On Thu, Mar 15, 2018 at 02:15:53AM +0800, John Garry wrote:
> From: Zhichang Yuan <yuanzhich...@hisilicon.com>
> 
> After introducing the new generic I/O space management(Logical PIO), the
> original PCI MMIO relevant helpers need to be updated based on the new
> interfaces defined in logical PIO.
> This patch adapts the corresponding code to match the changes introduced
> by logical PIO.
> 
> Signed-off-by: Zhichang Yuan <yuanzhich...@hisilicon.com>
> Signed-off-by: Gabriele Paoloni <gabriele.paol...@huawei.com>
> Signed-off-by: Arnd Bergmann <a...@arndb.de>        #earlier draft
> Acked-by: Bjorn Helgaas <bhelg...@google.com>
> Reviewed-by: Andy Shevchenko <andy.shevche...@gmail.com>
> Tested-by: dann frazier <dann.fraz...@canonical.com>
> ---
>  drivers/pci/pci.c        | 92 
> +++++++++---------------------------------------
>  include/asm-generic/io.h |  2 +-
>  2 files changed, 18 insertions(+), 76 deletions(-)

Today's linux-next regresses on NFS boot for Jetson TK1. I was able to
bisect it to this commit. I'll comment below for where I think this is
buggy.

> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 3f30b7d..09c2490 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -22,6 +22,7 @@
>  #include <linux/spinlock.h>
>  #include <linux/string.h>
>  #include <linux/log2.h>
> +#include <linux/logic_pio.h>
>  #include <linux/pci-aspm.h>
>  #include <linux/pm_wakeup.h>
>  #include <linux/interrupt.h>
> @@ -3436,17 +3437,6 @@ int pci_request_regions_exclusive(struct pci_dev 
> *pdev, const char *res_name)
>  }
>  EXPORT_SYMBOL(pci_request_regions_exclusive);
>  
> -#ifdef PCI_IOBASE
> -struct io_range {
> -     struct list_head list;
> -     phys_addr_t start;
> -     resource_size_t size;
> -};
> -
> -static LIST_HEAD(io_range_list);
> -static DEFINE_SPINLOCK(io_range_lock);
> -#endif
> -
>  /*
>   * Record the PCI IO range (expressed as CPU physical address + size).
>   * Return a negative value if an error has occured, zero otherwise
> @@ -3454,51 +3444,28 @@ struct io_range {
>  int pci_register_io_range(struct fwnode_handle *fwnode, phys_addr_t addr,
>                       resource_size_t size)
>  {
> -     int err = 0;
> -
> +     int ret = 0;
>  #ifdef PCI_IOBASE
> -     struct io_range *range;
> -     resource_size_t allocated_size = 0;
> -
> -     /* check if the range hasn't been previously recorded */
> -     spin_lock(&io_range_lock);
> -     list_for_each_entry(range, &io_range_list, list) {
> -             if (addr >= range->start && addr + size <= range->start + size) 
> {
> -                     /* range already registered, bail out */
> -                     goto end_register;
> -             }
> -             allocated_size += range->size;
> -     }
> +     struct logic_pio_hwaddr *range;
>  
> -     /* range not registed yet, check for available space */
> -     if (allocated_size + size - 1 > IO_SPACE_LIMIT) {
> -             /* if it's too big check if 64K space can be reserved */
> -             if (allocated_size + SZ_64K - 1 > IO_SPACE_LIMIT) {
> -                     err = -E2BIG;
> -                     goto end_register;
> -             }
> -
> -             size = SZ_64K;
> -             pr_warn("Requested IO range too big, new size set to 64K\n");
> -     }
> +     if (!size || addr + size < addr)
> +             return -EINVAL;
>  
> -     /* add the range to the list */
>       range = kzalloc(sizeof(*range), GFP_ATOMIC);
> -     if (!range) {
> -             err = -ENOMEM;
> -             goto end_register;
> -     }
> +     if (!range)
> +             return -ENOMEM;
>  
> -     range->start = addr;
> +     range->fwnode = fwnode;
>       range->size = size;
> +     range->hw_start = addr;
> +     range->flags = LOGIC_PIO_CPU_MMIO;
>  
> -     list_add_tail(&range->list, &io_range_list);
> -
> -end_register:
> -     spin_unlock(&io_range_lock);
> +     ret = logic_pio_register_range(range);

This ends up returning -EFAULT at some point, causing the driver's
(pci-tegra.c) ->probe() to fail.

Let me comment on a prior patch to pinpoint what exactly goes wrong.

Thierry

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