_COUNT 6 > > > > + > > > > +struct region { > > > > + u32 min; > > > > + u32 max; > > > > + u32 bit; > > > > +}; > > > > + > > > > +struct aspeed_p2a_model_data { > > > > + /* min, max, bit */ > > > > + struct region regions[P2A_REGION_COUNT]; > > > > +}; > > > > + > > > > +struct aspeed_p2a_ctrl { > > > > + struct miscdevice miscdev; > > > > + struct regmap *regmap; > > > > + > > > > + const struct aspeed_p2a_model_data *config; > > > > + > > > > + /* Access to these needs to be locked, held via probe, mapping ioctl, > > > > + * and release, remove. > > > > + */ > > > > + struct mutex tracking; > > > > + u32 readers; > > > > + u32 readerwriters[P2A_REGION_COUNT]; > > > > + > > > > + phys_addr_t mem_base; > > > > + resource_size_t mem_size; > > > > +}; > > > > + > > > > +struct aspeed_p2a_user { > > > > + struct file *file; > > > > + struct aspeed_p2a_ctrl *parent; > > > > + > > > > + /** The entire memory space is opened for reading once the bridge is > > > > + * enabled, therefore this needs only to be tracked once per user. > > > > + * If any user has it open for read, the bridge must stay enabled. > > > > + */ > > > > > > Generally the descriptions for the members are described in a kerneldoc > > > comment above the struct definition. Also you're mixing the kernel-doc > > > comment opener (`/**`) with non-kernel-doc comments (`/*` on the > > > tracking` mutex in `struct aspeed_p2a_ctrl` above). > > > > Ok, so anything that isn't really detailing the members, or functions, > > shouldn't be kerneldoc style. Will fix throughout. > > > > > > > > > + u32 read; > > > > + > > > > + /** Each entry of the array corresponds to a P2A Region. If the user > > > > + * opens for read or readwrite, the reference goes up here. On > > > > release, > > > > + * this array is walked and references adjusted accordingly. > > > > + */ > > > > + u32 readwrite[P2A_REGION_COUNT]; > > > > +}; > > > > + > > > > +static void aspeed_p2a_enable_bridge(struct aspeed_p2a_ctrl *p2a_ctrl) > > > > +{ > > > > + regmap_update_bits(p2a_ctrl->regmap, SCU180, SCU180_ENP2A, > > > > SCU180_ENP2A); > > > > > > Wrap this at 80 chars. > > > > Roger. > > > > > > > > > +} > > > > + > > > > +static void aspeed_p2a_disable_bridge(struct aspeed_p2a_ctrl *p2a_ctrl) > > > > +{ > > > > + regmap_update_bits(p2witha_ctrl->regmap, SCU180, SCU180_ENP2A, 0); > > > > +} > > > > + > > > > +static int aspeed_p2a_mmap(struct file *file, struct vm_area_struct > > > > *vma) > > > > +{ > > > > + struct aspeed_p2a_user *priv = file->private_data; > > > > + struct aspeed_p2a_ctrl *ctrl = priv->parent; > > > > + > > > > + if (ctrl->mem_base == 0 && ctrl->mem_size == 0) > > > > + return -EINVAL; > > > > + > > > > + unsigned long vsize = vma->vm_end - vma->vm_start; > > > > + pgprot_t prot = vma->vm_page_prot; > > > > + > > > > + if (vma->vm_pgoff + vsize > ctrl->mem_base + ctrl->mem_size) > > > > + return -EINVAL; > > > > + > > > > + /* ast2400/2500 AHB accesses are not cache coherent */ > > > > + prot = pgprot_noncached(prot); > > > > + > > > > + if (remap_pfn_range(vma, vma->vm_start, > > > > + (ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff, > > > > + vsize, prot)) > > > > + return -EAGAIN; > > > > + > > > > + return 0; > > > > +} > > > > + > > > > +static void aspeed_p2a_region_acquire(struct aspeed_p2a_user *priv, > > > > + struct aspeed_p2a_ctrl *ctrl, > > > > + struct aspeed_p2a_ctrl_mapping *map) > > > > +{ > > > > + int i; > > > > + u32 base, end; > > > > + > > > > + base = map->addr; > > > > + end = map->addr + (map->length - 1); > > > > + > > > > + /* If the value is a legal u32, it will find a match. */ > > > > + for (i = 0; i < P2A_REGION_COUNT; i++) { > > > > + const struct region *curr = &ctrl->config->regions[i]; > > > > + > > > > + /* If the top of this region is lower than your base, skip it. > > > > + */ > > > > + if (curr->max < base) > > > > + continue; > > > > + > > > > + /* If the bottom of this region is higher than your end, bail. > > > > + */ > > > > + if (curr->min > end) > > > > + break; > > > > + /* Lock this and update it, therefore it someone else is > > > > + * closing their file out, this'll preserve the increment. > > > > + */ > > > > + mutex_lock(&ctrl->tracking); > > > > + ctrl->readerwriters[i] += 1; > > > > + mutex_unlock(&ctrl->tracking); > > > > + > > > > + /* Track with the user, so when they close their file, we can > > > > + * decrement properly. > > > > + */ > > > > > > The comments about tracking for decrement-on-release purposes is > > > useful, but I think the other comments in this loop are probably > > > unnecessary. Up to you though. > > > > I've often found drivers under-documented, so I went in the other direction. > > > > > > > > > + priv->readwrite[i] += 1; > > > > + > > > > + /* Enable the region as read-write. */ > > > > + regmap_update_bits(ctrl->regmap, SCU2C, curr->bit, 0); > > > > + } > > > > +} > > > > + > > > > +static long aspeed_p2a_ioctl(struct file *file, unsigned int cmd, > > > > + unsigned long data) > > > > +{ > > > > + struct aspeed_p2a_user *priv = file->private_data; > > > > + struct aspeed_p2a_ctrl *ctrl = priv->parent; > > > > + void __user *arg = (void __user *)data; > > > > + struct aspeed_p2a_ctrl_mapping map; > > > > + > > > > + if (copy_from_user(&map, arg, sizeof(map))) > > > > + return -EFAULT; > > > > + > > > > + switch (cmd) { > > > > + case ASPEED_P2A_CTRL_IOCTL_SET_WINDOW: > > > > + /* If they want a region to be read-only, since the entire > > > > + * region is read-only once enabled, we just need to track this > > > > + * user wants to read from the bridge, and if it's not enabled. > > > > + * Enable it. > > > > + */ > > > > + if (map.flags == ASPEED_P2A_CTRL_READ_ONLY) { > > > > + mutex_lock(&ctrl->tracking); > > > > + ctrl->readers += 1; > > > > + mutex_unlock(&ctrl->tracking); > > > > + > > > > + /* Track with the user, so when they close their file, > > > > + * we can decrement properly. > > > > + */ > > > > + priv->read += 1; > > > > + } else if (map.flags == ASPEED_P2A_CTRL_READWRITE) { > > > > + aspeed_p2a_region_acquire(priv, ctrl, &map); > > > > + } else { > > > > + /* Invalid map flags. */ > > > > + return -EINVAL; > > > > + } > > > > + > > > > + aspeed_p2a_enable_bridge(ctrl); > > > > + return 0; > > > > + case ASPEED_P2A_CTRL_IOCTL_GET_MEMORY_CONFIG: > > > > + /* This is a request for the memory-region and corresponding > > > > + * length that is used by the driver for mmap. */ > > > > + > > > > + map.flags = 0; > > > > + map.addr = ctrl->mem_base; > > > > + map.length = ctrl->mem_size; > > > > > > Thinking out loud here - do we want to allow ourselves an escape hatch > > > for supporting multiple reserved memory locations? Otherwise we might > > > need a new ioctl() for it. On the flip-side, not actually having this use-case > > > means we might break the implementation anyway, so it could be a > > > double-edged sword. Thoughts? > > > > How about this, I use a different structure that has an index -- so > > you pass in the structure with the index set, requesting the region > > information, and it returns the details for that memory-region until > > the index exceeds the number of regions and returns -ENODEV. > > > > However, to avoid extra complexity today, the dts will only support > > one memory region... The complexity of dealing with checking what > > region they want to use in mmap by checking what region has been > > enabled by that specific user may be too much of a pain though for the > > probable life of this driver. So yeah, a bit of a double-edged sword > > of complexity to approach the extra complexity even partially. I > > think having one memory-region is fine for now, and I can't see the > > future. Perhaps having the ioctl structure change and no other > > changes is sufficient while being extendable in the future if > > someone's need should arise. That way there won't be an obsolete > > ioctl or ambiguous ioctl (code that calls the old one and its result > > is quasi-incorrect). > > > > > > > > > + > > > > + return copy_to_user(arg, &map, sizeof(map)) ? -EFAULT : 0; > > > > + } > > > > + > > > > + return -EINVAL; > > > > +} > > > > + > > > > + > > > > +/** > > > > + * When a user opens this file, we create a structure to track their > > > > mappings. > > > > + * > > > > + * A user can map a region as read-only (bridge enabled), or > > > > read-write (bit > > > > + * flipped, and bridge enabled). Either way, this tracking is used, > > > > s.t. when > > > > + * they release the device references are handled. > > > > + * > > > > + * The bridge is not enabled until a user calls an ioctl to map a > > > > region, > > > > + * simply opening the device does not enable it. > > > > + */ > > > > +static int aspeed_p2a_open(struct inode *inode, struct file *file) > > > > +{ > > > > + struct aspeed_p2a_user *priv; > > > > + > > > > + priv = kmalloc(sizeof(*priv), GFP_KERNEL); > > > > + if (!priv) > > > > + return -ENOMEM; > > > > + > > > > + priv->file = file; > > > > + priv->read = 0; > > > > + memset(priv->readwrite, 0, sizeof(priv->readwrite)); > > > > + > > > > + /* The file's private_data is initialized to the p2a_ctrl. */ > > > > + priv->parent = file->private_data; > > > > + > > > > + /* Set the file's private_data to the user's data. */ > > > > + file->private_data = priv; > > > > + > > > > + return 0; > > > > +} > > > > + > > > > +/** > > > > + * This will close the users mappings. It will go through what they > > > > had opened > > > > + * for readwrite, and decrement those counts. If at the end, this is > > > > the last > > > > + * user, it'll close the bridge. > > > > + */ > > > > +static int aspeed_p2a_release(struct inode *inode, struct file *file) > > > > +{ > > > > + int i; > > > > + u32 value; > > > > + u32 bits = 0; > > > > + bool open_regions = false; > > > > + struct aspeed_p2a_user *priv = file->private_data; > > > > + > > > > + /* Lock others from changing these values until everything is updated > > > > + * in one pass */ > > > > + mutex_lock(&priv->parent->tracking); > > > > + > > > > + priv->parent->readers -= priv->read;; > > > > + > > > > + for (i = 0; i < P2A_REGION_COUNT; i++) { > > > > + priv->parent->readerwriters[i] -= priv->readwrite[i]; > > > > + > > > > + if (priv->parent->readerwriters[i] > 0) > > > > + open_regions = true; > > > > + else > > > > + bits |= priv->parent->config->regions[i].bit; > > > > + } > > > > + > > > > + /* Setting a bit to 1 disables the region, so let's just OR with the > > > > + * above to disable any. > > > > + */ > > > > + > > > > + /* Note, if another user is trying to ioctl, they can't grab tracking, > > > > + * and therefore can't grab either register mutex. > > > > + * If another user is trying to close, they can't grab tracking > > > > either. > > > > + */ > > > > + regmap_update_bits(priv->parent->regmap, SCU2C, bits, bits); > > > > + > > > > + /* If parent->readers is zero and open windows is 0, disable the > > > > + * bridge. > > > > + */ > > > > + if (!open_regions && priv->parent->readers == 0) > > > > + aspeed_p2a_disable_bridge(priv->parent); > > > > + > > > > + mutex_unlock(&priv->parent->tracking); > > > > + > > > > + kfree(priv); > > > > + > > > > + return 0; > > > > +} > > > > + > > > > +static const struct file_operations aspeed_p2a_ctrl_fops = { > > > > + .owner = THIS_MODULE, > > > > + .mmap = aspeed_p2a_mmap, > > > > + .unlocked_ioctl = aspeed_p2a_ioctl, > > > > + .open = aspeed_p2a_open, > > > > + .release = aspeed_p2a_release, > > > > +}; > > > > + > > > > +/** The regions are controlled by SCU2C */ > > > > +static void aspeed_p2a_disable_all(struct aspeed_p2a_ctrl *p2a_ctrl) > > > > +{ > > > > + int i; > > > > + u32 value = 0; > > > > + > > > > + for (i = 0; i < P2A_REGION_COUNT; i++) > > > > + value |= p2a_ctrl->config->regions[i].bit; > > > > + > > > > + regmap_update_bits(p2a_ctrl->regmap, SCU2C, value, value); > > > > + > > > > + /* Disable the bridge. */ > > > > + aspeed_p2a_disable_bridge(p2a_ctrl); > > > > +} > > > > + > > > > +static int aspeed_p2a_ctrl_probe(struct platform_device *pdev) > > > > +{ > > > > + struct aspeed_p2a_ctrl *misc_ctrl; > > > > + struct device *dev; > > > > + struct resource *res, resm; > > > > + struct device_node *node; > > > > + int rc = 0; > > > > + > > > > + dev = &pdev->dev; > > > > + > > > > + misc_ctrl = devm_kzalloc(dev, sizeof(*misc_ctrl), GFP_KERNEL); > > > > + if (!misc_ctrl) > > > > + return -ENOMEM; > > > > + > > > > + mutex_init(&misc_ctrl->tracking); > > > > + misc_ctrl->readers = 0; > > > > + memset(misc_ctrl->readerwriters, 0, sizeof(misc_ctrl->readerwriters)); > > > > + > > > > + misc_ctrl->mem_size = 0; > > > > + misc_ctrl->mem_base = 0; > > > > + > > > > + /* optional. */ > > > > + node = of_parse_phandle(dev->of_node, "memory-region", 0); > > > > + if (node) { > > > > + rc = of_address_to_resource(node, 0, &resm); > > > > + of_node_put(node); > > > > + if (rc) { > > > > + dev_err(dev, "Couldn't address to resource for reserved memory\n"); > > > > > > I think the message could be improved, something like "No reserved memory > > > specified". Having said that, I don't think it should be an error condition either; > > > our experience with aspeed-lpc-ctrl was that it was useful for the memory-region > > > property to be optional. You already have: > > > > Ok. > > Ok, when I read this, I see it as an error condition. In this case > the node was specified but was invalid. Sorry, yeah you're right. I'm going to blame a 6-week old child and a lack of sleep :) Cheers, Andrew > > > > > > > > > > + > > > > + if (ctrl->mem_base == 0 && ctrl->mem_size == 0) > > > > + return -EINVAL; > > > > > > in the mmap() callback, but we don't get that far unless someone has specified a > > > zero-sized reserved-memory node. I think supporting memory-region as optional > > > is just a matter of adding the same check to the GET_MEMORY_CONFIG ioctl(). > > > > > > > + return -ENOMEM; > > > > > > The system isn't out of memory so this isn't an ENOMEM condition. I think ENODEV > > > is more appropriate, but if we make the memory region optional then this goes > > > away anyway. > > > > Roger. > > > > > > > > > + } > > > > + > > > > + misc_ctrl->mem_size = resource_size(&resm); > > > > + misc_ctrl->mem_base = resm.start; > > > > + } > > > > + > > > > + node = of_parse_phandle(dev->of_node, "syscon", 0); > > > > + if (!node) { > > > > + dev_err(dev, "Couldn't find syscon property\n"); > > > > + return -ENODEV; > > > > + } > > > > + > > > > + misc_ctrl->regmap = syscon_node_to_regmap(node); > > > > + if (IS_ERR(misc_ctrl->regmap)) { > > > > + dev_err(dev, "Couldn't get regmap\n"); > > > > + return -ENODEV; > > > > + } > > > > + of_node_put(node); > > > > + > > > > + misc_ctrl->config = of_device_get_match_data(dev); > > > > + > > > > + dev_set_drvdata(&pdev->dev, misc_ctrl); > > > > + > > > > + aspeed_p2a_disable_all(misc_ctrl); > > > > + > > > > + misc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR; > > > > + misc_ctrl->miscdev.name = DEVICE_NAME; > > > > + misc_ctrl->miscdev.fops = &aspeed_p2a_ctrl_fops; > > > > + misc_ctrl->miscdev.parent = dev; > > > > + > > > > + rc = misc_register(&misc_ctrl->miscdev); > > > > + if (rc) > > > > + dev_err(dev, "Unable to register device\n"); > > > > + > > > > + return rc; > > > > +} > > > > + > > > > +static int aspeed_p2a_ctrl_remove(struct platform_device *pdev) > > > > +{ > > > > + struct aspeed_p2a_ctrl *p2a_ctrl = dev_get_drvdata(&pdev->dev); > > > > + > > > > + misc_deregister(&p2a_ctrl->miscdev); > > > > + > > > > + return 0; > > > > +} > > > > + > > > > +/* > > > > + * bit | SCU2C | ast2400 > > > > + * 25 | DRAM | 0x40000000 - 0x5FFFFFFF > > > > + * 24 | SPI | 0x30000000 - 0x3FFFFFFF > > > > + * 23 | SOC | 0x18000000 - 0x1FFFFFFF, 0x60000000 - 0xFFFFFFFF > > > > + * 22 | FLASH | 0x00000000 - 0x17FFFFFF, 0x20000000 - 0x2FFFFFFF > > > > + * > > > > + * bit | SCU2C | ast2500 > > > > + * 25 | DRAM | 0x80000000 - 0xFFFFFFFF > > > > + * 24 | SPI | 0x60000000 - 0x7FFFFFFF > > > > + * 23 | SOC | 0x10000000 - 0x1FFFFFFF, 0x40000000 - 0x5FFFFFFF > > > > + * 22 | FLASH | 0x00000000 - 0x0FFFFFFF, 0x20000000 - 0x3FFFFFFF > > > > + */ > > > > > > The comment is probably unnecessary given the structure declarations > > > below. > > > > Fair enough, will drop it. > > > > > > > > > + > > > > +#define SCU2C_DRAM BIT(25) > > > > +#define SCU2C_SPI BIT(24) > > > > +#define SCU2C_SOC BIT(23) > > > > +#define SCU2C_FLASH BIT(22) > > > > + > > > > +static const struct aspeed_p2a_model_data ast2400_model_data = { > > > > + .regions = { > > > > + {0x00000000, 0x17FFFFFF, SCU2C_FLASH}, > > > > + {0x18000000, 0x1FFFFFFF, SCU2C_SOC}, > > > > + {0x20000000, 0x2FFFFFFF, SCU2C_FLASH}, > > > > + {0x30000000, 0x3FFFFFFF, SCU2C_SPI}, > > > > + {0x40000000, 0x5FFFFFFF, SCU2C_DRAM}, > > > > + {0x60000000, 0xFFFFFFFF, SCU2C_SOC}, > > > > + } > > > > +}; > > > > + > > > > +static const struct aspeed_p2a_model_data ast2500_model_data = { > > > > + .regions = { > > > > + {0x00000000, 0x0FFFFFFF, SCU2C_FLASH}, > > > > + {0x10000000, 0x1FFFFFFF, SCU2C_SOC}, > > > > + {0x20000000, 0x3FFFFFFF, SCU2C_FLASH}, > > > > + {0x40000000, 0x5FFFFFFF, SCU2C_SOC}, > > > > + {0x60000000, 0x7FFFFFFF, SCU2C_SPI}, > > > > + {0x80000000, 0xFFFFFFFF, SCU2C_DRAM}, > > > > + } > > > > +}; > > > > + > > > > +static const struct of_device_id aspeed_p2a_ctrl_match[] = { > > > > + { .compatible = "aspeed,ast2400-p2a-ctrl", > > > > + .data = &ast2400_model_data }, > > > > + { .compatible = "aspeed,ast2500-p2a-ctrl", > > > > + .data = &ast2500_model_data }, > > > > + { }, > > > > +}; > > > > + > > > > +static struct platform_driver aspeed_p2a_ctrl_driver = { > > > > + .driver = { > > > > + .name = DEVICE_NAME, > > > > + .of_match_table = aspeed_p2a_ctrl_match, > > > > + }, > > > > + .probe = aspeed_p2a_ctrl_probe, > > > > + .remove = aspeed_p2a_ctrl_remove, > > > > +}; > > > > + > > > > +module_platform_driver(aspeed_p2a_ctrl_driver); > > > > + > > > > +MODULE_DEVICE_TABLE(of, aspeed_p2a_ctrl_match); > > > > +MODULE_LICENSE("GPL"); > > > > +MODULE_AUTHOR("Patrick Venture "); > > > > +MODULE_DESCRIPTION("Control for aspeed 2400/2500 P2A VGA HOST to BMC > > > > mappings"); > > > > diff --git a/include/uapi/linux/aspeed-p2a-ctrl.h > > > > b/include/uapi/linux/aspeed-p2a-ctrl.h > > > > new file mode 100644 > > > > index 000000000000..e839cdc31db9 > > > > --- /dev/null > > > > +++ b/include/uapi/linux/aspeed-p2a-ctrl.h > > > > @@ -0,0 +1,59 @@ > > > > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ > > > > +/* > > > > + * Copyright 2019 Google Inc > > > > + * > > > > + * This program is free software; you can redistribute it and/or > > > > + * modify it under the terms of the GNU General Public License > > > > + * as published by the Free Software Foundation; either version > > > > + * 2 of the License, or (at your option) any later version. > > > > > > SPDX again. > > > > So, only SPDX? I'm not super on the ball with this type of thing. I > > just mirrored what I saw in other recent aspeed drivers. > > > > > > > > > + * > > > > + * Provides a simple driver to control the ASPEED P2A interface which > > > > allows > > > > + * the host to read and write to various regions of the BMC's memory. > > > > + */ > > > > + > > > > +#ifndef _UAPI_LINUX_ASPEED_P2A_CTRL_H > > > > +#define _UAPI_LINUX_ASPEED_P2A_CTRL_H > > > > + > > > > +#include > > > > +#include > > > > + > > > > +#define ASPEED_P2A_CTRL_READ_ONLY 0 > > > > +#define ASPEED_P2A_CTRL_READWRITE 1 > > > > + > > > > +/* > > > > + * This driver provides a mechanism for enabling or disabling the > > > > read-write > > > > + * property of specific windows into the ASPEED BMC's memory. > > > > + * > > > > + * A user can map a region of the BMC's memory as read-only or > > > > read-write, with > > > > + * the caveat that once any region is mapped, all regions are unlocked > > > > for > > > > + * reading. > > > > + */ > > > > + > > > > +/** > > > > + * Unlock a region of BMC physical memory for access from the host. > > > > + * > > > > + * Also used to read back the optional memory-region configuration for > > > > the > > > > + * driver. > > > > + */ > > > > +struct aspeed_p2a_ctrl_mapping { > > > > + __u32 addr; > > > > + __u32 length; > > > > + __u32 flags; > > > > +}; > > > > + > > > > +#define __ASPEED_P2A_CTRL_IOCTL_MAGIC 0xb3 > > > > + > > > > +/** > > > > + * This IOCTL is meant to configure a region or regions of memory > > > > given a > > > > + * starting address and length to be readable by the host, or > > > > + * readable-writeable. */ > > > > +#define ASPEED_P2A_CTRL_IOCTL_SET_WINDOW > > > > _IOW(__ASPEED_P2A_CTRL_IOCTL_MAGIC, \ > > > > + 0x00, struct aspeed_p2a_ctrl_mapping) > > > > + > > > > +/** > > > > + * This IOCTL is meant to read back to the user the base address and > > > > length of > > > > + * the memory-region specified to the driver for use with mmap. */ > > > > +#define ASPEED_P2A_CTRL_IOCTL_GET_MEMORY_CONFIG > > > > _IOWR(__ASPEED_P2A_CTRL_IOCTL_MAGIC, \ > > > > > > Wrap this at 80? > > > > > > Cheers, > > > > > > Andrew > > > > > > > + 0x01, struct aspeed_p2a_ctrl_mapping) > > > > + > > > > +#endif /* _UAPI_LINUX_ASPEED_P2A_CTRL_H */ > > > > -- > > > > 2.21.0.rc2.261.ga7da99ff1b-goog > > > > > > > > >