On Tue, 2018-02-27 at 00:40 +0800, John Garry wrote:
> From: Zhichang Yuan <yuanzhichang@xxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxxxx>
Intel Finland Oy
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