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SubjectRe: [PATCH v17 04/10] PCI: Apply the new generic I/O management on PCI IO hosts
On Thu, Mar 15, 2018 at 02:15:53AM +0800, John Garry wrote:
> From: Zhichang Yuan <yuanzhichang@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 <yuanzhichang@hisilicon.com>
> Signed-off-by: Gabriele Paoloni <gabriele.paoloni@huawei.com>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de> #earlier draft
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Tested-by: dann frazier <dann.frazier@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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