From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH v15 1/9] LIB: Introduce a generic PIO mapping method Date: Thu, 01 Mar 2018 21:11:23 +0200 Message-ID: <1519931483.10722.342.camel@linux.intel.com> References: <1519663249-9850-1-git-send-email-john.garry@huawei.com> <1519663249-9850-2-git-send-email-john.garry@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1519663249-9850-2-git-send-email-john.garry@huawei.com> Sender: linux-kernel-owner@vger.kernel.org To: John Garry , mika.westerberg@linux.intel.com, rafael@kernel.org, lorenzo.pieralisi@arm.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 Cc: 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, gregkh@linuxfoundation.org, akpm@linux-foundation.org, frowand.list@gmail.com, agraf@suse.de List-Id: devicetree@vger.kernel.org On Tue, 2018-02-27 at 00:40 +0800, John Garry wrote: > From: Zhichang Yuan > > In commit 41f8bba7f555 ("of/pci: Add pci_register_io_range() and > pci_pio_to_address()"), a new I/O space management was supported. With > that driver, the I/O ranges configured for PCI/PCIe hosts on some > architectures can be mapped to logical PIO, converted easily between > CPU address and the corresponding logicial PIO. Based on this, PCI > I/O devices can be accessed in a memory read/write way through the > unified in/out accessors. > > But on some archs/platforms, there are bus hosts which access I/O > peripherals with host-local I/O port addresses rather than memory > addresses after memory-mapped. > > To support those devices, a more generic I/O mapping method is > introduced > here. Through this patch, both the CPU addresses and the host-local > port > can be mapped into the logical PIO space with different logical/fake > PIOs. > After this, all the I/O accesses to either PCI MMIO devices or host- > local > I/O peripherals can be unified into the existing I/O accessors defined > in > asm-generic/io.h and be redirected to the right device-specific hooks > based on the input logical PIO. > A bit more small comments. > +#ifndef __LINUX_LOGIC_PIO_H > +#define __LINUX_LOGIC_PIO_H > + > +#ifdef __KERNEL__ Hmm... How the header in include/linux/ can be non-kernel? > + list_for_each_entry_rcu(range, &io_range_list, list) { > + if (range->flags == LOGIC_PIO_CPU_MMIO && > + new_range->flags == > LOGIC_PIO_CPU_MMIO) { It's rather fancy indentation. > + if (start >= range->hw_start + range->size || > + end < range->hw_start) Misses {} > + allocated_mmio_size += range->size; > + else { > + ret = -EFAULT; > + goto end_register; > + } > + if (allocated_mmio_size + new_range->size - 1 > > + MMIO_UPPER_LIMIT) { Fancy indentation. > + if (allocated_mmio_size + SZ_64K - 1 > > + MMIO_UPPER_LIMIT) { Ditto. > + if (allocated_iio_size + new_range->size - 1 > > + IO_SPACE_LIMIT) { While this is nothing wrong, like above I would consider to check how long it is and consider putting on one line. > +/** > + * logic_pio_to_hwaddr - translate logical PIO to HW address > + * @pio: logical PIO value > + * > + * Returns HW address if valid, -1 otherwise It can't return -1 when the return type is unsigned. > + * > + * Translate the input logical pio to the corresponding hardware > address. > + * The input pio should be unique in the whole logical PIO space. > + */ > +resource_size_t logic_pio_to_hwaddr(unsigned long pio) > +{ > + struct logic_pio_hwaddr *range; > + resource_size_t hwaddr = (resource_size_t)-1; Ditto. > + return hwaddr; > +} > + list_for_each_entry_rcu(range, &io_range_list, list) { > + if (range->flags != LOGIC_PIO_CPU_MMIO) > + continue; > + if (addr >= range->hw_start && > + addr < range->hw_start + range->size) Perhaps you may copy'n'paste in_range() macro from fs/ext* files and use in this module. At some point it would be good to make it generic. > + return addr - range->hw_start + > + range->io_start; > + } -- Andy Shevchenko Intel Finland Oy