Re: [PATCH v13 4/9] PCI: Apply the new generic I/O management on PCI IO hosts

[dann frazier]

On Wed, Feb 14, 2018 at 01:45:28AM +0800, John Garry wrote:
> From: Zhichang Yuan <yuanzhichang@xxxxxxxxxxxxx>
> 
> After introducing the new generic I/O space management in logic pio, the
> original PCI MMIO relevant helpers need to be updated based on the new
> interfaces.
> This patch adapts the corresponding code to match the changes introduced
> by logic pio.
> 
> Signed-off-by: Zhichang Yuan <yuanzhichang@xxxxxxxxxxxxx>
> Signed-off-by: Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>        #earlier draft
> Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

I saw that Bjorn Acked this back in v6, but it seems like the code in
pci.c was reworked a bit for v7 onwards and I didn't see a follow-up
review (apologies if I just missed it). In which case, maybe his Ack
should have the "#earlier draft" tag as well?

> ---
>  drivers/pci/pci.c        | 95 +++++++++---------------------------------------
>  include/asm-generic/io.h |  2 +-
>  2 files changed, 18 insertions(+), 79 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 07290a3..8aa5c54 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>
> @@ -3440,17 +3441,6 @@ 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
> @@ -3458,51 +3448,28 @@ 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 = PIO_CPU_MMIO;
>  
> -	list_add_tail(&range->list, &io_range_list);
> -
> -end_register:
> -	spin_unlock(&io_range_lock);
> +	ret = logic_pio_register_range(range);
> +	if (ret)
> +		kfree(range);
>  #endif
>  
> -	return err;
> +	return ret;
>  }
>  
>  phys_addr_t pci_pio_to_address(unsigned long pio)
> @@ -3510,21 +3477,10 @@ phys_addr_t pci_pio_to_address(unsigned long pio)
>  	phys_addr_t address = (phys_addr_t)OF_BAD_ADDR;
>  
>  #ifdef PCI_IOBASE
> -	struct io_range *range;
> -	resource_size_t allocated_size = 0;
> -
> -	if (pio > IO_SPACE_LIMIT)
> +	if (pio >= MMIO_UPPER_LIMIT)
>  		return address;
>  
> -	spin_lock(&io_range_lock);
> -	list_for_each_entry(range, &io_range_list, list) {
> -		if (pio >= allocated_size && pio < allocated_size + range->size) {
> -			address = range->start + pio - allocated_size;
> -			break;
> -		}
> -		allocated_size += range->size;
> -	}
> -	spin_unlock(&io_range_lock);
> +	address = logic_pio_to_hwaddr(pio);
>  #endif
>  
>  	return address;
> @@ -3533,25 +3489,8 @@ phys_addr_t pci_pio_to_address(unsigned long pio)
>  unsigned long __weak pci_address_to_pio(phys_addr_t address)
>  {
>  #ifdef PCI_IOBASE
> -	struct io_range *res;
> -	resource_size_t offset = 0;
> -	unsigned long addr = -1;
> -
> -	spin_lock(&io_range_lock);
> -	list_for_each_entry(res, &io_range_list, list) {
> -		if (address >= res->start && address < res->start + res->size) {
> -			addr = address - res->start + offset;
> -			break;
> -		}
> -		offset += res->size;
> -	}
> -	spin_unlock(&io_range_lock);
> -
> -	return addr;
> +	return logic_pio_trans_cpuaddr(address);
>  #else
> -	if (address > IO_SPACE_LIMIT)
> -		return (unsigned long)-1;
> -

Why is this check now safe to drop in the !PCI_IOBASE case?

  -dann

>  	return (unsigned long) address;
>  #endif
>  }
> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
> index b7996a79..5a59931 100644
> --- a/include/asm-generic/io.h
> +++ b/include/asm-generic/io.h
> @@ -901,7 +901,7 @@ static inline void iounmap(void __iomem *addr)
>  #define ioport_map ioport_map
>  static inline void __iomem *ioport_map(unsigned long port, unsigned int nr)
>  {
> -	return PCI_IOBASE + (port & IO_SPACE_LIMIT);
> +	return PCI_IOBASE + (port & MMIO_UPPER_LIMIT);
>  }
>  #endif
>