Messages in this thread | | | Subject | Re: [PATCH v15 1/9] LIB: Introduce a generic PIO mapping method | From | Andy Shevchenko <> | Date | Thu, 01 Mar 2018 21:11:23 +0200 |
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On Tue, 2018-02-27 at 00:40 +0800, John Garry wrote: > From: Zhichang Yuan <yuanzhichang@hisilicon.com> > > 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 <andriy.shevchenko@linux.intel.com> Intel Finland Oy
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