From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Garry Subject: Re: [PATCH v13 7/9] ACPI: Translate the I/O range of non-MMIO devices before scanning Date: Thu, 15 Feb 2018 11:19:00 +0000 Message-ID: References: <1518543933-22456-1-git-send-email-john.garry@huawei.com> <1518543933-22456-8-git-send-email-john.garry@huawei.com> <20180214161635.GA13849@e107981-ln.cambridge.arm.com> <65185a4d-c712-4486-d713-3fa9de14e35d@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <65185a4d-c712-4486-d713-3fa9de14e35d@huawei.com> Sender: linux-kernel-owner@vger.kernel.org To: Lorenzo Pieralisi , rafael@kernel.org Cc: mika.westerberg@linux.intel.com, rjw@rjwysocki.net, hanjun.guo@linaro.org, robh+dt@kernel.org, bhelgaas@google.com, arnd@arndb.de, mark.rutland@arm.com, olof@lixom.net, dann.frazier@canonical.com, andy.shevchenko@gmail.com, robh@kernel.org, joe@perches.com, benh@kernel.crashing.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linuxarm@huawei.com, minyard@acm.org, devicetree@vger.kernel.org, linux-arch@vger.kernel.org, rdunlap@infradead.org List-Id: devicetree@vger.kernel.org > Nothing apart from only being used by arm64 platforms today, which is > circumstantial. > >> >> I understand you need to find a place to add the: >> >> acpi_indirect_io_scan_init() >> >> to be called from core ACPI code because ACPI can't handle probe >> dependencies in any other way but other than that this patch is >> a Hisilicon ACPI driver - there is nothing generic in it (or at >> least there are no standard bindings to make it so). >> >> Whether a callback from ACPI core code (acpi_scan_init()) to a driver >> specific hook is sane or not that's the question and the only reason >> why you want to add this in drivers/acpi/arm64 rather than, say, >> drivers/bus (as you do for the DT driver). >> >> I do not know Rafael's opinion on the above, I would like to help >> you make forward progress but please understand my concerns, mostly >> on FW side. >> > > I did mention an alternative in my "ping" in v12 patch 7/9 (Feb 1), but > no response to this specific note so I kept on the same path. > > Here's what I then wrote: > "I think another solution - which you may prefer - is to avoid adding > this scan handler (and all this other scan code) and add a check like > acpi_is_serial_bus_slave() [which checks the device parent versus a list > of known indirectIO hosts] to not enumerate these children, and do it > from the LLDD host probe instead (https://lkml.org/lkml/2017/6/16/250)" > Hi Rafael, Lorenzo, I can avoid adding the scan handler in acpi_indirectio.c by skipping the child enumeration, like with this change in scan.c: +static const struct acpi_device_id indirect_io_hosts[] = { + {"HISI0191", 0}, /* HiSilicon LPC host */ + {}, +}; + +static bool acpi_is_indirect_io_slave(struct acpi_device *device) +{ + struct acpi_device *parent = dev->parent; + + if (!parent || acpi_match_device_ids(parent, indirect_io_hosts)) + return false; + + return true; +} + static bool acpi_is_serial_bus_slave(struct acpi_device *device) { struct list_head resource_list; bool is_serial_bus_slave = false; + if (acpi_is_indirect_io_slave(device)) + return true; + /* Macs use device properties in lieu of _CRS resources */ This means I can move all this scan code into the LLDD. What do you think? Please let me know. John